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1.
WANG Jun-Wen XU Fang-Bo LI Qiang-Shan SONG Hai-Bin LIU Yong-Sheng ZHANG Zheng-Zhi 《有机化学》2004,24(Z1):213
Transition metal complexes of stable N-heterocyclic carbenes have recently gained increasing attention as pre-catalysts for a number of important reactions primarily based on the analogy between N-heterocyclic carbenes and strong ó-donating tertiary phosphines,[1] Although a large number of transition-metal carbene complexes have been reported, very few incorporate chelating carbenes were reported.[2,3] Therefore, we have set out to prepare and study transition-metal compounds with chelating di-N-heterocyclic carbenes, and we now report new dicationic tetra(carbine)nickel(Ⅱ) complexes in this class (Scheme 1). Their structures have been determined by single-crystal X-ray diffraction studies (Figure 1). 相似文献
2.
Jingquan Sha Hongjun Lu Jun Peng Haijun Pang Aixiang Tian Yuguang Lv Hong Liu 《Solid State Sciences》2010,12(2):262-266
A new three-dimensional (3D) organic–inorganic hybrid compound based on the Wells–Dawson POMs modified by Ag(I) ions and bpe (bpe = bis(4-pyridyl)ethylene) molecules, {[Ag(C12N2H10)]3(H3P2W18O62)}·(C12N2H10)·4H2O, has been synthesized under hydrothermal condition and structurally characterized. Crystal data for the title compound: C48H51Ag3N8O66P2W18, monoclinic, space group P21/m, a = 13.623(5) Å, b = 25.345(5) Å, c = 13.858(5) Å, α = 90°, β = 98.038(5)°, γ = 90°, V = 4738(3) Å3. It represents an important example of the family of Wells–Dawson POMs modified by M–N chains, in which Wells–Dawson POMs covalently link eight transitional metal complex fragments and represent the highest track number (8) of M–N chains modifying Wells–Dawson POMs. Furthermore, the electrochemical properties of the title compound were studied. 相似文献
3.
4-Morpholinoacetophenone thiosemicarbazone, MAPT, and its nickel(Ⅱ) and copper(Ⅱ) complexes have been prepared and characterized by elemental analysis, magnetic susceptibility, spectral methods (FT-IR, ^1H NMR) and cyclic voltammetry. Electrochemical behaviors of the complexes have been studied by cyclic voltammetry in DMF media showing metal centered reduction processes for both of them. The redox properties, nature of the electrode processes and the stability of the complexes were discussed. [Cu(MAPT)2]Cl2 complex shows Cu(Ⅱ)/Cu(Ⅰ) couple and quasi-reversible wave associated with the Cu(Ⅲ)/Cu(Ⅱ) process. The reduction/oxidation potential values depend on the structures of complexes. Also, the antimicrobial activities of these complexes were determined against S. aureus, E. coli and B. subtilis. 相似文献
4.
Reactions of potassium molybdate with racemic malic acid (H3mal = C4H6O5) result in the isolation of two mesomeric molybdenum malate complexes Ks[(MoO2)2O(R-mal)2][(MoO2)2O(S- mal)2]·4H2O 1 and (Him)2K6[(MoO2)4O3(R-mal)2][(MoO2)4O3(S-mal)2]·8H2O 2. Complex 1 belongs to the monoclinic system, space group C2/c with a = 14.8637(3), b = 6.9544(1), c = 19.6783(5) A, β = 100.081(2)°, V= 2002.70(7)A3, Mr = 1452.88, Z= 2, F(000) = 1416, T= 173 K, Dc = 2.409 g/cm3, μ(MoKa) = 2.167, R = 0.0283 and wR = 0.0733.2 is of triclinic system, space group P1 with a = 8.7707(2), b = 9.3310(3), c = 17.9093(7) A, α = 83.781(3), β = 85.626(2), γ= 84.822(2)°, V = 1447.84(8) A3, Mr = 2160.68, Z = 1, F(000) = 1048, T= 173 K, Dc = 2.478 g/cm3, μ(MoKα) = 2.230, R = 0.0234 and wR = 0.0584.1 is the first isolated dinuclear molybdenum(Ⅵ) malato complex in 1:1 molar ratio. The molybdenum atoms in the two complexes are six-coordinated in an approximately octahedral geometry. Two malates coordinate tridentately with the Mo atom via their α-alkoxy, α-carboxy and α-carboxy groups in 1 and 2. β-Carboxy group in 2 further links with the other two Mo atoms to give a tetrameric unit. The solution 1H and 13C NMR spectra indicate that dimeric malate molybdenum in 1 dissociates partly in solution and exists in an equilibrium with tetrameric species, while 2 is stable and retains its tetrameric structure without any dissociation. 相似文献
5.
