Co-reporter:Ran Liu, Zhixia Sun, Xixi Song, Yuzhuo Zhang, Lin Xu, Lu Xi
Applied Catalysis A: General 2017 Volume 544(Volume 544) pp:
Publication Date(Web):25 August 2017
DOI:10.1016/j.apcata.2017.07.020
•The photocurrent density 1.12 mA/cm2 at 1.23 V vs. RHE of TiO2/Co9S8/POM photoanode is among the highest PEC water oxidation photoanodes.•An 8.5-fold improvement in photocurrent density and a 7-fold improvement in maximum photoconversion efficiency could be achieved.•It is the first introduction of Co9S8 into PEC water oxidation system.At present the photoelectrochemical (PEC) water splitting achieves a very high efficiency, but the development of the efficient and inexpensive photoanode materials is still desired for practical application. Herein, we fabricate a composite photoanode consisting of TiO2 nanotube arrays modified with polyoxometalate (POM) and Co9S8, in which POM aims to facilitate charge separation and Co9S8 acts as good electron transport mediator. It is the first introduction of Co9S8 into PEC water oxidation system. Although these three components are all non-precious inorganic materials, the photocurrent density of the TiO2/Co9S8/POM composite photoanode reaches up to 1.12 mA/cm2 at 1.23 V vs RHE under simulated solar light illumination, which is among the highest PEC water oxidation photoanodes. Particularly, the TiO2/Co9S8/POM composite photoanode shows an 8.5-fold improvement in photocurrent density compared to the pristine TiO2 nanotube array photoanode. The measurements of EIS and Mott-Schottky plots revealed that the TiO2/Co9S8/POM composite photoanode held the best efficiency of charge separation and transport at the interface as well as the highest carrier density. The aforementioned results demonstrate a feasible approach to improving the PEC water splitting efficiency by dual modification of TiO2 nanotube arrays with low-cost materials.The TiO2 nanotubes/Co9S8/PW12 composite photoanode shows an 8.5-fold improvement in photocurrent density compared to the TiO2 nanotubes photoanode in the photoelectrochemical water oxidation.Download high-res image (95KB)Download full-size image
Co-reporter:Tianqi Wang, Zhixia Sun, Ya Wang, Ran Liu, Minghui Sun, Lin Xu
Sensors and Actuators B: Chemical 2017 Volume 246(Volume 246) pp:
Publication Date(Web):1 July 2017
DOI:10.1016/j.snb.2017.02.108
•Polyoxometalate doping on SnO2 flower-like nanorods can enhance photoelectric gas sensing performance.•The photoconductivity of the composite was remarkably improved than pure SnO2.•The SnO2/polyoxometalate composite film exhibited effectively gas sensing of formaldehyde and methylbenzene at room temperature.SnO2 has become most popular sensor material because of its excellent optical and electrical properties, but the existence of fast electron-hole recombination in SnO2 material is a critical limitation on developing high-performance gas sensors based on the photoconductive change. Herein, we investigate on polyoxometalate (C4H10ON)23[HN(CH2CH2OH)3]10H2[FeIII(CN)6(α2-P2W17O61CoII)4]·27H2O (abbr. as HPT) doping on SnO2 nanorods for improving gas sensing of formaldehyde and methylbenzene at room temperature (25 °C). The relevant photoconductivity and gas sensing performances demonstrated that the SnO2/HPT composite film had a higher photoconductivity than the pristine SnO2 film. This was attributed to the occurrence of photoinduced electron transfer from SnO2 to HPT, so that the electron-hole recombination in SnO2 could effectively be retarded. Furthermore, the composite film of SnO2/HPT exhibited obvious improvements in photoelectrical gas sensing of formaldehyde and methylbenzene at room temperature. This study represents a new insight into improving the sensing performance of SnO2-based gas sensors by incorporating polyoxometalate.
Co-reporter:Ran Liu, Zhixia Sun, Yuzhuo Zhang, Lin Xu, Na Li
Journal of Physics and Chemistry of Solids 2017 Volume 109(Volume 109) pp:
Publication Date(Web):1 October 2017
DOI:10.1016/j.jpcs.2017.05.018
•POM-modified TiO2 nanotube photoanode was prepared to enhance photoelectric performance.•The mechanism of performance improvement was revealed by EIS.•The efficiency of the cell based on POM/TiO2 nanotube exhibited an improvement of 45%.In this work, we prepared for the first time the TiO2 nanotube arrays (TNAs) photoanode with polyoxometalate(POMs)-modified TiO2 electron-transport layer for improving the performance of zinc phthalocyanine(ZnPc)-sensitized solar cells. The as-prepared POMs/TNAs/ZnPc composite photoanode exhibited higher photovoltaic performances than the TNAs/ZnPc photoanode, so that the power conversion efficiency of the solar cell device based on the POMs/TNAs/ZnPc photoanode displayed a notable improvement of 45%. These results indicated that the POMs play a key role in reducing charge recombination in phthalocyanine-sensitized solar cells, together with TiO2 nanotube arrays being helpful for electron transport. The mechanism of the performance improvement was demonstrated by the measurements of electrochemical impedance spectra and open-circuit voltage decay curves. Although the resulting performance is still below that of the state-of-the-art dye-sensitized solar cells, this study presents a new insight into improving the power conversion efficiency of phthalocyanine-sensitized solar cells via polyoxometalate-modified TiO2 nanotube arrays photoanode.The photoanode combining polyoxometalate with TiO2 nanotube could enhance the photoelectric performance, and the mechanism of performance improvement was revealed by the measurements of electrochemical impedance spectra and open-circuit voltage decay curves.Download high-res image (335KB)Download full-size image
Co-reporter:Miaomiao Zhen, Fengyan Li, Ran Liu, Chunli Song, Lin Xu, X.Z. Luo
Journal of Photochemistry and Photobiology A: Chemistry 2017 Volume 340(Volume 340) pp:
Publication Date(Web):1 May 2017
DOI:10.1016/j.jphotochem.2017.03.021
•The M-G hybrid was fabricated by hydrothermal method.•M-G composite has shown better conversion efficiency as counter electrode than Pt and bare MoS2 in QDSSC.•The fabricated cell shows high efficiency (6.23%) under weak light intensity (25 mW/cm2).MoS2-graphene (M-G) hybrid was prepared by a hydrothermal method and used as counter electrode materials in CdS quantum dot-densitized solar cells (QDSSCs). Under simulated solar light irradiation, the cell with M-G counter electrode has higher efficiency than that of Pt and bare MoS2 counter electrode owing to the synergistic effects between MoS2 and graphene. The electrochemical impedance spectroscopy (EIS) and Tafel-polarization measurements reveal that M-G counter electrodes show better electrocatalytic activity. Moreover, the fabricated cell shows high efficiency (6.23%) under weak light intensity (25 mW/cm2).MoS2-graphene (M-G) hybrid was used as counter electrode materials in quantum dot-densitized solar cells (QDSSCs) and the M-G CEs have higher efficiency than MoS2 or Pt counter electrode.Download high-res image (208KB)Download full-size image
Co-reporter:Jie Bai, Fengyan Li, Zhixia Sun, Zhanbin Jin, Lin Xu
Inorganica Chimica Acta 2017 Volume 458(Volume 458) pp:
Publication Date(Web):24 March 2017
DOI:10.1016/j.ica.2016.12.010
•Three new heteronuclear sandwich-type complexes have been synthesized.•They were synthesized by an innovative “pH-controllable degradation approach”.•Complexes 1 and 3 exhibit catalytic activities for electrocatalytic reduction of nitrate.•Complexes 1–3 demonstrated unusual magnetic properties.Three new heteronuclear [FeW9O34]-based sandwich-type complexes [FeIII2MnII2(H2O)2(FeW9O34)2]12− (1), [FeIII2MnIII2(H2O)2(FeW9O34)2]10− (2) and [FeIII2NiII2(H2O)2(FeW9O34)2]12− (3) have been synthesized by an innovative method of pH-controllable degradation in aqueous solution, in which the [FeW12O40]5− precursor could be predominantly degraded into the trivacant [FeW9O34]11− anion. The active ligand of trivacant [FeW9O34]11− anion can catch in situ the mixed transition metal ions to conduce a directed coordination assembly reaction. These three heteronuclear complexes have been characterized by elemental analysis, single-crystal and powder X-ray diffraction analyses, IR spectra, UV–vis spectra, and thermal gravimetric analysis, cyclic voltammetry, magnetic properties, and thermal gravimetric analysis. Complexes 1 and 3 exhibit obvious catalytic activities for electrocatalytic reduction of nitrate. Compared with 1, the magnetic property of 2 shows a remarkable change by only a conversion of Mn(II) into Mn(III), so that a strong ferromagnetic interaction occurs in 2.Three new heteronuclear [FeW9O34]-based sandwich-type complexes have been synthesized by an innovative method of pH-controllable degradation in aqueous solution, in which the [FeW12O40]5− precursor could be predominantly degraded into the trivacant [FeW9O34]11− anion. The active ligand of trivacant [FeW9O34]11− anion can catch in situ the mixed transition metal ions to conduce a directed coordination assembly reaction.Download high-res image (82KB)Download full-size image
Co-reporter:Zhanbin Jin;Jie Bai;Tingting Wei;Fengyan Li;Chunli Song;Xinze Luo
New Journal of Chemistry (1998-Present) 2017 vol. 41(Issue 22) pp:13490-13494
Publication Date(Web):2017/11/06
DOI:10.1039/C7NJ02104F
A new series of mononuclear lanthanide single molecule magnets based on sandwich-type germanomolybdates, (C4H10ON)8H5[Er(GeMo11O39)2]·14H2O (1), (C4H10ON)8H5[Gd(GeMo11O39)2]·13H2O (2), (C4H10ON)8H5 [Dy(GeMo11O39)2]·15H2O (3), (C4H10ON)8H5[Tb(GeMo11O39)2]·14H2O (4), have been successfully synthesized. Compounds 1–4 are the first examples of the coordination assembly of monolacunary germanomolybdates and heavy rare earth elements, and were structurally characterized by single-crystal X-ray diffraction analyses. The magnetic investigation shows that 1 and 3 exhibit magnetic relaxation behavior in a zero applied dc field, indicative of SMM behavior. Slow magnetic relaxation behavior of 1–4 could be observed in a static magnetic field of 5000 Oe.
Co-reporter:Zhanbin Jin;Jie Bai;Tingting Wei;Fengyan Li;Chunli Song;Xinze Luo
New Journal of Chemistry (1998-Present) 2017 vol. 41(Issue 22) pp:13490-13494
Publication Date(Web):2017/11/06
DOI:10.1039/C7NJ02104F
A new series of mononuclear lanthanide single molecule magnets based on sandwich-type germanomolybdates, (C4H10ON)8H5[Er(GeMo11O39)2]·14H2O (1), (C4H10ON)8H5[Gd(GeMo11O39)2]·13H2O (2), (C4H10ON)8H5 [Dy(GeMo11O39)2]·15H2O (3), (C4H10ON)8H5[Tb(GeMo11O39)2]·14H2O (4), have been successfully synthesized. Compounds 1–4 are the first examples of the coordination assembly of monolacunary germanomolybdates and heavy rare earth elements, and were structurally characterized by single-crystal X-ray diffraction analyses. The magnetic investigation shows that 1 and 3 exhibit magnetic relaxation behavior in a zero applied dc field, indicative of SMM behavior. Slow magnetic relaxation behavior of 1–4 could be observed in a static magnetic field of 5000 Oe.
Co-reporter:Yuzhuo Zhang;Yanju Wang;Zhixia Sun;Fengyan Li;Ran Tao;Zhanbin Jin
Chemical Communications 2017 vol. 53(Issue 14) pp:2290-2293
Publication Date(Web):2017/02/14
DOI:10.1039/C6CC08516D
A large-grained perovskite film, with a crystal grain size of ca. 30–50 μm, was achieved by polyoxometalate-induced Ostwald ripening. Aiming at commercially-oriented fully printable hole-conductor-free perovskite solar cells, the power conversion efficiency of the device was significantly improved from 9.17% to 11.35% (average) via polyoxometalate molecular doping. This is because the large-grained perovskite film could effectively reduce bulk defects and charge recombination, thereby facilitating charge transport.
Co-reporter:Yuzhuo Zhang;Yanju Wang;Zhixia Sun;Fengyan Li;Ran Tao;Zhanbin Jin
Chemical Communications 2017 vol. 53(Issue 14) pp:2290-2293
Publication Date(Web):2017/02/14
DOI:10.1039/C6CC08516D
A large-grained perovskite film, with a crystal grain size of ca. 30–50 μm, was achieved by polyoxometalate-induced Ostwald ripening. Aiming at commercially-oriented fully printable hole-conductor-free perovskite solar cells, the power conversion efficiency of the device was significantly improved from 9.17% to 11.35% (average) via polyoxometalate molecular doping. This is because the large-grained perovskite film could effectively reduce bulk defects and charge recombination, thereby facilitating charge transport.
Co-reporter:Yuzhuo Zhang, Ran Tao, Xuemin Zhao, Zhixia Sun, Yanju Wang and Lin Xu
Chemical Communications 2016 vol. 52(Issue 16) pp:3304-3307
Publication Date(Web):22 Jan 2016
DOI:10.1039/C5CC08628K
A photoconductive perovskite–polyoxometalate composite was prepared for the first time by a facile low-temperature and solution-processed method, and this composite exhibited a significantly enhanced photoconductivity and photodetection performance due to introduction of polyoxometalate into the perovskite for fine energy-level matching and efficient charge transfer.
Co-reporter:Qiao Gao, Fengyan Li, Zhixia Sun, Lin Xu and Minghui Sun
Dalton Transactions 2016 vol. 45(Issue 6) pp:2422-2425
Publication Date(Web):05 Jan 2016
DOI:10.1039/C5DT03748D
Herein, we show a new photomagnetic system that gives rise to the magnetic transformation from diamagnetism to paramagnetism by photoinduced intramolecular charge transfer in the polyoxometalate-based organic–inorganic hybrid, [(VMo6O22)2{O2C(CH2)2CO2}3] (1).
Co-reporter:Minghui Sun, Fengyan Li, Longjiao Yu, Ya Wang and Lin Xu
Dalton Transactions 2016 vol. 45(Issue 6) pp:2417-2421
Publication Date(Web):06 Jan 2016
DOI:10.1039/C5DT04637H
The first Krebs-type tungstoantimonate containing ferrous ions Na2H4[C3H5N2]4[Sb2W20FeII2(H2O)6O70]·12H2O (1) was prepared by a new route of synthesis under mild reaction conditions. The facile synthesis route represented a favourable tactic for the successful synthesis of FeII-based polyoxometalate. Its applications in both catalytic Fenton reaction and electrochemical sensing of ascorbic acid were also investigated primarily.
Co-reporter:Chong Li, Minghui Sun, Lin Xu, Yuchao Wang and Jiawei Huang
CrystEngComm 2016 vol. 18(Issue 4) pp:596-600
Publication Date(Web):17 Dec 2015
DOI:10.1039/C5CE02074C
The first heteropoly blue-embedded metal–organic framework (MOF) compound [Cu3(BTC)2(H2O)3]4[SiW11MoVO40](C4H12N)5·30H2O (BTC = 1,3,5-benzenetricarboxylate) has been synthesized by a one-pot hydrothermal reaction method. The heteropoly blue-based MOFs were characterized by elemental analysis, single-crystal X-ray diffraction, IR spectroscopy, diffuse reflectance UV-vis spectroscopy, magnetic measurement, and thermal gravimetric analysis. Both the diffuse reflectance UV-vis spectra and magnetic study demonstrate that the reduction state of Mo(V) was still retained in the heteropoly blue-based MOFs. The performance in humidity-dependent proton conduction of the compound was also investigated, showing enhanced proton conductivity with increasing humidity; this may find potential applications in proton conductors.
Co-reporter:Zhixia Sun, Yuzhuo Zhang, Na Li, Lin Xu and Tianqi Wang
Journal of Materials Chemistry A 2015 vol. 3(Issue 24) pp:6153-6157
Publication Date(Web):14 May 2015
DOI:10.1039/C5TC00904A
A photoconductive device of phosphotungstic acid (denoted as PW12) and TiO2 composite was fabricated. Compared to pristine TiO2, the composite materials of PW12–TiO2 displayed a remarkable enhancement (ca. 2000-fold) in their photocurrent values. Furthermore, the composite materials also exhibited good gas sensing performance for acetone.
