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1.
Hui Wang Xu-Qing Guo Rui Zhong Xiu-Feng Hou 《Journal of organometallic chemistry》2009,694(9-10):1567-1570
The reactions of Cp1CoI2(CO) with heterocyclic thione ligands yields a η2-N, S coordination family of cobalt complexes for adjacent N, S donor atoms, and dinuclear disulfide cobalt complexes for opposite N, S donor atoms. 相似文献
2.
Franck Dumeignil Danhong Wang Eika W Qian Shinichi Inoue Akinori Muto Toshiaki Kabe Atsushi Ishihara 《Research on Chemical Intermediates》2005,31(9):819-832
The first part of this paper deals with the morphology of the MoS2 phase and its oxide precursor, the MoO3 phase, mainly from a geometrical point of view. After giving a brief review of the literature describing the structure of
these compounds, Mo densities in both phases were calculated along various crystallographic planes. Further, using structural
models recently proposed by others, Mo densities in MoS2 were also calculated in the case of an epitactic growth on γ-Al2O3 and TiO2 model surfaces. Then, the calculated Mo densities were compared with experimental results (Mo density when HDS activity is
maximal) previously obtained for catalysts constituted of MoS2 supported on a low SSA TiO2, a high SSA TiO2 and a conventional γ-alumina. It was suggested that either on alumina or titania the MoS2 phase is growing as (100) MoS2 planes. However, while on the alumina the optimal MoS2 phase might be constituted of dispersed MoS2 slabs covering only a part of the alumina surface (2.9–3.9 Mo atoms/nm2), on titania the optimal MoS2 phase might be constituted of a uniform MoS2 monolayer (5.2 atoms/nm2 for the high SSA titania, which is equal to the Mo density of a perfect MoS2 (100) plane). This difference may originate in the creation of a 'TiMoS' phase enhancing the S atoms mobility over Mo/TiO2-sulfided catalysts. Indeed, while in the case of a γ-alumina carrier the active sites (labile S atoms) are located on the edge of MoS2 slabs making the ratio Moedge/Mototal a crucial parameter for the catalytic performances, in the case of a titania carrier the labile sulfur atoms might be statistically
distributed all over the TiMoS active phase. Further, the higher Mo density observed over the high SSA titania (5.2 atoms/nm2) when compared to that over the low SSA titania (4.2 atoms/nm2) was supposedly due to the pH-swing method advantageously used to prepare the former carrier. Indeed, this method allows
giving a solid with enhanced mechanical properties providing a good stability to the derived catalysts under experimental
conditions. In addition, this TiO2 carrier exhibits a great homogeneity, with a surface structure substantially uniform, which might be adequate for a long-range
growth of (100) MoS2 slabs. 相似文献
3.
Haijun Hao Herbert W. Roesky Chunming Cui Hans‐Georg Schmidt Mathias Noltemeyer Peihua Yu Guangcai Bai 《无机化学与普通化学杂志》2000,626(2):368-373
Treating [Cp*V(μ‐Cl)2]3 (Cp* = C5Me5) and [(2,6‐i‐Pr2C6H3N)2MoMe2], respectively, with Me3SnF afforded the title compounds [Cp*V(μ‐F)2]4 ( 1 ) and [(2,6‐i‐Pr2C6H3N)2MoF2] · THF ( 2 ). 1 has a tetrameric structure, in which four V atoms can be regarded as being arranged at the vertices of a distorted tetrahedron, with four long edges bridged by one F atom and each of the other two short edges bridged by two F atoms with a mean V–F bond length of 2.00 Å. A hydrolyzed product of 2 , [(2,6‐i‐Pr2C6H3N)6Mo4(μ3‐F)2Me2(μ‐O)4] ( 3 ) was characterized by elemental analyses and X‐ray single crystal study. The X‐ray diffraction analysis reveals that 3 has a unique tetranuclear structure, containing two five and two six coordinated Mo atoms connecting each other by four μ‐O and two μ3‐F atoms. The geometries around the two Mo atoms can be described having distorted trigonal bipyramidal and distorted octahedral coordination spheres, respectively. The Mo–(μ‐O) bond lengths are 1.813 Å (average) for five coordinated Mo atoms and 2.030 Å (average) for those of six coordinated, respectively, indicating an additional π bonding between five coordinated Mo atoms and the μ‐O atoms. The Mo–(μ3‐F) distances range from 2.291 to 2.352 Å. 相似文献
4.