ZHANG Rong-Hua ZHOU Zhao-Hui WAN Hui-Lin 《结构化学》2008,27(8):919-926
Reactions of potassium molybdate with racemic malic acid (H3mal = C4H6O5) result in the isolation of two mesomeric molybdenum malate complexes K8[(MoO2)2O(R-mal)2][(MoO2)2O(Smal)2]-4H2O 1 and (Him)2K6[(MoO2)4O3(R-mal)2][(MoOE)4O3(S-mal)2]-8H2O 2. Complex 1 belongs to the monoclinic system, space group C2/c with a = 14.8637(3), b = 6.9544(1), c = 19.6783(5)A, β = 100.081(2)°, V = 2002.70(7) A^3, Mr = 1452.88, Z = 2, F(000) = 1416, T = 173 K, Dc = 2.409 g/cm3, fl(MoKa') = 2.167, R = 0.0283 and wR = 0.0733.2 is of triclinic system, space group P1^- with a = 8.7707(2), b = 9.3310(3), c = 17.9093(7)A, α= 83.781(3), β = 85.626(2), y= 84.822(2)°, V = 1447.84(8)A^3, Mr = 2160.68, Z = 1, F(000) = 1048, T = 173 K, Dc = 2.478 g/cm^3,μ(MoKα) = 2.230, R = 0.0234 and wR = 0.0584.1 is the first isolated dinuclear molybdenum(VI) malato complex in 1:1 molar ratio. The molybdenum atoms in the two complexes are six-coordinated in an approximately octahedral geometry. Two malates coordinate tridentately with the Mo atom via their α-alkoxy, α-carboxy and α-carboxy groups in 1 and 2. β-Carboxy group in 2 further links with the other two Mo atoms to give a tetrameric unit. The solution ^1H and ^13C NMR spectra indicate that dimeric malate molybdenum in 1 dissociates partly in solution and exists in an equilibrium with tetrameric species, while 2 is stable and retains its tetrameric structure without any dissociation. 相似文献
6.
LI Wei-Hua ZHAO Guang-Fa HUANG Zhao-Ge LIU Fa-Qian DING Nai-Xiu LIU Guang-Ye 《中国化学》2008,26(9):1607-1610
Two novel coordination polymers [Zn(pa)(vim)2]n (1) and [Zn(pa)(eim)2]n (2) (pa=phthalic acid dianion, vim=1-vinyl-1H-imidazole, eim=1-ethyl-1H-imidazole) have been synthesized and their structures characterized by X-ray single crystal diffractometry and elemental analysis. Both of the complexes consist of [Zn(L)2] (L=vim for 1; eim for 2) entities linked into polymeric zigzag chains along the crystallographic c-axis by bridging phthalate anions in the μ2-1,2 coordination mode. The coordination around each Zn(II) atom is tetrahedral. There are only van der Waals interactions between the chains in 1, while the three-dimensional network in 2 is assembled by C—H…O contacts. The electrochemical studies reveal that redoxes of Zn2+/Zn in complexes 1 and 2 are irreversible processes. 相似文献
7.
Electrochemical and Spectroelectrochemical Studies of Molybdenum and Neodymium Complex with Diethyld
YU Zhen-xing FU Qing-hong ZHANG Heng-bin NIU Shu-yun LI Shu-jia Xun Xiu-mei 《高等学校化学研究》1998,14(1):53-58
ElectrochemicalandSpectroelectrochemicalStudiesofMolybdenumandNeodymiumComplexwithDiethyldithiocarbamateLigandYUZhen-xing,FUQ... 相似文献
8.