Co-reporter:Lihao Wang, Lin Xu, Ya Wang, Zhongmin Su, Ran Liu
Electrochimica Acta 2015 Volume 155() pp:1-7
Publication Date(Web):10 February 2015
DOI:10.1016/j.electacta.2014.11.114
In this work, we fabricate a ternary nanocomposite photoelectrode consisting of TiO2 nanoparticles, polyoxometalate (P2W18) and copper quantum dots (Cu QDs) so as to create a synergistic effect of the ternary nanocomposite on photovoltaic and photoelectrocatalytic performances. Both the high electron mobility from low cost Cu QDs and the high electro-hole separation efficiency from P2W18 could evidently improve the photoelectrochemical performance of TiO2. Transient photocurrent and current-voltage curves measurements demonstrate that both the photocurrent response and power conversion efficiency of the P2W18/Cu/TiO2 film were markedly enhanced in comparison with that of the only TiO2 film and the P2W18/TiO2 film, respectively. Furthermore, the photoelectrode also exhibited significant photoelectrocatalytic activity for formic acid oxidation. The substitute of copper quantum dots for noble metals in electrode is a favorable innovation for the practical application of photoelectrochemical devices.
Co-reporter:Ya Wang, Ming-Hui Sun, Feng-Yan Li, Zhi-Xia Sun and Lin Xu
Dalton Transactions 2015 vol. 44(Issue 10) pp:4504-4511
Publication Date(Web):26 Jan 2015
DOI:10.1039/C4DT03447C
Two cyanometalate-functionalized heteropolytungstates (C4H10ON)23[HN(CH2CH2OH)3]11H[FeIII(CN)6(α2-P2W17O61NiII)4]·31H2O (1) and (C4H10ON)23[HN(CH2CH2OH)3]10H2[FeIII(CN)6(α2-P2W17O61CoII)4]·27H2O (2) (C4H10ON = morpholine, HN(CH2CH2OH)3 = triethanol amine) have been successfully synthesized in aqueous solution under conventional reaction conditions, which demonstrated that it is a successful strategy to incorporate the cyanometalate fragment into lacunary heteropolytungstates. These polyanions were characterized by single-crystal X-ray diffraction, IR spectra, elemental analysis, thermogravimetric analysis, magnetic studies, and electrochemistry. Interestingly, the electrochemical studies have shown that the two complexes have bifunctional electrocatalytic activities towards not only the reduction of potassium iodate (KIO3) ascribed to the function of POM, but also the oxidation of the biological molecule ascorbic acid (AA) ascribed to the Fe-center in [MII4FeIII(CN)6]5+. Significantly, the magnetic investigations demonstrate the presence of ferromagnetic exchange interactions in 1 (Ni4Fe) and antiferromagnetic interactions in 2 (Co4Fe).
Co-reporter:Miaomiao Liu, Fengyan Li, Zhixia Sun, Lin Xu, Yufei Song and Alexis Munventwali
RSC Advances 2015 vol. 5(Issue 59) pp:47314-47318
Publication Date(Web):19 May 2015
DOI:10.1039/C5RA08149A
An efficient photocatalyst was designed through dual modification of CdS by cobalt polyoxotungstosilic (SiW11Co) and MoS2/graphene (M/G). The activity of CdS is increased up to 21.3 times with 1 wt% SiW11Co and 5 wt% M/G loaded. In the absence of noble metals, the as-prepared sample reached a H2 evolution rate of 1.7 mmol h−1.
Co-reporter:Yuhong Bu, Ran Liu, Miaomiao Zhen, Fengyan Li, Zhixia Sun, Lin Xu
Inorganic Chemistry Communications 2015 Volume 62() pp:34-36
Publication Date(Web):December 2015
DOI:10.1016/j.inoche.2015.10.018
Co-reporter:Miaomiao Liu, Fengyan Li, Zhixia Sun, Lifang Ma, Lin Xu and Yuanhong Wang
Chemical Communications 2014 vol. 50(Issue 75) pp:11004-11007
Publication Date(Web):28 Jul 2014
DOI:10.1039/C4CC04653F
A highly active and stable photocatalyst MoS2–graphene/CdS nanoparticles/nanorods was prepared using a facile two-step hydrothermal method. The noble-metal-free photocatalyst achieved a remarkable quantum yield of 65.8% at 420 nm for photocatalytic H2 evolution from water.
Co-reporter:Tianqi Wang, Zhixia Sun, Fengyan Li, Lin Xu
Electrochemistry Communications 2014 Volume 47() pp:45-48
Publication Date(Web):October 2014
DOI:10.1016/j.elecom.2014.07.029
•It is first proof that POMs can improve the photoelectrochemical performance of SnO2.•The role of PMo12 in SnO2 was revealed by surface photovoltage (SPV) spectroscopy.•The PMo12/SnO2 films displayed the enhanced catalytic activity for methanol.SnO2 has attracted considerable attention due to its excellent photoelectrochemical properties. However, its light-to-electricity conversion in photoelectrochemical devices is still inferior because of the high electron–hole recombination rate. Polyoxometalates (POMs) act as an efficient electron acceptor, which could capture the photogenerated electrons from conduction band of semiconductors and thus retard the electron–hole recombination. Here we study for the first time the effect of polyoxometalate electron acceptor on photoelectrochemical performance of SnO2, and demonstrate that the photocurrent and power conversion efficiency of the SnO2/POMs composite photoanode are markedly enhanced in comparison with that of the pristine SnO2 photoanode. The enhanced photovoltaic performance is attributed to the occurrence of photogenerated electron transfer from SnO2 to POMs; this decreases electron–hole recombination in SnO2. Furthermore, the SnO2/POM photoanode also showed significant photoelectrooxidation activity for methanol, which provides a further support for the functional mechanism of POMs in SnO2. This study presents a new insight into improving the light-to-electricity conversion efficiency of SnO2 by combination with POMs.
Co-reporter:Qiao Gao, Fengyan Li, Minghui Sun, Lin Xu, Yuchao Wang and Jie Bai
CrystEngComm 2014 vol. 16(Issue 33) pp:7681-7688
Publication Date(Web):12 Jun 2014
DOI:10.1039/C4CE00831F
Three multi-copper molybdovanadate cluster compounds [Cu8(OH)2(H2O)2V10Mo30O132]20− (1), {[CuNa(H2O)6][Cu(H2O)4]2[Cu8(OH)2(H2O)2V9Mo30O128]}10− (2), {[Cu0.5Na0.5(H2O)3][Cu(H2O)4]2 [Cu6(OH)2(H2O)2V9Mo23O108]}9.5− (3), containing a novel [VMo7O28]9− fragment, have been isolated by using a one-pot self-assembly method. These three compounds were characterized by elemental analysis, single-crystal X-ray diffraction, IR spectroscopy, UV-vis spectroscopy, cyclic voltammetry, magnetic properties analysis, and thermal gravimetric analysis. The Z-shaped [Cu8(OH)2(H2O)2V9Mo30O128]17− anions of compound 2 can transform into the banana-shaped {Cu6(OH)2(H2O)2V9Mo23O108} units of compound 3 by only changing the pH from 4.5 to 5.0, while the introduction of nitrilotriacetic acid as an assistant ligand ensures the formation of the zero-dimensional compound 1. Magnetic studies indicate the presence of strong antiferromagnetic interactions in compounds 1–3, and the three compounds also exhibit obvious electrocatalytic activities for nitrate reduction. The semiconducting properties of these solid state compounds were revealed from the measurements of the diffuse reflectance UV-vis spectra, in which the band gap values at ca. 2.5 eV are similar to inorganic semiconductor materials, suggesting potential applications in areas of photocatalysis and light-to-electricity conversion.
Co-reporter:Lifang Ma, Fengyan Li, Zhixia Sun, Miaomiao Liu, Yuanhong Wang and Lin Xu
RSC Advances 2014 vol. 4(Issue 41) pp:21369-21372
Publication Date(Web):29 Apr 2014
DOI:10.1039/C4RA01827C
Composite photocatalyst K7HNb6O19–NiS/Cd0.65Zn0.35S is demonstrated to be highly active for H2 evolution under visible light due to the introduction of K7HNb6O19 and NiS as cocatalysts. In the absence of noble metals, a high quantum yield of 42% was achieved at 420 nm.
Co-reporter:Zhixia Sun, Mingliang Zhao, Fengyan Li, Tianqi Wang, Lin Xu
Materials Research Bulletin 2014 60() pp: 524-529
Publication Date(Web):
DOI:10.1016/j.materresbull.2014.09.025
Co-reporter:Fengyan Li, Fanzhi Meng, Lifang Ma, Lin Xu, Zhixia Sun and Qiao Gao
Dalton Transactions 2013 vol. 42(Issue 34) pp:12079-12082
Publication Date(Web):24 Jun 2013
DOI:10.1039/C3DT51057C
The first 3D pure inorganic framework based on heteropolymolybdate anion [V2Mo16O58]10− has been synthesized and its photoelectric properties demonstrated.
Co-reporter:Yuchao Wang, Fengyan Li, Lin Xu, Ning Jiang and Xizheng Liu
Dalton Transactions 2013 vol. 42(Issue 16) pp:5839-5847
Publication Date(Web):25 Jan 2013
DOI:10.1039/C3DT32658F
Four heteropoly blue complexes constructed from Keggin-type heteropoly blue molybdenum–tungsten clusters and Cu(II) ions as linkers, H2[α-SiW10MoV2O40][Cu(PDA)2·H2O]2 (1), H2[α-SiW10MoV2O40][Cu(DEF)3·H2O][Cu(DEF)2·2H2O]·6H2O (2), H2[α-SiW10MoV2O40][Cu(DMF)3H2O]2·6H2O (3), and H4[α-SiW10MoV2O40]2[CuK2(DMF)6][Na0.75K3.25(DMF)6] (4) [PDA = propanediamide, DEF = N,N-diethylformamide and DMF = N,N-dimethylformamide], have been synthesized by conventional reactions and characterized by single-crystal X-ray diffraction, elemental analysis, IR spectroscopy, thermogravimetry, X-ray powder diffraction (XRD) and UV spectra. The amount of Cu(II) and the nature of the ligand (DMF, DEF and PDA) can control both the linkage pattern of Cu(II) ions and the dimensionality of the frameworks; this demonstrates for the first time the possibility to assemble heteropoly blue architectures in different dimensionality ranging from zero-dimensional (0D) to one-dimensional (1D), two-dimensional (2D) and three-dimensional (3D). The magnetic investigation showed that the positive magnetic moment could be observed at room temperature, which should be unusual results in magnetochemistry of the two-electron reduced heteropoly blue. The stability and formation conditions of the four compounds are also discussed.
Co-reporter:Keyu Cui, Fengyan Li, Lin Xu, Yuchao Wang, Zhixia Sun and Honggang Fu
CrystEngComm 2013 vol. 15(Issue 23) pp:4721-4729
Publication Date(Web):08 Apr 2013
DOI:10.1039/C3CE40222C
Three-dimensional (3D) all-inorganic polyoxometalate compounds, Ca2Na6[H2W12O42]·30H2O (1), Sr4H2[H2W12O42]·26H2O (2), Sr4Na2[H2W12O42]·30H2O (3) and Ba4Na2[H2W12O42]·29.5H2O (4) have been synthesized and their structures consist of [H2W12O42]10− building units and alkaline-earth metal cations (Ca2+, Sr2+ and Ba2+) as linkers. The most interesting feature is that compound 2 represents the first example of a 3D all-inorganic framework in which the paradodecatungstate-B anions [H2W12O42]10− were linked by pure alkaline-earth metal cations. Moreover, each [H2W12O42]10− building unit in compound 2 acts as a decadentate ligand coordinated with ten Sr2+ ions, which represents the highest coordination number of [H2W12O42]10− with alkaline-earth metal cations so far. Another interesting feature is that compounds 1–4 exhibit a clear response to surface photovoltage and electric field-induced surface photovoltage, which is indicative of the semiconductor property and suggests these compounds have potential applications as photocatalysts and light-to-electricity conversion materials.
Co-reporter:Yanyan Yang, Lin Xu, Fengyan Li, Xiaoshu Qu
Inorganic Chemistry Communications 2013 Volume 33() pp:142-146
Publication Date(Web):July 2013
DOI:10.1016/j.inoche.2013.04.026
•Both {V10O28} units and {NiMo6O24H6} coexist in one compound.•The self-assembly process of each compound is pH-dependent.•The {V10O28} and {NiMo6O24H6} were linked to form the 1D and 2D structures.•Synthesis of these two complexes by the mild ‘one pot’ aqueous solution method.Two novel complexes [H2N(CH2CH2)2O]4[Na(H2O)2{O(CH2CH2)2NH2}]2[Na(H2O)4]2[V10O28][NiMo6O24H6]·8H2O (1) and [H2N(CH2CH2)2O]6[Na(H2O)3]2[V10O28H2][NiMo6O24H6]·4H2O (2) containing both isopolyvanadate {V10O28} and [NiMo6O24H6]4 − units have been synthesized and structurally characterized for the first time, showing that the pH value of the reaction plays a key role in structure control of self-assembled processes. Compound 1 exhibits a novel one-dimensional (1-D) chain-like structure consisting of Anderson-type [NiMo6O24H6]4 − and isopolyvanadate [V10O28]6 − anions linked by Na+ ions. In compound 2 with the lower pH value, [NiMo6O24H6]4 − and [V10O28H2]4 − anions are bridged by [Na2O10] units to form the 2D extended layer. The magnetic properties of 1 and 2 are presented.Two novel complexes consisting of both {V10O28} and [NiMo6O24H6]4 − units arise from a pH-dependent self-assembly process, in which both {V10O28} and [NiMo6O24H6]4 − anions could be bridged by Na+ ions to form the 1D chain-like and 2D layer structures under lower pH value.
Co-reporter:Zhixia Sun, Shuna Fang, Fengyan Li, Lin Xu, Yiming Hu, Jiaying Ren
Journal of Photochemistry and Photobiology A: Chemistry 2013 Volume 252() pp:25-30
Publication Date(Web):15 January 2013
DOI:10.1016/j.jphotochem.2012.11.007
The improvement of the photoconversion efficiency has become a crucial issue for the utilization of organic semiconductors. Here we prepared a composite film of copper phthalocyanine (CuPc) and polyoxometalates (POMs) which displayed the enhanced photovoltaic performance. Especially, the photocurrent response and power conversion efficiency of CuPc/POMs composite film showed a 6-fold and a 10-fold increase, respectively, as compared to the single CuPc film. Based on the measurements of surface photovoltage technique, the enhanced photocurrent should be attributed to the occurrence of the photoinduced electron transfer between CuPc and POMs, which increases the dissociation of excited electron–hole pairs (excitons). Moreover, the CuPc/POMs composite film exhibited good photoelectrocatalytic performance for the oxidation of hydrazine. These results demonstrate that the incorporating of appropriate POMs into organic semiconductors is a promising route for developing and optimizing organic photovoltaic and photoelectrochemical devices.Graphical abstract.Highlights► A film of copper phthalocyanine (CuPc) and polyoxometalate was prepared. ► The film displays higher photovoltaic performance than only CuPc. ► The polyoxometalate could reduce the electron–hole recombination in CuPc. ► The film exhibits good photoelectrocatalytic performance for hydrazine.
Co-reporter:Jianling Meng, Fengyan Li, Yiming Hu, Lin Xu, Zhixia Sun, Jian Liu
Materials Research Bulletin 2013 48(6) pp: 2111-2116
Publication Date(Web):
DOI:10.1016/j.materresbull.2013.02.013
Co-reporter:Zhixia Sun, Fengyan Li, Mingliang Zhao, Lin Xu, Shuna Fang
Electrochemistry Communications 2013 30() pp: 38-41
Publication Date(Web):
DOI:10.1016/j.elecom.2013.02.006
Co-reporter:Lihao Wang, Lin Xu, Zhongcheng Mu, Chungang Wang and Zhixia Sun
Journal of Materials Chemistry A 2012 vol. 22(Issue 44) pp:23627-23632
Publication Date(Web):24 Sep 2012
DOI:10.1039/C2JM35314H
To explore the synergistic effects of polyoxometalate and noble metal nanoparticles on the photovoltaic performance of titanium dioxide (TiO2), multilayer film photoanodes consisting of TiO2 nanoparticles, gold nanoparticles (Au) and Dawson-type polyoxometalate K6P2W18O62 (abbr. as P2W18) have been prepared by the layer-by-layer self-assembly method, and poly(styrenesulfonate) (PSS) was used as a film forming auxiliary material. These film electrodes were characterized by UV-vis spectra, X-ray photoelectron spectroscopy, atomic force microscopy, and photoelectrochemical measurements. Transient photocurrent and current–voltage curve measurements demonstrate that the photocurrent response and power conversion efficiency increase in the sequence: the TiO2 film < the P2W18/TiO2 film < the TiO2/P2W18/Au film. These results provide valuable information for photovoltaic and photoelectrochemical applications.
