Co-reporter:Ming Luo, Lipeng Long, Hong ZhangYuhui Yang, Yuhui Hua, Gang Liu, Zhenyang LinHaiping Xia
Journal of the American Chemical Society 2017 Volume 139(Issue 5) pp:
Publication Date(Web):January 20, 2017
DOI:10.1021/jacs.6b13275
η2-Iminoketenyl species have often been postulated as the intermediates in nucleophile-induced carbyne–isocyanide C–C coupling processes. However, such species are elusive. Here we report direct formation of η2-iminoketenyl complexes from reactions of metallapentalyne with isocyanides. Our studies show that steric effects of N-substituents of the isocyanides play an important role in the stability of the three-membered metallacycles of the η2-iminoketenyl complexes. Sterically bulky isocyanides, such as tert-butyl or 1-adamantyl isocyanides, inhibit bending at the isocyanide nitrogen atoms, a requirement for formation of η2-iminoketenyl structures. Reactions of metallapentalyne with excess isocyanide allow the metal-bridged metallaindene derivativesto be isolated as a result of the isocyanide insertion into the M–Cα σ bond of metallapentalyne.
Co-reporter:Xumin He;Xiehua He;Shenyan Li;Kaiyue Zhuo;Weixiang Qin;Shuyu Dong;Jiangxi Chen;Lei Ren;Gang Liu
Polymer Chemistry (2010-Present) 2017 vol. 8(Issue 24) pp:3674-3678
Publication Date(Web):2017/06/20
DOI:10.1039/C7PY00641A
Metal-containing macromolecules with extraordinary properties have attracted a great deal of interest owing to their potential application in the development of functional materials. Here, we report the synthesis of novel amphipathic metal-containing macromolecules by the click reaction of methoxypolyethylene glycol azides with a unique metalla-aromatic complex containing a terminal alkynyl group. The resultant amphipathic macromolecules self-assembled into micellar nanoparticles with diameters of ca. 145 nm in water, which exhibited high stability, water-dispersibility, biocompatibility, and excellent photothermal behavior under 808 nm laser irradiation. Our study opens promising avenues for providing metal-containing macromolecules as photothermal materials.
Co-reporter:Jinbo Huang;Xiaoxi Zhou;Qianyi Zhao;Shunhua Li
Chinese Journal of Chemistry 2017 Volume 35(Issue 4) pp:377-377
Publication Date(Web):2017/04/01
DOI:10.1002/cjoc.201770041
The cover picture shows the structures of rigid dinuclear metallacumulenes with diazafluorene or fluorine fragments. These complexes were derived from 9-ethynyl-9-fluorenol and 9-hydroxy-9-ethynyl-4,5-diazafluorene in the presence of cis-OsCl2(dppm)2 and cis-RuCl2(dppe)2. Eletrochemical studies have revealed that these complexes display a quasireversible redox behavior and a moderate electronic communication between the two metal centers. Moreover, these new structurally rigid complexes show a remarkably broad absorption in the long-wavelength region (λmax = 300−700 nm), which would be excellent candidates for optical materials. The bridge in center shows the implied meaning of the rigid structures of these complexes and the electronic communication between the two metal centers. More details are discussed in the article by Xia et al. on page 420–428.
Co-reporter:Jinbo Huang;Xiaoxi Zhou;Qianyi Zhao;Shunhua Li
Chinese Journal of Chemistry 2017 Volume 35(Issue 4) pp:420-428
Publication Date(Web):2017/04/01
DOI:10.1002/cjoc.201600910
AbstractA variety of rigid ruthenium and osmium allenylidene [M1Cl(PΛP)2 = C = C(4,5-diazafluoren-9-yl){M2(CHC(PPh3)CHC(PPh3)Cl2(PPh3)2}][PF6]3 (4a: M1=Os, M2=Os, PΛP=dppm; 4b: M1=Os, M2=Ru, PΛP=dppm; 4c: M1=Ru, M2=Os, PΛP=dppe; 4d: M1=Ru, M2=Ru, PΛP=dppe), ruthenium alkynyl-allenylidene complexes trans-[(dppe)2Ru(C≡CPh)Ru = C = C(R)][PF6] (6a: R = fluoren-9-yl; 6b: R = 4,5-diazafluoren-9-yl), trans-{(dppe)2[=C = C(fluoren-9-yl)]Ru(C ≡ C-R-C ≡ C)Ru[(=C = C(fluoren-9-yl)(dppe)2]} [PF6]2 (8a, R = 1,4-phenylene; 8b, R = 1,3-phenylene) terminated by 4,5-diazafluoren-9-yl and fluoren-9-yl group have been prepared. These allenylidene complexes were derived from 9-ethynyl-9-fluorenol and 9-hydroxy-9-ethynyl-4,5-diazafluorene in the presence of cis-OsCl2(dppm)2 and cis-RuCl2(dppe)2. The respective products have been fully characterized by 1H, 13C, 31P NMR spectrometry, IR spectrometry, elemental analysis, and UV/Vis spectrophotometry. Moreover, electrochemical studies reveal that the dinuclear complexes display a quasi-reversible redox behavior and a moderate electronic communication between the two metal centers in 8a. UV–vis studies show a remarkable absorption in the region (λmax = 300-700 nm) for these complexes.
Co-reporter:Dr. Congqing Zhu;Jingjing Wu;Shenyan Li;Yuhui Yang;Dr. Jun Zhu; Dr. Xin Lu; Dr. Haiping Xia
Angewandte Chemie 2017 Volume 129(Issue 31) pp:9195-9199
Publication Date(Web):2017/07/24
DOI:10.1002/ange.201704057
AbstractPolycyclic complexes containing a bridgehead transition metal are interesting species because the transition metal is shared by all the rings simultaneously. In this study, we present a novel osmium–bridgehead system with three fused five-membered rings. This novel framework can be viewed as a 10-atom carbon chain coordinating to the osmium center. In sharp contrast to the nonplanar organic analogue, this unique metallacycle exhibits good planarity, which was unambiguously verified by means of X-ray diffraction. Interestingly, preliminary DFT calculations show that the aromaticity in the three 5MRs of these osmatricycles can be easily tuned by the ligand substitution. Finally, the broad UV/Vis absorption spectra of these novel polycyclic complexes were also reported.
Co-reporter:Dr. Congqing Zhu;Jingjing Wu;Shenyan Li;Yuhui Yang;Dr. Jun Zhu; Dr. Xin Lu; Dr. Haiping Xia
Angewandte Chemie International Edition 2017 Volume 56(Issue 31) pp:9067-9071
Publication Date(Web):2017/07/24
DOI:10.1002/anie.201704057
AbstractPolycyclic complexes containing a bridgehead transition metal are interesting species because the transition metal is shared by all the rings simultaneously. In this study, we present a novel osmium–bridgehead system with three fused five-membered rings. This novel framework can be viewed as a 10-atom carbon chain coordinating to the osmium center. In sharp contrast to the nonplanar organic analogue, this unique metallacycle exhibits good planarity, which was unambiguously verified by means of X-ray diffraction. Interestingly, preliminary DFT calculations show that the aromaticity in the three 5MRs of these osmatricycles can be easily tuned by the ligand substitution. Finally, the broad UV/Vis absorption spectra of these novel polycyclic complexes were also reported.
Co-reporter:Qin Zhu;Congqing Zhu;Zhihong Deng;Guomei He;Jiangxi Chen;Jun Zhu
Chinese Journal of Chemistry 2017 Volume 35(Issue 5) pp:628-634
Publication Date(Web):2017/05/01
DOI:10.1002/cjoc.201600478
Treatment of osmapentalyne [Os{≡C-C(COOMe)=CH-C=CH-C(PPh3)=CH-}Cl(PPh3)2]+ with arylamines in the presence of Cs2CO3 produced osmium-bridged polycyclic aromatic complexes. In this reaction, metal carbyne of osmapentalyne was first attacked by nucleophiles, followed by a C-H oxidative addition. The UV-Vis spectra of these osmium-bridged polycyclic aromatic complexes were measured. The result shows that these osmium-bridged polycyclic aromatic complexes have broad absorption in the UV-Vis region up to 650 nm.
Co-reporter:Ming Luo, Congqing Zhu, Lina Chen, Hong Zhang and Haiping Xia
Chemical Science 2016 vol. 7(Issue 3) pp:1815-1818
Publication Date(Web):23 Nov 2015
DOI:10.1039/C5SC03963K
The halogenation of metallapentalyne led to the formation of metallapentalenes, which were fully characterized and studied by DFT calculations. The experimental and computational studies indicate that four resonance forms contribute to the overall structure of the metallapentalenes, and one resonance form could be viewed as the first examples of metallaiodirenium and metallabromirenium ions.
Co-reporter:Qingde Zhuo, Xiaoxi Zhou, Huijun Kang, Zhiyong Chen, Yuhui Yang, Feifei Han, Hong Zhang, and Haiping Xia
Organometallics 2016 Volume 35(Issue 10) pp:1497-1504
Publication Date(Web):April 13, 2016
DOI:10.1021/acs.organomet.6b00083
A convenient method to synthesize novel fused ruthena-/osmacycles via intramolecular C–H activation of thiophenes has been developed. Treatment of HC≡CCH(OH)R (R = 2-thienyl) with RuCl2(PPh3)3 or OsCl2(PPh3)3 afforded hydroxyl-coordinated metal vinyl compounds 1 and 4. Reaction of 1/4 with acid produced metal alkenylcarbene complexes 3/5, which can further convert to the corresponding fused metallaaromatics 2/7 via the C(sp2)–H activation of the thienyl groups. 7 is the first example of a metallabenzyne with a fused five-membered ring (thiophene ring). These fused metallaaromatics are thermally stable both in solution and in the solid state in air. The X-ray crystallographic analysis, NMR spectra, and DFT calculations all suggest that these fused metallaaromatics (2 and 7) show aromatic character.