Nina Sadlej-Sosnowska Lech Kozerski Elżbieta Bednarek Jerzy Sitkowski 《Journal of inclusion phenomena and macrocyclic chemistry》2000,37(1-4):383-394
Inclusion complexation processesinvolving four cyclodextrins and naproxen have beenstudied for the protonated and unprotonated forms ofthe guest molecule. The association constants havebeen evaluated from changes in the fluorescenceintensity of naproxen following addition of acyclodextrin to an aqueous naproxen solution. 1HNMR NOESY and ROESY spectra have shown that twoorientations of the guest molecule relative to-cyclodextrin are possible. 相似文献
9.
Inrecentyears,thenewsedricrystallinepolymersyndiotacticp0lystyrene(sPS)hasat-ITactedmuchattentionduetoitsg0odchendcalresistanceandenhancedmechanicalperformanceatelevatedtemPeratUre.'H0wever,itexhibitshighbrittlenessandpoorimPact-resistanceandtCar-resistance.2Therefore,itisnecessarytomodifyitwithtougheningpolyIners.AsimPlemeth0dto0verc0methedriscibilityofatwo-phaseblendofsPSandatougheningpolymristotwrovetheinterfacialaffmity,wheretheadditionofablockcoP0lymerisconsideredtobemosteffective.3… 相似文献
10.
YANG Tao WANG Zeng-Jian JIAO Kui LI Qing-Jun 《高等学校化学研究》2006,22(3):292-296
Introduction DNAbiosensorsareacompletelynewtypeoftech nologicalconceptionsbyusingspecificaffinitybetween mattersinlivingbeingstodistinguishdirectlyand quicklysequence specificDNA[1].Withtherapidde velopmentofgeneticengineering,oneofthekeyissues needtobere… 相似文献
11.
Formation of host–guest complexes with acetic acid and benzoic acid was studied by NMR for amide-based octaazacyclophanes having pendant methyl ester arms; the cyclophanes were tetramethyl 2,9,18,25-tetraoxo-1,4,7,10,17,20,23,26-octaaza[10.10]paracyclophane-4,7,20,23-tetraacetate, its meta-isomer and analogues. Amide NH proton and CH2 proton adjacent to amide C = O in every cyclophane host showed down-field NMR shifts in the presence of the guest acids in CHCl3-d, suggesting the formation of 1:1 complexes in which the carboxyl group of an acid molecule formed two hydrogen bonds with the amide NH and C = O moieties of a host molecule. Since the complex formation competed with the dimerization of the guest acids, the monomer–dimer equilibrium was restudied by NMR and the equilibrium constant was determined to be 330 M? 1 for acetic acid and 518 M? 1 for benzoic acid. By using these values, the formation constants of the host–guest complexes were determined to be 8–51 M? 1. The close contact between the host and guest molecules via hydrogen bonding was consistently confirmed by NMR shifts due to the ring current of aromatic group. 相似文献
12.
Xiao-Lan Wang Ying Lu Jing-Xin Meng En-Bo Wang Hai Fu 《Transition Metal Chemistry》2011,36(2):201-206
Three new organic–inorganic hybrid complexes based on the Wells–Dawson polyoxoanion, namely (H2bpp)[Ni2(bpp)2(H2O)4(P2W18O62)]·H2O 1, [Cu6(Hbpy)6(bpy)3(P2W18O62)2]·2H2O 2 and (Him)5[Cu(im)2(P2W18O62)]·4H2O 3 [bpp = 1,3-bis (4-pyridyl) propane, bpy = 4,4′-bipyridine, im = imidazole] have been synthesized and characterized. Complex
1 exhibits a three-dimensional (6, 3)-connected framework with anatase topology constructed from [α-P2W18O62]6− clusters and [Ni(bpp)]2+ fragments. Each [α-P2W18O62]6− anion links to six nickel atoms through six terminal oxygen atoms from four polar and two equatorial WO6 octahedra, which shows a novel coordination mode of a Wells–Dawson cluster with a transition-metal atom. Complex 2 displays an interesting one-dimensional double-chain structure built from [α-P2W18O62]6− clusters and [Cu2(bpy)(Hbpy)2]2+ fragments. To our knowledge, complex 2 represents the first double-chain organic–inorganic hybrid complex based on a Wells–Dawson-type cluster. Complex 3 possesses a one-dimensional zigzag chain structure constructed from [α-P2W18O62]6− anions and [Cu(im)2]+ units through weak Cu···O interactions. 相似文献
13.