Co-reporter:Xinze Luo, Fengyan Li, Bingbing Xu, Zhixia Sun and Lin Xu
Journal of Materials Chemistry A 2012 vol. 22(Issue 30) pp:15050-15055
Publication Date(Web):27 Jun 2012
DOI:10.1039/C2JM16018H
A photovoltaic electrode consisting of polyoxometalate (SiW12) and zinc oxide (ZnO) was fabricated on indium tin oxide (ITO) glass by one-step electrodeposition. The addition of SiW12 strongly influences the morphology and crystallographic orientation of the ZnO. The photovoltaic properties of the ZnO film and the SiW12–ZnO composite films were investigated via solar cell assembly. Both transient photocurrent and current–voltage curve measurements demonstrate that the photocurrent and power conversion efficiency of the SiW12–ZnO composite film were markedly enhanced in comparison with that of the ZnO film. Based on the results of fluorescence quenching measurements, the enhanced photovoltaic effect should be attributed to the occurrence of the photoinduced electron transfer between polyoxometalate and ZnO, which increases the efficient dissociation of excited electron–hole pairs (excitons).
Co-reporter:Fengyan Li, Weihua Guo, Lin Xu, Lifang Ma and Yuchao Wang
Dalton Transactions 2012 vol. 41(Issue 30) pp:9220-9226
Publication Date(Web):22 Jun 2012
DOI:10.1039/C2DT12277D
Two dysprosium-containing tungstoarsenates [C(NH2)3]11[Dy2(Hcit)2(AsW10O38)]·9H2O (1) and K8−nH3−n[Dy3−nKn(H2O)3(CO3)(A-α-AsW9O34)(A-β-AsW9O34)]·22H2O (n = 0 or 1) (2) have been synthesized and characterized by single-crystal X-ray diffraction, elemental analyses, thermogravimetric analyses and infrared spectroscopy. Compound 1 is a citrate-decorated Keggin type di-substituted Ln/POM derivative with the two non-adjacent substituted sites occupied. Compound 2 is composed of two different trivacant Keggin unit isomers [A-α-AsW9O34]9− and [A-β-AsW9O34]9−, linked to each other via one {Dy3−nKn(H2O)3(CO3)}(7 − 2n)+ (n = 0 or 1) unit, where CO32− is encapsulated in the triangle plane, resulting in a stable dysprosium carbonate-containing sandwich-type polyoxoanion with D2h symmetry. The investigation on both static and dynamic magnetic properties of 1 and 2 show that the magnetic relaxation behavior of 2 appear in a static magnetic field of 5000 Oe, while 1 shows no positive out-of-phase ac susceptibility.
Co-reporter:Keyu Cui, Fengyan Li, Lin Xu, Bingbing Xu, Ning Jiang, Yuchao Wang and Jianping Zhang
Dalton Transactions 2012 vol. 41(Issue 16) pp:4871-4877
Publication Date(Web):07 Mar 2012
DOI:10.1039/C2DT11478J
The reaction of Na12[Bi2W22O74(OH)2]·44H2O, Na9[BiW9O33]·16H2O, lanthanide chloride and Na2CO3 in aqueous solution at a pH value of about 7.0 resulted in the three unprecedented giant lanthanide–tungstobismuthate clusters NaxH22−x[(BiW9O33)4(WO3){Bi6(μ3-O)4(μ2-OH)3}(Ln3(H2O)6CO3)]·nH2O {Ln = Pr3+ (1), Nd3+ (2), La3+ (3), x = 22 (1), 22 (2), 20 (3), n = 95 (1), 91 (2), 73 (3)}. These three complexes represent the first examples of lanthanide ions encapsulated in polyoxotungstobismuthates and the largest polytungstobismuthates so far. Furthermore, a [{Bi6(μ3-O)4(μ2-OH)3}]7+ polyoxo cation was incorporated into the structure of these compounds. All complexes are characterized by single-crystal X-ray diffraction, IR spectra, electronic spectroscopy, thermogravimetric and elemental analysis. Magnetic investigation revealed that the progressive depopulation of excited Stark sublevels of the lanthanide ions at low temperature and the weak antiferromagnetic interaction between the neighboring metal centres are responsible for the magnetic properties of 1 and 2. The original synthesis strategy in this work may open a gateway to assembly of large lanthanide–tungstobismuthates clusters and novel multifunctional solid materials in aqueous solution under mild conditions.
Co-reporter:Lan-Jun Yang, Lin Xu, Feng-Yan Li, Yu-Chao Wang, Bing-Bing Xu
Inorganic Chemistry Communications 2012 Volume 15() pp:292-296
Publication Date(Web):January 2012
DOI:10.1016/j.inoche.2011.11.005
A sandwich-type europium-substituted germanomolybdate, H(H2en)5[Cu(en)2] [Eu(GeMo11O39)2]·11H2O (1) (en = ethylenediamine) has been synthesized and structurally characterized by elemental analysis, IR spectroscopy, UV electronic spectroscopy, thermogravimetric analysis and single crystal X-ray diffraction. Complex 1 displays a one-dimensional zigzag chain framework built up from the [Eu(GeMo11O39)2]13− polyanions alternatively linked by [Cu(en)2]2+ cations. The photoluminescence property of solid samples for compound 1 has been investigated, and the spectrum exhibits obvious red fluorescence. The magnetic investigation on complex 1 indicates that the magnetic behavior attributes to a combined effect of depopulation and intermolecular antiferromagnetic interactions.An organic–inorganic hybrid europium-substituted sandwich-type germanomolybdate, H(H2en)5[Cu(en)2] [Eu(GeMo11O39)2]·11H2O (1) (en = ethylenediamine) exhibits a one-dimensional zigzag chain structure formed by the [Eu(GeMo11O39)2]13− polyanions alternatively linked by [Cu(en)2]2+ cations.Highlights► A new organic–inorganic hybrid germanomolybdate exhibits one dimensional chain. ► The luminescence of compound 1 displays obvious red fluorescence. ► The depopulation and intermolecular antiferromagnetism affect the magnetic behavior.
Co-reporter:Zhixia Sun, Fengyan Li, Lin Xu, Shuping Liu, Mingliang Zhao, and Bingbing Xu
The Journal of Physical Chemistry C 2012 Volume 116(Issue 10) pp:6420-6426
Publication Date(Web):February 24, 2012
DOI:10.1021/jp2119982
For exploration of the effects of polyoxometalate on the photoelectrochemical properties of cadmium sulfide (CdS), a composite film of poly(allylamine hydrochloride)-modified CdS (CdS-PAH) and polyoxometalate (K6P2W18O62) has been prepared by the layer-by-layer self-assembly method. The thin film was characterized by UV–vis spectroscopy, infrared spectra, X-ray diffraction, X-ray photoelectron spectroscopy, atomic force microscopy, and scanning electron microscopy. Both photocurrent transient measurement and current–voltage curves displayed that the photocurrent response and power conversion efficiency of the CdS-PAH/P2W18 composite film were markedly enhanced in comparison with those of the single CdS-PAH film. Furthermore, CdS-PAH/P2W18 film exhibited higher photocurrent response intensity than the simple sum of individual components, and polyoxometalate (P2W18) could act as the photoinduced electron transfer shuttle to efficiently suppress electron–hole recombination in CdS. Such a mechanism was further proven by experimental data of fluorescence emission spectra and surface photovoltage spectroscopy. These results demonstrated a new strategy to promote the photocurrent response of CdS via the photoinduced electron transfer from the CdS to P2W18.
Co-reporter:Shuping Liu, Lin Xu, Fengyan Li, Bingbing Xu and Zhixia Sun
Journal of Materials Chemistry A 2011 vol. 21(Issue 6) pp:1946-1952
Publication Date(Web):01 Dec 2010
DOI:10.1039/C0JM02412K
A composite film containing poly(3,4-ethylenedioxythiophene) (PEDOT), polyoxometalate (POM) clusters K6P2W18O62·14H2O (P2W18) and polyallylamine hydrochloride (PAH) was fabricated by a smart combination of layer-by-layer (LbL) with electro-polymerization methods. The composite film displays enhanced electrochromic performance by incorporation of P2W18 into the PEDOT film. The electrochromic property of the film is significantly improved, resulting in an optical contrast of 54.7% at 600 nm and an absorbance that does not change after 1500 cycles. Additionally, the film provides broader absorption throughout the visible region. These results demonstrate the essential role of POMs in improving functionality on PEDOT for applications in electrochromic devices.
Co-reporter:Ning Jiang ; Feng-Yan Li ; Lin Xu ; Li−Li Zhao ;Yu-Chao Wang
Inorganic Chemistry 2011 Volume 50(Issue 4) pp:1544-1550
Publication Date(Web):December 28, 2010
DOI:10.1021/ic102145s
The reaction of the Mn(II) and [Fe(CN)6]3− ions in the presence of morpholine at 90 °C yields a new cyanide-bridged three-dimensional (3D) assembly, showing a ferrimagnetic ordering, frequency-dependent ac susceptibility, and hysteresis loops below 14.8 K. In addition, our feasible route to rationally design and prepare this new molecule-based ferrimagnet promises to provide new 3D cyanide-bridged complexes in the future research.
Co-reporter:Shuping Liu, Lin Xu, Fengyan Li, Weihua Guo, Yan Xing, Zhixia Sun
Electrochimica Acta 2011 Volume 56(Issue 24) pp:8156-8162
Publication Date(Web):1 October 2011
DOI:10.1016/j.electacta.2011.05.131
A nanocomposite film containing polyoxometalates (POMs) cluster K6P2W18O62·14H2O (P2W18), carbon nanotubes (CNTs) and chitosan (CS) was fabricated by layer-by-layer (LbL) methods. The composite material displays enhanced electrochromic performance, with the optical contrast of 20.3% and coloration efficiency of 91.5 cm2 C−1 at 620 nm. Furthermore, the composite material displays the increased thickness and surface roughness by incorporation of CNTs into the P2W18 film. Obviously, the presence of CNTs has the strong influence on the multilayer structure, leading to high optical contrast and coloration efficiency. The results demonstrate the essential role of CNTs in enhancing functionality on POMs for applications of electrochromic devices.Graphical abstractThe optical contrast achieves 20.3% by incorporation of CNTs into the P2W18 films, showing the CNTs could obviously improve the electrochromic performances of POMs-based films.Highlights► The effect of carbon nanotubes on the electrochromic performances of polyoxometalate-based films was investigated in detail. ► The electrochromic performances of the composite material is obviously improved by incorporation of carbon nanotubes into the P2W18 films ► The optical contrast and coloration efficiency achieve 20.3% and 91.5 cm2 C−1, respectively. ► Electrochemically induced oxidation–reduction reaction is related with electrochromism.
Co-reporter:Fengyan Li and Lin Xu
Dalton Transactions 2011 vol. 40(Issue 16) pp:4024-4034
Publication Date(Web):14 Feb 2011
DOI:10.1039/C0DT00691B
Polyoxomolybdates, an important branch in polyoxometalates chemistry, present complicated solution chemistry and unmatched physicochemical properties, which endows us with both great opportunities and considerable challenges in creating new functional materials. This perspective highlights the recent development on the coordination assembly of transition-metal-substituted heteropolymolybdates by using labile lacunary heteropolymolybdates as inorganic multidentate ligands. A series of strategies have been used to stabilize the lacunary heteropolymolybdate building blocks. Finally, we introduce some researches on the modification of polymolybdates by organic groups in aqueous media, which may shed light on the green chemistry of the functionalization of polyoxomolybdates.
Co-reporter:Yuchao Wang, Lin Xu, Ning Jiang, Lili Zhao, Fengyan Li and Xizheng Liu
CrystEngComm 2011 vol. 13(Issue 2) pp:410-413
Publication Date(Web):12 Nov 2010
DOI:10.1039/C0CE00514B
The reaction of polyoxometalate anion [GeW11O39]8− with the complex anion [MoV2O4(H2O)2(ox)2]2− in the presence of CuCl2·2H2O and DMF (DMF = N,N-dimethyl formamide) at 85 °C in aqueous solution produces both a two-dimensional heteropoly blue H2[α-GeW10MoV2O40][Cu(DMF)3H2O]2·5H2O (1) and a three-dimensional heteropoly blue H4[α-GeW10MoV2O40]2 [CuK2(DMF)6] [K4(DMF)6] (2), which demonstrates that different molar ratio of W:Cu in the reaction could conduct different multidimensional structures of 2D and 3D. The magnetic investigation of the two compounds in temperature range from 300 K to 2 K indicated the presence of strong antiferromagnetic interactions related with the two MoV ions in these two compounds.
Co-reporter:Xinze Luo, Lin Xu, Bingbing Xu, Fengyan Li
Applied Surface Science 2011 Volume 257(Issue 15) pp:6908-6911
Publication Date(Web):15 May 2011
DOI:10.1016/j.apsusc.2011.03.029
Abstract
Hybrid film of zinc oxide (ZnO) and tetrasulfonated copper phthalocyanine (TSPcCu) was grown on an indium tin oxide (ITO) glass by one-step cathodic electrodeposition from aqueous mixtures of Zn(NO3)2, TSPcCu and KCl. The addition of TSPcCu strongly influences the morphology and crystallographic orientation of the ZnO. The nanosheets stack of ZnO leads to a porous surface structure which is advantageous to further adsorb organic dyes. The photovoltaic properties were investigated by assembling the DSSC device based on both the only ZnO film and the ZnO/TSPcCu hybrid films. Photoelectrochemical analysis revealed that the optimized DSSC device with TSPcCu represented a more than three-fold improvement in power conversion efficiency than the device without TSPcCu. The DSSC based on ZnO/TSPcCu hybrid films demonstrates an open circuit voltage of 0.308 V, a short circuit current of 90 μA cm−2, a fill factor of 0.26, and a power conversion efficiency of 0.14%.
Co-reporter:Xiaohui Han, ;Fengyan Li ;Ning Jiang
European Journal of Inorganic Chemistry 2011 Volume 2011( Issue 29) pp:4564-4570
Publication Date(Web):
DOI:10.1002/ejic.201100359
Abstract
Based on polyoxometalate cluster anions and macrocations, KH2[Cr3O(OOCCH3)6(H2O)3][α-GeMo12O40]·10H2O (1), K1.5H1.5[Cr3O(OOCCH3)6(H2O)3][α-GeW12O40]·9.5H2O (2), NaH2[Cr3O(OOCCH3)6(H2O)3]3[α-P2W18O62]·32H2O (3), and Na3[Cr3O(OOCCH3)6(H2O)3]3[α-As2W18O62]·34H2O (4) have been prepared by a conventional method and characterized by single-crystal X-ray diffraction, IR and UV/Vis spectroscopy, elemental analysis, thermogravimetric analysis (TGA) and powder X-ray diffraction (PXRD). In addition, the gas adsorption properties of these four compounds for methanol and ethanol have been investigated. The adsorption studies display an apparent difference between methanol and ethanol vapor adsorption and demonstrate that such microporous materials could be applied as new molecular sieves for selective sorption from a mixture of C1 and C2 alcohols.
Co-reporter:Wenju Wang, Lin Xu, Guanggang Gao, Xizheng Liu
Inorganic Chemistry Communications 2011 Volume 14(Issue 4) pp:594-596
Publication Date(Web):April 2011
DOI:10.1016/j.inoche.2011.01.034
An unusual inorganic-organic hybrid based on β-Keggin polyanions and organic cations,[H4tpb]2.5[H2bpe]2[SiMoVI9MoV3O40]2 4H2O(1,tpb = 1,2,3,4-tetrakis-4-pyridinium butane), has been synthesized by hydrothermal method. Complex 1 demonstrates for the first time that the in situ multifunctional tpb ligand possesses chiral carbon atoms and thus opens a new route to the chiral synthesis by achiral precursor under environmentally benign conditions.A polyoxometalate-based supramolecular complex, in which three kinds of 1,2,3,4-tetrakis-4-pyridinium butane (tpb) ligands are found to possess RR, SS, or RS chiral carbon atoms, demonstrates for the first time that the in situ multifunctional tpb ligand has chiral carbon atoms under the presence of polyoxometalate.Research highlights► Both the racemic and the meso tpb ligands coexist in one complex. ► The in situ multifunctional tpb ligand possesses chiral carbon atoms. ► In situ production of chiral carbon atoms is induced by the presence of polyoxometalate. ► Synthesis of the chiral complex by the simple ‘one pot’ hydrothermal method.
