Co-reporter:Haipeng Wu, Min Li, Sheng Zhang, Hongshan Ke, Yiquan Zhang, Guilin Zhuang, Wenyuan Wang, Qing Wei, Gang Xie, and Sanping Chen
Inorganic Chemistry September 18, 2017 Volume 56(Issue 18) pp:11387-11387
Publication Date(Web):September 6, 2017
DOI:10.1021/acs.inorgchem.7b01840
Great interest is being shown in investigating magnetic interactions that efficiently influence lanthanide single-molecule magnet behavior. A series of heterometallic complexes [M2Ln2(Hhms)2(CH3COO)6(CH3OH)2(H2O)2]·(NO3)2 (M = NiII, Ln = DyIII (1), GdIII (2), and YIII (3); M = CoII, Ln = DyIII (4), GdIII (5), and YIII (6)) have been prepared with a compartmental Schiff-base ligand, 1-(2-hydroxy-3-methoxybenzylidene)-semicarbazide (H2hms), featuring a zigzag-shaped MII-LnIII-LnIII-MII metallic core arrangement. In complexes 1–6, a unique monophenoxo/diacetate asymmetric bridging connects MII ion with LnIII ion, and four acetates bridge two LnIII ions where acetates play essential roles as coligand in generating the tetranuclear units. Magnetic studies reveal the presence of predominant ferromagnetic coupling in DyIII and GdIII derivatives, and slow relaxation of magnetization is observed for {Ni2IIDy2III} and {CoII2DyIII2} with an energy barrier of 16.0 K for {Ni2IIDy2III} and 6.7 K for {CoII2DyIII2} under zero static field. Compared with the analogue {CoII2DyIII2}, the {Ni2IIDy2III} shows longer relaxation time and an absence of the quantum tunnelling of the magnetization (QTM) at low temperatures. Ab initio calculations suggest that the zero-field QTM of {Ni2IIDy2III} is effectively interrupted thanks to the ferromagnetic exchange coupling generated between NiII and DyIII ions. The presence of ferromagnetic exchange between NiII and DyIII ions is more conducive to zero-field single-molecule magnet behaviors than in isomorphic {CoII2DyIII2} where the exchange is antiferromagnetic.
Co-reporter:Pei-Pei Cen, Sheng Zhang, Xiang-Yu Liu, Wei-Ming Song, Yi-Quan Zhang, Gang Xie, and San-Ping Chen
Inorganic Chemistry March 20, 2017 Volume 56(Issue 6) pp:3644-3644
Publication Date(Web):March 8, 2017
DOI:10.1021/acs.inorgchem.7b00057
Two β-diketone mononuclear Dy(III) compounds, formulated as Dy(BTFA)3(H2O)2 (1) and Dy(BTFA)3(bpy) (2) (BTFA = 3-benzoyl-1,1,1-trifluoroacetone, bpy = 2,2′-bipyridine), were prepared. Compound 1 can be identified to transform to 2 in the attendance of bpy coligand, when the local geometry symmetry of eight-coordinated Dy(III) ion changes from a dodecahedron (D2d) in 1 to a square antiprism (D4d) in 2. Fine-tuning structure aroused by auxiliary ligand has dramatical impact on magnetic properties of compounds 1 and 2. Magnetic investigations demonstrate that both 1 and 2 display dynamic magnetic relaxation of single-molecule magnets (SMMs) behavior with different effective barriers (ΔE/kB) of 93.09 K for 1 under zero direct-current (DC) field as well as 296.50 K for 1 and 151.01 K for 2 under 1200 Oe DC field, respectively. As noticed, compound 1 possesses higher effective barrier than 2, despite 1 exhibiting a lower geometrical symmetry of the Dy(III) ion. Ab initio studies reveal that the Kramers doublet ground state is predominantly axial with the gz tensors of two compounds matching the Ising-limit factor of 20 anticipated for the pure MJ = ±15/2 state. Electrostatic analysis confirms the uniaxial anisotropy directions, highlighting that the proper electrostatic distribution of the coordination sphere around Ln(III) center is the critical factor to improve the magnetic anisotropy and determine the dynamic behaviors of SMMs.
Co-reporter:Qi Yang;Guoli Yang;Jing Ge;Langlei Yang
Journal of Thermal Analysis and Calorimetry 2017 Volume 128( Issue 2) pp:1175-1182
Publication Date(Web):17 December 2016
DOI:10.1007/s10973-016-6014-5
Three-dimensional MOFs, {[Cu3(tz)4Cl2] 2CH3OH}n (Htz = 1H-1,2,3,4-tetrazole), have been synthesized in methanol. It was characterized by chemical analysis, element analysis, IR spectroscopy, single-crystal X-ray diffraction and thermal analysis. Thermogravimetric analysis demonstrated that the MOFs after removing methanol molecules possessed good thermostability with decomposition temperature up to 533 K. The enthalpy change of liquid-phase formation reaction was determined by a RD496–2000 microcalorimeter at 298.15 K with the value of (−46.63 ± 0.26) kJ mol−1. The enthalpy change of solid-phase formation reaction was calculated as (−573.89 ± 0.89) kJ mol−1 on the basis of a designed thermochemical cycle. The thermodynamics of formation reaction of the MOFs was investigated by changing the temperature of liquid-phase reaction. Based on the experimental results, fundamental kinetic and thermodynamic parameters k, n, E, \(\Delta H_{ \ne }^{\theta }\), \(\Delta S_{ \ne }^{\theta }\) and \(\Delta G_{ \ne }^{\theta }\) were obtained. The specific heat capacity at 298.15 K was determined to be (1.87 ± 0.08) J K−1 g−1 by a RD496-2000 calorimeter. In addition, the constant volume combustion energy of title MOFs was determined by a RBC-II rotating-bomb calorimeter at 298.15 K. The standard molar enthalpy of combustion and standard molar enthalpy of formation were calculated to be (−4736.43 ± 4.03) kJ mol−1 and (293.42 ± 4.11) kJ mol−1, respectively.
Co-reporter:Chengfang Qiao;Lin Sun;Sheng Zhang;Ping Liu;Liangliang Chang;Chunsheng Zhou;Qing Wei;Sanping Chen;Shengli Gao
Journal of Materials Chemistry C 2017 vol. 5(Issue 5) pp:1064-1073
Publication Date(Web):2017/02/02
DOI:10.1039/C6TC05082D
Supramolecular interactions are fundamental to host–guest binding in many chemical and biological processes. Based on the direct quantification of such supramolecular interactions within metal–organic frameworks (MOFs), the interactions can be controlled through a flexible structural response to guests. We report a flexible Co-MOF [Co3(OH)2(L)2]·4H2O (1·4H2O, H2L = benzotriazole-5-carboxylic acid), which is liable to undergo structural transformation into [Co3(OH)2(L)2]·EtOH (1·EtOH) by pore breathing. Herein, a new strategy is developed to encapsulate more guest molecules of larger size into the Co-MOF via thermodynamics-directed de novo assembly of metal ions, organic linkers and the expected guest molecules by in situ microcalorimetry. As exemplified by the self-assembly of two N,N-dimethyl formamide (DMF) molecules into a Co-MOF, [Co3(OH)2(L)2]·2DMF (2·2DMF) was solvothermally attained at higher temperature, resulting in the elongation of the crystal unit via the b axis during the reconstruction of the framework and the dramatic change in the Co–O bond length and the Co–O–Co angle. Notably, for 2·2DMF, the calculated Langmuir surface area is nearly 5 times more than those of 1·4H2O and 1·EtOH, in agreement with the result of distorted cavities. Due to the two DMF molecules in the cavity, 2·2DMF displays excellent capability for the capture of Cr(VI) from wastewater by the formation of a new electrostatic interaction between the oxygen of the carbonyl from DMF and Cr(VI). Moreover, the fitting results of magnetic data show that the value of J2 in 2·2DMF is greater than that in 1·4H2O, which implies that ferromagnetic coupling increases. Our observations demonstrate that a detailed understanding of subtle intermolecular interactions between the framework and the guest can be used to induce changes to a different extent in the active (adsorption and magnetism) properties of a supramolecular network.
Co-reporter:Chengfang Qiao;Lin Sun;Sheng Zhang;Ping Liu;Liangliang Chang;Chunsheng Zhou;Qing Wei;Sanping Chen;Shengli Gao
Journal of Materials Chemistry C 2017 vol. 5(Issue 17) pp:4335-4335
Publication Date(Web):2017/05/04
DOI:10.1039/C7TC90068F
Correction for ‘Pore-size-tuned host–guest interactions in Co-MOFs via in situ microcalorimetry: adsorption and magnetism’ by Chengfang Qiao et al., J. Mater. Chem. C, 2017, 5, 1064–1073.
Co-reporter:Lin Sun;Shilong Wei;Jun Zhang;Wenyuan Wang;Sanping Chen;Yiquan Zhang;Qing Wei;Gang Xie;Shengli Gao
Journal of Materials Chemistry C 2017 vol. 5(Issue 36) pp:9488-9495
Publication Date(Web):2017/09/21
DOI:10.1039/C7TC02786A
Based on isomeric ligands, (2,4′-Hpcad = N3-(2-pyridoyl)-4-pyridinecarboxamidrazone and 2,3′-Hpcad = N3-(2-pyridoyl)-3-pyridinecarboxamidrazone), two carboxylate-bridged centrosymmetric DyIII dimers, [Dy2(2,4′-pcad)2(C2H3O2)4(H2O)2]·4H2O (1) and [Dy2(2,3′-pcad)2(C2H3O2)4(H2O)2] (2), were obtained, where DyIII ions adopted a monocapped square antiprism coordination geometry, but exhibiting different distortions. Fine-tuning the structure on using isomeric ligands had a significant impact on the magnetic properties of compounds 1 and 2. Magnetic studies revealed that 1 and 2 exhibit slow magnetic relaxation behaviours under a zero direct-current field exhibiting effective energy barriers (Ueff) of 53.5 K and 132.6 K, respectively, wherein compound 2 possesses the highest Ueff in nine-coordinated Dy2 compounds. Ab initio calculations of compound 2 for magnetic interactions, magnetic axes inclination and charge distribution around DyIII ions revealed simultaneous optimization of f–f interactions between the DyIII ions and the stronger ligand field axis of individual DyIII ion, which realizes excellent performance of 2. These findings demonstrate an efficient approach to enhancing the magnetic anisotropy barrier on using isomeric ligands.
Co-reporter:Qi Yang;Jing Ge;Xin Liu;Quan Shi;Hongshan Ke;Qing Wei;Gang Xie;Sanping Chen;Shengli Gao
Dalton Transactions 2017 vol. 46(Issue 6) pp:1878-1884
Publication Date(Web):2017/02/14
DOI:10.1039/C6DT04695A
A new 1D CuII coordination polymer, formulated as {[Cu(TZA)(PNA)]·H2O}n (1) (HTZA = tetrazole-1-acetic acid, HPNA = p-nitrobenzoic acid), was synthesized and structurally characterized. Thermogravimetric analysis demonstrated that the main frame of 1 exhibited good thermostability up to 473 K. The non-isothermal kinetics for the first exothermic process of 1 were studied by Kissinger and Ozawa methods. The magnetic study revealed that 1 possessed antiferromagnetic exchange interactions between CuII ions through the carboxyl-bridge. The low-temperature (1.9 to 300 K) heat capacity of 1 was measured using the heat-capacity option of a Quantum Design Physical Property Measurement System (PPMS). In addition, the thermodynamic functions in the experimental temperature range were derived by fitting the heat-capacity data to a series of theoretical and empirical models. The standard entropy and standard enthalpy of 1 were respectively calculated to be 411.37 ± 4.11 J mol−1 K−1 and 60.21 ± 0.60 kJ mol−1.
Co-reporter:Qi Yang;Xiaxia Song;Wendou Zhang;Lei hou;Qibing Gong;Gang Xie;Qing Wei;Sanping Chen;Shengli Gao
Dalton Transactions 2017 vol. 46(Issue 8) pp:2626-2634
Publication Date(Web):2017/02/21
DOI:10.1039/C6DT04439E
Three new energetic complexes, [Pb(bta)(H2O)]n (1), [PbCu(bta)2(H2O)5]·2H2O (2) and PbCu(bta)2 (3) (H2bta = N,N-bis(1H-tetrazole-5-yl)-amine), have been synthesized and characterised. In particular, 3 was readily synthesized by dehydration of 2 at 190 °C. Single crystal X-ray diffraction revealed that 1 has a 3D framework structure and 2 presents a 3D supermolecular architecture. Thermoanalyses demonstrated that the main frames of 1 and 2 have good thermostabilities up to 314 °C for 1 and 231 °C for 2. Non-isothermal kinetic and thermodynamic parameters of exothermic decomposition processes of 1 and 2 were obtained by Kissinger's and Ozawa's methods. Based on the constant-volume combustion energies measured by a precise rotating-bomb calorimeter, the standard molar enthalpies of formation of 1 and 2 were determined. The calculation of the detonation properties of 1 and 2 and the impact sensitivity tests of 1, 2 and 3 were carried out. In addition, 1, 2 and 3 were explored as combustion promoters to accelerate the thermal decompositions of RDX (1,3,5-trinitro-1,3,5-triazine) by differential scanning calorimetry. Experimental results showed that 1, 2 and 3 can be used as HEDMs in the field of combustion promoters and insensitive 2 can be regarded as a safer form for mass storage and transportation than sensitive 3.
Co-reporter:Xin Li;Qi Yang;Qing Wei;Gang Xie;Sanping Chen;Shengli Gao
Dalton Transactions 2017 vol. 46(Issue 38) pp:12893-12900
Publication Date(Web):2017/10/03
DOI:10.1039/C7DT02179H
The design and synthesis of explosives with high performance, good thermal stability, and low sensitivity is an important subject for the development of energetic materials. Energetic complexes have recently emerged as a promising energetic material form. As one of the representatives, [Cu(Htztr)2(H2O)2]n (H2tztr = 3-(1H-tetrazol-5-yl)-1H-triazole) was previously reported with good energetic performance, outstanding thermostability (Tdec = 345 °C) and low sensitivity to impact and friction stimuli. However, due to the existence of water molecules, its effective energy density is remarkably decreased, resulting in a diminished detonation performance. In order to further improve the detonation performance, using [Cu(Htztr)2(H2O)2]n as a precursor, {[Cu(Htztr)(H2O)]NO3}n (1) and [Cu(H2tztr)2(HCOO)2]n (2) were synthesized by the axial substitution reaction with NO3− and HCOO−. The structures of 1 and 2 were characterized by single crystal X-ray diffraction. Both of them exhibit high thermal stabilities and insensitivities to impact and friction. Moreover, the same DFT calculation methodology shows that the heat of detonation of 2 (3.5663 kcal g−1) is significantly higher than that of the precursor [Cu(Htztr)2(H2O)2]n (2.1281 kcal g−1). Meanwhile, the empirical Kamlet–Jacobs equations were used to theoretically predict the detonation properties of the title complexes, and the results show that 1 and 2 have excellent detonation velocity (D) and detonation pressure (P).
Co-reporter:Xiangyu Liu;Feifei Li;Xiaohui Ma;Peipei Cen;Shuchang Luo;Quan Shi;Shenru Ma;Yuewei Wu;Chengcheng Zhang;Zhao Xu;Weiming Song;Gang Xie;Sanping Chen
Dalton Transactions 2017 vol. 46(Issue 4) pp:1207-1217
Publication Date(Web):2017/01/24
DOI:10.1039/C6DT04108F
Employing two benzoate derivatives with different numbers of non-coordinated fluoro-substituents, 2-fluorobenzoic acid (2-Hfba) and 2,6-difluorobenzoic acid (2,6-Hdfba), two new azido-copper coordination polymers, [Cu(2-fba)(N3)(CH3OH)]n (1) and [Cu(2,6-dfba)(N3)(CH3OH)]n (2), have been successfully isolated, and then structurally and magnetically investigated. Single crystal structure analysis demonstrates that the metal cations in the two resulting compounds are connected by the alternating triple-bridge of μ-1,1-azido, syn,syn-carboxylate and μ2-methanol, contributing to analogously linear 1D Cu(II) chain-like motifs with slightly different intrachain and interchain geometric parameters. The fine-tuned structures lead to variant magnetic properties in the two title compounds. Although a dominant ferromagnetic coupling between adjacent Cu(II) ions within each chain due to the counter-complementarity of the multiple superexchange pathways is observed in both compounds, the interesting plots of magnetic ordering and slow magnetic relaxation, which are rare in most of the reported azido-Cu(II) architectures, only occur in compound 1, while 2 behaves as an antiferromagnet consisting of ferromagnetic Cu(II) chains. The heat-capacity experiments further emphasize the characteristic long-range ferromagnetic ordering in 1 and the typical behavior of antiferromagnets in 2. Moreover, density functional theory (DFT) calculations (using different methods and basis sets) have been performed on both compounds to obtain the qualitatively theoretical interpretation of the magnetic behaviors.
