共查询到20条相似文献,搜索用时 15 毫秒
1.
Timo J.J. Sciarone 《Inorganica chimica acta》2006,359(6):1815-1825
The three-coordinate, 12-valence electron complexes [(MeBDK)FeR] (MeBDK = [HC(C(Me)NAr)2]−, Ar = 2,6-iPr2C6H3, R = CH2Ph, CH2SiMe3) are reported as well as their reactivity towards Lewis bases. With perfluoroaryl borane and -borate type activators, the monoalkyls react to give alkyl-free paramagnetic cationic iron species counterbalanced by perfluorinated arylborate anions. The paramagnetic nature of the cations permits the observation of weak and dynamic interactions with these anions via 19F NMR spectroscopy. 相似文献
2.
Anindita Sarkar 《Inorganica chimica acta》2008,361(8):2296-2304
A family of complexes containing the {VO(OMe)}2+ motif with the O,N,S-donor Schiff bases (H2tbhsR) derived from thiobenzhydrazide and 5-substituted salicylaldehydes has been reported. Reactions of [VO(acac)2] with H2tbhsR in methanol provide the complexes having the general formula [VO(OMe)(tbhsR)] (R = H, OMe, Cl, Br and NO2) in 40-53% yields. Microanalytical, various spectroscopic (IR, UV-Vis and NMR) and electrochemical measurements have been used for the characterization of the complexes. All the complexes are redox active and display a near reversible metal centred reduction in the potential range 0.20-0.47 V (versus Ag/AgCl). The trend in these potential values reflects the polar effect of the substituent on the salicylidene fragment of tbhsR2−. The X-ray crystal structures of all the complexes have been determined. In each of the complexes where R = H, OMe, Cl and Br, the metal ion is in a distorted square-pyramidal O3NS coordination sphere assembled by the O,N,S-donor tbhsR2−, the methoxo and the oxo groups. The complex where R = NO2, crystallizes as a hexacoordinated species due to coordination of a methanol O-atom at the vacant sixth site. The bond parameters associated with the metal ions and the physical properties of the complexes are consistent with the +5 oxidation state of the metal ion in all the complexes. Scrutiny of crystal packing reveals dimeric, one-dimensional and two-dimensional self-assembled structures via intermolecular C-H?O and O-H?O interactions. The two-dimensional network contains the cyclic tetramer of methanol. 相似文献
3.
A series of malonato complexes of molybdenum(V) was prepared by reacting (PyH)5[MoOCl4(H2O)]3Cl2 or (PyH)n[MoOBr4]n with malonic acid (H2mal) or a half-neutralized acid, hydrogen malonate (Hmal−), at ambient conditions: (PyH)3[Mo2O4Cl4(μ2-Hmal)] · CH3CN (1), (PyH)3[Mo2O4Br4(μ2-Hmal)] · CH3CN (2), (PyH)2[Mo2O4Cl(η2-mal)(μ2-Hmal)Py] (3), (3,5-LutH)2(H3O) [Mo2O4(η2-mal)2(μ2-Hmal)] (4), (PyH)[Mo2O4Cl2(μ2-Memal)Py2] (5), (3,5-LutH)[Mo2O4Cl2(μ2-Memal)(3,5-Lut)2] (6), (PyH)[Mo2O4Cl2(μ2-Etmal)Py2] (7), (3,5-LutH)[Mo2O4Cl2(μ2-Prmal)(3,5-Lut)2] (8) and [{Mo2O4(μ2-Memal)Py2}2(μ2-OCH3)2] (9) (where Py = pyridine, C5H5N; PyH+ = pyridinium cation, C5H5NH+; 3,5-Lut = 3,5-lutidine, C7H9N; 3,5-LutH+ = 3,5-lutidinium cation, C7H9NH+; mal2− = malonate, −OOCCH2COO−; Memal− = monomethyl malonate, −OOCCH2COOCH3; Etmal− = monoethyl malonate, −OOCCH2COOC2H5 and Prmal− = monopropyl malonate, −OOCCH2COOC3H7). The complex anions of compounds 1-8 have a common structural feature: a dinuclear, singly metal-metal bonded {Mo2O4}2+ core with the carboxylate moiety of the malonato ligand coordinated in a syn-syn bidentate bridging manner to the pair of metal atoms. The remaining four coordination sites of the {Mo2O4}2+ core are occupied with halides in 1 and 2, with halides/pyridine