Co-reporter:Congqing Zhu;Caixia Yang;Yongheng Wang;Gan Lin;Yuhui Yang;Xiaoyong Wang;Jun Zhu;Xiaoyuan Chen;Xin Lu;Gang Liu
Science Advances 2016 Vol 2(8) pp:e1601031
Publication Date(Web):26 Aug 2016
DOI:10.1126/sciadv.1601031
Planar Möbius aromatic metallacycles show NIR absorption spectrum and the highest carbon coordination number for a metal atom.
Co-reporter:Tingwan Xie, Huan Zhang, Yangju Lin, Yuanze Xu, Yonghong Ruan, Wengui Weng and Haiping Xia
RSC Advances 2015 vol. 5(Issue 17) pp:13261-13269
Publication Date(Web):15 Jan 2015
DOI:10.1039/C4RA16449K
In this study, a simple and versatile approach to self-healing polymers and electrically conductive composites is reported. A series of self-healing polymers are readily synthesized by radical copolymerization of two acrylate monomers bearing a hydrogen-bonding motif. Subsequent blending with nanofillers leads to self-healing electrically conductive composites. Their glass transition temperature, the mechanical and electrical properties, and the self-healing capability can be readily tuned by the composition of the polymer as well as the filler fraction. The composite exhibits mechanical force sensing capabilities and high efficiency of both mechanical and electrical self-healing properties. Our design starts from simple chemistry and inexpensive materials, and may offer a new route towards economic self-healing electronic/electrical devices.
Co-reporter:Feifei Han;Jinhua Li;Dr. Hong Zhang;Dr. Tongdao Wang;Dr. Zhenyang Lin;Dr. Haiping Xia
Chemistry - A European Journal 2015 Volume 21( Issue 2) pp:565-567
Publication Date(Web):
DOI:10.1002/chem.201405220
Abstract
The transformations of metallabenzene to substituted benzenes have been achieved by reactions of osmabenzenes with silver/copper acetylides. In this investigation, novel tetraphenylphosphonium salts containing two phosphonium substituents on the same benzene ring are generated.
Co-reporter:Hui Xu;Dr. Xinchang Pang;Yanjie He;Dr. Ming He;Jaehan Jung;Dr. Haiping Xia;Dr. Zhiqun Lin
Angewandte Chemie 2015 Volume 127( Issue 15) pp:
Publication Date(Web):
DOI:10.1002/ange.201501766
Co-reporter:Hui Xu;Dr. Xinchang Pang;Yanjie He;Dr. Ming He;Jaehan Jung;Dr. Haiping Xia;Dr. Zhiqun Lin
Angewandte Chemie 2015 Volume 127( Issue 15) pp:4719-4723
Publication Date(Web):
DOI:10.1002/ange.201500763
Abstract
We developed an unconventional route to produce uniform and intimately contacted semiconducting organic–inorganic nanocomposites for potential applications in thermoelectrics. By utilizing amphiphilic star-like PAA-b-PEDOT diblock copolymer as template, monodisperse PEDOT-functionalized lead telluride (PbTe) nanoparticles were crafted via the strong coordination interaction between PAA blocks of star-like PAA-b-PEDOT and the metal moieties of precursors (i.e., forming PEDOT–PbTe nanocomposites). As the inner PAA blocks are covalently connected to the outer PEDOT blocks, the PEDOT chains are intimately and permanently tethered on the PbTe nanoparticle surface, thereby affording a well-defined PEDOT/PbTe interface, which prevents the PbTe nanoparticles from aggregation, and more importantly promotes the long-term stability of PEDOT–PbTe nanocomposites. We envision that the template strategy is general and robust, and offers easy access to other conjugated polymer–inorganic semiconductor nanocomposites for use in a variety of applications.
Co-reporter:Hui Xu;Dr. Xinchang Pang;Yanjie He;Dr. Ming He;Jaehan Jung;Dr. Haiping Xia;Dr. Zhiqun Lin
Angewandte Chemie International Edition 2015 Volume 54( Issue 15) pp:
Publication Date(Web):
DOI:10.1002/anie.201501766
Co-reporter:Hui Xu;Yuci Xu;Xinchang Pang;Jaehan Jung;Zhiqun Lin;Yanjie He
Science Advances 2015 Volume 1(Issue 2) pp:e1500025
Publication Date(Web):27 Mar 2015
DOI:10.1126/sciadv.1500025
Organic-inorganic 1D periodic necklace-like nanostructures are fabricated using confined synthesis of inorganic nanocrystals.
Co-reporter:Xiaoxi Zhou, Xiehua He, Jianfeng Lin, Qingde Zhuo, Zhixin Chen, Hong Zhang, Jianbo Wang, and Haiping Xia
Organometallics 2015 Volume 34(Issue 9) pp:1742-1750
Publication Date(Web):April 23, 2015
DOI:10.1021/acs.organomet.5b00242
Treatment of the osmium hydrido alkenylcarbyne complex [OsH{≡CC(PPh3)═CHPh}(PPh3)2Cl2]BF4 (1) with allenoates (CH2═C═CHCOOR, R = Me, Et) in the presence of excess AgBF4 leads to the insertion products 2/3. The reactions of complex 1 with substituted allenoates, i.e., diethyl 2-vinylidenesuccinate (CH2═C═C(CH2COOEt)(COOEt)) and ethyl penta-2,3-dienoate (CH(CH3)═C═CH(COOEt)), result in the formation of [3 + 2] annulation products 4 and 6, respectively. Mechanisms of the reactions have been proposed with the isolation of the key intermediates. The results reveal that the divergent pathways for these reactions are mainly of steric origin.
Co-reporter:Hui Xu, Zi-Ao Huang, Xugeng Guo, Yuhui Yang, Yuhui Hua, Zexing Cao, Shunhua Li, and Haiping Xia
Organometallics 2015 Volume 34(Issue 17) pp:4229-4237
Publication Date(Web):August 27, 2015
DOI:10.1021/acs.organomet.5b00652
A convenient and general strategy has been developed to synthesize stable iridapolycycles 5–8. Reaction of arylacetylenes with iridium-hydride complex [IrH(CO)Cl(PPh3)3]BF4 via nucleophilic addition, oxidative decarbonylation, and C–H bond activation results in the formation of a series of iridacyclopentadiene derivatives, including benzo-iridacyclopentadiene 5, naphtho-iridacyclopentadiene 6, pyreno-iridacyclopentadiene 7, and thieno-iridacyclopentadiene 8. These iridapolycycles display high thermal and air stability yet can be further functionalized via facile ligand substitution reactions. As an example, complex 5 was used as a metallosynthon to react with 2,2′-dipyridyl to give intensely luminescent Ir(III) complex 9 bearing one C∧C and one N∧N ligands. Density functional theory (DFT) calculations reveal that the lowest unoccupied molecular orbitals (LUMOs) of iridapolycycles 5–8 are located on the phosphonium groups while the highest occupied molecular orbitals (HOMOs) are mainly located on the metal-embedded C∧C frameworks. Our method offers a sequential construction strategy for constructing luminescent iridacycles, which potentially allows facile tuning of the photoluminescence properties by modulating the C∧C and N∧N moieties independently.
Co-reporter:Hui Xu;Dr. Xinchang Pang;Yanjie He;Dr. Ming He;Jaehan Jung;Dr. Haiping Xia;Dr. Zhiqun Lin
Angewandte Chemie International Edition 2015 Volume 54( Issue 15) pp:4636-4640
Publication Date(Web):
DOI:10.1002/anie.201500763
Abstract
We developed an unconventional route to produce uniform and intimately contacted semiconducting organic–inorganic nanocomposites for potential applications in thermoelectrics. By utilizing amphiphilic star-like PAA-b-PEDOT diblock copolymer as template, monodisperse PEDOT-functionalized lead telluride (PbTe) nanoparticles were crafted via the strong coordination interaction between PAA blocks of star-like PAA-b-PEDOT and the metal moieties of precursors (i.e., forming PEDOT–PbTe nanocomposites). As the inner PAA blocks are covalently connected to the outer PEDOT blocks, the PEDOT chains are intimately and permanently tethered on the PbTe nanoparticle surface, thereby affording a well-defined PEDOT/PbTe interface, which prevents the PbTe nanoparticles from aggregation, and more importantly promotes the long-term stability of PEDOT–PbTe nanocomposites. We envision that the template strategy is general and robust, and offers easy access to other conjugated polymer–inorganic semiconductor nanocomposites for use in a variety of applications.