Co-reporter:Xiangyu Liu;Xiaohui Ma;Peipei Cen;Yuewei Wu;Chengcheng Zhang;Quan Shi;Weiming Song;Gang Xie;Sanping Chen
Dalton Transactions 2017 vol. 46(Issue 23) pp:7556-7566
Publication Date(Web):2017/06/13
DOI:10.1039/C7DT01338H
Based on two fluoro-substituted phenylacetate isomers, o-fluorophenylacetic acid (o-Hfpa) and p-fluorophenylacetic acid (p-Hfpa), two new Cu(II)-azido compounds, [Cu(o-fpa)(N3)(C2H5OH)]n (1) and [Cu(p-fpa)(N3)(C2H5OH)]n (2), have been prepared, and structurally and magnetically characterized. Single-crystal structure analyses indicate that compounds 1 and 2 consist of 1D chain-like coordination networks in which adjacent copper cations are linked by the alternating triple-bridges of μ-1,1-azido, syn,syn-carboxylate and μ2-ethanol. For the two title compounds, the diverse charge distributions on the carboxyl groups caused by distinct substituent effects of the two phenylacetate coligands lead to the different structural parameters of intrachain Cu–Cu distances (3.218 Å for 1 and 3.168 Å for 2) and Cu–N–Cu angles (106.82° for 1 and 104.81° for 2), further resulting in the disparity of magnetic behaviors. The dominant ferromagnetic couplings between neighbouring Cu(II) ions in the two compounds (J = 87.08 cm−1 for 1, J = 66.05 cm−1 for 2) are due to the counter-complementarity of the multiple superexchange pathways, contributing to the interesting plots of a ferromagnetic order (Tc = 11.0 K for 1, 9.5 K for 2) and slow magnetic relaxation that are rarely observed in most of the reported azido-Cu(II) architectures. Heat-capacity experiments further emphasize the characteristic long-range ferromagnetic ordering in compounds 1 and 2. Magneto-structural relationships of 1 and 2 are investigated as well. Moreover, DFT calculations (using different methods and basis sets) have been performed on both compounds to provide a qualitative and quantitative theoretical explanation of their magnetic behavior.
Co-reporter:Lin Sun;Sheng Zhang;Zhijie Jiang;Qi Yang;Sanping Chen;Yiquan Zhang;Wenyuan Wang;Qing Wei;Gang Xie
Dalton Transactions 2017 vol. 46(Issue 34) pp:11159-11165
Publication Date(Web):2017/08/29
DOI:10.1039/C7DT02382K
It is crucial to promote axiality to enhance easy-axis magnetic anisotropy. Two mononuclear DyIII compounds, in which each DyIII is nine-coordinated, namely, [(C12H10N5O)Dy(NO3)2(H2O)2]·C2H5OH (1) and [(C12H10N5O)Dy(NO3)2(C2H5OH)2]·H2O (2) (HL = N3-(2-pyridoyl)-4-pyridinecarboxamidrazone), have been prepared through controlling the amount of C2H5OH and H2O solvents. Geometry modulations were realized by interchanging coordinated and lattice solvents, thus achieving a structure closer to the configuration of a capped square antiprism for 2 compared to that for 1. Notably, magnetic studies revealed that compound 1 displays no slow relaxation of magnetization while compound 2 exhibits single-molecule magnet (SMM) behaviour in the absence of a static magnetic field, with the highest energy barrier (203.11 K) of nine-coordinated DyIII SMMs. Ab initio calculations were performed to elucidate such a distinct performance, demonstrating that the combination of the larger charge distribution along the magnetic axis and the lower charge distribution in the equatorial plane generates a strong easy-axis ligand field to enhance magnetic properties, which is further associated with the structural symmetry. In addition, a possible coordination mode is proposed to realize high axis anisotropy for nine-coordinated DyIII compounds. This work presents an effective method to modulate the dynamic magnetic relaxation of the DyIII SMMs through interchange between coordinated and lattice solvents.
Co-reporter:Zhijie Jiang;Lin Sun;Qi Yang;Shilong Wei;Hongshan Ke;Sanping Chen;Yiquan Zhang;Qing Wei;Gang Xie
CrystEngComm (1999-Present) 2017 vol. 19(Issue 38) pp:5735-5741
Publication Date(Web):2017/10/02
DOI:10.1039/C7CE01269A
Two Dy(III) polymorphs, [Dy(Clapi)]2·(CH2Cl2)2 (H3Clapi = 2-(2′-hydroxy-5′-chlorophenyl)-1,3-bis[3′-aza-4′-(2′′-hydroxy-5′′-chlorophenyl)prop-4′-en-1′-yl]-1,3-imidazolidine), have been obtained, crystallizing in space groups P21/c (1a) and C2/c (1b), respectively. Both 1a and 1b have an identical eight-coordinated Dy(III) configuration with D4d symmetry; their only difference is the lattice orientation of the solvent molecule CH2Cl2. Alternating current (ac) magnetic susceptibility measurements reveal that they exhibit distinct magnetic behaviours. Theoretical calculations indicate that the exchange interactions play a vital role in the magnetic behavior of the polymorphs. This work presents a rational model to explore the magneto-structural relationship in both experimental and theoretical aspects of Dy(III) single-molecule magnets.
Co-reporter:Yinli Zhang;Sheng Zhang;Lin Sun;Qi Yang;Jing Han;Qing Wei;Gang Xie;Sanping Chen;Shengli Gao
Chemical Communications 2017 vol. 53(Issue 21) pp:3034-3037
Publication Date(Web):2017/03/09
DOI:10.1039/C7CC00545H
It is a tremendous challenge to prepare solvent-free dense energetic metal–organic frameworks (EMOFs), hence also to improve their stability and energetic performance. In this study, based on in situ microcalorimetry, an interpenetrating EMOF without solvent molecules, [Cu(tztr)]n (1, H2tztr = 3-(tetrazol-5-yl)triazole) was obtained, possessing high stability (Tdec = 360 °C) and outstanding energetic properties (ΔHdet = 7.53 kcal cm−3, D = 8.429 km s−1, P = 40.02 GPa).
Co-reporter:Jing Han;Mengfei Zhang;Guojun Chen;Yongqing Zhang;Qing Wei;Ying Zhuo;Gang Xie;Ruo Yuan;Sanping Chen
Journal of Materials Chemistry B 2017 vol. 5(Issue 42) pp:8330-8336
Publication Date(Web):2017/11/01
DOI:10.1039/C7TB02240A
Here a new type of ferrocene confined in a metal–organic framework (Fc-Zn-MOF) as an electrochemical signal tag has been synthesized and applied in an immunosensor for highly sensitive amyloid-β (Aβ, as a model protein) detection. In the present work, an electrochemically active molecule of Fc was covalently bonded in a Zn-MOF via postsynthetic modification to obtain a flower-like Fc-Zn-MOF, in which the high-content Fc signal units were periodically arranged in a well-defined porous structure, showing enhanced electrochemical activity. As noticed, Fc molecules are chemically anchored on the Zn-MOF, which avoids leakage of signal molecules, protects those electrochemical activities from potential damage and exhibits good stability. The Fc-Zn-MOF signal tag was further explored in constructing an electrochemical immunosensor for Aβ detection, with a linear range from 0.0001 to 100 ng mL−1 and a detection limit of 0.03 pg mL−1, showing improved analytical performance. This work presents an example of an Fc-MOF as a signal tag for Aβ detection, which would encourage atypical research lines for MOFs in bioassays where the introduction of ordered structures promises new opportunities.
Co-reporter:Sheng Zhang;Haipeng Wu;Lin Sun;Hongshan Ke;Sanping Chen;Bing Yin;Qing Wei;Desuo Yang;Shengli Gao
Journal of Materials Chemistry C 2017 vol. 5(Issue 6) pp:1369-1382
Publication Date(Web):2017/02/09
DOI:10.1039/C6TC05188J
To fine-tune the magnetic anisotropy and further modulate the magnetic properties and relaxation dynamics of dysprosium(III) single-ion magnets (SIMs), it is crucial to explore their controllable synthesis and conduct a systematic theoretical investigation. Herein, the mononuclear Dy(III) precursor, [Dy(DMF)2(tffb)3] (tffb = 4,4,4-trifluoro-1-(4-fluorophenyl)-1,3-butanedione), as a “metalloligand” towards different capping ligands, affords two new mononuclear Dy(III) complexes in different solvent systems, [Dy(bpy)(tffb)3]·(C4H8O2)1/3 (1) and [Dy(Phen)(tffb)3] (2) (bpy = 2,2′-bipyridine, Phen = 1,10-phenanthroline). Using 4,4,4-trifluoro-1-(4-methylphenyl)-1,3-butanedione (tfmb) as a ligand with the coligand bpy, [Dy(bpy)(tfmb)3] (3) is obtained. In 1,4-dioxane solution, interestingly, complex 3 undergoes a dissolution/reorganization process to transform into 4, [Dy(bpy)(tfmb)3]·0.5C4H8O2. Structural analyses indicate that Dy(III) in 1–4 adopts an approximately square-antiprismatic (SAP) coordination environment with D4d axial symmetry. The magnetic properties of 1–4 are investigated and the M versus H data exhibit evident butterfly-shaped hysteresis loops at 2 K for 1–4. Although all the Dy(III) ions in 1–4 adopt similar configurations, their magnetization dynamics are apparently different from each other, as shown by the various heights of the effective energy barrier (Ueff) of magnetization reversal. To deeply understand their different magnetic behaviours, the magnetic anisotropy of 1–4 is systematically studied by ab initio calculations. The theoretical results further indicate that the capping ligands could play an important role in the fine tuning of the SMM property via an effect on the equatorial electrostatic potential, whereas the inclusion of guest solvent molecules could significantly influence the axial electrostatic potential, leading to a strong effect on the SMM property.
Co-reporter:Haipeng Wu, Min Li, Qing Wei, Gang Xie, Sanping Chen
Inorganic Chemistry Communications 2017 Volume 80(Volume 80) pp:
Publication Date(Web):1 June 2017
DOI:10.1016/j.inoche.2017.04.003
•Isomorphous CoII/MnII MOFs featuring two types of 1D zig-zag and linear metal chains were solvothermal synthesized.•Magnetic studies reveal spin-canted antiferromagnetic couplings and a weak slow relaxation behavior in Co-MOF.•A magnetic hysteresis loop at 2K is observed indicating a 3D ordered in the network of Co complex.Two isostructural CoII and MnII metal-organic frameworks (MOFs), {[M2(tztr)2(H2O)]·CH3CN·H2O}n (M = CoII for 1 and MnII for 2), have been successfully synthesized based on a semi-rigid 3-(tetrazol-5-yl)triazole (H2tztr) ligand. Crystal structure analyses reveal that the complexes possess three-dimensional (3D) frameworks featuring two types of interesting 1D zig-zag and linear metal chains. Magnetic measurements reveal that the special bridge within the double chains of complex 1 provides unexpected spin canting, long-range antiferromagnetic ordering and relaxation dynamics. Whereas the isostructural 2 displays normal antiferromagnetic coupling.A semi-rigid azole ligand combined with anisotropic CoII ions leads to a CoII metal-organic framework, which represents the unexpected spin-canted antiferromagnetic coupling and a slow magnetic relaxation.Download high-res image (135KB)Download full-size image
Co-reporter:Xin Li, Jing Han, Sheng Zhang, Lianjie Zhai, Bozhou Wang, Qi Yang, Qing Wei, Gang Xie, Sanping Chen, Shengli Gao
Journal of Solid State Chemistry 2017 Volume 253(Volume 253) pp:
Publication Date(Web):1 September 2017
DOI:10.1016/j.jssc.2017.06.027
•Three high-energy coordination polymers (CPs) were synthesized and fully characterized.•All compounds have large positive enthalpy of formation, high thermal stability and low sensitivity for external stimuli.•The catalytic experiments show that 1a can significantly improve the characteristics of thermal decomposition of ammonium dinitramide (ADN).High-energy coordination polymers (CPs) not only exhibit good energetic performances but also have a good catalytic effect on the thermal decomposition of energetic materials. In this contribution, two high-energy CPs Cu2(DNBT)2(CH3OH)(H2O)3·3H2O (1) and [Cu3(DDT)2(H2O)2]n (2) (H2DNBT = 3,3′-dinitro-5,5′-bis(1H−1,2,4-triazole and H3DDT = 4,5-bis(1H-tetrazol-5-yl)-2H-1,2,3-triazole) were synthesized and structurally characterized. Furthermore, 1 was thermos-dehydrated to produce Cu2(DNBT)2(CH3OH)(H2O)3 (1a). The thermal decomposition kinetics of 1, 1a and 2 were studied by Kissinger's method and Ozawa's method. Thermal analyses and sensitivity tests show that all compounds exhibit high thermal stability and low sensitivity for external stimuli. Meanwhile, all compounds have large positive enthalpy of formation, which are calculated as being (1067.67 ± 2.62) kJ mol−1 (1), (1464.12 ± 3.12) kJ mol−1 (1a) and (3877.82 ± 2.75) kJ mol−1 (2), respectively. The catalytic effects of 1a and 2 on the thermal decomposition of ammonium dinitramide (ADN) were also investigated.Download high-res image (163KB)Download full-size image
Co-reporter:Sheng Zhang, Qi Yang, Xiangyu Liu, Xiaoni Qu, Qing Wei, Gang Xie, Sanping Chen, Shengli Gao
Coordination Chemistry Reviews 2016 Volume 307(Part 2) pp:292-312
Publication Date(Web):15 January 2016
DOI:10.1016/j.ccr.2015.08.006
•Based on various nitrogen-rich energetic ligands, high-energy metal–organic frameworks (HE-MOFs) have attracted considerable attention in the field of energetic materials.•HE-MOFs exhibit controllable structures, various modifiable functionalities, high density, remarkable heats of detonation, insensitivity, good thermal stability and favorable mechanical hardness.•The purpose of this review is to provide readers with an inductive overview of both in-depth understanding of energetic-sensitive-structural correlations.•This review is favorable to guide the future design of novel HEDMs through the combination of experiment and theory.Recent progress in high-energy metal–organic frameworks (HE-MOFs), not only a burgeoning branch of growing interest in energetic materials but also a particular class of metal–organic frameworks (MOFs), is covered in this review. HE-MOFs, based on various nitrogen-rich energetic ligands, may serve as an effective approach for systematically studying the energetic-sensitive-structural relationships and guiding the future design of new generation high-energy-density materials (HEDMs) because of their various advantages, including controllable structures, various modifiable functionalities, high density, remarkable heats of detonation, insensitivity, good thermal stability and favorable mechanical hardness. In the review, an inductive overview of the development and outlook in the field of HEDMs, particularly those with one-, two- and three-dimensional (1D–3D) architectures, are presented.
Co-reporter:Chengfang Qiao, Xiaoni Qu, Qi Yang, Qing Wei, Gang Xie, Sanping Chen and Desuo Yang
Green Chemistry 2016 vol. 18(Issue 4) pp:951-956
Publication Date(Web):27 Oct 2015
DOI:10.1039/C5GC02393A
A Cd(II) metal–organic framework, {NH2(CH3)2·Cd2.5(L)2(H2O)·(H2O)}n (1; H3L = tricarboxytriphenylamine), has been synthesized and features a 3D microporous framework with two different types of 1D channel. Addition of Cu2+ to crystals of 1 instantly leads to a clear color change from yellow to dark green crystalline samples (2), which are structurally identified as {NH2(CH3)22·Cd3Cu2(L)4(H2O)2·(H2O)2}n. In situ microcalorimetry shows that the response time of 1 to a Cu2+ concentration of 10−4 mol L−1 is as short as 9 s. Naturally, MOF 1 could potentially be used for the naked eye detection of Cu2+ ions in real-world applications. In addition, in situ microcalorimetry is successfully employed to real-time record a SC–SC guest transformation, where the guest water molecules can be selectively exchanged by methanol or N,N-dimethylacetamide (DMA) molecules (1·CH3OH and 1·DMA), and the molar enthalpies, ΔHθm, are quantitatively determined as being (−71.34 ± 0.52) and (−87.13 ± 0.86) kJ mol−1, respectively. This is the first report where the processes of SC–SC transformation and detection of Cu2+ are objectively presented.
Co-reporter:Lin Sun, Sheng Zhang, Chengfang Qiao, Sanping Chen, Bing Yin, Wenyuan Wang, Qing Wei, Gang Xie, and Shengli Gao
Inorganic Chemistry 2016 Volume 55(Issue 20) pp:10587-10596
Publication Date(Web):September 28, 2016
DOI:10.1021/acs.inorgchem.6b01803
It is crucial to understand and elucidate the self-assembly mechanism in solution systems for the construction of DyIII-based single-molecule magnets (SMMs). Herein, through fine-tuning of the anion and solvent, we prepared three nine-coordinate mononuclear dysprosium compounds, [Dy(2,3′-pcad)(NO3)2(CH3OH)2] (1), [Dy(2,3′-Hpcad)2(H2O)3]·3Cl·5H2O (2), and [Dy(2,3′-pcad)(NO3)(H2O)4]·NO3·H2O (3) [2,3′-Hpcad = N3-(2-pyridoyl)-3-pyridinecarboxamidrazone]. The reactions of formation for 1–3 are in situ thermodynamically monitored by isothermal titration calorimetry. Magnetic data analysis reveals that 2 shows SMM behavior under a zero direct-current (dc) field, whereas 1 and 3 exhibit distinct slow magnetic relaxation processes upon a 1200 Oe dc field. To deeply understand the different magnetic behaviors, the magnetic anisotropy of 1–3 has been systematically studied by ab initio calculations, which is consistent with the experimental observations. Moreover, the semiconductor behaviors of 1–3 have been investigated by experimental measurements of UV–vis spectroscopy.