ligands in 5-8, with a pair of bidentate malonate ions in 4 and with the combination of all in 3. The neutral molecules of 9 consist of two {Mo2O4}2+ cores linked with a pair of methoxide ions into a chain-like, tetranuclear cluster. An esterification of malonic acid was observed to take place in the reaction mixtures containing alcohols. Solvothermal reactions with malonic acid carried out at 115 °C produced anionic acetato complexes as found in (PyH)[Mo2O4Cl2(μ2-OOCCH3)Py2] · Py (10), (PyH)[Mo2O4Cl2(μ2-OOCCH3)Py2] (11), (3,5-LutH)[Mo2O4Cl2(μ2-OOCCH3)(3,5-Lut)2] (12) and (4-MePyH)3[Mo2O4Cl2(μ2-OOCCH3)(4-MePy)2]2Cl (13) (4-MePy = 4-methylpyridine, C6H7N). The acetate coordinated in the syn-syn bidentate bridging mode in all. Reactions of (PyH)5[MoOCl4(H2O)]3Cl2 with succinic acid (H2suc) at ambient conditions resulted in a complex with a half-neutralized acid, (PyH)[Mo2O4Cl2(μ2-Hsuc)Py2] · Py (14) (Hsuc− = hydrogen succinate, −OOC(CH2)2COOH), while those carried out at 115 °C in a tetranuclear succinato complex, (4-MePyH)2[{Mo2O4Cl2(4-MePy)2}2(μ4-suc)] (15) (suc2− = succinate, −OOC(CH2)2COO−). The tetranuclear anion of 15 consists of two {Mo2O4}2+ cores covalently linked with a tetradentate succinato ligand. The compounds were fully characterized by infrared vibrational spectroscopy, elemental analyses and X-ray diffraction studies. 相似文献
4.
A novel composite membrane has been developed by doping cesium phosphotungstate salt (CsxH3−xPW12O40 (0 ≤ x ≤3), Csx-PTA) into chitosan (CTS/Csx-PTA) for application in direct methanol fuel cells (DMFCs). Uniform distribution of Csx-PTA nanoparticles has been achieved in the chitosan matrix. The proton conductivity of the composite membrane is significantly affected by the Csx-PTA content in the composite membrane as well as the Cs substitution in PTA. The highest proton conductivity for the CTS/Csx-PTA membranes was obtained with x = 2 and Cs2-PTA content of 5 wt%. The value is 6 × 10−3 S cm−1 and 1.75 × 10−2 S cm−1 at 298 K and 353 K, respectively. The methanol permeability of CTS/Cs2-PTA membrane is about 5.6 × 10−7, 90% lower than that of Nafion-212 membrane. The highest selectivity factor (φ) was obtained on CTS/Cs2-PTA-5 wt% composite membrane, 1.1 × 104/S cm−3 s. The present study indicates the promising potential of CTS/Csx-PTA composite membrane as alternative proton exchange membranes in direct methanol fuel cells. 相似文献
5.
Four new polyoxometalate compounds, namely [Cu2(pyrazine)4][Cu(pyrazine)2][PMo12O40] · 2H2O (1), {[K(H2O)2]4H8PW12O44}F · 8H2O (2), H9[K2KMo36O112(H2O)34] · 35H2O (3), and H3Na3[V10O28] · 15H2O (4), were prepared and characterized by single crystal X-ray diffraction, elemental analysis and IR spectroscopy. Single crystal X-ray diffraction analysis results reveal that, in compound 1, Keggin anion of [PMoO12O40]3− is enchased in the bowl-like Cu(I)-pyrazine intervals via weak interactions between terminal oxygen atoms and cations of Cu(I). For compound 2, a three-dimensional architecture with pores of 7.70 × 7.70 Å is constructed from the anions of [PW12O44]11− cross-linked via corner-sharing alkali cations of K+. The [Mo36O112(H2O)16]12− units of compound 3 are linked to form one wave-like chain via cations of K+. Whereas, in compound 4, anions of [V10O28]3− are linked via NaO6 octahedra to form two-dimensional layer structure. On the basis of this two-dimensional layer, a three-dimensional architecture is further formed via hydrogen bonds involving edge-shared NaO6 double octahedron. 相似文献
6.