Co-reporter:Xiao-Yu Cao, Qianyi Zhao, Zhiqun Lin, and Haiping Xia
Accounts of Chemical Research 2014 Volume 47(Issue 2) pp:341
Publication Date(Web):November 14, 2013
DOI:10.1021/ar400087x
Aromatic compounds, such as benzene and its derivatives, porphyrins, fullerenes, carbon nanotubes, and graphene, have numerous applications in biomedicine, materials science, energy science, and environmental science. Metalla-aromatics are analogues of conventional organic aromatic molecules in which one of the (hydro)carbon segments is formally replaced by an isolobal transition-metal fragment. Researchers have studied these transition-metal-containing aromatic molecules for the past three decades, particularly the synthesis and reactivity of metallabenzenes. Another focus has been the preparation and characterization of other metalla-aromatics such as metallafurans, metallapyridines, metallabenzynes, and more. Despite significant advances, remaining challenges in this field include the limited number of convenient and versatile synthetic methods to construct stable and fully characterized metalla-aromatics, and the relative shortage of new topologies.To address these challenges, we have developed new methods for preparing metalla-aromatics, especially those possessing new topologies. Our synthetic efforts have led to a large family of closely related metalla-aromatics known as aromatic osmacycles. This Account summarizes the synthesis and reactivity of these compounds, with a focus on features that are different from those of compounds developed by other groups. These osmacycles can be synthesized from simple precursors under mild conditions. Using these efficient methods, we have synthesized aromatic osmacycles such as osmabenzene, osmabenzyne, isoosmabenzene, osmafuran, and osmanaphthalene. Furthermore, these methods have also created a series of new topologies, such as osmabenzothiazole and osmapyridyne. Our studies of the reactivity of these osma-aromatics revealed unprecedented reaction patterns, and we demonstrated the interconversion of several osmacycles.Like other metalla-aromatics, osma-aromatics have spectroscopic features of aromaticity, such as ring planarity and the characteristic bond lengths between a single and double bond, but the osma-aromatics we have prepared also exhibit good stability towards air, water, and heat. Indeed, some seemingly unstable species proved stable, and their stability made it possible to study their optical, electrochemical, and magnetic properties. The stability of these compouds results from their aromaticity and the phosphonium substituents on the aromatic plane: most of our osma-aromatics carry at least one phosphonium group. The phosphonium group offers stability via both electronic and steric mechanisms. The phosphonium acts as an electron reservoir, allowing the circulation of electron pairs along metallacycles and lowering the electron density of the aromatic rings. Meanwhile, the bulky phosphonium groups surrounding the aromatic metallacycle prevent most reactions that could decompose the skeleton.
Co-reporter:Feifei Han, Tongdao Wang, Jinhua Li, Hong Zhang, Laiying Zhang, Xumin He, and Haiping Xia
Organometallics 2014 Volume 33(Issue 19) pp:5301-5307
Publication Date(Web):September 9, 2014
DOI:10.1021/om500616s
Treatment of OsCl2(PPh3)2(CH═C(PPh3)CH(OH)-η2-C≡CH) (1) with PPh3 and Bu4NCl in CH2Cl2 under air gave paramagnetic osmacyclopentene [OsCl2(PPh3)2(CH═C(PPh3)CH(OH)C(═CH(PPh3)))]Cl (5). Heating the suspension of 5 in CH2Cl2 under a nitrogen atmosphere led to the formation of η2-allene-coordinated osmacycle OsCl2(PPh3)(CH═C(PPh3)CH═C═CH(P(C6H4)Ph2)) (6) and chloro-osmabenzene OsCl2(PPh3)2(CHC(PPh3)CHCClCH) (7) via disproportionation reaction. Oxidative transformation of 5 under an oxygen atmosphere yielded osmafuran [OsCl(PPh3)2(CHC(PPh3)CHO)(C≡C(PPh3))]Cl (10). In addtion, complexes 6, 7, and 10 can also undergo ligand substitution reactions with NaSCN to afford more stable analogues.
Co-reporter:Feifei Han;Dr. Tongdao Wang;Jinhua Li;Dr. Hong Zhang;Dr. Haiping Xia
Chemistry - A European Journal 2014 Volume 20( Issue 15) pp:
Publication Date(Web):
DOI:10.1002/chem.201400423
Abstract
Invited for the cover of this issue is the group of Haiping Xia at the University of Xiamen. The image depicts their recent work on the chemistry of transition-metal-containing metallaaromatics, organometallic compounds derived from formal replacement of a (hydro)carbon segment in an organic aromatic ring by an isolobal transition-metal fragment. Read the full text of the article at 10.1002/chem.201304957.
Co-reporter:Xuerui Wang, Congqing Zhu, Haiping Xia, and Jun Zhu
Organometallics 2014 Volume 33(Issue 7) pp:1845-1850
Publication Date(Web):March 21, 2014
DOI:10.1021/om500170w
Antiaromatic compounds and small cyclic alkynes or carbynes are both challenging for synthetic chemists because of the destabilization caused by their antiaromaticity and highly distorted triple bonds, respectively. These dual destabilizations could be the reason why pentalyne (I), a highly antiaromatic and extremely strained cyclic alkyne, has never been synthesized. Recently, we have successfully synthesized the first metallapentalyne (II), benefiting from the stabilization of a metal fragment by reducing the ring strain and switching the antiaromaticity in pentalyne to the aromaticity in metallapentalyne. An interesting question is raised: can the aromaticity in metallasilapentalyne (III) be retained, considering the fact that the silicon atom is reluctant to participate in π bonding? Here we report a thorough theoretical study on the stability and aromaticity of metallasilapentalynes. The computed energies and magnetic properties reveal the reduced aromatic character of osmasilapentalyne in comparison with osmapentalyne. The effect of the ligands, substituents, and base on the aromaticity and stability of osmasilapentalyne is also discussed, thus providing an important guide to the synthesis of osmasilapentalyne.
Co-reporter:Congqing Zhu;Qin Zhu;Jinglan Fan;Dr. Jun Zhu;Dr. Xumin He;Dr. Xiao-Yu Cao;Dr. Haiping Xia
Angewandte Chemie International Edition 2014 Volume 53( Issue 24) pp:6232-6236
Publication Date(Web):
DOI:10.1002/anie.201403245
Abstract
Aromaticity is one of the most important concepts in organic chemistry. A variety of metalla-aromatic compounds have been recently prepared and in most of those examples, the metal participates only in a monocyclic ring. In contrast, metal-bridged bicyclic aromatic molecules, in which a metal is shared between two aromatic rings, have been less developed. Herein, we report the first metal-bridged tricyclic aromatic system, in which the metal center is shared by three aromatic five-membered rings. These metalla-aromatics are formed by reaction between osmapentalyne and arene nucleophiles. Experimental results and theoretical calculations reveal that the three five-membered rings around the osmium center are aromatic. In addition, the broad absorption bands in the UV/Vis absorption spectra of these novel aromatic systems cover almost the entire visible region. This straightforward synthetic strategy may be extended to the synthesis of other metal-bridged polycyclic aromatics.
Co-reporter:Feifei Han;Dr. Tongdao Wang;Jinhua Li;Dr. Hong Zhang;Dr. Haiping Xia
Chemistry - A European Journal 2014 Volume 20( Issue 15) pp:
Publication Date(Web):
DOI:10.1002/chem.201490058
Co-reporter:Feifei Han;Dr. Tongdao Wang;Jinhua Li;Dr. Hong Zhang;Dr. Haiping Xia
Chemistry - A European Journal 2014 Volume 20( Issue 15) pp:4363-4372
Publication Date(Web):
DOI:10.1002/chem.201304957
Abstract
Treatment of the osmium complex [Os{CHC-(PPh3)CH(OH)-η2-C≡CH}(PPh3)2(NCS)2] (1) with excess triethylamine produces the first m-metallaphenol complex [Os{CHC(PPh3)CHC(OH)CH}(PPh3)2(NCS)2] (2). The NMR spectroscopic and structural data as well as the nucleus-independent chemical-shift (NICS) values suggest that osmaphenol 2 has aromatic character. The reactivity studies demonstrate that 2 can react with different isocyanates to form the annulation reaction products [Os{CHC(PPh3)CHC(OCONR)C}(PPh3)2(NCS)2] (R=Ph (3), iPr (7), Bn (8)) via the carbamate intermediates [Os{CHC(PPh3)CHC(O-CONHR)CH}(PPh3)2(NCS)2] (R=Ph (4), iPr (5), Bn (6)). In addition, the similar annulation reactions can be extended to other unsaturated compounds containing N–C multiple bonds, for example, isothiocyanates, pyridine, and sodium thiocyanate, which can produce the corresponding fused osmabenzene complexes. In contrast, the reactions of 2 with common electrophiles, such as NOBF4, NO2BF4, N-bromosuccinimide, and N-chlorosuccinimide only led to the decomposition of the metallaphenol ring. The experimental results suggest that 2 is very electrophilic and readily reacts with nucleophiles, which is mainly due to the metal center and the strong electron-withdrawing phosphonium group.