Co-reporter:Sheng Zhang, Hongshan Ke, Lin Sun, Xin Li, Quan Shi, Gang Xie, Qing Wei, Desuo Yang, Wenyuan Wang, and Sanping Chen
Inorganic Chemistry 2016 Volume 55(Issue 8) pp:3865-3871
Publication Date(Web):March 28, 2016
DOI:10.1021/acs.inorgchem.5b02971
Two Dy(III) single-ion magnets with a trigonal dodecahedron (D2d) for 1 and an approximately square-antiprismatic (SAP, D4d) N2O6 coordination environment for 2, formulated as [Dy(Phen)(tfmb)3] (1) and [Dy(Phen)(tfmb)3]·0.5(1,4-dioxane) (2) (tfmb = 4,4,4-trifluoro-1-(4-methylphenyl)-1,3-butanedione, Phen = 1,10-phenanthroline), were obtained. Therein, complex 1 was transformed to 2 in 1,4-dioxane solution. Structural analysis shows that complexes 1 and 2 have differing local symmetry of Dy(III) ions. Magnetic studies indicate that the barrier heights (ΔE/kB) of 1 and 2 are 63.56 and 102.82 K under zero dc field as well as 118.50 and 164.55 K under 1200 Oe dc field, respectively. Based on the frequency dependencies of the ac susceptibilities, the effective barriers (ΔE/kB) and the pre-exponential factors (τ0) are 67.05 K and 4.57 × 10–6 s for 1 and 95.88 K and 2.39 × 10–7 s for 2 under zero dc field. The present work illustrates that guest-determined notable structure change results in different barrier heights.
Co-reporter:Xiao-Ni Qu, Sheng Zhang, Bo-Zhou Wang, Qi Yang, Jing Han, Qing Wei, Gang Xie and San-Ping Chen
Dalton Transactions 2016 vol. 45(Issue 16) pp:6968-6973
Publication Date(Web):09 Mar 2016
DOI:10.1039/C6DT00218H
A novel Ag(I) energetic MOF [Ag16(BTFOF)9]n·[2(NH4)]n (1) assembled with Ag(I) ions and a furazan derivative, 4,4′-oxybis[3,3′-(1H-5-tetrazol)]furazan (H2BTFOF) was successfully synthesized and structurally characterized, featuring a three-dimensional porous structure incorporating ammonium cations. The thermal stability and energetic properties were determined, revealing that the 3D energetic MOF had an outstanding insensitivity (IS > 40 J), an ultrahigh detonation pressure (P) of 65.29 GPa and a detonation velocity (D) of 11.81 km cm−3. In addition, the self-accelerating decomposition temperature (TSADT) and the critical temperature of thermal explosion (Tb) are also discussed in detail. The finding exemplifies that the assembly strategy plays a decisive role in the density and energetic properties of MOF-based energetic materials.
Co-reporter:Sheng Zhang, Hongshan Ke, Quan Shi, Jangwei Zhang, Qi Yang, Qing Wei, Gang Xie, Wenyuan Wang, Desuo Yang and Sanping Chen
Dalton Transactions 2016 vol. 45(Issue 12) pp:5310-5320
Publication Date(Web):11 Feb 2016
DOI:10.1039/C6DT00219F
Three mononuclear dysprosium(III) complexes derived from three β-diketonate ligands, 4,4,4-trifluoro-1-(4-methylphenyl)-1,3-butanedione (tfmb), 4,4,4-trifluoro-1-(4-fluorophenyl)-1,3-butanedione (tffb) and 4,4,4-trifluoro-1-(2-naphthyl)-1,3-butanedione (tfnb) as well as auxiliary ligands, 5-nitro-1,10-phenanthroline (5-NO2-Phen), DMF and 2,2′-bipyridine (bpy) have been synthesized and structurally characterized, namely [Dy(5-NO2-Phen)(tfmb)3] (1), [Dy(DMF)2(tffb)3] (2) and [Dy(bpy)2(tfnb)3]·0.5(1,4-dioxane) (3). The metal ions in 1–3 adopt an approximately square-antiprismatic (SAP) coordination environment with D4d axial symmetry. The magnetic properties of 1–3 have been investigated, displaying weak out-of-phase AC signals under a zero-DC field. With an applied DC field of 1200 Oe, the quantum tunnelling of the magnetization was suppressed in 1–3 with the pre-exponential factor τ0 = 5.3 × 10−7 s and the effective barrier ΔE/kB = 83 K for 1 as well as the pre-exponential factor τ0 = 3.09 × 10−7 s and the effective barrier ΔE/kB = 39 K for 3. Interestingly, for the frequency dependence of the out-of-phase (χ′′) of the AC susceptibility of 2, two slow relaxation of the magnetization processes occurred under the applied magnetic field of 1200 Oe, corresponding to the fast relaxation (FR) phase and slow relaxation (SR) phase, respectively. Arrhenius analysis gave the effective energy barrier (ΔE/kB) of 55 K and the pre-exponential factor (τ0) of 8.23 × 10−12 for the SR. It is thus very likely that the FR process in complex 2 results from QTM enhanced by dipolar interactions between the Dy ions or the presence of the applied field. The structure–property relationship of some Dy(III) based mononuclear SMMs with the SAP configuration was further discussed.
Co-reporter:Xiaoni Qu, Qi Yang, Jing Han, Qing Wei, Gang Xie, Sanping Chen and Shengli Gao
RSC Advances 2016 vol. 6(Issue 52) pp:46212-46217
Publication Date(Web):26 Apr 2016
DOI:10.1039/C6RA07301H
An energetic metal–organic framework (EMOF) [Ag2(5-ATZ)(N3)] (1) was hydrothermally prepared and structurally characterized by single crystal X-ray diffraction analysis. 1 features a compacted three-dimensional framework structure and possesses the highest density (ρ = 3.4 g cm−3) in the known energetic compounds, in which each 5-ATZ ligand possesses a μ4-1,2,3,4 coordination mode and each azide group adopts a rare μ4-1,1,1,3 bridging mode. 1 exhibits a considerably high thermal stability, with a thermal decomposition temperature of about 300.0 °C, and insensitivity to external stimuli. Remarkably, the kinetic triplets (the apparent activation energy (Ea), the preexponential factor (A) and the mechanism function (f(α))) are discussed in detail. In addition, the energetic performance and the catalytic effect of 1 on the thermal decomposition of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) were also examined.
Co-reporter:Chengfang Qiao, Lin Sun, Sheng Zhang, Qing Wei, Chunsheng Zhou, Gang Xie, Sanping Chen, Xuwu Yang, Shengli Gao
Polyhedron 2016 Volume 119() pp:445-450
Publication Date(Web):24 November 2016
DOI:10.1016/j.poly.2016.09.037
Three manganese(II) complexes, [Mn(HL)(EtOH)2Cl]2 (1), [Mn2(HL)2(EtOH)3(H2O)Cl2]2·[Mn(HL)(EtOH)(H2O)Cl]2·[Mn(HL)(EtOH)2Cl]2·4EtOH (2) and Mn(HL)2·2H2O (3) (H2L = N-(2-propionic acid)-(4-methoxy benzoyl) hydrazone), have been synthesized by self-assembly of MnCl2 with H2L in different ethanol/water systems. To better understand the thermodynamic stability of complexes with diverse structures, theoretical investigation of the electronic structures of the compounds has been carried out using density function theoretical calculations. Isothermal titration calorimetry (ITC) was employed to monitor the interactions between Mn(II) and H2L in different solvents, in which the binding constants (Ka) of the systems are 3.54 × 104, 3.66 × 104 and 34.97 × 104 L mol−1 for 1, 2 and 3, respectively. The thermodynamic calculation results indicate that the self-assembly of 1 and 2 are entropy-dominated spontaneous processes, while that of 3 is an enthalpy-driven one. In addition, solvent-effect on antifungal activity for compounds 1–3 was investigated.Three different Mn(II)-acylhydrazone complexes were isolated with the same starting materials in different ethanol/water systems. The self-assembly of 1 and 2 are entropy-dominated, while that of 3 is enthalpy-driven. Solvent-effect on antifungal activity for them was investigated.
Co-reporter:Qi Yang, Xiaxia Song, Jing Ge, Guowei Zhao, Wendou Zhang, Gang Xie, Sanping Chen, Shengli Gao
The Journal of Chemical Thermodynamics 2016 Volume 92() pp:132-138
Publication Date(Web):January 2016
DOI:10.1016/j.jct.2015.09.009
•An energetic MOFs with dinuclear nickel unit has been synthesized and characterized.•The Arrhenius equation, derived from kinetics analysis, is ln k = 55.89 − 332.01 × 103/RT.•The standard molar enthalpy of formation of the compound is determined by a thermochemical cycle.•The molar heat capacity at T = 298.15 K is determined to be 1.42 ± 0.11 J · K−1 · g−1.A new energetic MOFs, {[Ni2(C2H5N5)2(C3H2O4)2(H2O)]·3H2O}n (Hdatrz (C2H5N5) = 3,5-diamino-1,2,4-triazole, H2mal (C3H4O4) = malonic acid), has been synthesized and characterized by element analysis, chemical analysis, IR spectroscopy, single-crystal X-ray diffraction and thermal analysis. X-ray diffraction analysis confirmed that the compound featured a 2D layer structure with dinuclear Ni(II) unit. Thermal analysis demonstrated that the compound after dehydration have good thermostability with decomposition temperature up to 633 K. The non-isothermal kinetics for the compound was studied by Kissinger’s and Ozawa’s methods. The Arrhenius equation of initial thermal decomposition process of compound can be expressed as ln k = 55.89 − 332.01 × 103/RT. Furthermore, a reasonable thermochemical cycle was designed based on the preparation reaction of the compound, and standard molar enthalpy of dissolution of reactants and products were measured by RD496-2000 calorimeter. Finally, the standard molar enthalpy of formation of the compound was determined to be −(2766.3 ± 2.3) kJ · mol−1 in accordance with Hess’s law. In addition, the specific heat capacity of the compound at T = 298.15 K was determined to be 1.42 ± 0.11 J · K−1 · g−1 by RD496-2000 calorimeter.
Co-reporter:Xin Li; Xiangyu Liu; Sheng Zhang; Haipeng Wu; Bozhou Wang; Qi Yang; Qing Wei; Gang Xie; Sanping Chen;Shengli Gao
Journal of Chemical & Engineering Data 2016 Volume 61(Issue 1) pp:207-212
Publication Date(Web):December 17, 2015
DOI:10.1021/acs.jced.5b00458
Reaction of 4,4′-oxybis[3,3′-(1H-5-tetrazol)]furazan (H2BTFOF, 1) with melamine (MA) leads to a energetic salt (MA+)·(HBTFOF¯)·H2O (2). The structure of 2 was characterized by single-crystal X-ray analysis. Thermogravimetry analysis indicates that the main framework of 2 possesses good thermal stability up to 501 K. Optimized structure, total energy and the frontier orbital energy of 2 were investigated in detail. As to the thermodecomposition reaction of the main framework for 2, the nonisothermal thermokinetics parameters were obtained by Kissinger’s and Ozawa’s methods. The standard molar enthalpy of formation of 2 was calculated as being (518.55 ± 6.30) kJ·mol–1 from the constant-volume combustion energy determined by a rotating-bomb microcalorimeter. Importantly, 2 has a very low sensitivity to friction (>360 N) and impact (38 J), which makes it of interest in new environmentally friendly, insensitive energetic materials.
Co-reporter:Xiangyu Liu, Wenjuan Gao, Panpan Sun, Zhiyong Su, Sanping Chen, Qing Wei, Gang Xie and Shengli Gao
Green Chemistry 2015 vol. 17(Issue 2) pp:831-836
Publication Date(Web):27 Nov 2014
DOI:10.1039/C4GC02184C
An alternative method to prepare new-generation green high-energy-density materials with excellent performances has been developed on the basis of a coordination chemistry strategy. In the present work, hydrothermal reaction of Cu(II)/Cu(I) with a rigid nitrogen-rich ligand, 3-(1H-tetrazol-5-yl)-1H-triazole (H2tztr), led to three high-energy metal–organic frameworks (MOFs): [Cu(Htztr)2(H2O)2]n (1), {[Cu(tztr)]·H2O}n (2) and [Cu(Htztr)]n (3). Referring to the coordination geometry configuration of Cu(II)/Cu(I) and flexible coordination fashion of the ligand, the energies of the complexes 1–3 are gradually improved when they are structurally transformed from 1, a mononuclear structure to 2, a 3D porous MOF incorporated with guest water molecules to 3, a well-isolated layer structure. The title complexes show outstanding thermostability (Tdec = 345 °C for 1, 325 °C for 2 and 355 °C for 3) and low sensitivity, confirmed by experimental and theoretical characterization. Notably, complex 3 features superior detonation properties to that of known energetic MOFs.
Co-reporter:Sheng Zhang, Hongshan Ke, Xiangyu Liu, Qing Wei, Gang Xie and Sanping Chen
Chemical Communications 2015 vol. 51(Issue 82) pp:15188-15191
Publication Date(Web):24 Aug 2015
DOI:10.1039/C5CC05694B
A 2D oxalate-bridged dysprosium(III) compound, formulated as [Dy(C2O4)1.5(H2O)3]n·2nH2O (1), has been hydrothermally isolated. As for compound 1, structural analysis reveals that the nine-coordinated Dy(III) ions reside in a slightly distorted tricapped trigonal prism. Under an applied magnetic field of 700 Oe, the compound was magnetically characterized as a new example that two slow relaxations of the magnetization processes can be observed in a 2D oxalate-bridged dysprosium(III) layer.
Co-reporter:Xiangyu Liu, Xiaoni Qu, Sheng Zhang, Hongshan Ke, Qi Yang, Quan Shi, Qing Wei, Gang Xie, and Sanping Chen
Inorganic Chemistry 2015 Volume 54(Issue 23) pp:11520-11525
Publication Date(Web):November 24, 2015
DOI:10.1021/acs.inorgchem.5b02196
A three-dimensional metal–organic framework based, high-energy-density compound, [Co5(3-atrz)7(N3)3] (3-atrz = 3-amine-1H-1,2,4-triazole), features superior detonation properties, insensitivity, and thermostability. Magnetic studies show that the compound characterizes the coexistence of remarkable coercivity, metamagnetism, long-range ordering, and relaxation dynamics. The heat-capacity measurement confirms the typical long-range antiferromagnetic ordering below 16 K. This difunctional system exemplifies an effective attempt at developing advanced magnetoenergetic materials.
Co-reporter:Xiangyu Liu; Lin Sun; Huiliang Zhou; Peipei Cen; Xiaoyong Jin; Gang Xie; Sanping Chen;Qilin Hu
Inorganic Chemistry 2015 Volume 54(Issue 18) pp:8884-8886
Publication Date(Web):September 8, 2015
DOI:10.1021/acs.inorgchem.5b01651
A novel two-dimensional (2D) coordination polymer, [Co(ppad)2]n (1), resulted from the assembly of CoII ions based on a versatile ligand termed N3-(3-pyridoyl)-3-pyridinecarboxamidrazone. Alternating/direct-current magnetic studies of compound 1 indicate that the spatially separated high-spin CoII ions act as single-ion magnets (SIMs). The present work represents the first case of a 2D CoII-based SIM composed of a monocomponent organic spacer.
Co-reporter:Sheng Zhang, Xiangyu Liu, Qi Yang, Qing Wei, Gang Xie and Sanping Chen
CrystEngComm 2015 vol. 17(Issue 17) pp:3312-3324
Publication Date(Web):13 Mar 2015
DOI:10.1039/C5CE00126A
Based on the InOm notion (In = the dimensionality of the inorganic connectivity; Om = the dimensionality of the organic connectivity; n + m ≤ 3), we obtained ten transition/alkaline earth mixed-metal–organic frameworks (M′MOFs) from 1D to 3D through a “metalloligand” strategy at room temperature. Single-crystal X-ray diffraction analyses indicate that the resulting compounds possess the square plane [MII(pzdc)2]2− (M = Co, Ni or Cu) “organic” connectivity and the Ae–O–Ae (Ae = Ca, Sr or Ba) inorganic connectivity, which can be classified as I1O0 connectivity for complexes 1, 4, 7 and 9, I1O1 connectivity for complexes 2, 3, 5, 6 and 8 and I1O2 connectivity for complex 10. The [MII(pzdc)2]2− moieties acting as bis(tetradentate) polycarboxylate ligands show three types of coordination modes, namely μ4-(η2-O,O)2,(η1-O′)2, μ6-(η2-O,O)2,(η1-O′)2,(η1-O′)2 and μ10-(η2-O,O)2,(η2-O′,O′)2, (η1-O′)2,(η1-O′)2,(η1-N′)2. Additionally, the thermal stabilities of complexes 1–10 and magnetic properties of complexes 1, 2, 4, 5 and 10 have also been investigated.