New ammonium derivatives of peroxo-carboxylato molybdenum(VI) complexes of general formula (NH4)2[MoO(O2)2(HxL)] · nH2O with L=oxalate (ox), citrate (cit), tartrate (tart), glycolate (glyc) and malate (mal) and (NH4)2[MoO2(O2)(L)] with L=oxalate (ox) have been prepared and characterized on the basis of elemental and thermal analysis as well as by IR and 13C NMR spectroscopy. These last two spectroscopic methods have been used to suggest the coordination mode of the ligand in the complexes. The X-ray crystal structures of the compounds (NH4)2[Mo2O2(O2)2(OH)2(ox)2], (NH4)2[MoO(O2)2(ox)] and (NH4)2[MoO(O2)2(glyc)] · 0.5EtOH have been determined, all showing a sevenfold-coordinated Mo atom with bidentate peroxides and carboxylate ligands. 相似文献
7.
Huseyin Isci 《Inorganica chimica acta》2004,357(14):4065-4072
Electronic absorption and 8.0 T magnetic circular dichroism (MCD) spectra are reported for M(CN)8 4−, M=Mo(IV) and W(IV), in aqueous solution and M(CN)8 3−, M=Mo(V) and W(V), in acetonitrile solutions. In addition some absorption and MCD spectra are reported for the M(CN)8 3− ions embedded in thin poly methyl methacrylate (PMMA) plastic films at temperatures from 295 to 10 K. The temperature dependence of the MCD spectra confirms the presence of C terms. The solution and PMMA spectra for the both Mo and W complexes in either the IV or V oxidation states are remarkably similar to each other for the same oxidation state and are interpreted within a D2d structural framework for the isotropic environment. The weak bands below 3.0 μm−1 (1 μm−1=104 cm−1) for the M(IV) complexes are assigned as metal-localized ligand field (LF) transitions. LF transitions are also suggested for weaker unresolved absorption between 3.0 and 3.6 μm−1 for the M(V) ions. The intense bands above 3.6 μm−1 for M(IV) and 4.6 μm−1 for M(V) complexes are interpreted as metal to ligand charge transfer (MLCT) from the metal b1(x2−y2) HOMO to CN−-based π * orbitals. The prominent intense bands observed below 4.5 μm−1for the M(V) complexes are assigned as ligand to metal charge transfer (LMCT) from occupied non-bonding or weakly π bonding CN− orbitals to the half-filled b1(x2−y2) HOMO. 相似文献
8.
Višnja Vrdoljak Jana Pisk Biserka Prugove?ki Dubravka Matkovi?-?alogovi? 《Inorganica chimica acta》2009,362(11):4059-449
New molybdenum complexes were prepared by the reaction of [MoVIO2(acac)2] or (NH4)2[MoVOCl5] with different N-substituted pyridoxal thiosemicarbazone ligands (H2L1 = pyridoxal 4-phenylthiosemicarbazone; H2L2 = pyridoxal 4-methylthiosemicarbazone, H2L3 = pyridoxal thiosemicarbazone). The investigation of monomeric [MoO2L1(CH3OH)] or polymeric [MoO2L1-3] molybdenum(VI) complexes revealed that molybdenum is coordinated with a tridentate doubly-deprotonated ligand. In the oxomolybdenum(V) complexes [MoOCl2(HL1-3)] the pyridoxal thiosemicarbazonato ligands are tridentate mono-deprotonated. Crystal and molecular structures of molybdenum(VI) [MoO2L1(CH3OH)]·CH3OH, and molybdenum(V) complexes [MoOCl2(HL1)]·C2H5OH, as well as of the pyridoxal thiosemicarbazone ligand methanol solvate H2L3·MeOH, were determined by the single crystal X-ray diffraction method. 相似文献
9.