Co-reporter:Jianmei Li;Ning Jiang;Lili Zhao;Fengyan Li
Structural Chemistry 2011 Volume 22( Issue 6) pp:
Publication Date(Web):2011 December
DOI:10.1007/s11224-011-9830-z
Two new molybdovanadates, (H3NCH2CH2NH3)3 [Mo6VO22(CH3COO)3]·5H2O (1) and (H3NCH2CH2NH3)2{(Mo6V2O26)[Cu(NH2CH2CH2NH2)(H2O)2]}·4H2O (2), have been synthesized in aqueous solution and characterized by IR, UV–vis, single-crystal X-ray diffraction, thermal gravimetric, elemental analysis, and magnetic analysis. Compound 1 is a crown-shaped ring consisted of six edge-sharing MoO6 octahedra linked to a central {VO4} unit. The MoO6 octahedra are in pairs connected with the carboxylato ligands from three acetic acid molecules. Compound 1 is the first example of a molybdovanadate coordinated by acetic acid molecules. In addition, multipoint hydrogen-bonding interactions exist in 1, which bridge the crown-shaped [Mo6VO22 (CH3COO)3]6− clusters and the protonated ethylenediamine molecules into three-dimensional (3D) networks. The structural feature of compound 2 is the formation of one-dimensional (1D) zip-zag chain in which [Mo6V2O26]6− clusters are covalently bonded to copper coordination groups through the terminal oxygen of the {VO4} tetrahedron. The magnetic investigation on compound 2 demonstrates the possible occurrence of antiferromagnetic interactions by intermolecular linkage.
Co-reporter:Xiaoshu Qu;Yanyan Yang;Fengyan Li;Weihua Guo
Structural Chemistry 2011 Volume 22( Issue 5) pp:965-969
Publication Date(Web):2011 October
DOI:10.1007/s11224-011-9782-3
A novel three-dimensional (3D) supramolecular assembly of Standberg-type polyoxometalate and flexible organic molecule (H2bpp)3[Mo5P2O23]·H2O (1) [bpp = 1,3-bis(4-pyridyl)propane] has been hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction, IR spectra, elemental analysis and thermogravimetric analysis (TGA). X-ray analyses show that compound 1 represent a twofold interpenetrating 3D supramolecular architecture constructed of Standberg-type polyoxometalate and bpp molecular through the hydrogen bonds as well as electrostatic interactions.
Co-reporter:Yaobin Yang, Lin Xu, Fengyan Li, Xiguang Du and Zhixia Sun
Journal of Materials Chemistry A 2010 vol. 20(Issue 48) pp:10835-10840
Publication Date(Web):06 Oct 2010
DOI:10.1039/C0JM01812K
A photovoltaic electrode material consisting of cobalt tetraaminophthalocyanine (CoTAPc) and Dawson-type phosphomolybdate (P2Mo18) was fabricated through the layer-by-layer (LbL) assembly method. The film electrode was characterized by UV–vis spectroscopy, IR spectroscopy, X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and photoelectrochemical measurements. Photovoltaic measurement of the film electrode under light irradiation of 365 nm demonstrated that the P2Mo18/CoTAPc composite film electrode exhibits higher photocurrent and power conversion efficiency (η) than the phthalocyanine-only electrode, furthermore the increased photocurrent of (P2Mo18/CoTAPc/PSS/PAH)5 is not equal to the direct photoresponse addition of P2Mo18 and CoTAPc. Based on the results of fluorescence quenching measurements, the enhanced photovoltaic effect should be attributed to the occurrence of the photoinduced electron transfer between CoTAPc and POM, which increases the efficient dissociation of excited electron–hole pairs (excitons). The present research represents the first example of enhancing the photovoltaic response of organic photovoltaic materials by the assistance of polyoxometalates.
Co-reporter:Weihua Guo, Lin Xu, Fengyan Li, Bingbing Xu, Yaobin Yang, Shuping Liu, Zhixia Sun
Electrochimica Acta 2010 Volume 55(Issue 5) pp:1523-1527
Publication Date(Web):1 February 2010
DOI:10.1016/j.electacta.2009.10.003
A novel chemically modified electrode based on the immobilization of heteropolytungstate in carbon nanotubes–chitosan (CNTs–chitosan) composite film by one step self-assembly technique was fabricated. Chitosan was chosen as a natural polymer for dispersing CNTs to form a stable CNTs–chitosan composite, which provided an interface containing amino groups for assembling [P2W18O62]6− (abbr. P2W18) by electrostatic interactions. The CNTs–chitosan composite film was investigated and characterized by infrared spectroscopy (IR), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The CNT–chitosan film provides a high active area and good conduction pathway, and enhances the adsorptive capability of P2W18 molecules on the film. The electrochemical behavior of the P2W18/CNTs–chitosan/GCE was studied in detail, including scan rate, pH dependence, and stability. The CV and amperometry studies demonstrate that the P2W18/CNTs–chitosan/GCE has fast response and good electrocatalytic activity for the reduction of S2O82− and IO3− anions in acidic aqueous solution.
Co-reporter:Lizhen Liu, Fengyan Li, Lin Xu, Xizheng Liu, Guanggang Gao
Journal of Solid State Chemistry 2010 Volume 183(Issue 2) pp:350-355
Publication Date(Web):February 2010
DOI:10.1016/j.jssc.2009.11.013
Two new polyoxometalate compounds [(CH3)4N]8[Ln(H2O)8]2[(α2-As2W17O61)Ln(H2O)2]2·nH2O (Ln=Er (1), Dy (2)) have been prepared by the trivacant Dawson-type anion [α-As2W15O56]12− and trivalent rare earth ion and characterized by single-crystal X-ray diffraction, IR spectra, thermogravimetric and electrochemical analyses. The centrosymmetric polyoxoanion, {[(α2-As2W17O61)Ln(H2O)2]2}14−, bounded to each other via Ln3+ connecting to terminal W–O oxygen atoms. Furthermore, the polyoxoanions are linked by [Ln(H2O)8]3+ to form an extensive 3D supramolecular network structure depending on hydrogen bond. The magnetic properties of the two compounds have been studied by measuring their magnetic susceptibilities in the temperature range 2.0–300.0 K, indicating the depopulation of the stark components at low temperature and/or very weak antiferromagnetic interactions between magnetic centers. Low-temperature ac magnetic susceptibility measurements reveal a slow magnetic relaxation behavior for 2.Two polyoxometalate compounds [(CH3)4N]8[Ln(H2O)8]2[(α2-As2W17O61)Ln(H2O)2]2·nH2O (Ln=Er (1), Dy (2)) have been prepared. The dynamic magnetic measurements for 2 display a slow relaxation of magnetization, showing a frequency-dependent susceptibility.
Co-reporter:Ning Jiang, Fengyan Li, Lin Xu, Yungao Li, Jianmei Li
Inorganic Chemistry Communications 2010 Volume 13(Issue 3) pp:372-375
Publication Date(Web):March 2010
DOI:10.1016/j.inoche.2009.12.025
Two new polyoxotungstates Na3H(C3H5N2)4[{Cu(C3N2H4)2}2Cu4(H2O)2(GeW9 O34)2]·27H2O (1) and Na10H8[Mn6Ge3W24O94(H2O)2]·37H2O (2) have been synthesized in aqueous solution. The polyoxoanion frameworks of the two compounds are built on the lacunary Keggin-type polyanion [GeW9O34]10−. The structure of compound 1 is a Weakley-type species capped by two [Cu(C3N2H4)2]2+ units through four bridging oxygen atoms on two opposite W4O4 faces. Compound 2 is a banana-shaped polyoxometalate consisting of two tri-Mn substituted [Mn3GeW9O34]4− Keggin units and a hexavacant bridging cluster [GeW6O26]12−. The magnetic investigations demonstrate the presence of both antiferromagnetic and ferromagnetic exchange interactions for 1 and weak antiferromagnetic interactions for 2.Two new polyoxotungstates Na3H(C3H5N2)4[{Cu(C3N2H4)2}2Cu4(H2O)2(GeW9O34)2]·27H2O (1) and Na10H10[Mn6Ge3W24O94(H2O)2]·37H2O (2) have been synthesized. Complex 1 is a Weakley-type species capped by two [Cu(C3N2H4)2]2+ units on two opposite W4O4 faces, which is the first case of the copper(II)–imidazole fragment coordinated with four bridging oxygen atoms from sandwich-type polyoxotungstogermanates. Complex 2 is a banana-shaped POM consisting of two tri-Mn substituted [Mn3GeW9O34]4− Keggin units and a hexavacant bridging cluster [GeW6O26]12−.
Co-reporter:Lili Zhao, Xinze Luo, Lin Xu, Ning Jiang, Fengyan Li, Yungao Li
Inorganic Chemistry Communications 2010 Volume 13(Issue 4) pp:554-557
Publication Date(Web):April 2010
DOI:10.1016/j.inoche.2010.02.003
A new heteropolymolybdate, (Him)8Na7H7[Cu(im)4(CuGeMo9O33)2][(CuGeMo9O33)2]·41H2O (1) (im = imidazole), was synthesized and structurally characterized by elemental analysis, IR spectra, UV electronic spectroscopy and X-ray diffraction. Compound 1 exhibits a one-dimensional chain-like framework [Cu(im)4(CuGeMo9O33)2]10− with isolated [(CuGeMo9O33)2]12− units residing among the chains, which is first observed in sandwich-type germanomolybdate system. Electrocatalytic experiments show that compound 1 exhibits good electrocatalytic activity for nitrite reduction. The magnetic investigation indicates the existence of antiferromagnetic interactions for 1.A new heteropolymolybdate, (Him)8Na7H7[Cu(im)4(CuGeMo9O33)2][(CuGeMo9O33)2]·41H2O (1) (im = imidazole) has been synthesized. The interesting feature of compound 1 is that these sandwich-type polyanions [Cu(im)4(CuGeMo9O33)2]10− are not discrete as their usual fashion but are alternately linked by [Cu(im)4]2+ cations into a one-dimensional chain structure. The polyanions of [(CuGeMo9O33)2]12− alternately located between the parallel one-dimensional chains.
Co-reporter:Yuchao Wang, Lin Xu, Ning Jiang, Xizheng Liu, Fengyan Li, Yungao Li
Inorganic Chemistry Communications 2010 Volume 13(Issue 8) pp:964-967
Publication Date(Web):August 2010
DOI:10.1016/j.inoche.2010.05.008
Co-reporter:Dr. Shu-Jun Li; Shu-Xia Liu;Cong-Cong Li;Dr. Feng-Ji Ma;Dr. Da-Dong Liang;Wei Zhang;Rui-Kang Tan;Yuan-Yuan Zhang ; Lin Xu
Chemistry - A European Journal 2010 Volume 16( Issue 45) pp:13435-13442
Publication Date(Web):
DOI:10.1002/chem.201001963
Abstract
The reactivity of polyoxoniobates has been studied in acidic solution by grafting niobium onto trivacant Keggin-type germanotungstates. Four niobium-containing compounds were obtained in the course of this study. Cs6.5K0.5[GeW9(NbO2)3O37]⋅6H2O (Cs6.5K0.5-1) synthesized by the reaction of K7H[Nb6O19] and A-α-Na10[GeW9034] in H2O2 solution is a tris(peroxoniobium)-substituted A-α-GeW9 derivative. Cs6.5K0.5[GeW9Nb3O40]⋅ 10H2O (Cs6.5K0.5-2) is a peroxo-free compound obtained by eliminating the peroxo groups in 1. Monomers 1 and 2 as precursors can each afford two nanoscale POMs, dimer Cs5[H15Ge2W18Nb8O88]⋅18H2O (Cs5-3) and tetramer Cs8K3H9[Ge4W36Nb16O166]⋅ 27H2O (Cs8K3H9-4), through the formation of NbONb bridges. Disassembly through the cleavage of NbONb bonds from 4 to 2 and 1 was achieved by controlling the pH and by adding H2O2, respectively. The transition from 1 to 2 can be achieved by simply adding H2O2 to a solution of 1. All four compounds were characterized in the solid state by elemental analysis, infrared spectroscopy, thermogravimetry, and single-crystal X-ray diffraction. 183W NMR analysis proved that the solid-state structures of polyanions 1–4 were retained after dissolution. Disassembly from 4 to 1 and 2 in solution was observed by 183W NMR spectroscopy. The UV/Vis spectra of 1 at different pH confirmed that it is stable in the pH range of 0.1–14.0 at room temperature.
Co-reporter:Zhixia Sun, Lin Xu, Weihua Guo, Bingbing Xu, Shuping Liu and Fengyan Li
The Journal of Physical Chemistry C 2010 Volume 114(Issue 11) pp:5211-5216
Publication Date(Web):March 1, 2010
DOI:10.1021/jp910665b
In order to fabricate photoelectrochemical devices, multilayer films composed of positively charged titanium dioxide (TiO2) colloids and anionic tungsto(molybdo)phosphate (PW12 and P2Mo18) or poly(styrenesulfonate) (PSS) have been prepared by the layer-by-layer (LbL) self-assembly method. These films were characterized by UV−vis spectroscopy, IR spectra, and atomic force microscopy. Photocurrent transient measurement suggested that the photocurrent response of the PW12/TiO2 composite film was highly dependent on film thickness (viz., the deposited number of layers). Both current−voltage curves and photocurrent transient measurement demonstrate that the photocurrent and power conversion efficiency of the PW12/TiO2 composite film were markedly enhanced in comparison with that of the P2Mo18/TiO2 film and the PSS/TiO2 film. Furthermore, the PW12/TiO2 composite film also exhibited the most significant photoelectrooxidation activity for methanol. These results provide valuable information for photovoltaic and photoelectrochemical applications.
Co-reporter:Bingbing Xu, Lin Xu, Guanggang Gao, Yaobin Yang, Weihua Guo, Shuping Liu, Zhixia Sun
Electrochimica Acta 2009 Volume 54(Issue 8) pp:2246-2252
Publication Date(Web):1 March 2009
DOI:10.1016/j.electacta.2008.10.030
Co-reporter:Yanyan Wang, Lin Xu, Ning Jiang, Bingbing Xu, Guanggang Gao, Fei Li
Journal of Colloid and Interface Science 2009 Volume 333(Issue 2) pp:771-775
Publication Date(Web):15 May 2009
DOI:10.1016/j.jcis.2009.01.042
Keggin-type heteropolyanion H3PMo12O40 encapsulated by a cationic surfactant dioctadecyldimethylammonium chloride (DODA⋅Cl) has been assembled on ITO substrates using an electrophoretic approach. The films were characterized by atomic force microscopy (AFM), scanning electron microscopy (SEM), IR spectra, X-ray photoelectron spectra (XPS) and cyclic voltammetry. The AFM images exhibit a spherical assembly of surfactant-encapsulated complex (SEC) nanoparticles with uniform size. The SEM was also used to investigate the surface topography. It is the first report that the thin films of SEC are fabricated using this method, which provides a new route to explore the possibility of application to polyoxometalate-based hybrid inorganic–organic materials.SEM images of the SEC colloids assembled as thin films on ITO electrode using (a)–(d) 0.2 mM. (a) A low magnification, face-on SEM image of the films. (b) A high magnification SEM image of (a). (c) A cross-section image of (a). (d) A high magnification SEM image of (c).
Co-reporter:Chris Ritchie, Fengyan Li, Chullikkattil P. Pradeep, De-Liang Long, Lin Xu and Leroy Cronin
Dalton Transactions 2009 (Issue 33) pp:6483-6486
Publication Date(Web):09 Jul 2009
DOI:10.1039/B907410D
Using multifunctional organocations a novel heteropolyanion, [(P4W6O34)2Co2Na2(H2O)2]18−, with unprecedented structural features, has been observed, and extension of these clusters from molecules into 1D chains occurs through a dimeric cobalt species, with this material exhibiting reversible colour/magnetic susceptibility changes upon dehydration.
Co-reporter:Wenju Wang, Lin Xu, Guanggang Gao, Li Liu and Xizheng Liu
CrystEngComm 2009 vol. 11(Issue 11) pp:2488-2493
Publication Date(Web):05 Aug 2009
DOI:10.1039/B903793D
By using both bipyridyl and acyclic amine ligands, two extended inorganic–organic hybrids based on ε-Keggin type of molybdogermanate capped with four nickel(II)-organic cations, [GeMoV8MoVI4O36(µ2-OH)4{Ni(pda)(H2O)}2{Ni(pda)}{Ni(pda)(bpe)}(bpe)0.5]n (1) and [GeMoV8MoVI4O36(µ2-OH)4{Ni(pda)}2{Ni(pda)(bpy)0.5}{Ni(pda)(bpy)}]n · 7nH2O (2) (pda = 1,2-propanediamine, bpe = 1,2-bis(4-pyridine)-ethane, bpy = 4,4′-bipyridine), have been synthesized and structurally characterized, and their magnetic properties have also been investigated at temperatures of 2–300 K. These two compounds represent the first example of ε-Keggin type molybdogermanate clusters employed as an effective building block to construct extended frameworks by the linkage of bidentate organic N-donor ligands, and the inorganic metal–oxygen clusters together with organic N-donor ligands form 1D chain and 2D layered structures.