Co-reporter:Yaya Feng, Xiangyu Liu, Linqiang Duan, Qi Yang, Qing Wei, Gang Xie, Sanping Chen, Xuwu Yang and Shengli Gao
Dalton Transactions 2015 vol. 44(Issue 5) pp:2333-2339
Publication Date(Web):05 Dec 2014
DOI:10.1039/C4DT03131H
A reticular 3D heterometallic metal–organic framework (MOF), [Cu4Na(Mtta)5(CH3CN)]n (1) (N% = 40.08%), has been synthesized, using a 5-methyl tetrazole (Mtta) ligand formed from acetonitrile and azide, through in situ synthesis and structurally characterized by X-ray single crystal diffraction. The fluorescence spectra demonstrate that 1 undergoes an interesting structural transformation in aqueous solution, yielding the compound [Cu4Na(Mtta)5H2O]n (1a) as confirmed by 1H NMR, IR and PXRD. Thermoanalysis showed that 1 possesses excellent thermostability up to 335 °C. The calculated detonation properties and the sensitivity test illustrate that compound 1 could be used as a potential explosive. In addition, the non-isothermal kinetics for 1 were studied using the Kissinger and Ozawa–Doyle methods. The enthalpy of formation was obtained from the determination of the constant-volume combustion energy.
Co-reporter:Hongshan Ke, Sheng Zhang, Xin Li, Qing Wei, Gang Xie, Wenyuan Wang and Sanping Chen
Dalton Transactions 2015 vol. 44(Issue 48) pp:21025-21031
Publication Date(Web):09 Nov 2015
DOI:10.1039/C5DT03607K
A Dy2 single-molecule magnet, namely [Dy2(H3L)2(PhCOO)4]·4H2O (1), was obtained from the reaction of Dy(PhCOO)3 with 1,5-bis(2-hydroxy-3-methoxybenzylidene)carbonohydrazide (H4L). Each DyIII ion is located in the chelating pocket [DyO8N] formed by the carboxyl-O, phenol-O, carbohydrazide-O and carbohydrazide-N, forming a tricapped trigonal prism configuration. The DyIII centers are bridged by the benzoate anions with μ2:η1,η2 coordination mode and the phenol-O− groups in the form of μ1:η2, respectively. The appearance of frequency-dependent out-of-phase (χ′′M) signals indicates that 1 displays single-molecule magnet (SMM) behaviour. Fits of the ac data gave an energy barrier (Ueff) of 42.7 K with a pre-exponential factor (τ0) of 1.31 × 10−7 s. The structure–property relationship of some selected Dy2 paradigmatic compounds was further discussed.
Co-reporter:Xiaolong Fu, Xiangyu Liu, Panpan Sun, Sheng Zhang, Qi Yang, Qing Wei, Gang Xie, Sanping Chen, Xuezhong Fan
Journal of Analytical and Applied Pyrolysis 2015 Volume 114() pp:79-90
Publication Date(Web):July 2015
DOI:10.1016/j.jaap.2015.05.005
•Six energetic copolymers incorporating active NO2 group and nitrogen-rich unit were synthesized and structurally characterized.•All compounds exhibit superior thermal stabilities and insensitiveness to external stimulation.•All compounds feature good detonation property.A series of nitro-containing energetic copolymers, HD·DNSA (1), G·DNSA (2), AG·DNBA (3), TZ·DNSA (4), 5-ATZ·DNSA (5) and 4-ATZ·DNSA (6) (DNSA, 3,5-dinitrosalicylic acid; HD, hydrazine; G, guanidine; AG, amino guanidine; TZ, 1H-1,2,4-triazole; 5-ATZ, 5-amino-tetrazole; 4-ATZ, 4-amino-1,2,4-triazole) are successfully synthesized based on intermolecular interactions. All compounds are structurally characterized by powder and single crystal X-ray diffractions, infrared spectrum (IR) and elemental analyses. Thermogravimetric analysis (TG), differential scanning calorimetry (DSC) and density functional theory (DFT) calculations show that compounds 1–6 present favorable thermal stabilities. Moreover, all compounds feature good detonation properties and low sensitivities, representing potential energetic materials and promising alternatives to traditional explosives.
Co-reporter:Xiaoni Qu, Sheng Zhang, Qi Yang, Zhiyong Su, Qing Wei, Gang Xie and Sanping Chen
New Journal of Chemistry 2015 vol. 39(Issue 10) pp:7849-7857
Publication Date(Web):23 Jul 2015
DOI:10.1039/C5NJ01623A
In this contribution two energetic coordination polymers, [Ag(atz)]n (1) and [Ag(ntz)]n (2) (Hatz = 3-amine-1H-1,2,4-triazole and Hntz = 3-nitro-1H-1,2,4-triazole), have been synthesized and structurally characterized. Crystal structure analyses reveal that the title compounds possess two-dimensional (2D) three-connected layers featuring six-membered rings and sixteen-membered rings. Depending on the reaction temperature and the reactant molar ratio, the two compounds with a smaller size have been prepared and their morphologies were studied. Additionally, solid-state photoluminescence of 1 and 2 at room temperature has been investigated. Noteworthily, physicochemical properties show that 1 and 2 exhibit excellent insensitivity and high decomposition temperatures (Tdec = 348 °C for 1 and Tdec = 305 °C for 2). The present research reveals that the substituent NH2/NO2 plays a crucial role in the performance of energetic materials.
Co-reporter:Sheng Zhang;Xiangyu Liu;Bin Liu;Zhengqiang Xia;Weitao Wang
Science China Chemistry 2015 Volume 58( Issue 6) pp:1032-1038
Publication Date(Web):2015 June
DOI:10.1007/s11426-015-5318-9
A 3D mixed-valence Co(III)-Co(II) compound [Co9(bta)10(Hbta)2(H2O)10]n·[22(H2O)]n (1) (H2bta=N,N-bis(1H-tetrazole-5-yl)-amine) was hydrothermally synthesized by reaction of Co(NO3)2·6H2O with H2bta·H2O. Compound 1 consists of three kinds of distorted-octahedral [CoII(N4O2)] paramagnetic nodes which are separated by [CoIII(bta)2(Hbta)]2−/[CoIII(bta)3]3− diamagnetic linkers to generate a 3D porous metal-organic framework (MOF) with alternative ⋯Co(III)⋯Co(II)⋯ array and channels incorporating water molecules. Under an applied magnetic field of 4000 Oe, compound 1 exhibits slow relaxation of magnetization at low temperatures, giving ΔE/kB=30.00 K and τ0 =2.0×10−8 s.
Co-reporter:Guochun Zhang;Chengfang Qiao;Jiehui Liang
Chemical Research in Chinese Universities 2015 Volume 31( Issue 4) pp:489-497
Publication Date(Web):2015 August
DOI:10.1007/s40242-015-5104-4
Five transition metal coordination compounds, [Mn2(8-qoac)2(bdc)(H2O)4](1)(8-qoacH=quinoline-8-oxy-acetate acid, H2bdc=benzene-1,4-dicarboxylic acid), [Zn4(8-qoac)4(bdc)2]n(2), {[Cd2(8-qoac)2(Hip)2(H2O)2]·(H2O)4}n(3)(H2ip=benzene-1,3-dicarboxylic acid), [Pb3(8-qoac)2(bdc)1.5(H2O)Cl]n(4) and [Zn2(8-qoac)(8-ql)(bdc)]n (5)(8-Hql=8-hydroxyquinoline), were synthesized by hydrothermal syntheses of metal salts with benzenedicarboxylic acid and 8-qoacH. Compound 1 possesses a discrete dimer bridged by bdc2− ligand. Compound 2 presents a 2D layer network constructed from bdc2− linkers and 1D infinite ribbons, in which Zn(II) centers are bridged by 8-qoac− with a tetradentate binding mode. Compound 3 displays a 1D zigzag chain, with adjacent chains further connected via extensive O-H…O hydrogen bonds to generate a 3D supramolecular structure. Compound 4 shows a 3D framework containing trinuclear lead secondary building units and bdc2− linkers, in which a new coordination mode of 8-qoac− ligand is observed. In compound 5, Zn(II) ions are simultaneously bridged by 8-qoac−, 8-ql− and bdc2− ligands to form tetranuclear zinc units, which are further interlinked by bdc2− linkers to yield a 2D wave-like layer. Based on intraligand(IL)(π-π*) fluorescent emission, compounds 1–5 possess strong purple fluorescent emissions. In addition, the thermal stabilities of compounds 1–5 were studied.
Co-reporter:Wenjuan Gao, Xiangyu Liu, Zhiyong Su, Sheng Zhang, Qi Yang, Qing Wei, Sanping Chen, Gang Xie, Xuwu Yang and Shengli Gao
Journal of Materials Chemistry A 2014 vol. 2(Issue 30) pp:11958-11965
Publication Date(Web):03 Jun 2014
DOI:10.1039/C4TA01746C
Two energetic compounds, [Pb(Htztr)2(H2O)]n (1) and [Pb(H2tztr)(O)]n (2), were synthesized and then structurally characterized (N% = 39.4% for 1, N% = 27.2% for 2), where Htztr represents 3-(tetrazol-5-yl)triazole. Structural analysis revealed that both compounds have reticular two-dimensional structures. Remarkably, thermogravimetric measurements demonstrated that the compounds possess excellent thermostabilities with high decomposition temperatures up to 340 °C for (1) and 318 °C for (2). The kinetic parameters of exothermic processes were studied by the Kissinger's and Ozawa–Doyle's methods. The standard molar enthalpies of formation were obtained from the determination of constant-volume combustion energies. The calculated detonation properties showed that compound (1) can be used as a potential explosive. Sensitivity tests revealed that the compounds are extremely insensitive. In addition, two compounds were examined for use as additives to promote the thermal decomposition of ammonium perchlorate and hexahydro-1,3,5-trinitro-1,3,5-triazine.
Co-reporter:Xiangyu Liu, Peipei Cen, Hui Li, Hongshan Ke, Sheng Zhang, Qing Wei, Gang Xie, Sanping Chen, and Shengli Gao
Inorganic Chemistry 2014 Volume 53(Issue 15) pp:8088-8097
Publication Date(Web):July 11, 2014
DOI:10.1021/ic5010769
Based on the solvent-induced effect, three new azido-copper coordination polymers—[Cu(2-na)(N3)] (1), [Cu(2-na)(N3)] (2), and [Cu(2-na)(N3)(C2H5OH)] (3) (where 2-na = 2-naphthoic acid)—have been successfully prepared. Structure analysis shows that the Cu(II) cations in compounds 1–3 present tetra-, penta-, and hexa-coordination geometries, respectively. Compound 1 is a well-isolated one-dimensional (1D) chain with the EO-azido group, while 2 is an isomer of 1 and exhibits a two-dimensional (2D) layer involving the EE-azido group. Thermodynamically, density functional theory (DFT) calculation reveals that 2 occupies the stable state and 1 locates in the metastable state. Compound 3 consists of a 1D chain with triple bridging mode, which is derived from 1, and undergoes a single-crystal-to-single-crystal transformation by soaking in ethanol solvent; the powdery product of 1, namely 1b, could be yielded after the dealcoholization of compound 3. Magnetic measurements indicate that compounds 1–3 perform strong intrachain ferromagnetic interactions, experiencing long-range magnetic ordering and slow magnetic relaxation. Compound 1 features the metamagnetic behavior with a transition temperature of 15 K, while 2 and 3 display spin glass behavior with the phase transition temperatures of 15 and 12 K, respectively. Magneto-structure relationships are investigated as well.
Co-reporter:Sheng Zhang, Yang Yang, Zheng-Qiang Xia, Xiang-Yu Liu, Qi Yang, Qing Wei, Gang Xie, San-Ping Chen, and Sheng-Li Gao
Inorganic Chemistry 2014 Volume 53(Issue 20) pp:10952-10963
Publication Date(Web):October 6, 2014
DOI:10.1021/ic501253c
Hydrothermal reactions of europium(III) salt with 2-(4-carboxyphenyl)imidazo[4,5-f]-1,10-phenanthroline and dicarboxylic acid as coligands—benzene-1,4-dicarboxylic acid, 4,4′-biphenyldicarboxylic acid, 2,5-dibromoterephthalic acid, and naphthalene-1,4-dicarboxylic acid—lead to four europium fluorescent materials (1–4). Structural analyses reveal that 1–4 have binuclear 3D metal–organic frameworks with different channels, void volumes, and conjugated structures tuned by ditopic carboxylates. There are no latticed and coordinated water molecules occurring in 1–3, while the free water molecules fill in 1D channels of 4. 4′ was readily obtained via water removal of 4. Thermal analyses of all compounds show the high thermal stability of the main framework up to 450 °C. Optical studies indicate that 1–4 and 4′ show the characteristic red luminescence emission of the EuIII ion in the visible regions at room temperature. On the basis of emission spectra, their luminescence lifetimes were determined. In particular, compound 4′ shows a longer lifetime (τ = 0.942 ms) and significantly enhanced quantum yield (39%) compared with those of 1 (11%, 0.770 ms), 2 (4%, 0.414 ms), 3 (18%, 0.807 ms), and 4 (26%, 0.858 ms).
Co-reporter:Zhiyong Su, Xiangyu Liu, Qi Yang, Sheng Zhang, Qing Wei, Gang Xie, Sanping Chen and Shengli Gao
CrystEngComm 2014 vol. 16(Issue 20) pp:4245-4253
Publication Date(Web):20 Feb 2014
DOI:10.1039/C4CE00259H
Based on supramolecular interactions, three stable energetic compounds, (TATA+)·(TZA−)·H2O (1), (AT+)2·(OX2−) (2), and (DAT2+)·(NO3−)2 (3), possessing nitrogen contents of 51.42%, 53.80 and 43.53%, respectively, were synthesized and structurally characterized (TATA = 1,3,5-triazine-2,4,6-triamine, TZA = tetrazole-1-acetic, AT = 5-amino-1H-tetrazole, OX = oxalic acid, DAT = 3,5-diamino-1,2,4-triazole). The physicochemical properties of the title compounds were theoretically and experimentally investigated in detail. Thermogravimetry and Density Functional Theory (DFT) calculations indicate that the three energetic compounds show superior thermal stability. The non-isothermal thermokinetics parameters were also obtained by Kissinger's and Ozawa's methods. In addition, the standard molar enthalpies of formation were calculated from the determination of constant-volume combustion energies. As energetic materials, the detonation performances of the compounds are discussed with the combination of low sensitivity and environmental friendliness.
Co-reporter:Lan Yang, Sheng Zhang, Xiangyu Liu, Qi Yang, Qing Wei, Gang Xie and Sanping Chen
CrystEngComm 2014 vol. 16(Issue 20) pp:4194-4201
Publication Date(Web):14 Feb 2014
DOI:10.1039/C3CE42532K
To explore and alter the structures of azido–copper(II) chain compounds, as well as investigate how their magnetic properties are influenced by substituents on the phenylacetic acid coligands, three new azido-bridged Cu(II) compounds, [Cu(o-npa)(N3)(H2O)]n (1), [Cu(p-npa)(N3)]n (2) and [Cu(p-mpa)(N3)]n (3) (o-Hnpa = o-nitrophenylacetic acid, p-Hnpa = p-nitrophenylacetic acid, and p-Hmpa = p-methylphenylacetic acid), have been successfully obtained, and structurally and magnetically characterized. Single-crystal structure analyses indicate that the azido ligands adopt the single end-on (EO) mode to connect adjacent Cu(II) centers in all three compounds. In compounds 1 and 2, the carboxylate groups exhibit the same μ2-bridging bidentate mode. Although compound 2 exhibits a 2D layer-structure formed through connections between the p-NO2 groups on the aromatic rings and 1D Cu(II)-chains, 2 shows similar intrachain ferromagnetic coupling to 1. When p-methylphenylacetic acid is employed as a coligand, compound 3 exhibits a 2D layer-structure, in which the carboxylate adopts a μ3-bridging tridentate mode to shorten the distance between Cu(II)-chains. Due to the counter-complementarity of the superexchange pathways in this system, compound 3 behaves as a magnet with a spontaneous magnetization temperature of 7 K.
Co-reporter:Xiangyu Liu, Qi Yang, Zhiyong Su, Sanping Chen, Gang Xie, Qing Wei and Shengli Gao
RSC Advances 2014 vol. 4(Issue 31) pp:16087-16093
Publication Date(Web):06 Feb 2014
DOI:10.1039/C4RA00635F
A novel 3D energetic coordination polymer of azide–Cu(II), Cu(3,5-DNBA)(N3), was synthesized and structurally characterized by single crystal X-ray diffraction, where 3,5-DNBA represents 3,5-dinitrobenzoic acid. Structural analysis reveals that the central Cu(II) ion coordinates with two azide anions and three 3,5-dinitrobenzoic acid anions to form a five-coordinated tetragonal pyramid structure. Remarkably, one oxygen atom in the nitro group displays rare coordination to the Cu(II) ions in the complex. The as-prepared compound showed abrupt thermal decomposition at 268 °C, representing explosive performance and superior thermostability based on DSC and TG-DTG analyses. Sensitivity tests revealed that the title complex was insensitive to external stimuli. The kinetic parameters of an exothermic process for the complex were studied by Kissinger's and Ozawa–Doyle's methods. In addition, the constant-volume combustion energy of the complex was determined using a precise rotating-bomb calorimeter, and the standard molar enthalpy of combustion and the standard molar enthalpy of formation were calculated.