《Journal of Coordination Chemistry》2012,65(3):495-505
Two new Wells–Dawson based compounds containing alkali metals, [Ag(H2biim)2]2·[Ag5(H2biim)10Na2(H2O)2(H3/2P2W18O62)2]·12H2O (1) and [Cd(H2biim)2?K(P2W18O62)1/2] (2) (H2biim?=?2,2′-biimidazole), have been synthesized under hydrothermal conditions. In 1, two-supporting Wells–Dawson anions are linked by a [Ag(H2biim)2]+ subunit to form a dimer. The adjacent dimers are further connected by Na+ through (POM)O-Na-O(POM) bonds to build a 1-D chain. In 2, adjacent anions are linked by two [Cd2(H2biim)2]4+ subunits and a 1-D chain is formed. Furthermore, the anion in the chain is fused by six K+ ions and a 3-D framework is obtained. The alkali metals exhibit crucial influence on the conversion of dimensionality assisting anions and Ag-H2biim subunits to construct 1-D and 3-D frameworks. The electrochemical and photocatalytic properties of 1 and 2 have been investigated. 相似文献
14.
《Journal of Coordination Chemistry》2012,65(22):3651-3658
A new polyoxometalate based on saturated Wells-Dawson polyanions and calcium cations, H2[Ca2(P2W18O62)(H2O)5]?·?7.5H2O (1), has been synthesized in aqueous solution and characterized by single-crystal X-ray diffraction and IR. Compound 1 is a new example of 3D framework based on Wells-Dawson anions that act as chelate ligands to coordinate with calcium cations. Cyclic voltammetry reveals that the pH of the supporting electrolytic solution has a marked effect on the electrochemical behavior. 相似文献
15.
The electrochemical oxidation of 1, 3-benzenedithiol was investigated in a 0. 100 mol/L tetrabutylammonium perchlorate/acetonitrile electrolyte. The electrochemical techniques used were potential sweep, bulk electrolysis, rotating disc and the potential step method. The combination of the techniques yielded the number of electrons transferred per molecule, the reaction order, the transfer coefficient, the diffusion coefficient and concentration of dithiol anions, the standard heterogeneous rate constant as well as the formal potential and equilibrium constant of the preceeding dissociation reaction. This paper also illustrates the methods for studying the electrode kinetics of reactions which (a) involve a chemical reaction preceeding the electron-transfer process, (b) have insoluble polymer products, and (c) are totally irreversible. 相似文献
16.
《中国化学快报》1997,(8)
l.INTR0DUCTIONVitaIninBlz(cyanocobalamin)anditScoenZymesasmostdrip0rtanmoleculeshavebeenextensivelystUdied.However,themetabolicreacti0nsofvitaIninBl2throughWhichtheintuellarconversi0ntoitSc0empeformsinmanunaliancellsarelargelyunkn0wnanduncharacterized[l].SeverallinesofevidencesuggestedthatvitaIninBl2mustbereducedpri0rtoformingitsc0e~es[2].Thus,theconversionofvitaIninBl2toitSc0enZyIneformsincellsneedsreductionreagents,suchasFMNapdNADHwithreducedglutathione[l].lnaddition,itwasreP0r… 相似文献
17.