Co-reporter:Jinxiang Chen, Chunhong Zhang, Tingwan Xie, Ting Bin Wen, Hong Zhang, and Haiping Xia
Organometallics 2013 Volume 32(Issue 14) pp:3993-4001
Publication Date(Web):July 3, 2013
DOI:10.1021/om400469e
Treatment of OsCl2(PPh3)3 with HC≡CCH(OH)Et produces the cyclic complex Os(PPh3)2Cl2(CHC(PPh3)CH(OH)CH2CH3) (1), which can undergo dehydration to give the hydrido–alkenylvinylidene complex Os(PPh3)2HCl2(═C═C(PPh3)CH═CHCH3) (2). Reaction of 2 with HBF4 generates the hydrido–butenylcarbyne complex [OsHCl2(≡CC(PPh3)═CH(Et))(PPh3)2]BF4 (3). The complex 3 evolves into the unstable metallabenzene [(PPh3)2(RCN)ClOs(CHC(PPh3)CHCHCH)]BF4 (4; RCN = benzonitrile, 2-cyanobenzaldehyde, 3-methoxyacrylonitrile, 2-cyanoacetamide) via triple hydrogen eliminations in the presence of excess nitriles in refluxing CHCl3 in an air atmosphere. The ligand substitution reaction of 4 with excess CO affords the stable metallabenzene product [(PPh3)2(CO)ClOs(CHC(PPh3)CHCHCH)]BF4 (5). The key intermediates, η2-allene-coordinated osmium complexes [(PPh3)2(RCN)ClOs(CH═C(PPh3)CH═C═CH2)]BF4 (6; RCN = benzonitrile, 2-cyanobenzaldehyde, 3-methoxyacrylonitrile, 2-cyanoacetamide) can be captured by performing the conversion at room temperature. Remarkably, in the absence of nitriles, reaction of 3 with excess CO only generates the vinylethenyl complex [(PPh3)2(CO)2ClOs(CH═C(PPh3)CH═CHCH3)]BF4 (7). The complexes 1–3, 5, 6a, and 7 have been structurally characterized by single-crystal X-ray diffraction. Detailed mechanisms of the conversions have been investigated with the aid of density functional theory (DFT) calculations. DFT calculations suggest that the high stablility of the carbonyl coordinated complexes in the conversion inhibits the further transformation to metallabenzene product. However, the transformation is both kinetically and thermodynamically favorable in the presence of the relatively weaker nitrile ligand, which is consistent with the experimental conversion of 3 to 5 via unstable metallabenzenes 4 observed for in situ NMR experiments.
Co-reporter:Chunhong Zhang, Hong Zhang, Laiying Zhang, Ting Bin Wen, Xumin He, and Haiping Xia
Organometallics 2013 Volume 32(Issue 13) pp:3738-3743
Publication Date(Web):June 17, 2013
DOI:10.1021/om400372w
In the presence of the acid HBF4, 3-alkenyl-2-phosphonium indolizines 3a–c can be produced respectively by adding PhC≡CCOCH3 (2a), CH3OCOC≡CCOOCH3 (2b), and CH3CH2C≡CCOCH3 (2c) to a mixture of ruthenium complex RuCl2(PPh3)3 and the propargyl alcohol (2-Py)CH(OH)C≡CH (1). We carefully investigated the mechanism of this reaction by means of structurally characterizing two key intermediates, ruthenium vinyl (4) and ruthenium carbene (5), and by deuterium-labeling experiments. A plausible mechanism is proposed, which involves addition of a proton to an alkyne carbon and the insertion of an alkyne into the Cα bond of an alkenylcarbene group, followed by an α-H elimination and reductive elimination.
Co-reporter:Tongdao Wang;Dr. Jun Zhu;Feifei Han;Chen Zhou;Hanyu Chen;Dr. Hong Zhang;Dr. Haiping Xia
Angewandte Chemie International Edition 2013 Volume 52( Issue 50) pp:13361-13364
Publication Date(Web):
DOI:10.1002/anie.201306911
Co-reporter:Tongdao Wang;Dr. Hong Zhang;Feifei Han;Lipeng Long;Dr. Zhenyang Lin;Dr. Haiping Xia
Angewandte Chemie International Edition 2013 Volume 52( Issue 35) pp:9251-9255
Publication Date(Web):
DOI:10.1002/anie.201302863
Co-reporter:Guangning Hong, Huan Zhang, Yangju Lin, Yinjun Chen, Yuanze Xu, Wengui Weng, and Haiping Xia
Macromolecules 2013 Volume 46(Issue 21) pp:8649-8656
Publication Date(Web):October 16, 2013
DOI:10.1021/ma4017532
The development of polymers that possess superb mechanical properties and at the same time are capable of sensing damage and self-healing is presented. Copper-catalyzed azide–alkyne cycloaddition (CuAAC) based tridentate ligand 2,6-bis(1,2,3-triazol-4-yl)pyridine (BTP) and covalent mechanophore spiropyran (SP) units are incorporated into the polymer backbone to prepare ligand macromolecule. Upon coordinating with transition or lanthanide metal salts, metallosupramolecular films with phased-separated soft/hard morphology are spontaneously formed. The resulting materials show a rare combination of strong, tough, and elastic mechanical properties and are able to sense damage by changing optical properties. The Zn2+-containing material can self-heal in the presence of solvent and fully restore its mechanical properties. The underlying structure–property relationship is unveiled. In particular, the interplay between the covalent SP mechanophore and the noncovalent metal–ligand interactions and their hard phase is demonstrated.
Co-reporter:Tongdao Wang;Dr. Hong Zhang;Feifei Han;Lipeng Long;Dr. Zhenyang Lin;Dr. Haiping Xia
Chemistry - A European Journal 2013 Volume 19( Issue 33) pp:10982-10991
Publication Date(Web):
DOI:10.1002/chem.201301398
Abstract
Alkali-resistant osmabenzene [(SCN)2(PPh3)2Os{CHC(PPh3)CHCICH}] (2) can undergo nucleophilic aromatic substitution with MeOH or EtOH to give cine-substitution products [(SCN)2(PPh3)2Os{CHC(PPh3)CHCHCR}] (R=OMe (3), OEt(4)) in the presence of strong alkali. However, the reactions of compound 2 with various amines, such as n-butylamine and aniline, afford five-membered ring species, [(SCN)2(PPh3)2Os{CHC(PPh3)CHC(CHNHR′)}] (R′=nBu(8), Ph(9)), in addition to the desired cine-substitution products, [(SCN)2(PPh3)2Os{CHC(PPh3)CHCHC(NHR′)}] (R′=nBu(6), Ph(7)), under similar reaction conditions. The mechanisms of these reactions have been investigated in detail with the aid of isotopic labeling experiments and density functional theory (DFT) calculations. The results reveal that the cine-substitution reactions occur through nucleophilic addition, dissociation of the leaving group, protonation, and deprotonation steps, which resemble the classical “addition-of-nucleophile, ring-opening, ring-closure” (ANRORC) mechanism. DFT calculations suggest that, in the reaction with MeOH, the formation of a five-membered metallacycle species is both kinetically and thermodynamically less favorable, which is consistent with the experimental results that only the cine-substitution product is observed. For the analogous reaction with n-butylamine, the pathway for the formation of the cine-substitution product is kinetically less favorable than the pathway for the formation of a five-membered ring species, but is much more thermodynamically favorable, again consistent with the experimental conversion of compound 8 into compound 6, which is observed in an in situ NMR experiment with an isolated pure sample of 8.
Co-reporter:Bin Liu;QianYi Zhao;HuiJuan Wang;BiRong Zeng;XiaoYu Cao
Science China Chemistry 2013 Volume 56( Issue 8) pp:1105-1111
Publication Date(Web):2013 August
DOI:10.1007/s11426-013-4876-y
We studied the reactivity of an osmium vinyl complex containing a coordinated hydroxyl group OsCl2(PPh3)2[CH=C(PPh3)-CHPh(OH)] (1) toward bidentate ligand 1,4-bis(diphenylphosphino)butane (DPPB), π acid ligand (CO), base (Cs2CO3) and heat. Two osmium vinyl complexes OsCl2(dppb)[CH=C(PPh3)CHPh(OH)] (2) and OsCl2(CO)2(PPh3)[CH=C(PPh3)CHPh(OH)] (3), as well as two relatively rare phosphonium-containing osmafuran complexes Os(η2-OCOO)(PPh3)2[CHC(PPh3)CPhO] (4) and OsCl2(PPh3)2[CHC(PPh3)CPhO] (5), were obtained in high yields from these reactions. All products were characterized by NMR spectroscopy, elemental analysis, and their structures were further confirmed by single crystal X-ray diffraction.
Co-reporter:Bin Liu;Qianyi Zhao;Huijuan Wang;Jinxiang Chen;Xiaoyu Cao;Zexing Cao
Chinese Journal of Chemistry 2012 Volume 30( Issue 9) pp:2158-2168
Publication Date(Web):
DOI:10.1002/cjoc.201200650
Abstract
A novel [4+2] cycloaddition reaction between osmium alkenylcarbyne complex [OsHCl2{CC(PPh3)CHPh}(PPh3)2]+BF4− (1) and nitriles (acetonitrile and benzonitrile) provided metallapyridiniums [OsCl2{CHC(PPh3)CPhCRNH}(PPh3)2]+BF4− (R=CH3 (2), Ph (3)) and OsCl3{CHC(PPh3)CPhCPhNH}(PPh3) (4). A possible mechanism was proposed. Treatment of 2 with n-BuLi and NEt3 afforded osmapyridines OsCl2{CHC(PPh3)CPhCCH3N}(PPh3)2 (5) and [OsCl{CHC(PPh3)CPhCCH3N}(C6H5N)(PPh3)2]+BF4− (6). The ligands of osmapyridiniums 2 and 4 were changed, thus providing a series of osmapyridiniums [OsCl(SCN){CHC(PPh3)CPhC(CH3)NH}(PPh3)2]+Cl− (7), OsCl(SCN)2{CHC(PPh3)CPhC(CH3)NH}(PPh3) (8), Os(SCN)3{CHC(PPh3)CPhC(CH3)NH}(PPh3) (9), [OsCl{CHC(PPh3)CPhC(CH3)NH}(CH3CN)(PPh3)2]+(BF4−)2 (10), [OsCl{CHC(PPh3)CPhC(CH3)NH}-(η2-1,10-phenanthroline)(PPh3)]+(BF4−)Cl− (11), [OsCl{CHC(PPh3)CPhC(CH3)NH}(η2-8-hydroxyquinoline) (PPh3)]+BF4− (12), and [Os{CHC(PPh3)CPhCPhNH}(CH3CN)3(PPh3)]+(BF4−)3 (13). Most of these products were characterized by NMR spectroscopy, elemental analysis and single crystal X-ray diffraction.