Co-reporter:Xiang-Yu Liu, Lin-Qiang Duan, Qing Wei, San-Ping Chen
Inorganica Chimica Acta 2014 Volume 423(Part A) pp:462-468
Publication Date(Web):1 November 2014
DOI:10.1016/j.ica.2014.09.009
•Two new cyanide-bridged Mn(III) compounds with Schiff base as ligand are synthesized and characterized.•1 and 2 present interesting 1D chain-like structure with hexa-coordinated Mn(III) ions.•Two compounds show excellent thermostability and exhibit antiferromagnetic coupling between Mn(III) ions.Two new cyanide-bridged compounds, [Mn(L)(μ1,3-N(CN)2)]n (1) and {[Mn2(L)2(H2O)2]K(H2O)2Co(CN)6}n (2). (H2L = N,N′-bis-5-chloro-salicylidene)-1,2-diaminoethane), are synthesized and structurally characterized. Single-crystal X-ray diffraction analysis reveals that compounds 1 and 2 are composed of interesting 1D chain-like structure in which the manganese center is hexa-coordinated in the distorted octahedral geometry. In compound 1, Mn(III) ions are bridged by N(CN)2− ligands with μ1,3 modes, while two CN− groups in Co(CN)63− ligand bridge two Mn(III) ions leading to a heterometallic trinuclear unit in compound 2, several of the units are further connected by the linkage of CN− groups and K(I) ions to form the chain-like structure. TGA results indicate that two compounds possess excellent thermostabilities. Magnetic measurement demonstrates that compounds 1 and 2 perform antiferromagnetic interaction with the coupling parameters (J) of −0.722 and −0.849 cm−1, respectively. Magneto-structural correlation has been discussed as well.Graphical abstractTwo cyanido-bridged 1D chain-like Mn(III) compounds with Schiff base as ligand are synthesized and characterized. Mn(III) ions in 1 and 2 present hexa-coordinated octahedral geometry. Two compounds show excellent thermostabilities and exhibit antiferromagnetic coupling between Mn(III) ions.
Co-reporter:Sheng Zhang;Qing Wei;XiangYu Liu;Qi Yang;Gang Xie
Science China Chemistry 2014 Volume 57( Issue 9) pp:1225-1234
Publication Date(Web):2014 September
DOI:10.1007/s11426-014-5070-6
Three new heterometallic coordination compounds, namely, [KCu(I3)(L)2(H2O)2]n (1), [KCu(I3)(L)2(H2O)]n (2) and [CuK4(I3)2(L′)4]n (3), were prepared and characterized (HL=5-methylpyrazine-2-carboxylic acid, HL′=p-tolylacetic acid). Structural studies revealed that 1 and 2 exhibit 3D frameworks with rectangular channels occupied by triiodide ions. Both compounds can be symbolized as a 5-connected net with pcu topology. In compound 3, a one-dimensional polyhedral chain is connected by hexanuclear mask like clusters [Cu2K4O8]. These chains are further linked each other via rare (1,1,3,3)-triiodide ion-bridging units to generate a 3D (4,5,6)-connected net with the point symbol of {12}2{4·122}4{46}{48·62}4{49·66}4. It is noteworthy that water-induced reversible dissolution/reorganization processes occur between 1/2 and [Cu(L)2(H2O)]n·3nH2O. The thermal and photoluminescence properties of compounds 1, 2, and 3 were investigated as well.
Co-reporter:Dr. Sheng Zhang;Dr. Xiangyu Liu;Dr. Qi Yang;Dr. Zhiyong Su;Dr. Wenjuan Gao; Qing Wei; Gang Xie; Sanping Chen; Shengli Gao
Chemistry - A European Journal 2014 Volume 20( Issue 26) pp:7906-7910
Publication Date(Web):
DOI:10.1002/chem.201402783
Abstract
Reaction of Co(II) with the nitrogen-rich ligand N,N-bis(1H-tetrazole-5-yl)-amine (H2bta) leads to a mixed-valence, 3D, porous, metal–organic framework (MOF)-based, energetic material with the nitrogen content of 51.78%, [Co9(bta)10(Hbta)2(H2O)10]n⋅(22 H2O)n (1). Compound 1 was thermohydrated to produce a new, stable, energetic material with the nitrogen content of 59.85% and heat of denotation of 4.537 kcal cm−3, [Co9(bta)10(Hbta)2(H2O)10]n (2). Sensitivity tests show that 2 is more sensitivity to external stimuli than 1, reflecting guest-dependent energy and sensitivity of 3D, MOF-based, energetic materials. Less-sensitive 1 can be regarded as a more safe form for storage and transformation to sensitive 2.
Co-reporter:Xiangyu Liu ; Zhiyong Su ; Wenxin Ji ; Sanping Chen ; Qing Wei ; Gang Xie ; Xuwu Yang ;Shengli Gao
The Journal of Physical Chemistry C 2014 Volume 118(Issue 41) pp:23487-23498
Publication Date(Web):September 25, 2014
DOI:10.1021/jp5062418
Four nitro-containing energetic compounds, cocrystal of AT·DNBA (1), salt of MA·DNSA (2), salt of AG·DNBA·H2O (3), and salt of DAT·DNSA H2O (4), are synthesized and structurally characterized based on supramolecular interactions (AT, 4-amino-1,2,4-triazole; DNBA, 3,5-dinitrobenzoic acid; MA, melamine; DNSA, 3,5-dinitrosalicylic acid; AG, amino guanidine; DAT, 3,5-diamino-1,2,4-triazole). The physicochemical properties of the compounds are theoretically and experimentally investigated in detail. The optimized structures, molecular total energies, frontier orbit energies, and charge densities of 1–4 are calculated by theoretical methods. The experimental results indicate that all compounds exhibit good thermostability and low sensitivity. It is worth noting that the values of impact sensitivity are measured to be 30, >40, 38, and >40 J for 1, 2, 3, and 4, respectively, which correspond well to the order of nitro group charge (QNitro) calculated by density functional theory. The detonation performances of 1–4 are discussed; in particular, 1 and 2 exhibit heats of detonation (2.191 kcal g–1 for 1 and 2.214 kcal g–1 for 2) superior to those of classical nitro-rich compounds. In addition, the nonisothermal thermokinetic parameters are obtained by Kissinger and Ozawa methods, and the standard molar enthalpies of formation are calculated from the determination of constant volume combustion energies.
Co-reporter:Qi Yang, Qing Wei, San-Ping Chen, Guo-Chun Zhang, Chun-Sheng Zhou, Sheng-Li Gao
Journal of Analytical and Applied Pyrolysis 2013 Volume 99() pp:66-70
Publication Date(Web):January 2013
DOI:10.1016/j.jaap.2012.10.026
Self-assembly of Ni(II) with 3,5-diamino-1,2,4-triazole resulted in a 3D supramolecular compound [Ni3(Hdatrz)6(fma)2(H2O)4]fma·11H2O (1) in the presence of coligand fumaric acid (Hdatrz = 3,5-diamino-1,2,4-triazole, H2fma = fumaric acid). X-ray structural analysis reveals that three nickel ions are bridged by six neutral Hdatrz ligands, and abundant lattice water molecules exist in 1. Based on the structural framework and TG curve of 1, a new energetic compound [Ni3(Hdatrz)6(fma)2(H2O)4]fma (2) with 35.5% of nitrogen content was readily prepared through dehydration of 1 at 398 K under N2 atmosphere. The enthalpy change of the reaction of formation for 1 was determined to be (−23.24 ± 0.05) kJ mol−1 by microcalorimetry at (298.15 ± 0.01) K. Thermodynamic and thermokinetic parameters k, E, n , ΔS≠θ, ΔH≠θ and ΔG≠θ of the reaction of formation for 1 were obtained. Thermoanalytical kinetics of the reaction of formation for 2 was further investigated. The sensitivity experiment results indicated that 2 was more sensitive to impact and friction stimuli that 1. As an additive, 2 effectively promoted the thermal decomposition of ammonium perchlorate (AP), which projected the potential application of the compound 2 as combustion modifier in solid propellants.Highlights► A new energetic compound 2 was prepared via thermo-dehydration of compound 1. ► Thermodynamics and thermokinetics for both compounds were investigated. ► 2 was more sensitive than 1, which would provide an insight for storage of high-energy materials. ► 2 efficiently accelerated the thermal decomposition of AP.
Co-reporter:Zhengqiang Xia, Qing Wei, Qi Yang, Chengfang Qiao, Sanping Chen, Gang Xie, Guochun Zhang, Chunsheng Zhou and Shengli Gao
CrystEngComm 2013 vol. 15(Issue 1) pp:86-99
Publication Date(Web):03 Oct 2012
DOI:10.1039/C2CE26120K
A flexible multidentate ligand, 1H-benzimidazole-2-carboxylic acid, was synthesized to construct a series of lanthanide coordination polymers [Ln(HBIC)3]n (Ln = Eu (1), Tb (2), Gd (3), Pr (4), Nd (5); H2BIC = 1H-benzimidazole-2-carboxylic acid) under hydrothermal conditions. All the compounds were fully characterized by elemental analysis, IR spectroscopy, single-crystal X-ray diffraction, thermal analysis and various spectroscopic techniques. Structural analyses reveal that they are isostructural and feature a 2D wave-like layer structure with distorted grids, in which the adjacent Ln3+ centers are bridged by the HBIC− ligands with two kinds of new coordination modes and the adjacent HBIC− ligands are tightly bound by two types of distinct intra-layer hydrogen bonds. The adjacent 2D layers are further interconnected by strong inter-layer hydrogen bond ring motifs R22(10) to generate a 3D supramolecular architecture. Optical studies indicate that the compounds 1, 2, 4 and 5 exhibit characteristic luminescence emission bands of the corresponding lanthanide ions in the visible or near-infrared regions at room temperature. In particular, compound 2 displays bright green luminescence in the solid state with a satisfactory 5D4 lifetime of 1.2 ms and a high overall quantum yield of 31%, due to an ideal energy gap between the lowest triplet state energy level of H2BIC ligand and the 5D4 state energy level of Tb3+. The energy transfer mechanisms in compounds 1 and 2 were also described and discussed.
Co-reporter:Wei Wei, Zhengqiang Xia, Qing Wei, Gang Xie, Sanping Chen, Chengfang Qiao, Guochun Zhang, Chunsheng Zhou
Microporous and Mesoporous Materials 2013 Volume 165() pp:20-26
Publication Date(Web):1 January 2013
DOI:10.1016/j.micromeso.2012.07.036
Co-reporter:Zheng-Qiang Xia, Qing Wei, San-Ping Chen, Xin-Ming Feng, Gang Xie, Cheng-Fang Qiao, Guo-Chun Zhang, Sheng-Li Gao
Journal of Solid State Chemistry 2013 Volume 197() pp:489-498
Publication Date(Web):January 2013
DOI:10.1016/j.jssc.2012.08.028
A series of 3d–4f heterometallic coordination polymers, formulated as {[Cu3Ln2(pydc)6(H2O)12]·4H2O}n [Ln=Tb (1), Eu (2), Dy (3), Ho (4), Lu (5)], {[CuNd2(pydc)4(H2O)3]·H2O}n (6) and {[Cu3Pr2(pydc)6(H2O)13]·4H2O}n (7) (where H2pydc=pyridine-2,5-dicarboxylic acid), have been hydrothermally prepared by reactions of H2pydc ligand with lanthanide ions in the presence of Cu(II) ion. X-ray crystal structure analysis reveals that these compounds exhibit rich structural chemistry. 1–5 are isomorphous and present a two-dimensional network constructed from Ln2Cu2L2(H2O)2 SBU rings and CuL2(H2O) building blocks. In 6, two-dimensional ladder-like layers based on Nd(III) belts and CuL2O2 units are assembled by H2pydc ligands into a three-dimensional open framework. Polymer 7 displays a two-dimensional wave-like layer structure containing two distinct ring units, in which a new coordination mode of the pydc2− ligand is observed. The results indicate that the coordination flexibility of the pydc2− ligand and lanthanide contraction effect play cooperative roles in the formation of coordination polymers with different polymeric architectures. Compounds 1–2 exhibit intense green and red luminescence emission characteristics of Tb(III) and Eu(III), respectively. Furthermore, elemental analyses (EA), infrared spectra (IR) and thermogravimetric analyses (TGA) of these compounds were also studied.Graphical abstractSeven 3d–4f heterometallic coordination polymers were synthesized by reactions of H2pydc with lanthanide metal ions in the presence of Cu2+, the effects of Cu2+ on the structures and photoluminescent properties of Ln–pydc2− systems were investigated .Highlights► Seven 3d–4f heterometallic compounds have been prepared and characterized. ► 1–5 and 7 are constructed from Ln2Cu2L2(H2O)2 rings and CuL2(H2O) building blocks. ► One new coordination mode of the pydc2− ligand is first observed. ► 1–2 exhibit intense characteristic luminescence emission spectra of lanthanide ions.
Co-reporter:Wei Wei, Sanping Chen, Qing Wei, Gang Xie, Qi Yang, Shengli Gao
Microporous and Mesoporous Materials 2012 Volume 156() pp:202-208
Publication Date(Web):1 July 2012
DOI:10.1016/j.micromeso.2012.02.042
Hydrothermal reactions of Co(II)/Ni(II) salts with the ligands 3,5-dipyridyl-1,2,4triazole (4-Hbpt) and 3,3′,4,4′-biphenyltetracarboxylic acid (H4bptc) generated the robust, microporous metal-organic frameworks {[Co2(4-Hbpt)2(bptc)(H2O)2]·10H2O}n (I) and {[Ni3(4-Hbpt)2(Hbptc)2(H2O)6]·8H2O}n (II). The two coordination frameworks were performed to absorb hydrogen at low and high pressures, respectively. Experimental and theoretical analyses indicate that the high enthalpy of adsorption for H2 benefit the high hydrogen absorption capacity.Graphical abstractTwo microporous MOFs {[Co2(4-Hbpt)2(bptc)(H2O)2]·10H2O}n (I) and {[Ni3(4-Hbpt)2(Hbptc)2(H2O)6]·8H2O}n (II) were hydrothermally synthesized and structurally characterized. The hydrogen uptakes in I and II were investigated, indicating that the hydrogen uptakes were 1.33 and 0.78 wt% at 77 K under 20 bar, respectively. Theoretical analysis reveals that the high binding energy of interaction between H2 and the framework benefit the high hydrogen uptakes.Highlights► Two microporous MOFs have been hydrothermally synthesized. ► The compounds were employed for hydrogen adsorption. ► The enthalpy of adsorption with the adsorption amount has been correlated.
Co-reporter:Sheng Zhang, Qing Wei, Gang Xie, Qi Yang, Sanping Chen
Inorganica Chimica Acta 2012 Volume 387() pp:52-57
Publication Date(Web):30 May 2012
DOI:10.1016/j.ica.2011.12.051
Three coordination polymers based on 3-amidecarbonylpyrazine-2-carboxylic acid (HPyzca), [Cd(Pzdc)(H2O)]n·(H2O)n, [Pb3(Pzdc)3(H2O)]n, [Cu0.5(HPzdc)]n (H2Pzdc = 2,3-pyrazinedicarboxylic acid) have been in situ hydrothermally synthesized and characterized by single crystal X-ray diffraction analysis. The structural analysis revealed that HPyzca underwent hydrolysis to H2Pzdc under hydrothermal conditions. In compound 1, the Pzdc2− ligands link Cd(II) ions into a 2D architecture with the μ4-η1:η1:η2:η2 coordination mode. In compound 2, the ligands Pzdc2− adopt μ5-η1:η1:η2:η2:η2 and μ4-η1:η2:η2:η2 coordination modes connecting metal centers to form a new (3,4,5)-connected 6-nodal net with {42·6}{44·62}{43·62·8}{45·63·82}2{48·62} topology symbol. In compound 3, the adjacent Cu(II) centers are connected by HPzdc− to furnish polymeric chains along the [0 1 0] direction. These 1D arrays are further interlinked through Pzdc2− spacers to a 2D (4,4) coordination layer along the bc plane. Furthermore, thermal stabilities and photoluminescent properties of the compounds were also studied in the solid state.Graphical abstractThree novel coordination polymers [Cd(Pzdc)(H2O)]n·(H2O)n (1), [Pb3(Pzdc)3(H2O)]n (2), [Cu0.5(HPzdc)]n (3) have been in situ synthesized under hydrothermal conditions. Compounds 1 and 3 display 2D layer and compound 2 exhibits a 3D framework.Highlights► Three compounds are in situ hydrothermally synthesized based on HPyzca. ► HPyzca is hydrolyzed into Pzdc2−/HPzdc− under hydrothermal conditions. ► Pzdc2− presents three kinds of unreported coordination modes in compound 2.
Co-reporter:Shengli Gao, Sheng Zhang, Sanping Chen, Desuo Yang
Thermochimica Acta 2012 Volume 543() pp:118-124
Publication Date(Web):10 September 2012
DOI:10.1016/j.tca.2012.05.023
Low-temperature heat capacities of the coordination compound, chromium(III) tri(pyrazine-2-carboxylate), formulated as Cr(pyza)3 (pyza = pyrazine-2-carboxylate), were measured by a precision automated adiabatic calorimeter over the temperature range of 78–400 K. A polynomial equation of heat capacities as a function of the temperature was fitted by the least square method. Based on the fitted polynomial equation, the fitted heat capacities and thermodynamic functions of the compound relative to the standard reference temperature 298.15 K were calculated at the interval of 5 K. In accordance with a reasonable thermochemical cycle designed, the standard molar enthalpy of formation of the title complex was determined to be −1207.86 ± 3.39 kJ mol−1 by an isoperibol solution–reaction calorimeter.Highlights▸ Low-temperature heat capacities of chromium(III) tri(pyrazine-2-carboxylate) were measured from 78 to 400 K. ▸ Thermodynamic functions of the compound at 298.15 K were calculated based on low-temperature heat capacity. ▸ The standard molar enthalpy of formation of the target was determined to be −1207.86 ± 3.39 kJ mol−1 through a designed thermochemical cycle.