Maxim A. Ivanov Vladimir V. Sharutin Antonya P. Pakusina Willis Forsling 《Inorganica chimica acta》2007,360(9):2897-2904
O,O′-dipropyldithiophosphate and O,O′-di-iso-butyldithiophosphate (Dtph) tetraphenylantimony(V) complexes of the general formula [Sb(C6H5)4{S2P(OR)2}] (R = C3H7, i-C4H9) were prepared and studied by means of 13C, 31P CP/MAS NMR spectroscopy and single-crystal X-ray diffraction. Distorted octahedral and trigonal bipyramidal molecular structures have been established for prepared complexes. These unexpected structural distinctions between chemically related compounds are defined by the principally different coordination modes of O,O′-dipropyldithiophosphate and O,O′-di-iso-butyldithiophosphate ligands in their molecular structures (i.e., S,S′-bidentate chelating and S-unidentately coordinated, respectively). To characterise quantitatively phosphorus sites in both species of dithiophosphate ligands, 31P chemical shift anisotropy parameters (δaniso and η) were calculated from spinning sideband manifolds in MAS NMR spectra. The 31P chemical shift tensors for the bidentate chelating and unidentately coordinated dithiophosphate ligands display a profoundly rhombic and nearly axially symmetric characters, respectively. 相似文献
10.
Two 15N-labelled cis-Pt(II) diamine complexes with dimethylamine (15N-dma) and isopropylamine (15N-ipa) ligands have been prepared and characterised. [1H,15N] HSQC NMR spectroscopy is used to obtain the rate and equilibrium constants for the aquation of cis-[PtCl2(15N-dma)2] at 298 K in 0.1 M NaClO4 and to determine the pKa values of cis-[PtCl(H2O)(15N-dma)2]+ (6.37) and cis-[Pt(H2O)2(15N-dma)2]2+ (pKa1 = 5.17, pKa2 = 6.47). The rate constants for the first and second aquation steps (k1 = (2.12 ± 0.01) × 10−5 s−1, k2 = (8.7 ± 0.7) × 10−6 s−1) and anation steps (k−1 = (6.7 ± 0.8) × 10−3 M−1 s−1, k−2 = 0.043 ± 0.004 M−1 s−1) are very similar to those reported for cisplatin under similar conditions, and a minor difference is that slow formation of the hydroxo-bridged dimer is observed. Aquation studies of cis-[PtCl2(15N-ipa)2] were precluded by the close proximity of the NH proton signal to the 1H2O resonance. 相似文献
11.
The synthesis and structure of a new 1-D molybdenum-arsenic compound based on the bi-capped Keggin anion [MoVI6MoV6O36(AsO4)(MoVO)2]− have been reported, and its catalytic property has been examined. The title compound was characterized by IR, TG and X-ray diffraction analysis. Single crystal X-ray diffraction shows that it crystallizes in cubic crystal system, space group Pn-3m with cell dimension: a = 11.749(2) Å, V = 1622.0(5) Å3, Z = 2. Its structure has a 1-D infinite chain, in which the bi-capped Keggin anions are connected by sharing one terminal oxygen atom from the caps. The compound shows a moderate styrene conversion (48%), the major product for the oxidation of styrene is benzaldehyde (85.2%). 相似文献
12.
Gisbert Grossmann Kim A. Burkov Lubov A. Myund Claudia Verwey 《Inorganica chimica acta》2004,357(3):797-808
Dissociation and alkali complex formation equilibria of nitrilotris(methylenephosphonic acid) (NTMP, H6L) have been studied by dilatometric, potentiometric and 31P NMR-controlled titrations. Dilatometry indicated the formation of alkali complexes ML (M=Li, Na, K, Rb, Cs) at high pH with a stability decreasing from Li to Cs. An efficient combination of potentiometric and NMR methods confirmed two types of alkali metal complexes MHL and ML. Stability constants for the equilibria following M+ + HL5− ? MHL4− and M+ + L6− ? ML5−, respectively, were determined: logKNaHL=1.08(0.07), logKKHL=0.86(0.08), logKNaL=2.24(0.03). Systematic errors are introduced by using alkali metal hydroxides as titrants for routine potentiometric determinations of dissociation constants pKa5app and pKa6app. Correction formulae were derived to convert actual dissociation constants pKa into apparent dissociation constants pKaapp (or vice versa). The actual dissociation constants were found: pKa5(H2L4− ? H+ + HL5−)=7.47(0.03) and pKa6(HL5− ? H+ + L6−)=14.1(0.1). The anisotropy of 31P chemical shifts of salts MnH6 − nL (M=Li, Na, n=0-5) is more sensitive towards titration (n) than isotropic solution state chemical shifts. 相似文献
13.