Co-reporter:YunGao Li, Lin Xu, GuangGang Gao, Ning Jiang, Hong Liu, FengYan Li and YanYan Yang
CrystEngComm 2009 vol. 11(Issue 8) pp:1512-1514
Publication Date(Web):15 May 2009
DOI:10.1039/B820269A
New-type two lanthanide complexes based on a germanotungstate ligand, Na12[Ln4(α(1,4)-GeW10O38)2 (H2O)6]·nH2O (Ln = Dy (1); Er (2)) which contain four trivalent lanthanide ions and two [α(1,4)-GeW10O38]12− units, have been synthesized and structurally characterised, and their magnetic properties have also been investigated. Each lanthanide ion resides in the vacant site of the [α(1,4)-GeW10O38]12− fragment through bonding to five oxygen atoms, four of which are from the WO6 octahedra, while the other one is from the central GeO4 tetrahedron group.
Co-reporter:Yanyan Yang, ;Guanggang Gao;Fengyan Li;Xizheng Liu ;Weihua Guo
European Journal of Inorganic Chemistry 2009 Volume 2009( Issue 11) pp:1460-1463
Publication Date(Web):
DOI:10.1002/ejic.200801133
Abstract
An unexpected ferromagnetically coupled dinuclear manganese(II) linked trivacant heteropolymolybdate [HN(CH3)3]10[Mn2(VVMo9O33)2]·10H2O (1) has been synthesized in aqueous solution and characterized by elemental analysis, IR spectroscopy, thermal gravimetric analysis, and single-crystal X-ray diffraction. A new kind of heteropolymolybdate [VMo9O33]7– anion is shown. The magnetic properties of 1 indicate typical ferromagnetic interactions through the MnII–O–MnII bridge unit.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Co-reporter:Xizheng Liu, Guanggang Gao, Lin Xu, Fengyan Li, Li Liu, Ning Jiang, Yanyan Yang
Solid State Sciences 2009 Volume 11(Issue 8) pp:1433-1438
Publication Date(Web):August 2009
DOI:10.1016/j.solidstatesciences.2009.04.028
Two inorganic polymers constructed from transition metal-substituted heteropolymolybdates, [(CH3)3NH]5n[PMo11MO39]n·xH2O (M = Mn2+, x = n (1); M = Co2+, x = 2n (2)), have been synthesized in aqueous solutions and characterized by IR, TGA, and single-crystal X-ray diffraction analysis. Crystal data: 1, monoclinic, C2/c, a = 17.1322(7) Å, b = 17.6062(7) Å, c = 17.6459(7) Å, β = 103.2220(10)°, V = 5181.5(4) Å3 and Z = 4; 2, triclinic, P-1, a = 12.1986(7) Å, b = 13.0973(7) Å, c = 16.7736(9) Å, α = 97.1810(10)°, β = 98.5040(11)°, γ = 96.3920(10)°, V = 2606.5(2) Å3 and Z = 2. The cyclic voltammograms of 1 and 2 show irreversible redox peaks in DMF solution and there are three reversible couples after addition of 0.1 M H2SO4 aqueous solutions. The cyclic voltammograms of 1/2-modified carbon paste electrode (1-CPE/2-CPE) show two consecutive reversible two-electron redox processes. Especially, 2-CPE shows good electrocatalytic activity toward the reduction of nitrite and hydrogen peroxide. The magnetic properties of the two complexes have also been investigated.Compounds 1 and 2 were synthesized by conventional methods. Both of them exhibit 1D chain structure and similar magnetic behaviors. Compound 2 shows good electrocatalytic activity.
Co-reporter:Wenju Wang, Lin Xu, Guanggang Gao, Fengyan Li, Xizheng Liu, Li Liu
Inorganic Chemistry Communications 2009 Volume 12(Issue 9) pp:875-878
Publication Date(Web):September 2009
DOI:10.1016/j.inoche.2009.07.001
An unprecedented inorganic–organic framework, containing octamolybdate polyoxoanions as 8-connected nodes, defines a new 5,8-connected topology and represents 8-fold interpenetrated srs (SrS2) topological Cu(I)-organic secondary network for the first time. While the free bipy ligand displays weak luminescence in the solid state at room temperature, this compound exhibits an intense yellow radiation emission maximum at λ ≈ 567 nm upon excitation at λ ≈ 365 nm.An unprecedented inorganic–organic framework, containing octamolybdate polyoxoanions as 8-connected nodes, defines a new 5,8-connected topology and represents 8-fold interpenetrated srs (SrS2) topological Cu(I)-organic secondary network for the first time.
Co-reporter:Wenju Wang, Lin Xu, Guanggang Gao, Xizheng Liu, Li Liu
Inorganic Chemistry Communications 2009 Volume 12(Issue 3) pp:259-262
Publication Date(Web):March 2009
DOI:10.1016/j.inoche.2008.12.022
A new inorganic–organic hybrid [{CuII(pda)(H2O)Cu2I(bpy)3}{GeMo12O40]n·2nH2O (1), (pda = 1,2-propanediamine, bpy = 4,4′-bipyridine), was synthesized by hydrothermal method and its structure was determined by X-ray crystallography. The copper(I/II) complex located in 1 shows an unusual meso-helical chain structure. Different intertwined chains further connected with Keggin-type polyoxoanions by covalent Cu–Ot (terminal oxygen atom from polyanion) bonds to form 3D framework. The electrochemical and luminescence properties of 1 were investigated.A new inorganic–organic hybrid [{CuII(pda)(H2O)Cu2I(bpy)3}{GeMo12O40]n·2nH2O was synthesized by hydrothermal method and its structure was determined by X-ray crystallography. The copper(I/II) complex located in 1 shows an unusual meso-helical chain structure, showing synergetic electrochemical and luminescence properties.
Co-reporter:Li Liu, Xiaofeng Wang, Yunling Liu, Lin Xu, Guanghua Li, Lizhen Liu, Wenqin Pang
Inorganica Chimica Acta 2009 Volume 362(Issue 11) pp:4053-4058
Publication Date(Web):15 August 2009
DOI:10.1016/j.ica.2009.05.056
Two new zincophosphites [C6H14N2]0.5[Zn(H2PO3)2] 1 and [C4H12N2]0.5[(CH3)2NH2][Zn2(HPO3)3] 2 have been solvothermally synthesized in mixed solvents of N,N-dimethylformamide (DMF) and 1,4-dioxane (DOA), respectively. Single-crystal X-ray diffraction analysis reveals that compound 1 exhibits a neutral inorganic chain formed by ZnO4 and HPO2(OH) units. Interestingly, the left- and right-handed hydrogen-bonded helical chains are alternately formed via the hydrogen-bonds between two adjacent chains. Compound 2 exhibits a layer structure with 4- and 12-MRs formed by ZnO4 and HPO3 units, in which two kinds of organic amine molecules both act as countercations to compensate the overall negative electrostatic charge of the anionic network.Compound 1 and 2 were solvothermally synthesized in the mixed solvents system. Compound 1 exhibits a neutral inorganic chain with hydrogen-bonded helix. Compound 2 presents a layer structure with 12-MRs.
Co-reporter:Li Liu, Xiaofeng Wang, Lin Xu, Xizheng Liu, Lizhen Liu, Bo Bi, Wenqin Pang
Inorganica Chimica Acta 2009 Volume 362(Issue 10) pp:3881-3884
Publication Date(Web):1 August 2009
DOI:10.1016/j.ica.2009.04.048
A novel fluorinated iron phosphite Fe2(HPO3)F2 (1) has been hydrothermally synthesized and characterized by single-crystal X-ray diffraction. Compound 1 crystallizes in the orthorhombic space group Pnma (No. 51) with a = 7.3458(15) Å, b = 10.038(2) Å, c = 5.4947(11) Å, V = 405.16(14) Å3, Z = 4. Its structure is built up from iron(II) oxygen–fluorine FeO3F3 octahedra and HPO3 pseudo-tetrahedra, giving rise to a 3D inorganic framework. The infinite –Fe–O–Fe–F–Fe– linkage and –Fe–F–Fe– layer in the framework are the noteworthy structural features. Mössbauer spectrum shows the presence of Fe2+ in the octahedral coordination. Magnetic measurements indicate the existence of antiferromagnetic interactions.A novel fluorinated iron phosphite Fe2(HPO3)F2 with the infinite –Fe–F–Fe–O–Fe– linkage and –Fe–F–Fe– layer has been characterized by X-ray crystallography and several other methods. Variable temperature magnetic measurements reveal the existence of antiferromagnetic interactions.
Co-reporter:Yaobin Yang, Lin Xu, Bingbing Xu, Xiguang Du, Weihua Guo
Materials Letters 2009 Volume 63(6–7) pp:608-610
Publication Date(Web):15 March 2009
DOI:10.1016/j.matlet.2008.11.057
New bifunctional nanocomposite films containing water-insolvable cobalt tetraaminophthalocyanine (CoTAPc) and 2:18 tungstophosphate anions (P2W18) were successfully fabricated using the electrostatic layer-by-layer (LbL) assembled method in nonaqueous (DMF) media. UV–vis spectroscopy, IR spectroscopy, X-ray photoelectron spectroscopy, atomic force microscopy (AFM) and electrochemical method were used to characterize the assembled multilayer films. UV–vis measurements revealed regular film growth with each four-layer {P2W18/CoTAPc/PSS/PAH} adsorption. AFM analysis provides the morphology of the multilayer films. The cyclic voltammetric curves indicate that the film shows electrocatalytic activity for chlorate anion.
Co-reporter:Shuping Liu, Lin Xu, Guanggang Gao, Bingbing Xu, Weihua Guo
Materials Chemistry and Physics 2009 Volume 116(Issue 1) pp:88-93
Publication Date(Web):15 July 2009
DOI:10.1016/j.matchemphys.2009.02.054
Electrochromic multilayer films consisting of polyoxometalate (POM) cluster K6[P2W18]·14H2O (P2W18), TiO2 and polyallylamine hydrochloride (PAH) were fabricated on quartz, silicon wafer and ITO substrates by the layer-by-layer self-assembly method. The multilayer films were characterized by UV–vis spectrum, scanning electron microscopy (SEM), cyclic voltammetry (CV) and chronoamperometric (CA) and in situ spectral electrochemical measurements. The interesting feature is that the electrochromic films can increase stability due to the presence of TiO2. The multilayer films exhibit high optical contrast, suitable response time and low operation potential. TiO2 is employed to enhance stability of the electrochromic multilayer films based on POMs by the layer-by-layer method, which gives valuable information for exploring new stable electrochromic materials.
Co-reporter:Shuping Liu, Lin Xu, Guanggang Gao, Bingbing Xu
Thin Solid Films 2009 Volume 517(Issue 16) pp:4668-4672
Publication Date(Web):30 June 2009
DOI:10.1016/j.tsf.2009.02.125
Electrochromic ultrathin films composed of the polyoxometalate cluster K10[P2W17O61]·17H2O (P2W17), polyallylamine hydrochloride (PAH) and Neutral Red (NR) were fabricated on quartz, silicon wafer and indium–tin oxide substrates by the layer-by-layer self-assembly method. The multilayer [P2W17/PAH/P2W17/NR]n films were characterized by UV–vis spectroscopy, scanning electron microscopy, cyclic voltammetry and chronoamperometry and in-situ spectral electrochemical measurements, which exhibited suitable response time, high optical contrast and low operation potential. The monolacunary polyoxometalate-based electrochromic film displays adjustable colors and undergoes transitions from deep pink to light purple, then to dark purple-blue over the potential range from +0.2 V to − 1.0 V. Furthermore, two types of data storage using optical changes of the [P2W17/PAH/P2W17/NR]35 film are proposed. The results provide valuable information for exploring applications in tunable-color electrochromic devices and data-storage devices.
Co-reporter:ChullikkattilP. Pradeep Dr.;MauricioF. Misdrahi;Feng-Yan Li;Jie Zhang Dr. ;De-Liang Long Dr.;Tianbo Liu ;Leroy Cronin
Angewandte Chemie 2009 Volume 121( Issue 44) pp:8459-8463
Publication Date(Web):
DOI:10.1002/ange.200903070
Co-reporter:ChullikkattilP. Pradeep Dr.;MauricioF. Misdrahi;Feng-Yan Li;Jie Zhang Dr. ;De-Liang Long Dr.;Tianbo Liu ;Leroy Cronin
Angewandte Chemie International Edition 2009 Volume 48( Issue 44) pp:8309-8313
Publication Date(Web):
DOI:10.1002/anie.200903070
Co-reporter:Weihua Guo;Bingbing Xu;Yanyan Yang
Journal of Applied Electrochemistry 2009 Volume 39( Issue 5) pp:647-652
Publication Date(Web):2009 May
DOI:10.1007/s10800-008-9704-2
Keggin-type polyoxometalate (H4SiMo12O40) and carbon nanotubes (CNTs) coated by poly(allylamine hydrochloride) (PAH) were alternately deposited on glassy carbon (GC) electrodes by an electrochemical growth method in acidic aqueous solution. The preparation of the film electrode was simple and convenient. Thus-prepared multilayer films and the electrochemical behavior of the composite film modified electrode were characterized by UV–vis spectroscopy and cyclic voltammetry. It was shown that the multilayer films are uniform and stable. The resulting multilayer film modified electrode behaves as an electrochemical sensor because of its low overpotential for the catalytic reduction of S2O82− and NO2− in acidic aqueous solution.
Co-reporter:Yu Liu, Lin Xu, Bingbing Xu, Zhikui Li, Liping Jia, Weihua Guo
Journal of Molecular Catalysis A: Chemical 2009 Volume 297(Issue 2) pp:86-92
Publication Date(Web):14 January 2009
DOI:10.1016/j.molcata.2008.09.007
The liquid phase alkylation of toluene with 1-octene catalyzed by bulk and MCM-41 supported Keggin-type heteropoly acids (HPA), such as tungstophosphoric acid (HPW), tungstosilicic acid (HSiW), and molybdophosphoric acid (HPMo), has been studied. Among these catalysts, the supported catalysts exhibited more activity than bulk HPA, especially, HSiW and HPW supported on MCM-41 (HSiW/MCM-41 and HPW/MCM-41). The conversion of 1-octene was 100% and selectivity for monoalkylation products was 99.9% after 2 h of reaction at 120 °C over HSiW/MCM-41. The studies of FT-IR, thermogravimetric analyses (TGA) and X-ray diffraction (XRD) confirmed the presence and high dispersion of HPA on MCM-41 mesoporous structure. We also examined the reusability of the supported catalysts. The catalysts retained their catalytic activity for five reaction times in the present study. These results indicate that HSiW/MCM-41 and HPW/MCM-41 are excellent catalysts for this reaction under mild conditions.The liquid phase alkylation of toluene with 1-octene catalyzed by bulk and MCM-41 supported Keggin-type heteropoly acids (HPA), has been studied. The supported catalysts exhibit excellent activity and reusability. The conversion of 1-octene was 100% and selectivity for monoalkylation products was 99.9% after 2 h of reaction at 120 °C.
Co-reporter:Hong Liu, Chao Qin, Yong-Ge Wei, Lin Xu, Guang-Gang Gao, Feng-Yan Li and Xiao-Shu Qu
Inorganic Chemistry 2008 Volume 47(Issue 10) pp:4166-4172
Publication Date(Web):April 15, 2008
DOI:10.1021/ic7022264
Two sandwich-type complexes Na9n(Cu(im)4(H2O)2)1.5n(Cu(im)4(H2O))n [{Cu(im)4}{Na(H2O)2}3{Cu3(im)2(H2O)}(XW9O33)2]2n·(xH2O)n (im = imidazole, X = Bi (1), Sb (2), x = 42.5 (1), 40 (2)) have been synthesized and structurally characterized. Basic frameworks of 1 and 2 are built from sandwich-type [{Na(H2O)2}3{Cu3(im)2(H2O)}(XW9O33)2]9− (X = Bi or Sb) anions and [Cu(im)4]2+ cations. The Cu2+ and Na+ ions in the central belt are coordinated by α-[XW9O33]9− units, im, and water molecules to form {CuO4(im)}, {CuO4(H2O)}, and {NaO4(H2O)2} groups in which Cu2+ ions are partially modified with im ligands. These groups connect alternately forming a six-membered ring including six α-[XW9O33]9− units. Neighboring anions are further linked by [Cu(im)4]2+ cations to display an unprecedented anionic chain, which is first observed in sandwich-type tungsto-bismuthate (-antimonite) system. Two kinds of isolated copper complexes and sodium ions are located as counterions, which cause three-dimensional packings of 1 and 2 to present interesting cage structures. The magnetic properties for 1 and 2 both indicate dominant antiferromagnetic interactions among trinuclear Cu(II) clusters.