Co-reporter:Jiehui Liang;Qing Wei;Chengfang Qiao;Zhengqiang Xia;Gang Ye;Sanping Chen
Chinese Journal of Chemistry 2012 Volume 30( Issue 3) pp:715-720
Publication Date(Web):
DOI:10.1002/cjoc.201280017
Abstract
Quinoline-8-oxy-acetate acid (8-qoacH) reacts with M(II) (M=Pb and Cd) to give rise to two coordination complexes [Pb(8-qoac)2] (1) and [Cd(8-qoac)(bdc)0.5(H2O)2] (2) under hydrothermal conditions. They are characterized by single-crystal X-ray diffraction, IR, elemental, thermal analyses and luminescent analysis. The Pb metal centers connect the 8-qoac anions to form a 1D linear chain in 1. In 2, two symmetrical [Cd(8-qoac)(H2O)2] are bridged by a 1,4-bdc2− to generate a coordination unit [Cd(8-qoac)(bdc)0.5(H2O)2], and all the units are further connected to a 2D supramolecular layer-like structure via hydrogen bonds. TG analyses indicate that 1 exhibits higher thermostability than 2. Fluorescence spectrum of compound 2 in solid state shows strong fluorescence property.
Co-reporter:Gang Xie;Bing Li;SanPing Chen;Qi Yang;Wei Wei;ShengLi Gao
Science China Chemistry 2012 Volume 55( Issue 3) pp:443-450
Publication Date(Web):2012 March
DOI:10.1007/s11426-012-4527-8
Three new cobalt(II) coordination compounds, [Co(3,3′-Hbpt)2(H2pm)(H2O)2]·2H2O (1), [Co(4,4′-Hbpt)(pm)0.5(H2O)]·3H2O (2) and [Co(3,4′-Hbpt)(pm)0.5(H2O)3]·2H2O (3) (3,3′-Hbpt = 3,5-bis(3-pyridyl)-1H-1,2,4-triazole; 4,4′-bpt = 3,5-bis(4-pyridyl)-1H-1,2,4-triazole, 3,4′-Hbpt = 3-(3-pyridyl)-5-(4′-pyridyl)-1H-1,2,4-triazole and H4pm = pyromellitic acid) have been synthesized by hydrothermal reactions. Single-crystal X-ray diffraction reveals that compound 1 has a one-dimensional (1D) chain network, 2 exhibits a four-connected three-dimensional (3D) structure with 1D open channels encapsulated by water molecules, while 3 displays a regular two-dimensional (2D) architecture connected through 1D metal helical chains. In addition, the efficacy of compounds 1–3 as additives to promote the thermal decomposition of ammonium perchlorate (AP) is explored by differential scanning calorimetry (DSC).
Co-reporter:Fumin Wang;Sanping Chen;Qi Yang;Bing Li;Shengli Gao
Structural Chemistry 2012 Volume 23( Issue 1) pp:55-60
Publication Date(Web):2012 February
DOI:10.1007/s11224-011-9788-x
The self-assembly of 5-methylpyrazine-2-carboxylate (Hmpca) with silver nitrate generated two coordination polymers [Ag2(Hmpca)(mpca)(NO3)]n (1) and [Ag(mpca)]n (2) in the presence of Er3+ or Mn2+ via hydrothermal synthesis. The complexes have been characterized by IR, elemental analyses and single-crystal X-ray diffraction. Complex 1 possesses a novel 1D looped-chain topology structure. Complex 2 shows an extended honeycomb-like 3D framework. The luminescent properties of complexes 1 and 2 were investigated.
Co-reporter:Bing Li;Sanping Chen;Gang Xie;Qi Yang;Shengli Gao
Structural Chemistry 2012 Volume 23( Issue 2) pp:417-423
Publication Date(Web):2012 April
DOI:10.1007/s11224-011-9886-9
Based on the polydentate ligand 3,5-bis(3-pyridyl)-1H-1,2,4-triazole (3,3′-Hbpt), three coordination compounds [Zn(3,3′-Hbpt)(ip)]·2H2O (1), [Zn(3,3′-Hbpt)(5-NO2-ip)]·H2O (2), and [Zn(3,3′-Hbpt)2(H2pm)(H2O)2]·2H2O (3) have been hydrothermally constructed with H2ip, 5-NO2-H2ip and H4pm as auxiliary ligands (H2ip = isophthalic acid, 5-NO2-H2ip = 5-NO2-isophthalic acid, H4pm = pyromellitic acid). Structural analysis reveals that Zn(II) ions serve as four-coordinated, five-coordinated, and six-coordinated connectors in 1–3, respectively, while 3,3′-Hbpt adopts μ-Npy and Npy coordination modes in two typical conformations in these target coordination compounds. Dependently the applied ligand, compounds 1–3 exhibit either 1D channel, cage or chain structures, respectively. In addition, the luminescence properties of 1–3 have been investigated in the solid state at room temperature.
Co-reporter:Cheng-Fang Qiao;Qing Wei;Zheng-Qiang Xia
Journal of Thermal Analysis and Calorimetry 2012 Volume 107( Issue 2) pp:527-533
Publication Date(Web):2012 February
DOI:10.1007/s10973-011-1607-5
Six lanthanide compounds [Ln(H2O)9](m-BDTH)3·9(H2O) where Ln = La (1), and [Ln(H2O)8](m-BDTH)3·9(H2O) (m-BDTH2 = 1,3-benzeneditetrazol-5-yl) where Ln = Lu (2), Yb (3), Er (4), Ho (5) and Y (6) were hydrothermally synthesized and characterized by elemental analyses, infrared spectra, powder X-ray diffraction (PXRD) and X-ray single crystal diffraction. PXRD indicates that 2–6 are isomorphous. Structural analyses reveal that 1 is coordinated by nine water molecules forming a capped-square antiprism, while 2–6 are coordinated by eight water molecules forming a simple square antiprismatic geometry. Effects of water molecules on thermal stability were also discussed by thermogravimetric (TG), DSC, and PXRD under different temperatures. TG analyses suggest that 1 loses lattice and coordinated water molecules with no diacritical boundary, and 6 removes lattice water molecules first and then coordinated water molecules. DSC and PXRD further confirm the consequence.
Co-reporter:Xiao-Ling Wang, Zheng-Qiang Xia, Wei Wei, Gang Xie, San-Ping Chen, Sheng-Li Gao
The Journal of Chemical Thermodynamics 2012 Volume 55() pp:124-129
Publication Date(Web):December 2012
DOI:10.1016/j.jct.2012.06.029
A lanthanide coordination compound, [Sm3(5-nip)4(5-Hnip)(H2O)7·9H2O]n (5-H2nip = 5-nitroisophthalic acid), has been synthesized and characterized by elemental analysis, IR, TG-DSC, and single-crystal X-ray diffraction. Structural analysis reveals that the compound features two kinds of 1D channels with guest water molecules. TG-DSC curves show that the dehydrated product of the compound exhibits high stability up to 673 K. The enthalpy change of reaction of formation in water, ΔrHmθ(l), was determined to be (27.608 ± 0.133) kJ · mol−1 at (298.15 ± 0.01) K by microcalorimetry. Based on a designed thermochemical cycle and other auxiliary thermodynamic data, the enthalpy change of reaction of formation in solid at (298.15 ± 0.01) K and the standard molar enthalpy for the compound, ΔrHmθ(s) and ΔfHmθ, were calculated to be (96.8 ± 0.8) kJ · mol−1 and (−831.4 ± 16.0) kJ · mol−1, respectively. In addition, thermodynamics and thermokinetics of the reaction of formation of the compound were investigated in water.Highlights► A microporous LnMOF have been prepared and characterized. ► The standard molar enthalpy for the compound was determined to be to be −(831.4 ± 16.0) kJ · mol−1. ► Thermodynamics and kinetics of the reaction of formation of the compound were invesitigated.
Co-reporter:Yanhua Zou, Qing Wei, Zhenling Guo, Sanping Chen, Shengli Gao
Inorganica Chimica Acta 2011 Volume 375(Issue 1) pp:181-186
Publication Date(Web):1 September 2011
DOI:10.1016/j.ica.2011.04.045
Two types of novel lanthanide complexes with the 6-hydroxynicotinic acid (OHnicH) {[Ln(OHnic)(Onic)(H2O)5·(OHnicH)]·H2O}n [Ln = La(1), Ce(2), Gd(3)] and {[Ln(OHnic)3(H2O)]·3H2O}n [Ln = La(4), Pr(5)] have been synthesized and characterized by elemental analyses, IR spectra, UV absorption spectra and single crystal X-ray diffraction. The structures of the as-prepared complexes vary with the different coordination modes of the ligands. In complexes 1–3, the adjacent metal centers are linked by the chelating-bridging tridentate modes of the ligands to form 1D chains; while in 4 and 5, the adjacent metal ions are bridged by the ligands in the chelating-bridging bidentate modes to form dinuclear units, then linked into 1D chains through the ligands in the bridging bidentate modes, and further linked to form 2D plane structures via the bridging tridentate modes of the ligands. Thermostabilities and luminescent properties of the complexes have been discussed in detail.Graphical abstractFive novel coordination polymers {[Ln(OHnic)(Onic)(H2O)5·(OHnicH)]·H2O}n [OHnicH = 6-hydroxynicotinic acid, Ln = La(1), Ce(2), Gd(3)]; {[Ln(OHnic)3(H2O)]·3H2O}n [Ln = La(4), Pr(5)] have been synthesized in aqueous solution. Compounds 1–3 display 1D chains and 4, 5 possess 2D plane structures.Highlights► Five lanthanide complexes were constructed based on the 6-hydroxynicotinic acid. ► Complexes 1–3 exhibit 1D chains and complexes 4–5 possess 2D plane structures. ► Different coordination modes of the ligands lead to the structural differences.
Co-reporter:Yan Huang, Gang Xie, Sanping Chen, Shengli Gao
Journal of Solid State Chemistry 2011 Volume 184(Issue 3) pp:502-508
Publication Date(Web):March 2011
DOI:10.1016/j.jssc.2010.12.009
Sb2S3/Bi2S3 doped TiO2 were prepared with the coordination compounds [M(S2CNEt)3] (M=Sb, Bi; S2CNEt=pyrrolidinedithiocarbamate) as precursors via gel–hydrothermal techniques. The doped TiO2 were characterized by XRD, SEM, XPS and UV–vis diffuse reflectance means. The photocatalyst based on doped TiO2 for photodecolorization of 4-nitrophenol (4-NP) was examined. The optimal Bi2S3/Sb2S3 content, pH and different doped techniques have been investigated. Photocatalytic tests reveal that M2S3 doped TiO2 via the gel–hydrothermal route performs better photocatalytic activity for photodegradation reaction of 4-nitrophenol (4-NP).Graphical abstractSb2S3/Bi2S3 doped TiO2 were prepared using [M(S2COEt)3] (M=Sb, Bi; S2COEt=pyrrdidine-1-dithiocarbamaate) as precursors via gel–hydrothermal techniques. M2S3 doped TiO2 performs better photocatalytic activity for photodegradation reaction of 4-nitrophenol.Highlights► The coordination compounds [M(S2CNEt)3] (M=Sb, Bi; S2CNEt=pyrrolidinedithiocarbamate) as precursors to prepare Sb2S3/Bi2S3 doped TiO2. ► The sol–hydrothermal, sol–gel and gel–hydrothermal processes for photocatalysis fabrication were employed and compared. ► Sb2S3/Bi2S3 doped TiO2 obtained via the gel–hydrothermal process showed better performance for photodecolorization test of 4-nitrophenol (4-NP).
Co-reporter:Zhengqiang Xia, Sanping Chen, Qing Wei, Chengfang Qiao
Journal of Solid State Chemistry 2011 Volume 184(Issue 7) pp:1777-1783
Publication Date(Web):July 2011
DOI:10.1016/j.jssc.2011.05.017
Two new energetic compounds, [M(BTE)(H2O)5]n (M=Sr(1), Ba(2)) [H2BTE=1,2-bis(tetrazol-5-yl)ethane], have been hydrothermally synthesized and structurally characterized. Single-crystal X-ray diffraction analyses reveal that they are isomorphous and exhibit 2D (4,4) net framework, generated by 4-connected Sr2(H2O)10/Ba2(H2O)10 SBUs linked up by two independent binding modes of H2BTE, and the resulting 2D structure is interconnected by hydrogen-bond and strong face to face π–π stacking interactions between two tetrazole rings to lead to a 3D supramolecular architecture. DSC measurements show that they have significant catalytic effects on thermal decomposition of ammonium perchlorate. Moreover, the photoluminescence properties, thermogravimetric analyses, and flame colors of the as-prepared compounds are also investigated in this paper.Graphical abstractTwo novel 2D isomorphous alkaline earth metal complexes were assembled by 4-connected Sr2(H2O)10/Ba2(H2O)10 SBUs and two independent binding modes of H2BTE ligands, and the catalytic performances toward thermal decomposition of ammonium perchlorate and photoluminescent properties of them were investigated.Highlights► Two novel alkaline earth energetic coordination polymers have been prepared.► Both structures are layered based on 4-connected Sr2(H2O)10/Ba2(H2O)10 SBUs and two distinct H2BTE coordination modes.► The dehydrated products of the compounds possess good thermostability and significant catalytic effects on thermal decomposition of AP.
Co-reporter:Chengfang Qiao;Qing Wei;Zhangqiang Xia;Jiehui Liang ;Sanping Chen
Chinese Journal of Chemistry 2011 Volume 29( Issue 4) pp:724-730
Publication Date(Web):
DOI:10.1002/cjoc.201190147
Abstract
Two coordination compounds [Pb4(BDT)3(OH)2(H2O)4]·H2O (1) and [Mn(H2O)6]·(HBDT)2·2H2O (2) [H2BDT5,5′-(1,4-phenylene)bis(1H-tetrazole)] had been hydrothermally synthesized. 1 and 2 had been characterized by single-crystal X-ray diffraction, IR, elemental and thermal analyses. Structural analysis reveals that 1 exhibits 2D layer structure extended through BDT with two different coordination modes rings in transverse and vertical. 2 consists of [Mn(H2O)6]2+, free HBDT and water. In addition, 1 and 2 were explored as luminescent materials and additives to promote the thermal decomposition of ammonium perchlorate by differential scanning calorimetry.
Co-reporter:Guo-Chun Zhang, San-Ping Chen, Qi Yang, Sheng-Li Gao
Thermochimica Acta 2011 Volume 518(1–2) pp:66-71
Publication Date(Web):10 May 2011
DOI:10.1016/j.tca.2011.02.008
Two hybrid transition-alkali metal complexes, K2[M(DPA)2]·7H2O(s) (M = Cu and Ni, H2DPA = pyridine-2,6-dicarboxylic acid), were structurally determined by X-ray crystallography. In accordance with Hess's law, two reasonable thermochemical cycles were designed and 100 cm3 of 5% (v/v) dilute aquaammonia was chosen as the calorimetric solvent. The standard molar enthalpies of dissolution for the reactants and products of the supposed reactions in the selected solvent were measured at 298.15 K by means of isoperibol solution-reaction calorimeter, respectively. The standard molar enthalpies of formation of K2[M(DPA)2]·7H2O(s) (M = Cu and Ni) were derived to be −(3947.7 ± 4.7) kJ mol−1 and −(4007.8 ± 4.7) kJ mol−1, respectively.Research highlights► Two isostructural complexes were structurally determined by X-ray crystallography. ► The standard molar enthalpy of formation was derived by isoperibol solution reaction calorimetry. ► The similarity in enthalpies is ascribed to the isostructural nature of the complexes.
Co-reporter:Bing Li, Qing Wei, Qi Yang, Sanping Chen, and Shengli Gao
Journal of Chemical & Engineering Data 2011 Volume 56(Issue 7) pp:3043-3046
Publication Date(Web):June 8, 2011
DOI:10.1021/je2000364
A new energetic complex, Co(2,3′-bpt)3·H2O (1) (2,3′-Hbpt = 3-(2-pyridyl)-5-(3′-pyridyl)-1H-1,2,4-triazole), was synthesized and characterized by single crystal X-ray diffraction method. Crystallographic data are as follows: triclinic, P1̅ space group, a = 10.323(2) Å, b = 11.261(2) Å, c = 16.139(3) Å, α = 89.022(3)°, β = 71.794(2)°, γ = 66.990(2)°, Z = 2. In addition, the thermal analysis of Co(2,3′-bpt)3·H2O has been performed by thermogravimetric-differential thermogravimetric (TG-DTG) techniques. The thermal decomposition of ammonium perchlorate (AP) with complex 1 was explored by differential scanning calorimetry (DSC) over the temperature range from (323 to 773) K. AP is completely decomposed in a shorter time in the presence of complex 1, and the decomposition heat of the mixture is 2.034 kJ·g–1, significantly higher than pure AP. By Kissinger's method, the ratio of Ea/ln(A) is 12.66 for the mixture, which indicates that complex 1 shows good catalytic activity toward AP decomposition.