Co-reporter:Tongdao Wang;Dr. Hong Zhang;Feifei Han;Dr. Ran Lin;Dr. Zhenyang Lin;Dr. Haiping Xia
Angewandte Chemie International Edition 2012 Volume 51( Issue 39) pp:9838-9841
Publication Date(Web):
DOI:10.1002/anie.201204073
Co-reporter:Qianyi Zhao;Jun Zhu;Zi-Ao Huang;Dr. Xiao-Yu Cao;Dr. Haiping Xia
Chemistry - A European Journal 2012 Volume 18( Issue 37) pp:
Publication Date(Web):
DOI:10.1002/chem.201290159
Co-reporter:Qianyi Zhao;Jun Zhu;Zi-Ao Huang;Dr. Xiao-Yu Cao;Dr. Haiping Xia
Chemistry - A European Journal 2012 Volume 18( Issue 37) pp:11597-11603
Publication Date(Web):
DOI:10.1002/chem.201201558
Abstract
We report herein the first example of the conversion of metallabenzyne II and isometallabenzene III. The osmium hydride vinylidene complex 1 reacts with HCCCH(OEt)2 to give osmabenzyne 3 via isoosmabenzene 2. Compound 3 exhibits high thermal stability in air. Nonetheless, nucleophilic attack at 3 provides isoosmabenzenes 4 a and 4 b, or opens the ring to produce 5 a and 5 b. We propose mechanisms to disclose the intrinsic connection between the six-membered metallacycles, and carry out DFT calculations to rationalize the regioselectivity of the nucleophilic addition reactions.
Co-reporter:Ran Lin;Jing Zhao;Hanyu Chen;Dr. Hong Zhang;Dr. Haiping Xia
Chemistry – An Asian Journal 2012 Volume 7( Issue 8) pp:1915-1924
Publication Date(Web):
DOI:10.1002/asia.201200231
Abstract
Treatment of the osmabenzene [Os{CHC(PPh3)CHC(PPh3)CH} Cl2(PPh3)2]Cl (1) with excess 8-hydroxyquinoline produces monosubstituted osmabenzene [Os{CH C(PPh3) CHC(PPh3)CH}(C9H6NO)Cl(PPh3)]Cl (2) or disubstituted osmabenzene [Os{CHC(PPh3)CHC(PPh3)CH} (C9H6NO)2]Cl (3) under different reaction conditions. Osmabenzene 2 evolves into cyclic η2-allene-coordinated complex [Os{CHC(PPh3)CH=(η2-CCH2)}(C9H6NO)(PPh3)2]Cl (4) in the presence of excess PPh3 and NaOH, presumably involving a PC bond cleavage of the metallacycle. Reaction of 4 with excess 8-hydroxyquinoline under air affords the SNAr product [(C9H6NO)Os{CHC(PPh3)CHCHC} (C9H6NO)(PPh3)]Cl (5). Complex 4 is fairly reactive to a nucleophile in the presence of acid, which could react with water to give carbonyl complex [Os{CHC(PPh3)CHCH2}(C9H6NO) (CO)(PPh3)2]Cl (6). Complex 4 also reacts with PPh3 in the presence of acid and results in a transformation to [Os {CHC(PPh3)CHCHC}(C9H6NO)Cl (PPh3)2]Cl (7) and [Os{CHC(PPh3) CH=(η2-CCH(PPh3))}(C9H6NO) Cl(PPh3)]Cl (8). Further investigation shows that the ratio of 7 and 8 is highly dependent on the amount of the acid in the reaction.
Co-reporter:Zhaoju Yu;Ran Li;Junying Zhan;Cong Zhou;Le Yang;Guomei He
Journal of Applied Polymer Science 2011 Volume 121( Issue 6) pp:3400-3406
Publication Date(Web):
DOI:10.1002/app.33838
Abstract
A propargyl-substituted polycarbosilane (PCS), namely, propargyl-substituted hyperbranched hydrodipolycarbosilane (PHPCS), was prepared by a modified synthesis route, which involved Grignard coupling of partially methoxylated Cl3SiCH2Cl and CHCCH2Cl, followed by reduction with lithium aluminum hydride. The resultant PHPCSs were characterized by gel permeation chromatography, Fourier transform infrared (FTIR) spectroscopy, and NMR. Moreover, the thermal properties of the PHPCSs were investigated by thermogravimetric analysis. The ceramic yield of PHPCS at 1400°C was about 82.5%, which was about 10 wt % higher than that of hyperbranched hydrodipolycarbosilane without the substitution of propargyl groups. The PHPCS-derived ceramics were characterized by X-ray diffraction (XRD), FTIR spectroscopy, and elemental analysis. The XRD and FTIR results indicate that the heat treatment significantly influenced the evolution of crystalline β-SiC. It can be convenient to get near-stoichiometric ceramics from PHPCS through the control of feed ratios of the starting materials. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci 121:3400–3406, 2011
Co-reporter:Zhaoju Yu;Yunhui Fang;Muhe Huang;Ran Li;Junying Zhan;Cong Zhou;Guomei He
Polymers for Advanced Technologies 2011 Volume 22( Issue 12) pp:2409-2414
Publication Date(Web):
DOI:10.1002/pat.1777
Abstract
A boron-modified ethynylhydridopolycarbosilane (B-EHPCS) was successfully prepared via the hydroboration reaction of ethynylhydridopolycarbosilane (EHPCS) with 9-borabicyclo-[3.3.1]nonane (9-BBN). The as-synthesized B-EHPCS with a branched structure was characterized by means of gel permeation chromatography (GPC), Fourier transform infrared spectroscopy (FTIR), and nuclear magnetic resonance (NMR). The structural evolution of ceramic conversion of B-EHPCS was investigated by solid-state NMR. The 13C magic angle spinning (MAS) NMR results indicated that the CC and CC groups of B-EHPCS take part in the hydrosilation cross-linking at a relatively low temperature (170°C). According to the 29Si MAS NMR analysis, the CSiH3 end groups are most reactive hydride functionality involved in the hydrosilation cross-linking. With increasing curing temperature, the C2SiH2 and CSiH3 units are completely consumed, while C3SiH units remain even after curing at 600°C. The TGA results show the 1200°C ceramic yield of B-EHPCS reaches 86%, which is 10% higher than that of the parent EHPCS (76%). At high temperatures, the introduction of <1 wt% boron significantly inhibits silicon carbide (SiC) crystallization. The 1800°C ceramics derived from B-EHPCS are found to be significantly denser than that from EHPCS. Copyright © 2010 John Wiley & Sons, Ltd.
Co-reporter:Zhaoju Yu;Junying Zhan;Cong Zhou;Le Yang
Journal of Inorganic and Organometallic Polymers and Materials 2011 Volume 21( Issue 3) pp:
Publication Date(Web):2011 September
DOI:10.1007/s10904-011-9483-9
A hybrid precursor of titanium-containing polycarbosilane is prepared by blending hyperbranched polycarbosilane (HBPCS) and tetrabutyl titanate (TBT), and then crosslinking at 160 °C, followed by pyrolyzing at high temperatures to afford SiC(Ti) ceramics. The crosslinking reaction of HBPCS–TBT hybrid precursor is investigated by FT-IR, solid state 29Si MAS NMR, and GPC. The results indicate that the crosslinking reaction takes place via condensation between the Si–H bond of HBPCS and butoxy group in TBT leading to the formation of Si–O–Ti bonds. The thermal properties and structural evolution of crosslinked hybrid precursor and the crystallization behavior and composition of final ceramics are investigated by TGA, FT-IR, Raman spectroscopy, XRD and energy dispersive elemental analysis. The ceramic yield of hybrid precursor is significantly enhanced by introduction of TBT. The ceramic yield at 1,400 °C is 83% for HBPCS–TBT-5 as measured by TGA. The Ti-content in the ceramic is controlled by varying the TBT content in the feed. The SiC(Ti) ceramic is amorphous at 900 °C. The characteristic peaks of β-SiC and TiC appear until 1,600 °C. The growth of SiC crystals is inhibited by the formation of TiC.