《Journal of Coordination Chemistry》2012,65(1-3):235-251
The titanyl complex, TiO(C22H22N4), a complex of the ligand (I) obtained by the hydrolysis of the corresponding dichloride, has a reactive Ti=O function which readily interacts with other metal species forming μ-oxo heterobinuclear dimers. In these adducts, the Ti=O functions as a base toward oxophilic metal centres such as Fe(lII) and as a π-acid, analogous to the carbonyl group, forming an adduct with a low valent species such as the Mo(CO)5 group, yielding a Ti(IV)-O-Mo linkage. Crystals of the titanyl complex, TiO(C22H22N4).C2O2H6, are monoclinic, P21/C with a = 23.083(3), b = 7.740(7), c = 23.208(5) Å, β = 96.54. (2) and d(calcd) = 1.443 g cm ?3 for Z = 4. The Ti=O distance is 1.653(3) Å with a large displacement of 0.754(3) Å for the Ti atom from the N4 macrocyclic coordination plane. The adduct of the titanyl complex with Fe(SALEN)Cl, SALEN = (salicylaldimine)ethylenediamine, in the presence of NaB(C6H5)4 yields a μ-oxo-heterobinuclear complex_of stoichiometry (C22H22N4)Ti-O-Fe- (SALEN)B(C6H5)4. Crystals of the complex are triclinic, P1 with a = 13.122(4), b = 13.883(12), c = 14.539(5) Å, a = 94.21(5), β = 93.08(3), γ = 99.46(3)° with d(calcd) = 1.336gem?3 for Z = 2. In addition to the expected dimeric Ti-O-Fe structure, weak interactions between the SALEN oxygen atoms and the iron atom of the centrosymmetrically related Fe(SALEN) group yields a tetrameric cluster, The Ti-O distance of the Ti-O-Fe linkage is lengthened to 1.706(4) Å and the Fe-O distance is 1.935(6) Å with the Ti-O-Fe angle 160.9(2)°. The Fe-O “intramolecular” interaction distance, 2.178 Å, is indicative of a weak bond. 相似文献
18.
《Electrochemistry communications》2000,2(7):471-474
Poly(dibutylstannylene-co-dibutylsilylene) and poly(dibutylstannylene-co-dibutylgermylene) were synthesized for the first time, by electrochemical reduction of dibutyldichlorostannane together with dibutyldichlorosilane and dibutyldichlorogermane, respectively, in a one-compartment cell equipped with a platinum cathode and a silver anode, using tetrabutylammonium perchlorate and 1,2-dimethoxyethane as the supporting electrolyte and the solvent, respectively. Most of absorption peaks observed for the copolymers were located between those of polystannylene and polysilylene/polygermylene. A copolymer with relatively high stannane content had a relatively long absorption peak, which is close to that of a homopolymer polydibutylstannylene. A copolymer with a higher stannane content was more sensitive to the moisture in air. 相似文献
19.
Li Lan-Feng Zhao Hai-Yan Liu Jia-Ming Ren Wen- Qiang Dong Da- Peng Wang Li 《Journal of Cluster Science》2021,32(6):1499-1506
Journal of Cluster Science - A new organic–inorganic hybrid, namely [Ni2(en)4(C2H3NO2)(H2O)][Ni(en)3][Ni(en)2][P2W18O62]·6H2O (1, en?=?1,2-ethylenediamine), was synthesized... 相似文献
20.
Baicalin is an anti-HIV drug purified from the traditional Chinese medicinal plant Scutellaria Baicalensis Georgi. Baicalin has proven to be electroactive at pyrolytic graphite (PG) electrodes. We thus studied its interaction with DNA via the electrochemical approach. We observed that the peak currents corresponding to the baicalin reduction–oxidation (redox) reaction significantly decrease upon the addition of DNA. With complementary ultraviolet/visible (UV/Vis) spectroscopic evidence, we suggest that baicalin binds to DNA through intercalation. This feature has enabled baicalin to discriminate between double-stranded DNA (dsDNA) and single-stranded DNA (ssDNA).Electronic Supplementary Material Supplementary material is available in the online version of this article at . A link in the frame on the left on that page takes you directly to the supplementary material. 相似文献