Co-reporter:Bing Li, San-Ping Chen, Qi Yang, Sheng-Li Gao
Polyhedron 2011 30(7) pp: 1213-1218
Publication Date(Web):
DOI:10.1016/j.poly.2011.01.038
Co-reporter:San-Ping Chen, Yi-Xia Ren, Wei-Tao Wang and Sheng-Li Gao
Dalton Transactions 2010 vol. 39(Issue 6) pp:1552-1557
Publication Date(Web):15 Dec 2009
DOI:10.1039/B914879E
The reactions of lanthanide nitrates with 5-nitroisophthalic acid (ab. 5-H2nip) in DMF and ethanol (1:1) mixed solution gave rise to three nanoporous lanthanide polymers, {[Ln2(5-nip)3(DMF)4](DMF)2}n (Ln = Nd (1), Dy (2), Ho (3), 5-nip = 5-nitroisophthalate). Single-crystal X-ray diffraction analyses reveal that they are isomorphous and feature three-dimensional metal–organic frameworks with two-dimensional intersecting channels occupied by guest DMF molecules constructed from the linkage of dimer Ln2C6O12 SBUs and 5-nip ligands. The guest DMF molecules can be reversibly removed from 2 as identified using TGA-DSC and PXRD. The heat of adsorption of the guest-free sample of 2 with DMF was measured with a value of 10.3 kJ mol−1 by an RD496-III type microcalorimeter. In addition, the photoluminescent property of 2 was investigated.
Co-reporter:Jian Wu, Sanping Chen, Shengli Gao
Materials Chemistry and Physics 2010 Volume 122(Issue 1) pp:301-304
Publication Date(Web):1 July 2010
DOI:10.1016/j.matchemphys.2010.02.025
The evolution of Zn(OH)42−Zn(OH)42− solution during hydrothermal processing was studied using in situ calorimetry and the solid products were characterized by X-ray diffraction, scanning electron microscopy. It was shown that the formation of flower-like ZnO nanostructures exhibited first endothermic and then exothermic processes, of which the associated heat effect was measured as being −50.45 ± 0.01 J mol−1. Flower-like ZnO nanostructures and ZnO microrod may be selectively formed simply based on the hydrothermal reaction temperatures. The mechanism for the flower-like ZnO nanostructures and ZnO microrod has been suggested.
Co-reporter:Xinming Feng;Qing Wei;Sanping Chen ;Shengli Gao
Chinese Journal of Chemistry 2010 Volume 28( Issue 1) pp:11-15
Publication Date(Web):
DOI:10.1002/cjoc.201090024
Abstract
The complexes of formulas [Ln2(pydc)2(Hpydc)2(H2O)4]·2H2O [Ln=Ce (1), Pr (2), H2pydc=pyridine-2,5-di-carboxylic acid] have been hydrothermally synthesized and characterized by elemental analysis, IR, TG and single-crystal X-ray diffraction. The structure analyses for 1 and 2 indicate that one-dimensional metal helical chains are linked through carboxylate groups, and the helical chains are connected with the bridging pydc2− anion, forming two-dimensional layered polymeric structures. The luminescent properties of complexes were also discussed.
Co-reporter:Zhenling Guo;Sanping Chen;Qi Yang ;Shengli Gao
Chinese Journal of Chemistry 2010 Volume 28( Issue 3) pp:383-387
Publication Date(Web):
DOI:10.1002/cjoc.201090083
Abstract
Three novel lanthanide coordination polymers {[Ce2(HOnic)4(Onic)2(H2O)2]·6H2O}n (1), {[Ln(HOnic)(Onic)- (H2O)5·(HOnicH)]·H2O}n [HOnicH=6-hydroxynicotinic acid, Ln=Nd (2), Pr (3)] have been synthesized and characterized by elemental analyses, IR spectrum and single crystal X-ray diffraction. Structure analyses reveal that 1 features a 2D plane structure while compounds 2 and 3 possess a 1D chain-like polymeric structure. TG analyses indicate that 1 exhibits higher thermostability than 2 and 3, which was attributed to the layer polymeric structure of 1.
Co-reporter:Zhu-Jun Wang, San-Ping Chen, Qi Yang and Sheng-Li Gao
Journal of Chemical & Engineering Data 2010 Volume 55(Issue 7) pp:2558-2562
Publication Date(Web):April 6, 2010
DOI:10.1021/je900936t
Low-temperature heat capacities of sodium 5-nitroisophthalic acid monohydrate (C8O6NH3Na2·H2O, s) were measured by a precision automated adiabatic calorimeter over the temperature range from (78 to 398) K. The experimental values of the molar heat capacities were fitted to a polynomial equation of heat capacities (Cp,m) with the reduced temperatures (X), [X = f(T)], by a least-squares method. The smoothed molar heat capacities and thermodynamic functions of the compound (C8O6NH3Na2·H2O, s) were calculated on the basis of the fitted polynomial. The constant volume energy of combustion of the compound at T = 298.15 K was measured by a precise rotating-bomb combustion calorimeter to be ΔcU = −(3969.41 ± 1.74) kJ·mol−1. The standard molar enthalpy of combustion of the compound was determined to be ΔcHθm = −(3965.07 ± 1.74) kJ·mol−1. The standard molar enthalpy of formation of the compound was calculated to be ΔfHθm (C8O6NH3Na2·H2O, s) = −(408.45 ± 2.03) kJ·mol−1 in accordance with Hess’s law. The standard molar enthalpy of solution of the compound, ΔsolHθm (C8O6NH3Na2·H2O, s), has been determined as (22.133 ± 0.111) kJ·mol−1. The standard molar enthalpy of the hydrated anion of the compound was determined as ΔfHθm (C8O6NH32−, aq) = (380.11 ± 2.04) kJ·mol−1, from the standard molar enthalpy of solution and other auxiliary thermodynamic data through a thermochemical cycle. The thermostability of the compound was investigated by thermogravimetric/differential thermogravimetric/differential scanning calorimetry (TG-DTG-DSC).
Co-reporter:Zhu-Jun Wang, San-Ping Chen, You-Ying Di, Qi Yang, and Sheng-Li Gao
Journal of Chemical & Engineering Data 2010 Volume 55(Issue 12) pp:5786-5790
Publication Date(Web):November 17, 2010
DOI:10.1021/je100713p
A series of sodium isophthalic acid derivatives 5-R-Na2bdc·nH2O (H2bdc = isophthalic acid, R = H, NH2, OH, CH3, NO2, n = 0.5, 1, 1, 1, 1) were synthesized in water. Molar enthalpies of dissolution (ΔsolHm) of the compounds in double-distilled water under various molalities were determined at 298.15 K by an RD496-2000 type microcalorimeter. Following Pitzer’s theory, the molar enthalpy of dissolution of the title compounds at infinite dilution (ΔsolHm∞) and Pitzer’s parameters (βMX(0)L and βMX(1)L) were obtained. The values of the title compounds of relative apparent molar enthalpies (ΔsolHϕ), relative partial molar enthalpies (ΔsolHL,2), and relative partial molar enthalpies (ΔsolHL,1) of the solvent at different concentrations c/(mol·L−1) were derived from the experimental values of the enthalpies of dissolution of the compounds, respectively.
Co-reporter:Qi Yang, Sanping Chen, Shengli Gao
Inorganic Chemistry Communications 2009 Volume 12(Issue 12) pp:1224-1226
Publication Date(Web):December 2009
DOI:10.1016/j.inoche.2009.09.026
A crystalline 3D MOF {[Cu5(trz)2(mal)2(fma)(H2O)4]·2H2O}n (1) (trz = 1,2,4-triazolate, mal = malate, fma = fumarate) has been synthesized through hydrothermal method and characterized by X-ray crystallography, IR, elemental analysis and thermal gravimetric analysis. The crystal structure revealed that the fma was partly in situ converted into the mal under hydrothermal conditions and the compound was consisted of a 3D (6, 8)-connected honeycomb-like network. Furthermore, the catalytic performance of compound for the thermal decomposition of ammonium perchlorate (AP) was investigated by DSC. The experiment results indicated that the compound accelerated the decomposition of AP.A new mixed-ligand 3D MOF has been synthesized under hydrothermal conditions, which indicated a (6, 8)-connected honeycomb-like network topology. The results of X-ray crystallography revealed that the fumaric acid as the original reactant in situ converted into malate partly under the hydrothermal conditions.
Co-reporter:Yinli Zhang, Sheng Zhang, Lin Sun, Qi Yang, Jing Han, Qing Wei, Gang Xie, Sanping Chen and Shengli Gao
Chemical Communications 2017 - vol. 53(Issue 21) pp:NaN3037-3037
Publication Date(Web):2017/02/17
DOI:10.1039/C7CC00545H
It is a tremendous challenge to prepare solvent-free dense energetic metal–organic frameworks (EMOFs), hence also to improve their stability and energetic performance. In this study, based on in situ microcalorimetry, an interpenetrating EMOF without solvent molecules, [Cu(tztr)]n (1, H2tztr = 3-(tetrazol-5-yl)triazole) was obtained, possessing high stability (Tdec = 360 °C) and outstanding energetic properties (ΔHdet = 7.53 kcal cm−3, D = 8.429 km s−1, P = 40.02 GPa).
Co-reporter:Qi Yang, Xiaxia Song, Wendou Zhang, Lei hou, Qibing Gong, Gang Xie, Qing Wei, Sanping Chen and Shengli Gao
Dalton Transactions 2017 - vol. 46(Issue 8) pp:NaN2634-2634
Publication Date(Web):2017/01/23
DOI:10.1039/C6DT04439E
Three new energetic complexes, [Pb(bta)(H2O)]n (1), [PbCu(bta)2(H2O)5]·2H2O (2) and PbCu(bta)2 (3) (H2bta = N,N-bis(1H-tetrazole-5-yl)-amine), have been synthesized and characterised. In particular, 3 was readily synthesized by dehydration of 2 at 190 °C. Single crystal X-ray diffraction revealed that 1 has a 3D framework structure and 2 presents a 3D supermolecular architecture. Thermoanalyses demonstrated that the main frames of 1 and 2 have good thermostabilities up to 314 °C for 1 and 231 °C for 2. Non-isothermal kinetic and thermodynamic parameters of exothermic decomposition processes of 1 and 2 were obtained by Kissinger's and Ozawa's methods. Based on the constant-volume combustion energies measured by a precise rotating-bomb calorimeter, the standard molar enthalpies of formation of 1 and 2 were determined. The calculation of the detonation properties of 1 and 2 and the impact sensitivity tests of 1, 2 and 3 were carried out. In addition, 1, 2 and 3 were explored as combustion promoters to accelerate the thermal decompositions of RDX (1,3,5-trinitro-1,3,5-triazine) by differential scanning calorimetry. Experimental results showed that 1, 2 and 3 can be used as HEDMs in the field of combustion promoters and insensitive 2 can be regarded as a safer form for mass storage and transportation than sensitive 3.
Co-reporter:Yaya Feng, Xiangyu Liu, Linqiang Duan, Qi Yang, Qing Wei, Gang Xie, Sanping Chen, Xuwu Yang and Shengli Gao
Dalton Transactions 2015 - vol. 44(Issue 5) pp:NaN2339-2339
Publication Date(Web):2014/12/05
DOI:10.1039/C4DT03131H
A reticular 3D heterometallic metal–organic framework (MOF), [Cu4Na(Mtta)5(CH3CN)]n (1) (N% = 40.08%), has been synthesized, using a 5-methyl tetrazole (Mtta) ligand formed from acetonitrile and azide, through in situ synthesis and structurally characterized by X-ray single crystal diffraction. The fluorescence spectra demonstrate that 1 undergoes an interesting structural transformation in aqueous solution, yielding the compound [Cu4Na(Mtta)5H2O]n (1a) as confirmed by 1H NMR, IR and PXRD. Thermoanalysis showed that 1 possesses excellent thermostability up to 335 °C. The calculated detonation properties and the sensitivity test illustrate that compound 1 could be used as a potential explosive. In addition, the non-isothermal kinetics for 1 were studied using the Kissinger and Ozawa–Doyle methods. The enthalpy of formation was obtained from the determination of the constant-volume combustion energy.
Co-reporter:Hongshan Ke, Sheng Zhang, Xin Li, Qing Wei, Gang Xie, Wenyuan Wang and Sanping Chen
Dalton Transactions 2015 - vol. 44(Issue 48) pp:NaN21031-21031
Publication Date(Web):2015/11/09
DOI:10.1039/C5DT03607K
A Dy2 single-molecule magnet, namely [Dy2(H3L)2(PhCOO)4]·4H2O (1), was obtained from the reaction of Dy(PhCOO)3 with 1,5-bis(2-hydroxy-3-methoxybenzylidene)carbonohydrazide (H4L). Each DyIII ion is located in the chelating pocket [DyO8N] formed by the carboxyl-O, phenol-O, carbohydrazide-O and carbohydrazide-N, forming a tricapped trigonal prism configuration. The DyIII centers are bridged by the benzoate anions with μ2:η1,η2 coordination mode and the phenol-O− groups in the form of μ1:η2, respectively. The appearance of frequency-dependent out-of-phase (χ′′M) signals indicates that 1 displays single-molecule magnet (SMM) behaviour. Fits of the ac data gave an energy barrier (Ueff) of 42.7 K with a pre-exponential factor (τ0) of 1.31 × 10−7 s. The structure–property relationship of some selected Dy2 paradigmatic compounds was further discussed.
Co-reporter:Wenjuan Gao, Xiangyu Liu, Zhiyong Su, Sheng Zhang, Qi Yang, Qing Wei, Sanping Chen, Gang Xie, Xuwu Yang and Shengli Gao
Journal of Materials Chemistry A 2014 - vol. 2(Issue 30) pp:NaN11965-11965
Publication Date(Web):2014/06/03
DOI:10.1039/C4TA01746C
Two energetic compounds, [Pb(Htztr)2(H2O)]n (1) and [Pb(H2tztr)(O)]n (2), were synthesized and then structurally characterized (N% = 39.4% for 1, N% = 27.2% for 2), where Htztr represents 3-(tetrazol-5-yl)triazole. Structural analysis revealed that both compounds have reticular two-dimensional structures. Remarkably, thermogravimetric measurements demonstrated that the compounds possess excellent thermostabilities with high decomposition temperatures up to 340 °C for (1) and 318 °C for (2). The kinetic parameters of exothermic processes were studied by the Kissinger's and Ozawa–Doyle's methods. The standard molar enthalpies of formation were obtained from the determination of constant-volume combustion energies. The calculated detonation properties showed that compound (1) can be used as a potential explosive. Sensitivity tests revealed that the compounds are extremely insensitive. In addition, two compounds were examined for use as additives to promote the thermal decomposition of ammonium perchlorate and hexahydro-1,3,5-trinitro-1,3,5-triazine.
Co-reporter:San-Ping Chen, Yi-Xia Ren, Wei-Tao Wang and Sheng-Li Gao
Dalton Transactions 2010 - vol. 39(Issue 6) pp:NaN1557-1557
Publication Date(Web):2009/12/15
DOI:10.1039/B914879E
The reactions of lanthanide nitrates with 5-nitroisophthalic acid (ab. 5-H2nip) in DMF and ethanol (1:1) mixed solution gave rise to three nanoporous lanthanide polymers, {[Ln2(5-nip)3(DMF)4](DMF)2}n (Ln = Nd (1), Dy (2), Ho (3), 5-nip = 5-nitroisophthalate). Single-crystal X-ray diffraction analyses reveal that they are isomorphous and feature three-dimensional metal–organic frameworks with two-dimensional intersecting channels occupied by guest DMF molecules constructed from the linkage of dimer Ln2C6O12 SBUs and 5-nip ligands. The guest DMF molecules can be reversibly removed from 2 as identified using TGA-DSC and PXRD. The heat of adsorption of the guest-free sample of 2 with DMF was measured with a value of 10.3 kJ mol−1 by an RD496-III type microcalorimeter. In addition, the photoluminescent property of 2 was investigated.
Co-reporter:Xiao-Ni Qu, Sheng Zhang, Bo-Zhou Wang, Qi Yang, Jing Han, Qing Wei, Gang Xie and San-Ping Chen
Dalton Transactions 2016 - vol. 45(Issue 16) pp:NaN6973-6973
Publication Date(Web):2016/03/09
DOI:10.1039/C6DT00218H
A novel Ag(I) energetic MOF [Ag16(BTFOF)9]n·[2(NH4)]n (1) assembled with Ag(I) ions and a furazan derivative, 4,4′-oxybis[3,3′-(1H-5-tetrazol)]furazan (H2BTFOF) was successfully synthesized and structurally characterized, featuring a three-dimensional porous structure incorporating ammonium cations. The thermal stability and energetic properties were determined, revealing that the 3D energetic MOF had an outstanding insensitivity (IS > 40 J), an ultrahigh detonation pressure (P) of 65.29 GPa and a detonation velocity (D) of 11.81 km cm−3. In addition, the self-accelerating decomposition temperature (TSADT) and the critical temperature of thermal explosion (Tb) are also discussed in detail. The finding exemplifies that the assembly strategy plays a decisive role in the density and energetic properties of MOF-based energetic materials.