Co-reporter:Ran Lin;Dr. Hong Zhang;Dr. Shunhua Li;Jiani Wang ;Dr. Haiping Xia
Chemistry - A European Journal 2011 Volume 17( Issue 15) pp:
Publication Date(Web):
DOI:10.1002/chem.201190072
Co-reporter:Ran Lin;Dr. Hong Zhang;Dr. Shunhua Li;Jiani Wang ;Dr. Haiping Xia
Chemistry - A European Journal 2011 Volume 17( Issue 15) pp:4223-4231
Publication Date(Web):
DOI:10.1002/chem.201003566
Abstract
Treatment of the ruthenabenzene [Ru{CHC(PPh3)CHC(PPh3)CH}Cl2(PPh3)2]Cl (1) with excess 8-hydroxyquinoline in the presence of CH3COONa under air atmosphere produced the SNAr product [(C9H6NO)Ru{CHC(PPh3)CHC(PPh3)C}(C9H6NO)(PPh3)]Cl2 (3). Ruthenabenzene 3 could be stable in the solution of weak alkali or weak acid. However, reaction of 3 with NaOH afforded a 7:1 mixture of ruthenabenzenes [(C9H6NO)Ru{CHC(PPh3)CHCHC}(C9H6NO)(PPh3)]Cl (4) and [(C9H6NO)Ru{CHCHCHC(PPh3)C}(C9H6NO)(PPh3)]Cl (5), presumably involving a PC bond cleavage of the metallacycle. Complex 3 was also reactive to HCl, which results in a transformation of 3 to ruthenabenzene [Ru{CHC(PPh3)CHC(PPh3)C}Cl2(C9H6NO)(PPh3)]Cl (6) in high yield. Thermal stability tests showed that ruthenabenzenes 4, 5, and 6 have remarkable thermal stability both in solid state and in solution under air atmosphere. Ruthenabenzenes 4 and 5 were found to be fluorescent in common solvents and have spectral behaviors comparable to those organic multicyclic compounds containing large π-extended systems.
Co-reporter:Ran Lin;Dr. Hong Zhang;Dr. Shunhua Li;Leiqi Chen;Dr. Weiguang Zhang;Dr. Ting Bin Wen; Hui Zhang;Dr. Haiping Xia
Chemistry - A European Journal 2011 Volume 17( Issue 8) pp:
Publication Date(Web):
DOI:10.1002/chem.201001867
Abstract
We report herein the first study on the chemical interaction between metallabenzenes and bioactive molecules. Due to its unique stereoelectronic activities, a phenanthroline-derived ruthenabenzene [Ru{CHC(PPh3)CHC(PPh3)CH}Cl(C12H8N2)(PPh3)]Cl2 (1) selectively binds cysteine in aqueous solution at physiological pH and then undergoes a dynamic inversion of configuration at the Ru center. The structure of the L-cysteine-binding product of 1 has been determined by means of X-ray diffraction. The replacement of the L-cysteine with the D form results in an inverted stereodynamic effect. Furthermore, the inversion process of the Ru-centered configuration could be conveniently controlled by a simple pH adjustment. This is attributed to the significant influence of a special intramolecular electrostatic interaction on the dynamic epimerization process of the cysteine-binding product.
Co-reporter:Qianyi Zhao;Lei Gong;Chunfa Xu;Dr. Jun Zhu;Dr. Xumin He ;Dr. Haiping Xia
Angewandte Chemie International Edition 2011 Volume 50( Issue 6) pp:1354-1358
Publication Date(Web):
DOI:10.1002/anie.201006442
Co-reporter:Zhaoju Yu, Muhe Huang, Yunhui Fang, Ran Li, Junying Zhan, Birong Zeng, Guomei He, Haiping Xia, Litong Zhang
Reactive and Functional Polymers 2010 70(6) pp: 334-339
Publication Date(Web):June 2010
DOI:10.1016/j.reactfunctpolym.2010.02.007
Co-reporter:Jinbo Huang, Ran Lin, Liqiong Wu, Qianyi Zhao, Congqing Zhu, Ting Bin Wen and Haiping Xia
Organometallics 2010 Volume 29(Issue 13) pp:2916-2925
Publication Date(Web):June 15, 2010
DOI:10.1021/om1001155
Treatment of osmabenzene [Os(CHC(PPh3)CHC(PPh3)CH)Cl2(PPh3)2]OH (3) with various diisocyanides in the presence of NH4PF6 afforded a series of diisocyanide-bridged bisosmabenzenes [(μ-CN−R−NC){Os(CHC(PPh3)CHC(PPh3)CH)Cl2(PPh3)}2][PF6]2 (R = 4,4′-C6H4-C6H4 (5a), 4,4′-C6H4CH2C6H4 (5b), 4,4′-C6H4OC6H4 (5c), 1,4-C6H4 (5d)) in good yields through ligand substitution reactions. Similarly, reaction of osmafuran [Os(CHC(PPh3)C(OEt)O)Cl2(PPh3)2] (6) with 1,4-phenylenediisocyanide produced the diisocynide-bridged bisosmafuran [μ-(1,4-phenylenediisocyanide){Os(CHC(PPh3)C(OEt)O)Cl(PPh3)2}2]Cl2 (7). Bisosmabenzenes containing a chloro and a phosphonium substituent on each metallacycle [(μ-CN−R−NC){Os(CHC(PPh3)CHCClCH)Cl(PPh3)2}2]Cl2 (R = 4,4′-C6H4-C6H4 (9a), 4,4′-C6H4CH2C6H4 (9b), 4,4′-C6H4OC6H4 (9c), 1,4-C6H4 (9d)) could be obtained in modest yields from the reactions of the osmacycle [Os(CH═C(PPh3)CH(OH)-η2-C≡CH)Cl2(PPh3)2] (8) with corresponding diisocyanides in the presence of NH4PF6 and NaCl via nucleophilic addition reactions. All of these complexes have been fully characterized by 1H, 31P{1H}, and 13C{1H} NMR spectrometry, IR spectrometry, and elemental analyses. Moreover, the structure of 9d has been established by X-ray crystallography. The electrochemical properties of stable bisosmabenzenes 9a−d have been investigated, which revealed that the two metal centers in 9c and 9d can interact with each other through a diisocyanide bridge.
Co-reporter:Xumin He Dr.;Lei Gong Dr.;Katja Kräling;Katharina Gründler;Corazon Frias;Richard D. Webster Dr.;Eric Meggers Dr.;Aram Prokop Dr. Dr.
ChemBioChem 2010 Volume 11( Issue 11) pp:1607-1613
Publication Date(Web):
DOI:10.1002/cbic.201000055
Abstract
Screening of a library of structurally unusual osmacyclic complexes for their antiproliferate properties in HeLa cells led to the discovery of a highly cytotoxic η2-allene osmacycle. In this remarkably stable complex, osmium constitutes part of a metallacycle through the formation of a σ-bond to a carbon in combination with coordination to an allene moiety. The osmacycle strongly induces apoptosis in Burkitt-like lymphoma cells at submicromolar concentrations. The reduction of the mitochondrial membrane potential, the induction of DNA fragmentation, and the activation of caspases-9 and -3 reveal that programmed cell death occurs through the intrinsic mitochondrial pathway. From the lipophilic and cationic nature of the osmacycle, in addition to a low oxidation potential (E1/2=+0.27 V vs. Fc/Fc+, Fc=ferrocene) it is proposed that mitochondria are the cellular target where oxidative decomposition initiates apoptosis.
Co-reporter:Zhaoju Yu;Junying Zhan;Muhe Huang;Ran Li;Cong Zhou
Journal of Materials Science 2010 Volume 45( Issue 22) pp:6151-6158
Publication Date(Web):2010 November
DOI:10.1007/s10853-010-4701-3
Room-temperature cross-linking of a hyperbranched polycarbosilane (HBPCS) with divinylbenzene (DVB) in the presence of the cyclohexanone peroxide–cobaltous naphthenate (CHP–CN) initiator system was studied. According to the Fourier transform infrared spectroscopy (FT-IR) and 1H nuclear magnetic resonance (1H NMR) results, the cross-linking reaction occurred via the vinyl polymerization. The GPC analysis confirmed the molecular weight of the cross-linked HBPCS significantly increased. Thermal behaviors of cross-linked HBPCS and original HBPCS were investigated by thermal gravimetric analysis-differential thermal analysis (TGA–DTA). The TGA results indicated that the ceramic yield of HBPCS remarkably increased by the cross-linking treatment. For the HBPCS/10 wt% DVB system, the maximum of reaction degree of HBPCS was obtained, which might be responsible for the highest ceramic yield of 70.1 wt% at 1000 °C. However, the ceramic yield of the non-crosslinked HBPCS was only 45 wt% at 1000 °C. The evolution of crystal structure of SiC as a function of pyrolysis temperature was traced by means of X-ray diffraction (XRD) and FT-IR. With the pyrolysis temperature increasing, the β-SiC peaks became sharper and the grain size also grew larger. As the DVB content increased, the intensity of β-SiC peaks significantly reduced, indicating smaller β-SiC grain size.
Co-reporter:Hong Zhang Dr.;Ran Lin;Guangning Hong;Tongdao Wang;Ting Bin Wen Dr. Dr.