Co-reporter:Guang-Gang Gao ; Lin Xu ; Xiao-Shu Qu ; Hong Liu ;Yan-Yan Yang
Inorganic Chemistry 2008 Volume 47(Issue 8) pp:3402-3407
Publication Date(Web):March 5, 2008
DOI:10.1021/ic7025126
The reaction of molybdates with multicarboxylic ligands resulted in the crystalline materials of [Na8(MoVI10O32EDTA)(H2O)35]n (1) and (NH4)8n[MoVI10O32PDTA]n(H2O)30n (2) (EDTA = 1,2-diaminoethanetetraacetate; PDTA = 1,3-diaminopropanetetraacetate). In the two compounds, decamolybdate clusters are covalently linked by multicarboxylic ligands to form unusual meso-helical chains. For the first time, the synthesis of an organopolyoxometalate polymer is realized in aqueous media, which opens a green chemical approach to the fabrication of polyoxometalate-based polymers. The photochromic properties of 1 in the poly(vinyl alcohol) film displayed reddish-brown coloration upon UV irradiation, providing a new coloration material for photochromic films.
Co-reporter:Guang-Gang Gao ; Lin Xu ; Wen-Ju Wang ; Xiao-Shu Qu ; Hong Liu ;Yan-Yan Yang
Inorganic Chemistry 2008 Volume 47(Issue 7) pp:2325-2333
Publication Date(Web):February 23, 2008
DOI:10.1021/ic700797v
New Keggin-type cobalt(II)/nickel(II)-centered heteropolymolybdates, (C3H5N2)6[CoIIMo12O40]·10H2O (1) and (NH4)3(C4H5N2O2)3[NiIIMo12O40] (2), were isolated and characterized by IR, UV–vis, single-crystal X-ray diffraction, thermogravimetric, magnetic, as well as electrochemical analyses. The polyanion in the two compounds displays the well-known α-Keggin structure, which is composed of four Mo3O13 units formed by edge-sharing octahedra. Four Mo3O13 units connect each other by vertices, and the Co2+ or Ni2+ is located in the center. Magnetic measurements show that the central Co2+ and Ni2+ are in high spin states (with S = 3/2 and S = 1, respectively) exhibiting paramagnetic behaviors. Cyclic voltammetric experiments for 1 represent a quasi-reversible one-electron redox Co3+/Co2+ couple and two four-electron reversible redox processes ascribed to Mo centers, while 2 only shows two four-electron redox processes attributed to Mo centers in pH = 0.5 H2SO4 solution.
Co-reporter:Jianfang Cao, Shuxia Liu, Ruige Cao, Linhua Xie, Yuanhang Ren, Chaoying Gao and Lin Xu
Dalton Transactions 2008 (Issue 1) pp:115-120
Publication Date(Web):23 Oct 2007
DOI:10.1039/B713275A
A series of organic–inorganic hybrid compounds, K2H7[{Ln(PW11O39)2}{Cu2(bpy)2(μ-ox)}]·xH2O (Ln = La, x≈ 18 (1); Ln = Pr, x≈ 18 (2); Ln = Eu, x≈ 16 (3); Ln = Gd, x≈ 22 (4); Ln = Yb, x≈ 19 (5); bpy = 2,2′-bipyridine and ox = oxalate), have been isolated by the conventional solution method. Single-crystal X-ray diffraction studies reveal that compounds 1–5 are isomorphic and consist of one-dimensional chains, which are constructed by alternating bis(undecatungstophosphate) lanthanates [Ln(PW11O39)2]11− and dinuclear copper(II)–oxalate complexes [Cu2(bpy)2(μ-ox)]2+. π–π interactions of the bpy ligands from adjacent chains lead to their three-dimensional structures. An analogue of potassium K2H9[{K(PW11O39)2}{Cu2(bpy)2(μ-ox)}]·∼20.5H2O (6) has also been obtained. The syntheses and structures of these compounds are reported here. Magnetic properties of 1, 2 and 3 are discussed as well. Attempts to crystallize similar compounds containing Co(II) and Ni(II) were unsuccessful.
Co-reporter:Bingbing Xu, Lin Xu, Guanggang Gao, Zhikui Li, Yu Liu, Weihua Guo and Liping Jia
New Journal of Chemistry 2008 vol. 32(Issue 6) pp:1008-1013
Publication Date(Web):21 Apr 2008
DOI:10.1039/B801764F
Materials capable of gasochromic behavior are still rare. In this paper, amorphous gasochromic hybrid silica material containing phosphomolybdic acid (PMo12) is prepared by the sol–gel technique. The structure and properties of the material are investigated by cyclic voltammetry, thermal gravimetric analysis, FT-IR spectra, X-ray diffraction, UV-Vis spectra and X-ray photoelectron spectra. The structural integrity of phosphomolybdic acid has been preserved after incorporation into the porous silica framework. Furthermore, the PMo12–SiO2 hybrid material shows sensing activity for H2S and SO2 gases at room temperature based on the color change.
Co-reporter:Hong Liu, Lin Xu, Guanggang Gao, Fengyan Li, Ning Jiang
Journal of Molecular Structure 2008 Volume 878(1–3) pp:124-130
Publication Date(Web):30 April 2008
DOI:10.1016/j.molstruc.2007.08.015
Two novel sandwich-type coordination compounds of tungstobismuthate Na9[{Na(H2O)2}3{CoII(mim)}3(BiIIIWVI9O33)2]·36H2O (1) and Na7H2[{Na(H2O)2}3{MnII(mim)}3(BiIIIWVI9O33)2]·21H2O (2) (mim = 1-methylimidazole) have been synthesized in alkaline aqueous solution. Their composition and structures were established by elemental analyses, IR spectra, and single crystal X-ray diffraction. These two complexes consist of two tri-vacant [α-B-BiIIIWVI9O33]9− moieties linked through three CuII or MnII and three Na+ ions. These Na+ cations around the complex anion were bonded with some terminal and bridging oxo atoms from the complex anion and water molecules. In addition to tungstobismuthate ligands, 1-methylimidazoles also coordinate to sandwich transitional metal ions. Magnetic measurement indicates the existence of antiferromagnetic interaction between the trimeric transitional metal ions for 1 and 2.
Co-reporter:Xiaocui Wei, Youzhi Fu, Lin Xu, Fengyan Li, Bo Bi, Xizheng Liu
Journal of Solid State Chemistry 2008 Volume 181(Issue 6) pp:1292-1297
Publication Date(Web):June 2008
DOI:10.1016/j.jssc.2008.02.030
A new polyoxometalate anion-pillared layered double hydroxide (LDH) was prepared by aqueous ion exchange of a Mg-Al LDH precursor in nitrate form with the tungstocobaltate anions [CoW12O40]5−. The physicochemical properties of the product were characterized by the methods of powder X-ray diffraction, elemental analysis, infrared spectroscopy, thermogravimetric analysis and cyclic voltammetry. It was confirmed that [CoW12O40]5− was intercalated between the brucite-type layers of the LDHs without a change in the structure. Magnetic measurement shows the occurrence of antiferromagnetic interactions between the magnetic centers. The investigation of catalytic performance for this sample exhibits high activity for the oxidation of benzaldehyde by hydrogen peroxide.A tungstocobaltate anion [CoW12O40]5− pillared layered double hydroxide (LDH) was prepared by aqueous ion exchange with a Mg-Al LDH precursor in nitrate form, demonstrating that [CoW12O40]5− was intercalated between the brucite-type layers of the LDHs without change in structure. Magnetic measurement shows the occurrence of antiferromagnetic interactions between the magnetic centers. The investigation of catalytic performance for this sample exhibits high activity for the oxidation of benzaldehyde by hydrogen peroxide.
Co-reporter:Xizheng Liu, Xiaocui Wei, Lin Xu, Guanggang Gao, Fengyan Li
Inorganic Chemistry Communications 2008 Volume 11(Issue 11) pp:1313-1315
Publication Date(Web):November 2008
DOI:10.1016/j.inoche.2008.08.010
A new complex based on decatungstophosphate and chelated copper atoms, [Hen][Cu(en)2(H2O)]2 · {[Cu(en)2(H2O)] · [γ-PW10O36]} · 9H2O (1) (en = ethylenediamine) has been synthesized by conventional methods and characterized by single crystal X-ray diffraction, IR spectra and electronic spectra. The structure analysis of 1 indicates that the complex contains a divacant polyanion [γ-PW10O36]7− connected with a chelated copper atom. Magnetic susceptibility measurement for 1 in the temperature range 2–300 K reveals the occurrence of intermolecular antiferromagnetic interactions between chelate copper (II) complexes at lower temperature.A new complex based on decatungstophosphate and chelated copper atoms, [Hen][Cu(en)2(H2O)]2 · {[Cu(en)2(H2O)] · [γ-PW10O36]} · 9H2O (1) (en = ethylenediamine) was structurally characterized by single crystal X-ray diffraction, and the polyoxoanions [γ-PW10O36]7− was connected with chelate copper complex.
Co-reporter:Ning Jiang, Lin Xu, Fengyan Li, Guanggang Gao, Lihua Fan
Inorganic Chemistry Communications 2008 Volume 11(Issue 1) pp:24-27
Publication Date(Web):January 2008
DOI:10.1016/j.inoche.2007.10.008
A novel sandwich-type polyoxometalate built on the lancunary Keggin-type polyanion [GeW11O39]8− and trivalent rare earth ion, K11.5H1.5[Pr(GeW11O39)2] · 29H2O (1) has been synthesized and characterized by IR spectroscopy, UV electronic spectroscopy, luminescence spectroscopy, cyclic voltammetry and single crystal X-ray diffraction. This is the first report of crystal structure for the sandwich Keggin-type polyoxotungstogermanate containing lanthanide. In compound 1, PrIII cation sandwiched between two [GeW11O39]8− anions is of eight coordination and occupies square anti-prismatic geometry. The magnetic investigation of compound 1 demonstrate the presence of an antiferromagnetic interaction in 1.A new sandwich-type lanthanide polyoxometalate K11.5H1.5[Pr(GeW11O39)2] · 29H2O (1), which is assembled by the lancunary Keggin-type polyanion [GeW11O39]8− and trivalent lanthanide cation, and PrIII cation sandwiched between two [GeW11O39]8− anions is of eight coordination and occupies square anti-prismatic geometry.
Co-reporter:Xiaoshu Qu;Yanyan Yang;Fengyan Li;Weihua Guo;Liping Jia
Structural Chemistry 2008 Volume 19( Issue 5) pp:801-805
Publication Date(Web):2008 October
DOI:10.1007/s11224-008-9367-y
A novel three-dimensional (3-D) supramolecular assembly of organic bicapped heptamolybdate Na(NH4)[C13N2H16]2[Mo7O24]·8H2O has been hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction, IR spectra, elemental analysis, and thermogravimetric analysis (TGA). X-ray analyses show that compound 1 represent a novel 3-D extended supramolecular “host” networks with 1-D channels encapsulating flexible cation “guests”.
Co-reporter:Fengyan Li, Lin Xu, Guanggang Gao, Xiaosu Qu and Yanyan Yang
Dalton Transactions 2007 (Issue 17) pp:1661-1664
Publication Date(Web):22 Mar 2007
DOI:10.1039/B701346A
The first O,O′-bonded metal-stabilized sulfinate has been isolated and structurally characterized to show a novel one-dimensional chain structure containing both the enantiomers of the subunit Mn(2-sinic)(DMSO)2.
Co-reporter:Yanyan Yang;Guanggang Gao;Fengyan Li;Yunfeng Qiu;Xiaoshu Qu;Hong Liu
European Journal of Inorganic Chemistry 2007 Volume 2007(Issue 17) pp:
Publication Date(Web):9 MAY 2007
DOI:10.1002/ejic.200600519
Two novel heteropolymolybdates, [(CH3)4N]8n[M(H2O)5]2n(H3O)2n[{M(H2O)5}2(MAsVMo9O33)2]n[M(H2O)4(MAsVMo9O33)2]n·20nH2O (M = Mn2+, 1; M = Co2+, 2), constructed from the new fragment (AsVMo9O33)7– and a transition metal have been synthesized in aqueous solution and characterized by elemental analysis, IR spectroscopy, thermal gravimetric analysis, and single-crystal X-ray diffraction. Structurally the title complexes resemble a sandwich-type complex because they involve the coordination of two transition metals to two [AsVMo9O33]7– fragments, which derive from the well-known B-β-Keggin structure. Compounds 1 and 2 exhibit a one-dimensional chain-like framework [M(H2O)4(MAsVMo9O33)2]8n– with isolated {[M(H2O)5]2(MAsVMo9O33)2}6– units residing among the chains. The magnetic properties of the two complexes were investigated to indicate typical antiferromagnetic interactions through the MnII–O–MnII bridge unit for complex 1 and the CoII–O–CoII bridge unit for complex 2. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Co-reporter:Feng-Yan Li;Guang-Gang Gao;Li-Hua Fan;Bo Bi
European Journal of Inorganic Chemistry 2007 Volume 2007(Issue 21) pp:
Publication Date(Web):5 JUN 2007
DOI:10.1002/ejic.200601113
A new lanthanide citrate coordination polymer [Dy(citrate)(H2O)]n (1) was hydrothermally synthesized and structurally characterized by elemental analyses, single-crystal X-ray diffraction, IR spectroscopy, thermogravimetric analysis, photoluminescence spectrum, and magnetic measurements. The structure of 1 exhibits a 2D layer structure, in which the Dy2O2 dimer serves as the building block. The photoluminescence spectrum shows blue luminescence in the solid state at room temperature. Owing to the special frustration structure, unusual magnetic relaxation was found in compound 1. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Co-reporter:Hong Liu, Lin Xu, Guang-Gang Gao, Feng-Yan Li, Yan-Yan Yang, Zhi-Kui Li, Yu Sun
Journal of Solid State Chemistry 2007 Volume 180(Issue 5) pp:1664-1671
Publication Date(Web):May 2007
DOI:10.1016/j.jssc.2007.03.011
Reaction of Keggin polyoxotungstate with copper(II)–EDTA (EDTA=ethylenediamine tetraacetate) complex under mild conditions led to the formation of hybrid inorganic–organic compounds Na4(OH)[(Cu2EDTA)PW12O40]·17H2O (1) and Na4[(Cu2EDTA)SiW12O40]·19H2O (2). The single-crystal X-ray diffraction analyses reveal their two structural features: (1) one-dimensional chain structure consisting of Keggin polyoxotungstate and copper(II)–EDTA complex; (2) Two-dimensional layer architecture assembled by the one-dimensional chain structure and sodium linker. The results of magnetic measurements in the temperature range 300–2 K indicated the existence of ferromagnetic exchange interactions between the CuII ions for both compounds. In addition, TGA analysis, IR spectra, and electrochemical properties were also investigated to well characterize these two compounds.Two new polyoxometalate-based hybrids, Na4(OH)[Cu2(EDTA)PW12O40]·17H2O (1) and Na4[Cu2(EDTA)SiW12O40]·19H2O (2), have been synthesized and structurally characterized, which consist of one-dimensional chain structure assembled by Keggin polyoxotungstate and copper(II)–EDTA complex. The chains are further connected to form two-dimensional layer architecture assembled by the one-dimensional chain structure and sodium linker.
Co-reporter:Yanyan Yang;Liping Jia;Fengyan Li;Xiaoshu Qu;Yunfeng Qiu;Guanggang Gao
Crystal Research and Technology 2007 Volume 42(Issue 10) pp:1036-1040
Publication Date(Web):20 JUN 2007
DOI:10.1002/crat.200710937
A supramolecular compound, [Himi]6[As2Mo18O62]·11H2O (1) (imi = imidazole), has been synthesized and characterized by single crystal X-ray analysis, IR spectra, thermal gravimetric analysis, electrochemical and elemental analysis. The crystals are monoclinic, P 2(1)/n, a = 14.9529(8) Å, b = 20.9521(11) Å, c = 25.2464(13) Å, β = 93.8130(10)°, V = 7892.1(7) Å3, Z = 4. X-ray diffraction indicated that protonated imidazole cation and polyanion were linked together through electrostatic interactions and intermolecular forces (hydrogen bonding). (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
Co-reporter:Yang Cui;Wen-Ju Wang;Guang-Gang Gao;En-Bo Wang
Chinese Journal of Chemistry 2006 Volume 24(Issue 3) pp:
Publication Date(Web):13 MAR 2006
DOI:10.1002/cjoc.200690060
The electrochemical behavior of monomolybdenum-substituted Keggin-type polyoxometalates [XW11MoO40]n− (X=P, Si, Ge with n=3, 4) was studied in aqueous and N,N-dimethylformamide (DMF) solution. These anionic clusters showed different electrochemical behaviors in two kinds of media. The initial potentials of [XW11MoO40]n− in DMF were more negative than those in aqueous solution, showing a lower oxidation ability of [XW11MoO40]n− in DMF. The investigation results suggested that the redox properties of polyoxometalates be tuned by the substitutions of Mo for W and by replacing aqueous solution with organic solvent, which provided valuable information to rationally choose polyoxometalates (POM) in preparation of POM-based organic/inorganic hybrid materials.