Co-reporter:Sheng Zhang, Hongshan Ke, Xiangyu Liu, Qing Wei, Gang Xie and Sanping Chen
Chemical Communications 2015 - vol. 51(Issue 82) pp:NaN15191-15191
Publication Date(Web):2015/08/24
DOI:10.1039/C5CC05694B
A 2D oxalate-bridged dysprosium(III) compound, formulated as [Dy(C2O4)1.5(H2O)3]n·2nH2O (1), has been hydrothermally isolated. As for compound 1, structural analysis reveals that the nine-coordinated Dy(III) ions reside in a slightly distorted tricapped trigonal prism. Under an applied magnetic field of 700 Oe, the compound was magnetically characterized as a new example that two slow relaxations of the magnetization processes can be observed in a 2D oxalate-bridged dysprosium(III) layer.
Co-reporter:Xiangyu Liu, Sanping Chen, Thais Grancha, Emilio Pardo, Hongshan Ke, Bing Yin, Qing Wei, Gang Xie and Shengli Gao
Dalton Transactions 2014 - vol. 43(Issue 41) pp:NaN15366-15366
Publication Date(Web):2014/08/14
DOI:10.1039/C4DT02195A
A new azido-Cu(II) compound, [Cu(4-fba)(N3)(C2H5OH)] (4-fba = 4-fluorobenzoic acid) (1), has been synthesized and characterized. The X-ray crystal structure analysis demonstrates that only one crystallographically independent Cu(II) ion in the asymmetric unit of 1 exhibits a stretched octahedral geometry in which two azido N atoms and two carboxylic O atoms locate in the equatorial square, while two ethanol O atoms occupy the apical positions, forming a 1D Cu(II) chain with an alternating triple-bridge of EO-azido, syn,syn-carboxylate, and μ2-ethanol. The title compound consists of ferromagnetically interacting ferromagnetic chains, which exhibit ferromagnetic order (Tc = 7.0 K). The strong ferromagnetic coupling between adjacent Cu(II) ions within each chain is due to the countercomplementarity of the super-exchange pathways, whereas the ferromagnetic interchain interactions – responsible for the long-range magnetic ordering – are most likely due to the presence of coordinated ethanol molecules establishing hydrogen bonds with neighboring chains. DFT calculations have been performed on compound 1 to offer a qualitative theoretical explanation of the magnetic behavior.
Co-reporter:Xiaoni Qu, Lianjie Zhai, Bozhou Wang, Qing Wei, Gang Xie, Sanping Chen and Shengli Gao
Dalton Transactions 2016 - vol. 45(Issue 43) pp:NaN17311-17311
Publication Date(Web):2016/10/03
DOI:10.1039/C6DT03631G
The persistent challenge in the field of energetic materials is how to synthesize energetic compounds with high density, high heat of detonation and outstanding detonation performance by gathering the maximum number of energetic groups in the smallest volume. The self-assembly of energetic groups with metal ions is crucially influenced by the solvent conditions. Here, the reaction of Cu(NO3)2·3H2O with 3-nitro-1H-1,2,4-triazole (Hntz) in aqueous ammonia under hydrothermal conditions via a self-assembly strategy yielded the Cu(I) energetic compound [Cu(ntz)]n (1). In order to further enhance the energetic property, an N3− anion was introduced into the system and two Cu(II) energetic compounds, [Cu(ntz)(N3)(DMF)]n (2) and [Cu(ntz)(N3)(H2O)]n (3), were successfully synthesized under different solvent conditions. Structural analyses show that compound 1 features a compacted 3D structure framework and compounds 2–3 exhibit 1D butterfly-like chain structures. The experimental results reveal that 1 possesses attractive thermal stability up to 315.0 °C and 1–3 present excellent insensitivity. Importantly, the heat of detonation of compound 2 has been factually improved due to the abundant energetic bonds in the coordinated DMF molecules compared to 1 and lots of energies are taken away during the release of the coordinated solvent molecules in the low temperature range resulting in the obvious decreases in detonation pressure and detonation velocity for compounds 2–3, which further exemplifies that the subtle change of reaction conditions may have a crucial effect on the resultant detonation performance. In addition, the detonation performances of 1–3 calculated by both a simple method for metal-containing explosives developed by Pang et al. and the commercial program EXPLO5 v6.01, are discussed in detail.
Co-reporter:Xiangyu Liu, Xiaohui Ma, Peipei Cen, Yuewei Wu, Chengcheng Zhang, Quan Shi, Weiming Song, Gang Xie and Sanping Chen
Dalton Transactions 2017 - vol. 46(Issue 23) pp:NaN7566-7566
Publication Date(Web):2017/05/18
DOI:10.1039/C7DT01338H
Based on two fluoro-substituted phenylacetate isomers, o-fluorophenylacetic acid (o-Hfpa) and p-fluorophenylacetic acid (p-Hfpa), two new Cu(II)-azido compounds, [Cu(o-fpa)(N3)(C2H5OH)]n (1) and [Cu(p-fpa)(N3)(C2H5OH)]n (2), have been prepared, and structurally and magnetically characterized. Single-crystal structure analyses indicate that compounds 1 and 2 consist of 1D chain-like coordination networks in which adjacent copper cations are linked by the alternating triple-bridges of μ-1,1-azido, syn,syn-carboxylate and μ2-ethanol. For the two title compounds, the diverse charge distributions on the carboxyl groups caused by distinct substituent effects of the two phenylacetate coligands lead to the different structural parameters of intrachain Cu–Cu distances (3.218 Å for 1 and 3.168 Å for 2) and Cu–N–Cu angles (106.82° for 1 and 104.81° for 2), further resulting in the disparity of magnetic behaviors. The dominant ferromagnetic couplings between neighbouring Cu(II) ions in the two compounds (J = 87.08 cm−1 for 1, J = 66.05 cm−1 for 2) are due to the counter-complementarity of the multiple superexchange pathways, contributing to the interesting plots of a ferromagnetic order (Tc = 11.0 K for 1, 9.5 K for 2) and slow magnetic relaxation that are rarely observed in most of the reported azido-Cu(II) architectures. Heat-capacity experiments further emphasize the characteristic long-range ferromagnetic ordering in compounds 1 and 2. Magneto-structural relationships of 1 and 2 are investigated as well. Moreover, DFT calculations (using different methods and basis sets) have been performed on both compounds to provide a qualitative and quantitative theoretical explanation of their magnetic behavior.
Co-reporter:Qi Yang, Jing Ge, Xin Liu, Quan Shi, Hongshan Ke, Qing Wei, Gang Xie, Sanping Chen and Shengli Gao
Dalton Transactions 2017 - vol. 46(Issue 6) pp:NaN1884-1884
Publication Date(Web):2017/01/05
DOI:10.1039/C6DT04695A
A new 1D CuII coordination polymer, formulated as {[Cu(TZA)(PNA)]·H2O}n (1) (HTZA = tetrazole-1-acetic acid, HPNA = p-nitrobenzoic acid), was synthesized and structurally characterized. Thermogravimetric analysis demonstrated that the main frame of 1 exhibited good thermostability up to 473 K. The non-isothermal kinetics for the first exothermic process of 1 were studied by Kissinger and Ozawa methods. The magnetic study revealed that 1 possessed antiferromagnetic exchange interactions between CuII ions through the carboxyl-bridge. The low-temperature (1.9 to 300 K) heat capacity of 1 was measured using the heat-capacity option of a Quantum Design Physical Property Measurement System (PPMS). In addition, the thermodynamic functions in the experimental temperature range were derived by fitting the heat-capacity data to a series of theoretical and empirical models. The standard entropy and standard enthalpy of 1 were respectively calculated to be 411.37 ± 4.11 J mol−1 K−1 and 60.21 ± 0.60 kJ mol−1.
Co-reporter:Xiangyu Liu, Feifei Li, Xiaohui Ma, Peipei Cen, Shuchang Luo, Quan Shi, Shenru Ma, Yuewei Wu, Chengcheng Zhang, Zhao Xu, Weiming Song, Gang Xie and Sanping Chen
Dalton Transactions 2017 - vol. 46(Issue 4) pp:NaN1217-1217
Publication Date(Web):2016/12/21
DOI:10.1039/C6DT04108F
Employing two benzoate derivatives with different numbers of non-coordinated fluoro-substituents, 2-fluorobenzoic acid (2-Hfba) and 2,6-difluorobenzoic acid (2,6-Hdfba), two new azido-copper coordination polymers, [Cu(2-fba)(N3)(CH3OH)]n (1) and [Cu(2,6-dfba)(N3)(CH3OH)]n (2), have been successfully isolated, and then structurally and magnetically investigated. Single crystal structure analysis demonstrates that the metal cations in the two resulting compounds are connected by the alternating triple-bridge of μ-1,1-azido, syn,syn-carboxylate and μ2-methanol, contributing to analogously linear 1D Cu(II) chain-like motifs with slightly different intrachain and interchain geometric parameters. The fine-tuned structures lead to variant magnetic properties in the two title compounds. Although a dominant ferromagnetic coupling between adjacent Cu(II) ions within each chain due to the counter-complementarity of the multiple superexchange pathways is observed in both compounds, the interesting plots of magnetic ordering and slow magnetic relaxation, which are rare in most of the reported azido-Cu(II) architectures, only occur in compound 1, while 2 behaves as an antiferromagnet consisting of ferromagnetic Cu(II) chains. The heat-capacity experiments further emphasize the characteristic long-range ferromagnetic ordering in 1 and the typical behavior of antiferromagnets in 2. Moreover, density functional theory (DFT) calculations (using different methods and basis sets) have been performed on both compounds to obtain the qualitatively theoretical interpretation of the magnetic behaviors.
Co-reporter:Chengfang Qiao, Lin Sun, Sheng Zhang, Ping Liu, Liangliang Chang, Chunsheng Zhou, Qing Wei, Sanping Chen and Shengli Gao
Journal of Materials Chemistry A 2017 - vol. 5(Issue 17) pp:NaN4335-4335
Publication Date(Web):2017/04/24
DOI:10.1039/C7TC90068F
Correction for ‘Pore-size-tuned host–guest interactions in Co-MOFs via in situ microcalorimetry: adsorption and magnetism’ by Chengfang Qiao et al., J. Mater. Chem. C, 2017, 5, 1064–1073.
Co-reporter:Chengfang Qiao, Lin Sun, Sheng Zhang, Ping Liu, Liangliang Chang, Chunsheng Zhou, Qing Wei, Sanping Chen and Shengli Gao
Journal of Materials Chemistry A 2017 - vol. 5(Issue 5) pp:NaN1073-1073
Publication Date(Web):2016/12/19
DOI:10.1039/C6TC05082D
Supramolecular interactions are fundamental to host–guest binding in many chemical and biological processes. Based on the direct quantification of such supramolecular interactions within metal–organic frameworks (MOFs), the interactions can be controlled through a flexible structural response to guests. We report a flexible Co-MOF [Co3(OH)2(L)2]·4H2O (1·4H2O, H2L = benzotriazole-5-carboxylic acid), which is liable to undergo structural transformation into [Co3(OH)2(L)2]·EtOH (1·EtOH) by pore breathing. Herein, a new strategy is developed to encapsulate more guest molecules of larger size into the Co-MOF via thermodynamics-directed de novo assembly of metal ions, organic linkers and the expected guest molecules by in situ microcalorimetry. As exemplified by the self-assembly of two N,N-dimethyl formamide (DMF) molecules into a Co-MOF, [Co3(OH)2(L)2]·2DMF (2·2DMF) was solvothermally attained at higher temperature, resulting in the elongation of the crystal unit via the b axis during the reconstruction of the framework and the dramatic change in the Co–O bond length and the Co–O–Co angle. Notably, for 2·2DMF, the calculated Langmuir surface area is nearly 5 times more than those of 1·4H2O and 1·EtOH, in agreement with the result of distorted cavities. Due to the two DMF molecules in the cavity, 2·2DMF displays excellent capability for the capture of Cr(VI) from wastewater by the formation of a new electrostatic interaction between the oxygen of the carbonyl from DMF and Cr(VI). Moreover, the fitting results of magnetic data show that the value of J2 in 2·2DMF is greater than that in 1·4H2O, which implies that ferromagnetic coupling increases. Our observations demonstrate that a detailed understanding of subtle intermolecular interactions between the framework and the guest can be used to induce changes to a different extent in the active (adsorption and magnetism) properties of a supramolecular network.
Co-reporter:Sheng Zhang, Hongshan Ke, Quan Shi, Jangwei Zhang, Qi Yang, Qing Wei, Gang Xie, Wenyuan Wang, Desuo Yang and Sanping Chen
Dalton Transactions 2016 - vol. 45(Issue 12) pp:NaN5320-5320
Publication Date(Web):2016/02/11
DOI:10.1039/C6DT00219F
Three mononuclear dysprosium(III) complexes derived from three β-diketonate ligands, 4,4,4-trifluoro-1-(4-methylphenyl)-1,3-butanedione (tfmb), 4,4,4-trifluoro-1-(4-fluorophenyl)-1,3-butanedione (tffb) and 4,4,4-trifluoro-1-(2-naphthyl)-1,3-butanedione (tfnb) as well as auxiliary ligands, 5-nitro-1,10-phenanthroline (5-NO2-Phen), DMF and 2,2′-bipyridine (bpy) have been synthesized and structurally characterized, namely [Dy(5-NO2-Phen)(tfmb)3] (1), [Dy(DMF)2(tffb)3] (2) and [Dy(bpy)2(tfnb)3]·0.5(1,4-dioxane) (3). The metal ions in 1–3 adopt an approximately square-antiprismatic (SAP) coordination environment with D4d axial symmetry. The magnetic properties of 1–3 have been investigated, displaying weak out-of-phase AC signals under a zero-DC field. With an applied DC field of 1200 Oe, the quantum tunnelling of the magnetization was suppressed in 1–3 with the pre-exponential factor τ0 = 5.3 × 10−7 s and the effective barrier ΔE/kB = 83 K for 1 as well as the pre-exponential factor τ0 = 3.09 × 10−7 s and the effective barrier ΔE/kB = 39 K for 3. Interestingly, for the frequency dependence of the out-of-phase (χ′′) of the AC susceptibility of 2, two slow relaxation of the magnetization processes occurred under the applied magnetic field of 1200 Oe, corresponding to the fast relaxation (FR) phase and slow relaxation (SR) phase, respectively. Arrhenius analysis gave the effective energy barrier (ΔE/kB) of 55 K and the pre-exponential factor (τ0) of 8.23 × 10−12 for the SR. It is thus very likely that the FR process in complex 2 results from QTM enhanced by dipolar interactions between the Dy ions or the presence of the applied field. The structure–property relationship of some Dy(III) based mononuclear SMMs with the SAP configuration was further discussed.
Co-reporter:Sheng Zhang, Haipeng Wu, Lin Sun, Hongshan Ke, Sanping Chen, Bing Yin, Qing Wei, Desuo Yang and Shengli Gao
Journal of Materials Chemistry A 2017 - vol. 5(Issue 6) pp:NaN1382-1382
Publication Date(Web):2017/01/09
DOI:10.1039/C6TC05188J
To fine-tune the magnetic anisotropy and further modulate the magnetic properties and relaxation dynamics of dysprosium(III) single-ion magnets (SIMs), it is crucial to explore their controllable synthesis and conduct a systematic theoretical investigation. Herein, the mononuclear Dy(III) precursor, [Dy(DMF)2(tffb)3] (tffb = 4,4,4-trifluoro-1-(4-fluorophenyl)-1,3-butanedione), as a “metalloligand” towards different capping ligands, affords two new mononuclear Dy(III) complexes in different solvent systems, [Dy(bpy)(tffb)3]·(C4H8O2)1/3 (1) and [Dy(Phen)(tffb)3] (2) (bpy = 2,2′-bipyridine, Phen = 1,10-phenanthroline). Using 4,4,4-trifluoro-1-(4-methylphenyl)-1,3-butanedione (tfmb) as a ligand with the coligand bpy, [Dy(bpy)(tfmb)3] (3) is obtained. In 1,4-dioxane solution, interestingly, complex 3 undergoes a dissolution/reorganization process to transform into 4, [Dy(bpy)(tfmb)3]·0.5C4H8O2. Structural analyses indicate that Dy(III) in 1–4 adopts an approximately square-antiprismatic (SAP) coordination environment with D4d axial symmetry. The magnetic properties of 1–4 are investigated and the M versus H data exhibit evident butterfly-shaped hysteresis loops at 2 K for 1–4. Although all the Dy(III) ions in 1–4 adopt similar configurations, their magnetization dynamics are apparently different from each other, as shown by the various heights of the effective energy barrier (Ueff) of magnetization reversal. To deeply understand their different magnetic behaviours, the magnetic anisotropy of 1–4 is systematically studied by ab initio calculations. The theoretical results further indicate that the capping ligands could play an important role in the fine tuning of the SMM property via an effect on the equatorial electrostatic potential, whereas the inclusion of guest solvent molecules could significantly influence the axial electrostatic potential, leading to a strong effect on the SMM property.
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