Chemistry - A European Journal 2010 Volume 16( Issue 23) pp:6999-7007
Publication Date(Web):
DOI:10.1002/chem.201000324
Abstract
The reactions of phosphonium-substituted metallabenzenes and metallapyridinium with bis(diphenylphosphino)methane (DPPM) were investigated. Treatment of [Os{CHC(PPh3)CHC(PPh3)CH}Cl2(PPh3)2]Cl with DPPM produced osmabenzenes [Os{CHC(PPh3)CHC(PPh3)CH}Cl2{(PPh2)CH2(PPh2)}]Cl (2), [Os{CHC(PPh3)CHC(PPh3)CH}Cl{(PPh2)CH2(PPh2)}2]Cl2 (3), and cyclic osmium η2-allene complex [Os{CHC(PPh3)CH(η2-CCH)}Cl2{(PPh2)CH2(PPh2)}2]Cl (4). When the analogue complex of osmabenzene 1, ruthenabenzene [Ru{CHC(PPh3)CHC(PPh3)CH}Cl2(PPh3)2]Cl, was used, the reaction produced ruthenacyclohexadiene [Ru{CHC(PPh3)CHC(PPh3)CH}Cl{(PPh2)CH2(PPh2)}2]Cl2 (6), which could be viewed as a Jackson–Meisenheimer complex. Complex 6 is unstable in solution and can easily be convert to the cyclic ruthenium η2-allene complexes [Ru{CHC(PPh3)CH(η2-CCH)}Cl{(PPh2)CH2(PPh2)}2]Cl2 (7) and [Ru{CHC(PPh3)CH(η2-CCH)}Cl2{(PPh2)CH2(PPh2)}2]Cl (8). The key intermediates of the reactions have been isolated and fully characterized, further supporting the proposed mechanism for the reactions. Similar reactions also occurred in phosphonium-substituted metallapyridinium [OsCl2{NHC(CH3)C(Ph)C(PPh3)CH}(PPh3)2]BF4 to give the cyclic osmium η2-allene-imine complex [OsCl2{NHC(CH3)C(Ph)(η2-CCH)}{(PPh2)CH2(PPh2)}(PPh3)]BF4 (11).
Co-reporter:Yumei Lin, Hui Xu, Lei Gong, Ting Bin Wen, Xu-Min He and Haiping Xia
Organometallics 2010 Volume 29(Issue 13) pp:2904-2910
Publication Date(Web):June 4, 2010
DOI:10.1021/om100187t
Treatment of HC≡CCH(OH)CH═CH2 with [IrHCl(CO)(PPh3)3]BF4 at room temperature afforded an iridacyclohexadiene, [Ir(CH═C(PPh3)CH═CHCH2)Cl(CO)(PPh3)2]BF4 (1). The reactivity of complex 1 had been investigated. Reaction of 1 with 1 equiv of bromine produced an iridacyclopentadiene, [Ir(CH═C(PPh3)CH═C(CH2Br))Cl(CO)(PPh3)2]BF4 (2). When excess bromine was used, iridacyclopentadiene 2 underwent subsequent intramolecular C(sp2)−C(sp3) coupling between the exocyclic −CH2Br group and a phenyl of the PPh3 ligand, leading to the formation of a fused iridacycle complex, [Ir(CH═C(PPh3)C(Br)═C(CHBr))(P(C6H4)Ph2)Cl(CO)PPh3]Br3 (3). A mechanism for the formation of complex 3 starting from 1 was proposed, in which the process involved a triple C−H activation as well as a rare C(sp2)−C(sp3) reductive elimination.
Co-reporter:Guomei He;Jiangxi Chen;Lifu Chen;Litong Zhang
Journal of Applied Polymer Science 2009 Volume 113( Issue 6) pp:3725-3731
Publication Date(Web):
DOI:10.1002/app.30153
Abstract
Polyaluminocarbosilane (PACS) was synthesized directly by the one-pot reaction of polydimethylsilane (PDMS) with aluminum acetylacetonate [Al(acac)3] in an autoclave. In this closed system, all the aluminum in Al(acac)3 was converted into PACS. Therefore, the content of aluminum could be readily controlled quantitatively. On the basis of Fourier transform infrared, 1H-NMR, 13C-NMR, 29Si-NMR, and 27Al magic-angle spinning NMR analysis, the reaction mechanism was proposed as follows: PDMS dissociated during pyrolysis to generate silicon free radicals, and then they reacted with Al(acac)3 to yield PACS containing (SiO)nAl groups (n = 4, 5, or 6). Meanwhile, these reactions resulted in the cleavage of OC and/or OC bonds in Al(acac)3. Some of the free-radical fragments generated by this cleavage continued to react with the silicon free radicals and were incorporated into the structural units of PACS; the rest of them may have been converted into small oxygen-containing compounds, which were removed in the subsequent processing after the reactions. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Co-reporter:Tongdao Wang;Shunhua Li Dr.;Hong Zhang Dr.;Ran Lin;Feifei Han;Yumei Lin;TingBin Wen Dr. Dr.
Angewandte Chemie 2009 Volume 121( Issue 35) pp:6575-6578
Publication Date(Web):
DOI:10.1002/ange.200902738
Co-reporter:Bin Liu;Huijuan Wang;Hujun Xie;Birong Zeng;Jinxiang Chen;Jun Tao Dr.;TingBin Wen Dr.;Zexing Cao Dr. Dr.
Angewandte Chemie International Edition 2009 Volume 48( Issue 30) pp:5430-5434
Publication Date(Web):
DOI:10.1002/anie.200900998
Co-reporter:Lei Gong Dr.;Zhening Chen;Yumei Lin;Xumin He Dr.;Ting Bin Wen Dr.;Xin Xu Dr. Dr.
Chemistry - A European Journal 2009 Volume 15( Issue 25) pp:6258-6266
Publication Date(Web):
DOI:10.1002/chem.200900214
Co-reporter:Hong Zhang Dr.;Liqiong Wu;Ran Lin;Qianyi Zhao;Guomei He;Fangzu Yang;TingBin Wen Dr. Dr.
Chemistry - A European Journal 2009 Volume 15( Issue 14) pp:3546-3559
Publication Date(Web):
DOI:10.1002/chem.200801774
Co-reporter:Yumei Lin, Lei Gong, Hui Xu, Xumin He, Ting Bin Wen and Haiping Xia
Organometallics 2009 Volume 28(Issue 5) pp:1524-1533
Publication Date(Web):February 11, 2009
DOI:10.1021/om8010867
Ring-expansion reactions of the five-membered osmafuran Os{═CHC(PPh3)═C(O) OEt}Cl2(PPh3)2 (1) via alkyne insertion have been investigated, which lead to the formation of several nine-membered osmacycles. Reaction of 1 with PhC≡CH gives the nine-membered complexes Os{═CPhCH═CPh-η2-CH═CHC(PPh3)═C(O)OEt}Cl2(PPh3) as a mixture of a couple of isomers 2a and 2b with different disposition of the two chloride ligands on the metal centers. The reaction involves a head-to-tail double insertion of PhC≡CH into osmacycle 1 via [2 + 2] cycloaddition process, which is relevant to the polymerization of alkynes by metathesis reaction. Treatment of the mixture of 2a and 2b with PMe3 gives selectively Os{═CPhCH═CPh-η2-CH═CHC(PPh3)═C(O)OEt}Cl2(PMe3) (3), the PMe3-substituted counterpart of 2a. These complexes might serve as the intermediates for alkyne polymerization which are stabilized by the coordination of internal olefin. Heating the mixture of 2a and 2b in CHCl3 under reflux gives complex Os{η2-CHPh═CHCPh═CHCC(PPh3)C(O)OEt}Cl2(PPh3) (4) by an intramolecular hydrogen shift. In addition, reaction of 1 with HC≡CCH(OH)Ph affords [Os{O═CPhCH2-η2-CH═CHC(PPh3)═C(O)OEt}Cl(PPh3)2]Cl (5) as a monoinsertion product, which can dissociate a phosphine ligand under reflux in CH2Cl2 to give complex Os{O═CPhCH2-η2-CH═CHC(PPh3)═C(O)OEt}Cl2(PPh3) (6). The one of the α-H of the carbonyl group in complex 5 can be deprotonated by NEt3 to give an η3-allylic structure Os[η3-CH{CPh(═O)}CHCHC(PPh3)═C(O)OEt]Cl(PPh3)2 (7). Treatment of 7 in CHCl3 with 1 equiv of HCl regenerates 5. All of the complexes can be prepared under mild condition in good yield. Moreover, these reactions provide convenient and efficient routes to synthesize the nine-membered osmacycles. Complexes 1, 3, 4, 5′, 6, and 7 have been characterized by X-ray diffraction analysis.