The [As2W18U3O74]12− complex is formed by the “self-assembly” reaction of and (uranyl nitrate) ions in acidic media. The anion complex is isolated as the potassium salt and characterized by elemental analysis, IR, UV-Vis, and X-ray single crystal analysis. The complex contains an anion in which three ions are unsymmetrically sandwiched between two A-α-[AsW9O34]9− groups leading to a structure of C3v symmetry. Each uranium atom adopts pentagonal-bipyramidal coordination, achieved by three equatorial bonds to one [AsW9O34]9−and two bonds to the other. The [As2W18U2V2O73]12−and also [As2W18U3O74]12− complexes are formed also, by reaction of the [KAs2W18U2O72]13− with VO2+ and ions in 1:1 mole ratio. The cyclic voltammogram of [As2W18U2VO73]12− in acetate buffer (pH 4.7) shows a reversible one-electron redox process for VIV/V couple at +0.396 (Epc) and +0.432 V (Epa). 相似文献
14.
Carlos Bustos Desmond Mac-Leod Carey René Thouvenot Pierre Gouzerh 《Inorganica chimica acta》2010,363(15):4262-4268
A series of aryldiazenido polyoxomolybdates of the type (nBu4N)2[Mo5O13(OMe)4(NNAr){Na(MeOH)}] (Ar = C6F5, 1; Ar = O2N-o-C6H4, 2; Ar = O2N-m-C6H4, 3; Ar = O2N-p-C6H4, 4a; Ar = (O2N)2-o,p-C6H3, 5) have been obtained by controlled degradation of the parent compounds (nBu4N)3[Mo6O18(NNAr)] with NaOH in methanol. They have been characterized by elemental analysis and UV-Vis and IR spectroscopy. In addition, 4a has been characterized by 95Mo NMR spectroscopy and the crystal structure of (nBu4N)2[Mo5O13(OMe)4(NNC6H4-p-NO2){Na(H2O))]·H2O (4b) has been determined by X-ray diffraction. The molecular structure of the anion of 4b features a lacunary Lindqvist-type anion [Mo5O13(OMe)4(NNC6H4-p-NO2)]3− interacting with a sodium cation through the four terminal axial oxygen atoms. The 1:1 sodium complexes react with BaCl2 and BiCl3 to yield 2:1 complexes which have been isolated as (nBu4N)4[Ba{Mo5O13(OMe)4(NNAr)}2] (Ar = C6F5, 6; Ar = O2N-p-C6H4, 7) and (nBu4N)3[Bi{Mo5O13(OMe)4(NNAr)}2] (Ar = C6F5, 8; Ar = O2N-p-C6H4, 9). X-ray crystallography analysis of 9·Me2CO has shown that the tetradentate [Mo5O13(OMe)4(N2C6H4-p-NO2)]3− anions provide a square-antiprismatic environment for Bi. In contrast, IR spectroscopy provides evidence for a square-prismatic environment of Ba in 6 and 7. In acetonitrile-methanol mixed solvent, [Mo5O13(OMe)4(NNAr)]3− and [PW11O39]7−, generated in situ by alkaline degradation of their respective parents, [Mo6O18(NNAr)]3− and [PW12O40]3−, react together to give the Keggin-type diazenido compounds (nBu4N)4[PW11O39(MoNNAr)] (Ar = O2N-o-C6H4, 10; Ar = O2N-m-C6H4, 11; Ar = O2N-p-C6H4, 12), which have been characterized by 31P and 183W NMR spectroscopy. 相似文献
15.