Co-reporter:Yunfeng Qiu, Lin Xu, Guanggang Gao, Wenju Wang, Fengyan Li
Inorganica Chimica Acta 2006 Volume 359(Issue 2) pp:451-458
Publication Date(Web):20 January 2006
DOI:10.1016/j.ica.2005.07.020
A novel bifunctionalized arylimido derivative of hexamolybdate, (Bu4N)2[Mo6O17(NAr)2] [Ar = 2,6-(CH3)2C6H3] (1), in which the two 2,6-dimethylaniline groups are bounded to hexamolybdate at the cis positions, was synthesized by a facile reaction of α-octamolybdate with 2,6-dimethylaniline using DCC as a dehydration agent. The existence of strong non-typical C–H⋯O hydrogen bonds plays an important role in crystal structure stabilization of compound 1. The results of fluorescence spectra show that the formation of a covalent bond between 2,6-dimethylaniline molecule and hexamolybdate could efficiently quench the fluorescence intensity of 2,6-dimethylaniline molecule, with a fluorescence quencher efficiency of 87.7%. Thermal analysis results indicate that two substituted 2,6-(CH3)2C6H3 molecules bonding to the same cluster dissociated at different temperature, in well agreement with the different MoN bond length in compound 1. The electrochemical behavior of modified 1-CPE has been studied in detail. Compared with the conventional polyoxometalate (POM)-modified electrode, 1-CPE presents a merit of remarkable stability over 500 cycles due to the insolubility of the POM nanoparticles, which is especially important for practical applications.A arylimido derivative of hexamolybdate, (Bu4N)2[Mo6O17(NAr)2] [Ar = 2,6-(CH3)2C6H3] (1), was synthesized by a facile reaction of α-octamolybdate with 2,6-dimethylaniline. The existence of strong non-typical C–H⋯O hydrogen bonds plays an important role in crystal structure stabilization and the formation of a covalent bond between 2,6-dimethylaniline molecule and hexamolybdate could efficiently quench the fluorescence intensity of 2,6-dimethylaniline molecule.
Co-reporter:Fengyan Li, Lin Xu, Yongge Wei, Guanggang Gao, Lihua Fan, Zhikui Li
Inorganica Chimica Acta 2006 Volume 359(Issue 12) pp:3795-3799
Publication Date(Web):1 September 2006
DOI:10.1016/j.ica.2005.10.050
Two lanthanide-decorated polyoxometalates K[Ln2(α-SiW11O39)(H2O)11] (Ln = La, Ce) have been successfully synthesized and characterized with single-crystal X-ray diffraction, IR spectroscopy and thermogravimetric analysis. The two compounds have analogy structures, which consist of one-dimensional chains based on [α-SiW11O39]8− building blocks. The chains are further connected to a two-dimensional layer by potassium ions. The magnetic studies of compound 1 demonstrate a ferromagnetic interaction in 1.Two new lanthanide-decorated polyoxometalates K[Ln2(α-SiW11O39)(H2O)11] (Ln = La, Ce) have been synthesized and structurally characterized, which consist of one-dimensional chains based on [α-SiW11O39]8− building blocks. The chains are further connected to a two-dimensional layer by potassium ions.
Co-reporter:Jishuang Zhang, Lin Xu, Yang Cui, Weixiao Cao, Zhuang Li
Materials Chemistry and Physics 2005 Volume 90(Issue 1) pp:47-52
Publication Date(Web):15 March 2005
DOI:10.1016/j.matchemphys.2004.09.033
A composite multilayer film constructed of Dawson anion [P2Mo18O62]6− and diazo resin (DR) was prepared by the electrostatic layer-by-layer (LbL) self-assembly method. The film could be stabilized by the photoinduced interaction between Dawson anion and diazo resin. IR spectra and X-ray photoelectron spectra revealed the possible occurrence of partial transformation from electrostatic interaction to covalent interaction between layers of the film after irradiation by UV light. Such transformation evidently increases the endurance of the film, which was demonstrated by AFM images and etching experiments with organic solvent. This study provides a new route to stabilze the polyoxometalate-based multilayer film by virtue of the photoinduced reaction with photosensitive polymer.
Co-reporter:Wenju Wang, Lin Xu, Yongge Wei, Fengyan Li, Guanggang Gao, Enbo Wang
Journal of Solid State Chemistry 2005 Volume 178(Issue 3) pp:608-612
Publication Date(Web):March 2005
DOI:10.1016/j.jssc.2004.11.034
A novel polyoxometalate-based organic–inorganic hybrid compound, [Co(bpy)3]2 [Mo6O19] [β-(H2Mo8O26)]·4H2O (1), have been hydrothermally synthesized and structurally characterized by elemental analysis, single-crystal X-ray diffraction, IR and X-ray photoelectron spectra. Compound 1 represents the first example that racemic complexes coexisting with two kinds of polyoxomolybdate anions in the same crystal architecture, which should be of rare chance that four kinds of complexes crystallizes into a compound.
Co-reporter:Fengyan Li, Lin Xu, Yongge Wei, Xinlong Wang, Wenju Wang, Enbo Wang
Journal of Molecular Structure 2005 Volume 753(1–3) pp:61-67
Publication Date(Web):28 October 2005
DOI:10.1016/j.molstruc.2005.05.047
The tetra-capped Keggin anion-supported Cobalt–Phenanthroline complex [Co2(phen)2(OH)2(H2O)4]0.5[{Co(phen)2(H2O)}2AsMo6VIMo2VV8IVO44]·2H2O (1) and the bicapped Keggin anion-based Nickel–phenanthroline compound [Ni(phen)2H2O]2[AsMo11VIMoVO40(VIVO2)0.5].2H2O(2), have been hydrothermally synthesized and structurally characterized by elemental analyses, single crystal X-ray diffraction, IR and X-ray photoelectron spectrum. The interesting structural feature of 1 is that there are two types of free complex cation [Co2(phen)2(OH)2(H2O)4]2+ in different orientations in the crystal structure of 1, and these free complex cations coexist in the space between polyoxometalate clusters. The structure of compound 2 is very like compound 1 except that the Keggin unit is bi-capped instead of tetra-capped. Compounds 1 and 2 are examples that Arsenicum-centered vanadomolybdate anion acts as an active building block in the fabrication of polyoxometalates-supported hybrid solids. Then, the magnetic characteristic of 1 is typical of a dominant ferromagnetic interactions in the 6–300 K temperature range and a succedent antiferromagnetic interactions in the very low temperature range (2–6 K), while the magnetic behavior for 2 is characteristic of a dominant ferromagnetic interactions in the 6–300 K temperature range and succedent antiferromagnetic interactions in the very low temperature range (2–6 K).
Co-reporter:Guanggang Gao, Lin Xu, Wenju Wang, Wenjia An and Yunfeng Qiu
Journal of Materials Chemistry A 2004 vol. 14(Issue 13) pp:2024-2029
Publication Date(Web):26 May 2004
DOI:10.1039/B400021H
Ultra-thin multilayer films consisting of polyoxotungsceriumate cluster K17[CeIII(P2W17O61)2]·30H2O [Ce(P2W17)2] and polyallylamine hydrochloride were fabricated on quartz and ITO substrates by a layer-by-layer self-assembly method. The multilayer films were characterized by UV-vis spectra, cyclic voltammetry (CV) and chronoamperometric (CA) measurement. Compared with other polyoxometalates, the electrochromic film exhibits suitable response times, low operation potentials, high optical contrast and thermal stability, which provide valuable information for exploring the possibility of application to polyoxometalate-based electrochromic materials.
Co-reporter:L. Xu, J.S. Zhang, W.X. Cao, A.G. Wu, Z. Li
Materials Letters 2004 Volume 58(27–28) pp:3441-3446
Publication Date(Web):November 2004
DOI:10.1016/j.matlet.2004.04.039
Ultrathin multilayers films consisting of Keggin anion [PMo12O40]3− and diazo resin were first prepared by the electrostatic layer-by-layer self-assembly method. This film material could be stabilized by the photoinduced interaction between Keggin anion and diazo resin. IR spectra and X-ray photoelectron spectra revealed the occurrence of the partial transformation from ionic bond to covalent bond between layers of the film under irradiation by UV light. Such transformation increases the stability of the film, which was demonstrated by AFM images and the etching experiments with organic solvent.
Co-reporter:Lin Xu, Hongyu Zhang, Enbo Wang, Aiguo Wu, Zhuang Li
Materials Chemistry and Physics 2003 Volume 77(Issue 2) pp:484-488
Publication Date(Web):15 January 2003
DOI:10.1016/S0254-0584(02)00098-6
Ultrathin multilayer films of a polyoxotungstoeuropate cluster K15[Eu(BW11O39)2](Eu(BW11)2) and poly(allylamine hydrochloride) (PAH) have been prepared by the layer-by-layer (LbL) self-assembly method. The Eu(BW11)2/PAH multilayer films have been characterized by X-ray photoelectron spectra (XPS) and atomic force microscopy (AFM). UV–VIS measurements reveal regular film growth with each Eu(BW11)2 adsorption. The photoluminescent behavior of the film at room temperature was investigated to show the characteristic Eu3+ emission pattern of . The occurrence of photoluminescent activity confirms the potential for creating luminescent multilayers with polyoxometalates (POMs).
Co-reporter:Lin Xu, Hongyu Zhang, Enbo Wang, Dirk G. Kurth and Zhuang Li
Journal of Materials Chemistry A 2002 vol. 12(Issue 3) pp:654-657
Publication Date(Web):28 Jan 2002
DOI:10.1039/B108283C
Ultrathin multilayer films consisting of the polyoxotungstoeuropate cluster K12[EuP5W30O110]
(EuP5W30) and poly(allylamine hydrochloride)
(PAH) have been prepared by the layer-by-layer self-assembly method. The (EuP5W30/PAH) multilayer films have been characterized by small-angle X-ray reflectivity measurements, X-ray photoelectron spectra, and atomic force microscopy (AFM). From the AFM images, the thickness of the {PEI/PSS/PAH(EuW30/PAH)} multilayer film was estimated to be 6.5 nm, corresponding to an average thickness of ca.1.1 nm for a EuW30/PAH layer pair. The photoluminescent behavior of the film at room temperature was investigated to show the characteristic Eu3+ emission pattern of 5D0 → 7FJ.
The fluorescence behavior of the multilayer film is essentially identical to that of Hn[EuP5W30O110](12 − n)− in a concentrated aqueous solution, except for the relative intensities and peak bandwidths. The occurence of photoluminescent activity confirms the potential for creating luminescent multilayers with polyoxometalates (see ).
Co-reporter:Lin Xu, Enbo Wang, Zhuang Li, Dirk G. Kurth, Xiguang Du, Hongyu Zhang and Chao Qin
New Journal of Chemistry 2002 vol. 26(Issue 6) pp:782-786
Publication Date(Web):07 Jun 2002
DOI:10.1039/B110671F
An ultrathin composite film containing both polyoxometalate anion [PMo12O40]3−
(PMo12) and a planar binuclear phthalocyanine, bi-CoPc, has been prepared by the electrostatic layer-by-layer self-assembly method. UV-vis measurements revealed regular film growth with each four-layer {PMo12/bi-CoPc/PSS/PAH} adsorption. The film structure was characterized by small-angle X-ray reflectivity measurements, X-ray photoelectron spectra, and AFM images. The nanothick film shows a third-order nonlinear optical response of χ(3)=4.21×10−12 esu. Experimental investigations also indicate that the combination of polyoxometalate anions [PMo12O40]3− with the phthalocyanine bi-CoPc in multilayer films can enhance the third-order NLO susceptibility and modify the third-order NLO absorption of bi-CoPc.
Co-reporter:Lin Xu, Hongyu Zhang, Enbo Wang, Aiguo Wu, Zhuang Li
Materials Letters 2002 Volume 54(5–6) pp:452-457
Publication Date(Web):June 2002
DOI:10.1016/S0167-577X(01)00652-8
Ultrathin multilayer films of poly(allylamine hydrochloride) (PAH) and a polyoxotungstoeuropate cluster K13[Eu(SiW11O39)2] (Eu(SiW11)2) have been prepared by the layer-by-layer self-assembly method. The Eu(SiW11)2/PAH multilayer films have been characterized by X-ray photoelectron spectra and atomic force microscopy (AFM). UV–Vis measurements reveal regular film growth with each Eu(SiW11)2 adsorption. The photoluminescent behavior of the film at room temperature was investigated to show the characteristic Eu3+ emission pattern of 5Do→7FJ. The occurrence of photoluminescent activity confirms the potential for creating luminescent multilayers with polyoxometalates.
Co-reporter:Bo Bi, Lin Xu, Bingbing Xu, Xizheng Liu
Applied Clay Science (December 2011) Volume 54(Issues 3–4) pp:242-247
Publication Date(Web):December 2011
DOI:10.1016/j.clay.2011.09.003
Co-reporter:Lu Xi, Zhanbin Jin, Zhixia Sun, Ran Liu, Lin Xu
Applied Catalysis A: General (25 April 2017) Volume 536() pp:67-74
Publication Date(Web):25 April 2017
DOI:10.1016/j.apcata.2017.02.017
Co-reporter:Yuzhuo Zhang, Yanju Wang, Zhixia Sun, Fengyan Li, Ran Tao, Zhanbin Jin and Lin Xu
Chemical Communications 2017 - vol. 53(Issue 14) pp:NaN2293-2293
Publication Date(Web):2017/01/24
DOI:10.1039/C6CC08516D
A large-grained perovskite film, with a crystal grain size of ca. 30–50 μm, was achieved by polyoxometalate-induced Ostwald ripening. Aiming at commercially-oriented fully printable hole-conductor-free perovskite solar cells, the power conversion efficiency of the device was significantly improved from 9.17% to 11.35% (average) via polyoxometalate molecular doping. This is because the large-grained perovskite film could effectively reduce bulk defects and charge recombination, thereby facilitating charge transport.
Co-reporter:Yuzhuo Zhang, Yanju Wang, Zhixia Sun, Fengyan Li, Ran Tao, Zhanbin Jin and Lin Xu
Chemical Communications 2017 - vol. 53(Issue 14) pp:NaN2293-2293
Publication Date(Web):2017/01/24
DOI:10.1039/C6CC08516D
A large-grained perovskite film, with a crystal grain size of ca. 30–50 μm, was achieved by polyoxometalate-induced Ostwald ripening. Aiming at commercially-oriented fully printable hole-conductor-free perovskite solar cells, the power conversion efficiency of the device was significantly improved from 9.17% to 11.35% (average) via polyoxometalate molecular doping. This is because the large-grained perovskite film could effectively reduce bulk defects and charge recombination, thereby facilitating charge transport.
Co-reporter:Yuzhuo Zhang, Ran Tao, Xuemin Zhao, Zhixia Sun, Yanju Wang and Lin Xu
Chemical Communications 2016 - vol. 52(Issue 16) pp:NaN3307-3307
Publication Date(Web):2016/01/22
DOI:10.1039/C5CC08628K
A photoconductive perovskite–polyoxometalate composite was prepared for the first time by a facile low-temperature and solution-processed method, and this composite exhibited a significantly enhanced photoconductivity and photodetection performance due to introduction of polyoxometalate into the perovskite for fine energy-level matching and efficient charge transfer.
Co-reporter:Fengyan Li and Lin Xu
Dalton Transactions 2011 - vol. 40(Issue 16) pp:NaN4034-4034
Publication Date(Web):2011/02/14
DOI:10.1039/C0DT00691B
Polyoxomolybdates, an important branch in polyoxometalates chemistry, present complicated solution chemistry and unmatched physicochemical properties, which endows us with both great opportunities and considerable challenges in creating new functional materials. This perspective highlights the recent development on the coordination assembly of transition-metal-substituted heteropolymolybdates by using labile lacunary heteropolymolybdates as inorganic multidentate ligands. A series of strategies have been used to stabilize the lacunary heteropolymolybdate building blocks. Finally, we introduce some researches on the modification of polymolybdates by organic groups in aqueous media, which may shed light on the green chemistry of the functionalization of polyoxomolybdates.