Co-reporter:Lei Gong, Yumei Lin, Ting Bin Wen and Haiping Xia
Organometallics 2009 Volume 28(Issue 4) pp:1101-1111
Publication Date(Web):January 27, 2009
DOI:10.1021/om800907v
The study on the reactivity of an osmium-coordinated alkyne alcohol complex OsCl2(CH═C(PPh3)CH(OH)-η2-C≡CH)(PPh3)2 (1) has been carried out. Treatment of 1 with acetic acid, ethylene diamine, 2,2′-bipyridine, trimethylphospine, or tributylphosphine led to the formation of several coordinated η2-α,β-unsaturated ketone osmacycles, including OsCl2(CH═C(PPh3)C(O)-η2-CH═CH2)(PPh3)2 (3), [OsCl(CH═C(PPh3)C(O)-η2-CH═CH2)(PPh3)(H2NCH2CH2NH2)]Cl (4), [OsCl(CH═C(PPh3)C(O)-η2-CH═CH2)(PPh3)(2,2′-bipy)]Cl (5), OsCl2(CH═C(PPh3)C(O)-η2-CH═CH2)(PMe3)2 (6), [OsCl(CH═C(PPh3)C(O)-η2-CH═CH2)(PMe3)3]Cl (8), and OsCl2(CH═C(PPh3)C(O)-η2-CH═CH2)(PBu3)2 (9). Similar chemistry was also observed starting from OsBr2(CH═C(PPh3)CH(OH)-η2-C≡CH)(PPh3)2 (10), which afforded OsBr2(CH═C(PPh3)C(O)-η2-CH═CH2)(PPh3)2 (11) on treatment with acetic acid. All these cyclic α,β-unsaturated ketone complexes are air-stable in the solid state, and most of them are also stable in solution except for OsCl2(CH═C(PPh3)C(O)-η2-CH═CH2)(PMe3)2 (6) and [OsCl(CH═C(PPh3)C(O)-η2-CH═CH2)(PMe3)3]Cl (8). Complex 8 can isomerize to the osmaphenol [OsCl(CHC(PPh3)C(OH)CHCH)(PMe3)3]Cl (12) as the major product in dry chloroform, but transforms into the osmafuran [Os(CO)(CHC(PPh3)C(CH3)O)(PMe3)3]Cl2 (13) in wet chloroform, while complex 6 is stable in dry solvent, but can convert to the osmafuran [OsCl(CO)(CHC(PPh3)C(CH3)O)(PMe3)2]Cl (14). The remarkable thermostability and chemical stability of the coordinated α,β-unsaturated ketone osmacycles have been studied preliminarily with 3 as a representative example. The coordinated α,β-unsaturated ketone metallacyclic framework of 3 is stable in different ligand environments. For example, treatment of 3 with carbon monoxide led only to ligand substitution to produce OsCl2(CH═C(PPh3)C(O)-η2-CH═CH2)(CO)(PPh3) (15).
Co-reporter:Bin Liu;Huijuan Wang;Hujun Xie;Birong Zeng;Jinxiang Chen;Jun Tao Dr.;TingBin Wen Dr.;Zexing Cao Dr. Dr.
Angewandte Chemie 2009 Volume 121( Issue 30) pp:5538-5542
Publication Date(Web):
DOI:10.1002/ange.200900998
Co-reporter:Tongdao Wang;Shunhua Li Dr.;Hong Zhang Dr.;Ran Lin;Feifei Han;Yumei Lin;TingBin Wen Dr. Dr.
Angewandte Chemie International Edition 2009 Volume 48( Issue 35) pp:6453-6456
Publication Date(Web):
DOI:10.1002/anie.200902738
Co-reporter:Bin Liu;Hujun Xie;Huijuan Wang;Liqiong Wu;Qianyi Zhao;Jinxiang Chen;TingBin Wen Dr.;Zexing Cao Dr. Dr.
Angewandte Chemie International Edition 2009 Volume 48( Issue 30) pp:5461-5464
Publication Date(Web):
DOI:10.1002/anie.200902238
Co-reporter:Jiangxi Chen;Guomei He;Zhinan Liao;Birong Zeng;Jianglei Ye;Lifu Chen;Litong Zhang
Journal of Applied Polymer Science 2008 Volume 108( Issue 5) pp:3114-3121
Publication Date(Web):
DOI:10.1002/app.27262
Abstract
The control of structure formation of polycarbosilane (PCS) synthesized from polydimethylsilane (PDMS) was studied. It was found that the molecular structure of PCS was strongly dependent on the reaction time and reaction temperature. Shorter reaction time or lower reaction temperature is preferred to produce higher concentration of HSiC3 group and less SiC4 group in PCS skeleton, which was confirmed by 29Si NMR analysis. Higher reaction temperature or longer reaction time tended to dissociate more Si–Si chains to give PCS with higher molecular weight and broader distribution, as verified by GPC characterization. By interrupting the structure evolution of PCS from PDMS at low reaction temperature with short reaction time, solid PCS with controllable molecular structure can be obtained after the removal of the low molecular fraction by precipitation with ethanol. A scissor-couple rearrangement model was proposed for the formation of the PCS skeleton. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Co-reporter:Lei Gong, Yumei Lin, Ting Bin Wen, Hong Zhang, Birong Zeng and Haiping Xia
Organometallics 2008 Volume 27(Issue 11) pp:2584-2589
Publication Date(Web):April 24, 2008
DOI:10.1021/om8001558
Treatment of HC≡CCH(OH)CH═CH2 with OsCl2(PPh3)3 in THF produced the η2-allyl alcohol osmacycle OsCl2(PPh3)2(CH═C(PPh3)CH(OH)CH═CH2) (2) with poor solubility and low stability, which underwent a ligand substitution reaction with PMe3 to give the more stable analogue [OsCl(PMe3)3(CH═C(PPh3)CH(OH)CH═CH2)]Cl (3). Heating the suspension of 2 in CH2Cl2 led to the formation of four interesting conjugated osmacycles in one pot, including the osmabenzene OsCl2(PPh3)2(CHC(PPh3)CHCHCH) (4), the cyclic osmium η2-allene complex OsCl2(PPh3)2(CH═C(PPh3)CH═C═CH2) (5), the osmafuran OsCl2(PPh3)2(CHC(PPh3)C(CH2CH3)O) (6), and the α,β-unsaturated ketone complex OsCl2(PPh3)2(CH═C(PPh3)C(O)C═CH2) (7). All of the four products could also be produced in higher yield under appropriate conditions.
Co-reporter:Lei Gong, Yumei Lin, Guomei He, Hong Zhang, Huijuan Wang, Ting Bin Wen and Haiping Xia
Organometallics 2008 Volume 27(Issue 3) pp:309-311
Publication Date(Web):January 16, 2008
DOI:10.1021/om7012265
The synthesis and characterization of an air-stable p-osmaphenol and some related complexes are presented.
Co-reporter:Lei Gong, Liqiong Wu, Yumei Lin, Hong Zhang, Fangzu Yang, Tingbin Wen and Haiping Xia
Dalton Transactions 2007 (Issue 37) pp:4122-4125
Publication Date(Web):04 Jul 2007
DOI:10.1039/B706900F
A special sp2-carbon chain bridged bimetallic iridium complex has been synthesized and characterized; the compound has excellent air-stability, thermo-stability and electrochemical properties.
Co-reporter:Hong Zhang Dr.;Guomei He;Ting Bin Wen Dr.;Lei Gong;Guochen Jia Dr.
Angewandte Chemie International Edition 2006 Volume 45(Issue 18) pp:
Publication Date(Web):27 MAR 2006
DOI:10.1002/anie.200600055
A rare breed: Although many stable metallabenzene derivatives with a metal atom from the third transition series are known, those with a metal atom from the first and the second transition series are rare. Air-stable ruthenabenzenes (e.g. 1 and 2) have now been isolated and characterized.
Co-reporter:Hong Zhang Dr.;Guomei He;Ting Bin Wen Dr.;Lei Gong;Guochen Jia Dr.
Angewandte Chemie 2006 Volume 118(Issue 18) pp:
Publication Date(Web):27 MAR 2006
DOI:10.1002/ange.200600055
Eine seltene Spezies: Während viele stabile Metallabenzolderivate mit einem Metallatom aus der dritten Übergangsmetallreihe bekannt sind, gibt es nur wenige mit einem Metallatom aus der ersten oder zweiten Übergangsmetallreihe. Hier wird die Synthese und Charakterisierung luftstabiler Ruthenabenzole (z. B. 1 und 2) vorgestellt.
Co-reporter:Xiaoxi Zhou, Chunhong Zhang, Yumei Lin, Xumin He, Yan Zhang, Jianbo Wang and Haiping Xia
Inorganic Chemistry Frontiers 2014 - vol. 1(Issue 9) pp:NaN1082-1082
Publication Date(Web):2014/08/26
DOI:10.1039/C4QO00152D
Reactions of the ruthenium vinyl carbene complex [Ru{CHC(PPh3)CH(2-Py)}Cl2PPh3]BF4 (1) with five propargyl alcohols HCCC(OH)R1R2, (R1 = R2 = Ph; R1 = Ph, R2 = CH3; R1 = H, R2 = Ph; R1 = H, R2 = CH3; R1 = CHCH2, R2 = CH3) have been investigated, which led to the formation of several ten-membered η2-olefin coordinated ruthenacycles [Ru{OCR2CHR1-η2-CHCHC(PPh3)CH(2-Py)}Cl2PPh3]BF4 (R1 = R2 = Ph, 2; R1 = Ph, R2 = CH3, 3; R1 = H, R2 = Ph, 4; R1 = H, R2 = CH3, 5; R1 = CHCH2, R2 = CH3, 6), respectively. In these reactions, insertion of alkynes and intramolecular 1,2-migration of propargyl alcohols were performed in tandem. The results show that the 1,2-migratory preference of the groups is in the order of H > Ph > CH3. Complexes 2, 3, 5, and 6 were characterized by X-ray diffraction analysis and NMR spectra.
Co-reporter:Ming Luo, Congqing Zhu, Lina Chen, Hong Zhang and Haiping Xia
Chemical Science (2010-Present) 2016 - vol. 7(Issue 3) pp:
Publication Date(Web):
DOI:10.1039/C5SC03963K
Co-reporter:Lei Gong, Liqiong Wu, Yumei Lin, Hong Zhang, Fangzu Yang, Tingbin Wen and Haiping Xia
Dalton Transactions 2007(Issue 37) pp:NaN4125-4125
Publication Date(Web):2007/07/04
DOI:10.1039/B706900F
A special sp2-carbon chain bridged bimetallic iridium complex has been synthesized and characterized; the compound has excellent air-stability, thermo-stability and electrochemical properties.