Zhifeng Zhao Baibin Zhou Shoutian Zheng Chunmei Wang 《Inorganica chimica acta》2009,362(14):5038-1337
Three novel hexa-transition-metal complexes substituted tungstoarsenates, [Ni6(imi)6(B-α-H3AsW9O33)2]·2H2O (1), [Zn6(imi)6(B-α-H3AsW9O33)2]·2H2O (2) and [Mn6(imi)6(B-α-H3AsW9O33)2]·4H2O (3) (imi = imidazole), have been synthesized hydrothermally without using any polyoxoanion as precursor and characterized by elemental analyses, IR, TG and X-ray single-crystal diffraction. Compounds 1-3 are isostructural, composed of [B-α-H3AsW9O33]12− anions and [M6(imi)6]12+ complex cations (M = Ni, Zn and Mn), all M atoms are square pyramidal geometry, and held together to form hexagonal metallocycles by edge-sharing oxygen atoms. In compounds 2 and 3, [M6(imi)6(B-α-AsW9O33)2] (M = Zn, Mn) segments act as 12-connected nodes to form complicated 3D network via hydrogen-bonding interactions, respectively. Magnetic measurements for 1 show the presence of ferromagnetic interactions within the hexanuclear Ni2+ cations. 相似文献
16.
The oxidation of thiocyanate by iron(V) (Fe(V)) was studied as a function of pH in alkaline solutions by a premix pulse radiolysis technique. The rates decrease with an increase in pH. The rate law for the oxidation of SCN− by Fe(V) was obtained as −d[Fe(V)]/dt = k10{[H+]2/([H+]2 + K2[H+] + K2K3)}[Fe(V)][SCN−], where k10 = 5.72 ± 0.19 × 106 M−1 s−1, pK2 = 7.2, and pK3 = 10.1. The reaction precedes via a two-electron oxidation, which converts Fe(V) to Fe(III). Thiocyanate reacts approximately 103× faster with iron(V) than does with iron(VI). 相似文献
17.
Asha Rajapakshe Andrei V. Astashkin David J. Evans Dennis H. Evans 《Inorganica chimica acta》2009,362(12):4603-9469
The tris(pyrazolyl)borate and related tripodal N-donor ligands originally developed by Trofimenko stabilize mononuclear compounds containing MoVIO2, MoVIO, MoVO, and MoIVO units and effectively inhibit their polynucleation in organic solvents. Dioxo-Mo(VI) complexes of the type LMoO2(SPh), where L = hydrotris(3,5-dimethylpyrazol-1-yl)borate (Tp∗), hydrotris(3-isopropylpyrazol-1-yl)borate (TpiPr), and hydrotris(3,5-dimethyl-1,2,4-triazol-1-yl)borate (Tz) and related derivatives are the only model systems that mimic the complete reaction sequence of sulfite oxidase, in which oxygen from water is ultimately incorporated into product. The quasi-reversible, one-electron reduction of Tp∗MoO2(SPh) in acetonitrile exhibits a positive potential shift upon addition of a hydroxylic proton donor, and the magnitude of the shift correlates with the acidity of the proton donor. These reductions produce two Mo(V) species, [Tp∗MoVO2(SPh)]− and Tp∗MoVO(OH)(SPh), that are related by protonation. Measurement of the relative amounts of these two Mo(V) species by EPR spectroscopy enabled the pKa of the MoV(OH) unit in acetonitrile to be determined and showed it to be several pKa units smaller than that for water in acetonitrile. Similar electrochemical-EPR experiments for TpiPrMoO2(SPh) indicated that the pKa for its MoV(OH) unit was ∼1.7 units smaller than that for Tp∗MoVO(OH)(SPh). Density functional theory calculations also predict a smaller pKa for TpiPrMoVO(OH)(SPh) compared to Tp∗MoVO(OH)(SPh). Analysis of these results indicates that coupled electron-proton transfer (CEPT) is thermodynamically favored over the indirect process of metal reduction followed by protonation. The crystal structure of TpiPrMoO2(SPh) is also presented. 相似文献
18.