Co-reporter:Jianfang Cao, Shuxia Liu, Ruige Cao, Linhua Xie, Yuanhang Ren, Chaoying Gao and Lin Xu
Dalton Transactions 2008(Issue 1) pp:NaN120-120
Publication Date(Web):2007/10/23
DOI:10.1039/B713275A
A series of organic–inorganic hybrid compounds, K2H7[{Ln(PW11O39)2}{Cu2(bpy)2(μ-ox)}]·xH2O (Ln = La, x≈ 18 (1); Ln = Pr, x≈ 18 (2); Ln = Eu, x≈ 16 (3); Ln = Gd, x≈ 22 (4); Ln = Yb, x≈ 19 (5); bpy = 2,2′-bipyridine and ox = oxalate), have been isolated by the conventional solution method. Single-crystal X-ray diffraction studies reveal that compounds 1–5 are isomorphic and consist of one-dimensional chains, which are constructed by alternating bis(undecatungstophosphate) lanthanates [Ln(PW11O39)2]11− and dinuclear copper(II)–oxalate complexes [Cu2(bpy)2(μ-ox)]2+. π–π interactions of the bpy ligands from adjacent chains lead to their three-dimensional structures. An analogue of potassium K2H9[{K(PW11O39)2}{Cu2(bpy)2(μ-ox)}]·∼20.5H2O (6) has also been obtained. The syntheses and structures of these compounds are reported here. Magnetic properties of 1, 2 and 3 are discussed as well. Attempts to crystallize similar compounds containing Co(II) and Ni(II) were unsuccessful.
Co-reporter:Xinze Luo, Fengyan Li, Bingbing Xu, Zhixia Sun and Lin Xu
Journal of Materials Chemistry A 2012 - vol. 22(Issue 30) pp:NaN15055-15055
Publication Date(Web):2012/06/27
DOI:10.1039/C2JM16018H
A photovoltaic electrode consisting of polyoxometalate (SiW12) and zinc oxide (ZnO) was fabricated on indium tin oxide (ITO) glass by one-step electrodeposition. The addition of SiW12 strongly influences the morphology and crystallographic orientation of the ZnO. The photovoltaic properties of the ZnO film and the SiW12–ZnO composite films were investigated via solar cell assembly. Both transient photocurrent and current–voltage curve measurements demonstrate that the photocurrent and power conversion efficiency of the SiW12–ZnO composite film were markedly enhanced in comparison with that of the ZnO film. Based on the results of fluorescence quenching measurements, the enhanced photovoltaic effect should be attributed to the occurrence of the photoinduced electron transfer between polyoxometalate and ZnO, which increases the efficient dissociation of excited electron–hole pairs (excitons).
Co-reporter:Yaobin Yang, Lin Xu, Fengyan Li, Xiguang Du and Zhixia Sun
Journal of Materials Chemistry A 2010 - vol. 20(Issue 48) pp:NaN10840-10840
Publication Date(Web):2010/10/06
DOI:10.1039/C0JM01812K
A photovoltaic electrode material consisting of cobalt tetraaminophthalocyanine (CoTAPc) and Dawson-type phosphomolybdate (P2Mo18) was fabricated through the layer-by-layer (LbL) assembly method. The film electrode was characterized by UV–vis spectroscopy, IR spectroscopy, X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and photoelectrochemical measurements. Photovoltaic measurement of the film electrode under light irradiation of 365 nm demonstrated that the P2Mo18/CoTAPc composite film electrode exhibits higher photocurrent and power conversion efficiency (η) than the phthalocyanine-only electrode, furthermore the increased photocurrent of (P2Mo18/CoTAPc/PSS/PAH)5 is not equal to the direct photoresponse addition of P2Mo18 and CoTAPc. Based on the results of fluorescence quenching measurements, the enhanced photovoltaic effect should be attributed to the occurrence of the photoinduced electron transfer between CoTAPc and POM, which increases the efficient dissociation of excited electron–hole pairs (excitons). The present research represents the first example of enhancing the photovoltaic response of organic photovoltaic materials by the assistance of polyoxometalates.
Co-reporter:Shuping Liu, Lin Xu, Fengyan Li, Bingbing Xu and Zhixia Sun
Journal of Materials Chemistry A 2011 - vol. 21(Issue 6) pp:NaN1952-1952
Publication Date(Web):2010/12/01
DOI:10.1039/C0JM02412K
A composite film containing poly(3,4-ethylenedioxythiophene) (PEDOT), polyoxometalate (POM) clusters K6P2W18O62·14H2O (P2W18) and polyallylamine hydrochloride (PAH) was fabricated by a smart combination of layer-by-layer (LbL) with electro-polymerization methods. The composite film displays enhanced electrochromic performance by incorporation of P2W18 into the PEDOT film. The electrochromic property of the film is significantly improved, resulting in an optical contrast of 54.7% at 600 nm and an absorbance that does not change after 1500 cycles. Additionally, the film provides broader absorption throughout the visible region. These results demonstrate the essential role of POMs in improving functionality on PEDOT for applications in electrochromic devices.
Co-reporter:Lihao Wang, Lin Xu, Zhongcheng Mu, Chungang Wang and Zhixia Sun
Journal of Materials Chemistry A 2012 - vol. 22(Issue 44) pp:NaN23632-23632
Publication Date(Web):2012/09/24
DOI:10.1039/C2JM35314H
To explore the synergistic effects of polyoxometalate and noble metal nanoparticles on the photovoltaic performance of titanium dioxide (TiO2), multilayer film photoanodes consisting of TiO2 nanoparticles, gold nanoparticles (Au) and Dawson-type polyoxometalate K6P2W18O62 (abbr. as P2W18) have been prepared by the layer-by-layer self-assembly method, and poly(styrenesulfonate) (PSS) was used as a film forming auxiliary material. These film electrodes were characterized by UV-vis spectra, X-ray photoelectron spectroscopy, atomic force microscopy, and photoelectrochemical measurements. Transient photocurrent and current–voltage curve measurements demonstrate that the photocurrent response and power conversion efficiency increase in the sequence: the TiO2 film < the P2W18/TiO2 film < the TiO2/P2W18/Au film. These results provide valuable information for photovoltaic and photoelectrochemical applications.
Co-reporter:Zhixia Sun, Yuzhuo Zhang, Na Li, Lin Xu and Tianqi Wang
Journal of Materials Chemistry A 2015 - vol. 3(Issue 24) pp:NaN6157-6157
Publication Date(Web):2015/05/14
DOI:10.1039/C5TC00904A
A photoconductive device of phosphotungstic acid (denoted as PW12) and TiO2 composite was fabricated. Compared to pristine TiO2, the composite materials of PW12–TiO2 displayed a remarkable enhancement (ca. 2000-fold) in their photocurrent values. Furthermore, the composite materials also exhibited good gas sensing performance for acetone.
Co-reporter:Fengyan Li, Lin Xu, Guanggang Gao, Xiaosu Qu and Yanyan Yang
Dalton Transactions 2007(Issue 17) pp:NaN1664-1664
Publication Date(Web):2007/03/22
DOI:10.1039/B701346A
The first O,O′-bonded metal-stabilized sulfinate has been isolated and structurally characterized to show a novel one-dimensional chain structure containing both the enantiomers of the subunit Mn(2-sinic)(DMSO)2.
Co-reporter:Chris Ritchie, Fengyan Li, Chullikkattil P. Pradeep, De-Liang Long, Lin Xu and Leroy Cronin
Dalton Transactions 2009(Issue 33) pp:NaN6486-6486
Publication Date(Web):2009/07/09
DOI:10.1039/B907410D
Using multifunctional organocations a novel heteropolyanion, [(P4W6O34)2Co2Na2(H2O)2]18−, with unprecedented structural features, has been observed, and extension of these clusters from molecules into 1D chains occurs through a dimeric cobalt species, with this material exhibiting reversible colour/magnetic susceptibility changes upon dehydration.
Co-reporter:Fengyan Li, Fanzhi Meng, Lifang Ma, Lin Xu, Zhixia Sun and Qiao Gao
Dalton Transactions 2013 - vol. 42(Issue 34) pp:NaN12082-12082
Publication Date(Web):2013/06/24
DOI:10.1039/C3DT51057C
The first 3D pure inorganic framework based on heteropolymolybdate anion [V2Mo16O58]10− has been synthesized and its photoelectric properties demonstrated.
Co-reporter:Fengyan Li, Weihua Guo, Lin Xu, Lifang Ma and Yuchao Wang
Dalton Transactions 2012 - vol. 41(Issue 30) pp:NaN9226-9226
Publication Date(Web):2012/06/22
DOI:10.1039/C2DT12277D
Two dysprosium-containing tungstoarsenates [C(NH2)3]11[Dy2(Hcit)2(AsW10O38)]·9H2O (1) and K8−nH3−n[Dy3−nKn(H2O)3(CO3)(A-α-AsW9O34)(A-β-AsW9O34)]·22H2O (n = 0 or 1) (2) have been synthesized and characterized by single-crystal X-ray diffraction, elemental analyses, thermogravimetric analyses and infrared spectroscopy. Compound 1 is a citrate-decorated Keggin type di-substituted Ln/POM derivative with the two non-adjacent substituted sites occupied. Compound 2 is composed of two different trivacant Keggin unit isomers [A-α-AsW9O34]9− and [A-β-AsW9O34]9−, linked to each other via one {Dy3−nKn(H2O)3(CO3)}(7 − 2n)+ (n = 0 or 1) unit, where CO32− is encapsulated in the triangle plane, resulting in a stable dysprosium carbonate-containing sandwich-type polyoxoanion with D2h symmetry. The investigation on both static and dynamic magnetic properties of 1 and 2 show that the magnetic relaxation behavior of 2 appear in a static magnetic field of 5000 Oe, while 1 shows no positive out-of-phase ac susceptibility.
Co-reporter:Yuchao Wang, Fengyan Li, Lin Xu, Ning Jiang and Xizheng Liu
Dalton Transactions 2013 - vol. 42(Issue 16) pp:NaN5847-5847
Publication Date(Web):2013/01/25
DOI:10.1039/C3DT32658F
Four heteropoly blue complexes constructed from Keggin-type heteropoly blue molybdenum–tungsten clusters and Cu(II) ions as linkers, H2[α-SiW10MoV2O40][Cu(PDA)2·H2O]2 (1), H2[α-SiW10MoV2O40][Cu(DEF)3·H2O][Cu(DEF)2·2H2O]·6H2O (2), H2[α-SiW10MoV2O40][Cu(DMF)3H2O]2·6H2O (3), and H4[α-SiW10MoV2O40]2[CuK2(DMF)6][Na0.75K3.25(DMF)6] (4) [PDA = propanediamide, DEF = N,N-diethylformamide and DMF = N,N-dimethylformamide], have been synthesized by conventional reactions and characterized by single-crystal X-ray diffraction, elemental analysis, IR spectroscopy, thermogravimetry, X-ray powder diffraction (XRD) and UV spectra. The amount of Cu(II) and the nature of the ligand (DMF, DEF and PDA) can control both the linkage pattern of Cu(II) ions and the dimensionality of the frameworks; this demonstrates for the first time the possibility to assemble heteropoly blue architectures in different dimensionality ranging from zero-dimensional (0D) to one-dimensional (1D), two-dimensional (2D) and three-dimensional (3D). The magnetic investigation showed that the positive magnetic moment could be observed at room temperature, which should be unusual results in magnetochemistry of the two-electron reduced heteropoly blue. The stability and formation conditions of the four compounds are also discussed.
Co-reporter:Keyu Cui, Fengyan Li, Lin Xu, Bingbing Xu, Ning Jiang, Yuchao Wang and Jianping Zhang
Dalton Transactions 2012 - vol. 41(Issue 16) pp:NaN4877-4877
Publication Date(Web):2012/03/07
DOI:10.1039/C2DT11478J
The reaction of Na12[Bi2W22O74(OH)2]·44H2O, Na9[BiW9O33]·16H2O, lanthanide chloride and Na2CO3 in aqueous solution at a pH value of about 7.0 resulted in the three unprecedented giant lanthanide–tungstobismuthate clusters NaxH22−x[(BiW9O33)4(WO3){Bi6(μ3-O)4(μ2-OH)3}(Ln3(H2O)6CO3)]·nH2O {Ln = Pr3+ (1), Nd3+ (2), La3+ (3), x = 22 (1), 22 (2), 20 (3), n = 95 (1), 91 (2), 73 (3)}. These three complexes represent the first examples of lanthanide ions encapsulated in polyoxotungstobismuthates and the largest polytungstobismuthates so far. Furthermore, a [{Bi6(μ3-O)4(μ2-OH)3}]7+ polyoxo cation was incorporated into the structure of these compounds. All complexes are characterized by single-crystal X-ray diffraction, IR spectra, electronic spectroscopy, thermogravimetric and elemental analysis. Magnetic investigation revealed that the progressive depopulation of excited Stark sublevels of the lanthanide ions at low temperature and the weak antiferromagnetic interaction between the neighboring metal centres are responsible for the magnetic properties of 1 and 2. The original synthesis strategy in this work may open a gateway to assembly of large lanthanide–tungstobismuthates clusters and novel multifunctional solid materials in aqueous solution under mild conditions.
Co-reporter:Ya Wang, Ming-Hui Sun, Feng-Yan Li, Zhi-Xia Sun and Lin Xu
Dalton Transactions 2015 - vol. 44(Issue 10) pp:NaN4511-4511
Publication Date(Web):2015/01/26
DOI:10.1039/C4DT03447C
Two cyanometalate-functionalized heteropolytungstates (C4H10ON)23[HN(CH2CH2OH)3]11H[FeIII(CN)6(α2-P2W17O61NiII)4]·31H2O (1) and (C4H10ON)23[HN(CH2CH2OH)3]10H2[FeIII(CN)6(α2-P2W17O61CoII)4]·27H2O (2) (C4H10ON = morpholine, HN(CH2CH2OH)3 = triethanol amine) have been successfully synthesized in aqueous solution under conventional reaction conditions, which demonstrated that it is a successful strategy to incorporate the cyanometalate fragment into lacunary heteropolytungstates. These polyanions were characterized by single-crystal X-ray diffraction, IR spectra, elemental analysis, thermogravimetric analysis, magnetic studies, and electrochemistry. Interestingly, the electrochemical studies have shown that the two complexes have bifunctional electrocatalytic activities towards not only the reduction of potassium iodate (KIO3) ascribed to the function of POM, but also the oxidation of the biological molecule ascorbic acid (AA) ascribed to the Fe-center in [MII4FeIII(CN)6]5+. Significantly, the magnetic investigations demonstrate the presence of ferromagnetic exchange interactions in 1 (Ni4Fe) and antiferromagnetic interactions in 2 (Co4Fe).
Co-reporter:Qiao Gao, Fengyan Li, Zhixia Sun, Lin Xu and Minghui Sun
Dalton Transactions 2016 - vol. 45(Issue 6) pp:NaN2425-2425
Publication Date(Web):2016/01/05
DOI:10.1039/C5DT03748D
Herein, we show a new photomagnetic system that gives rise to the magnetic transformation from diamagnetism to paramagnetism by photoinduced intramolecular charge transfer in the polyoxometalate-based organic–inorganic hybrid, [(VMo6O22)2{O2C(CH2)2CO2}3] (1).
Co-reporter:Minghui Sun, Fengyan Li, Longjiao Yu, Ya Wang and Lin Xu
Dalton Transactions 2016 - vol. 45(Issue 6) pp:NaN2421-2421
Publication Date(Web):2016/01/06
DOI:10.1039/C5DT04637H
The first Krebs-type tungstoantimonate containing ferrous ions Na2H4[C3H5N2]4[Sb2W20FeII2(H2O)6O70]·12H2O (1) was prepared by a new route of synthesis under mild reaction conditions. The facile synthesis route represented a favourable tactic for the successful synthesis of FeII-based polyoxometalate. Its applications in both catalytic Fenton reaction and electrochemical sensing of ascorbic acid were also investigated primarily.
Co-reporter:Miaomiao Liu, Fengyan Li, Zhixia Sun, Lifang Ma, Lin Xu and Yuanhong Wang
Chemical Communications 2014 - vol. 50(Issue 75) pp:NaN11007-11007
Publication Date(Web):2014/07/28
DOI:10.1039/C4CC04653F
A highly active and stable photocatalyst MoS2–graphene/CdS nanoparticles/nanorods was prepared using a facile two-step hydrothermal method. The noble-metal-free photocatalyst achieved a remarkable quantum yield of 65.8% at 420 nm for photocatalytic H2 evolution from water.
![Tungstate(3-),tetracosa-m-oxododecaoxo[m12-[phosphato(3-)-kO:kO:kO:kO':kO':kO':kO'':kO'':kO'':kO''':kO''':kO''']]dodeca-,hydrogen (1:3)](http://img.cochemist.com/ccimg/1400/1343-93-7.png)
![Tungstate(3-),tetracosa-m-oxododecaoxo[m12-[phosphato(3-)-kO:kO:kO:kO':kO':kO':kO'':kO'':kO'':kO''':kO''':kO''']]dodeca-,hydrogen (1:3)](http://img.cochemist.com/ccimg/1400/1343-93-7_b.png)
![[1,1'-Biphenyl]dicarboxylic acid](http://img.cochemist.com/ccimg/27500/27479-68-1.png)
![[1,1'-Biphenyl]dicarboxylic acid](http://img.cochemist.com/ccimg/27500/27479-68-1_b.png)