Richard L. Keiter Ping Ye John William Benson Douglas E. Brandt Arnold L. Rheingold Kraig A. Wheeler 《Inorganica chimica acta》2010,364(1):176-184
The linkage isomers, (OC)5M[κ1-PPh2 CH2CH(PPh2)2] 1 and (OC)5M[κ1-PPh2 CH(PPh2)CH2PPh2] 2 (M = Cr, Mo and W) exist in equilibrium at room temperature. Equilibrium constants for 1Cr ? 2Cr, 1Mo ? 2Mo and 1W ? 2W at 25 °C in CDCl3 are 2.61, 5.0 and 4.74, respectively. Enthalpy favors the forward reaction (ΔH = −13.5, −12 and −12.2 kJ mol−1, respectively) while entropy favors the reverse reaction (ΔS = −37.6, −28 and −28.2 J K−1 mol−1, respectively). Isomerization is much faster than chelation with 1Mo ? 2Mo ? 1W ? 2W > 1Cr ? 2Cr. Enthalpies of activation for 1Cr ? 2Cr and 1W ? 2W are 119.0 and 92.6 kJ mol−1, respectively, and entropies of activation are 1.4 and −28.2 J K−1 mol−1, respectively. Isomerization is 104 times faster for these complexes than for (OC)5M[κ1-PPh2CH2CH2P(p-tolyl)2]. A novel mechanism is proposed to account for the rate differences. The X-ray crystal structure of 2W shows that the phosphorus atom of the short phosphine arm lies very close to a carbon atom of the W(CO)4 equatorial plane (3.40 Å) which could allow “through-space” coupling, accounting in part for the observation of long-range JPC and JPW coupling. The X-ray structure of (OC)5W[κ1-PPh2 C(CH2)PPh2] 5W has been determined for comparison to 2W. 相似文献
19.
Three new organic-inorganic hybrid materials with 4,4′-bipy ligands and copper cations as linkers, [CuII(H2O)(4,4′-bipy)2][CuII(H2O)(4,4′-bpy)2]2H[CuIIP8Mo12O62H12] · 5H2O (1), [CuI(4,4′-bipy)][CuII(4,4′-bipy)]2 (BW12O40) · (4,4′-bipy) · 2H2O (2) and [CuI (4,4′-bipy)]3 (PMo12O40) · (pip) · 2H2O (3) (pip = piperazine; 4,4′-bipy = 4,4′-bipyridine), have been hydrothermally synthesized. The single X-ray structural analysis reveals that the structure of 1 is constructed from [Cu(H2O)(4,4′-bipy)2] complexes into a novel, three-dimensional supermolecular network with 1-D channels in which Cu[P4Mo6]2 dimer clusters reside. To the best of our knowledge, compound 1 is the first complex in which the [P4Mo6] clusters have been used as a non-coordinating anionic template for the construction of a novel, three-dimensional supermolecular network. Compound 2 is constructed from the six-supported [BW12O40]5− polyoxoanions and [CuI(4,4′-bipy)] and [CuII(4,4′-bipy)] groups into a novel, 3-D network. Compound 3 exhibits unusual 3-D supramolecular frameworks, which are constructed from tetrasupporting [PMo12O40]3− clusters and [CuI (4,4′-bipy)n] coordination polymer chains. The electrochemical properties of 2 and 3 have been investigated in detail. 相似文献
20.
Hua-Fen Hsu Wan-Yu Peng Ru-Rong Wu Yu Wang Minghuey Shieh 《Inorganica chimica acta》2005,358(6):2149-2154
The synthesis and crystal structures of two high valent molybdenum complexes containing trisbenzenethiolatophosphine ligands, [Mo2(PS3)2(PS3H)] (1) and [Mo(PS3″)2] (2), where PS3 = [P(C6H4-2-S)3]3−, PS3H = [P(C6H4-2-S)2(C6H4-2-SH)]2−, and PS3″ = [P(C6H3-3-Me3Si-2-S)3]3−, are described. Compound 1 is a dimeric Mo(IV) species containing three PS3 ligands with an uncoordinated thiol group. An intramolecular hydrogen bonding S-H?S was found in the structure. Two molybdenum ions are bridged by three thiolates. The geometry can be described as two pentagonal bipyramids sharing a triangle face formed by three bridging S atoms. Compound 2 is a Mo(VI) species binding with two tetradentate PS3″ ligands. The eight-coordinate molybdenum center adopts a dodecahedral geometry. 相似文献