The title compound was prepared by the oxidation of MoCl3 in liquid phase. The crystal belongs to the orthorhombic system with space group D-Pmnb and unit cell parameters: a = 11.403 (1), b = 12.345 (2), c = 14.292 (2) Å; V = 2011.8 Å3; Z = 4, Dc = 2.396g/cm3. Altogether 2303 independent reflections were collected on a CAD-4 four-circle diffractometer with Mo Kα radiation in range 2° ≤ θ ≤ 27°. The crystal structure was solved by heavy-atoms method and refined by full-matrix least-squares technique to final discrepancy factors R = 0.050 and Rw= 0.056 for 1513 reflections of I ≥ 3σ (I). The configuration of the cluster anion was characterized to be of the same Ml type structure as presented in the previous paper. The average bond lengths of Mo—Mo and Mo-(μ3-O) are 2.577 Å and 1.982 Å respectively. In addition, the effects of bridging atoms, other ligands and bond orders on Mo—Mo bonds are discussed briefly. 相似文献
5.
Crystal Structure of the Molybdenum Dioxide Dichloride — Phosphorus Oxide Trichloride Adduct MoO2Cl2 · POCl3 The crystal structure of MoO2Cl2 · POCl3 was determined by X-ray methods (R = 0.046; 2497 independent reflexions). MoO2Cl2 · POCl3 crystallizes monoclinic in the space group P21/c with Z = 8. It forms nearly linear chains in which the Mo atoms are linked together via weakly bent and asymmetric oxo bridges (Mo? O = 172 and 218 pm). The Mo atoms are surrounded in a distorted octahedral coordination by one O and two Cl atoms (Mo? Cl = 230–232 pm) as terminal ligands and by the POCl3 molecule and the bridging O atoms as well. The POCl3 molecule (Mo? O = 233 pm) is located in trans position to the terminal oxo ligand (Mo? O = 166 pm). 相似文献
6.
Anja Burkhardt Dr. Eike T. Spielberg Sascha Simon Helmar Görls Dr. Axel Buchholz Dr. Winfried Plass Prof. Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(5):1261-1271
The reaction of benzyl 2-amino-4,6-O-benzylidene-2-deoxy-α-D -glucopyranoside (HL) with the metal salts Cu(ClO4)2 ⋅ 6 H2O and Ni(NO3)2 ⋅ 6 H2O affords via self-assembly a tetranuclear μ4-hydroxido bridged copper(II) complex [(μ4-OH)Cu4(L)4(MeOH)3(H2O)](ClO4)3 ( 1 ) and a trinuclear alcoholate bridged nickel(II) complex [Ni3(L)5(HL)]NO3 ( 2 ), respectively. Both complexes crystallize in the acentric space group P21. The X-ray crystal structure reveals the rare (μ4-OH)Cu4O4 core for complex 1 which is μ2-alcoholate bridged. The copper(II) ions possess a distorted square-pyramidal geometry with an [NO4] donor set. The core is stabilized by hydrogen bonding between the coordinating amino group of the glucose backbone and the benzylidene protected oxygen atom O4 of a neighboring {Cu(L)} fragment as hydrogen-bond acceptor. For complex 2 an [N4O2] donor set is observed at the nickel(II) ions with a distorted octahedral geometry. The trinuclear isosceles Ni3 core is bridged by μ3-alcoholate O3 oxygen atoms of two glucose ligands. The two short edges are capped by μ2-alcoholate O3 oxygen atoms of the two ligands coordinated at the nickel(II) ion at the vertex of these two edges. Along the elongated edge of the triangle a strong hydrogen bond (244 pm) between the O3 oxygen atoms of ligands coordinating at the two relevant nickel(II) ions is observed. The coordinating amino groups of the these two glucose ligands are involved in additional hydrogen bonds with O4 oxygen atoms of adjacent ligands further stabilizing the trinuclear core. The carbohydrate backbones in all cases adopt the stable 4C1 chair conformation and exhibit the rare chitosan-like trans-2,3-chelation. Temperature dependent magnetic measurements indicate an overall antiferromagnetic behavior for complex 1 with J1=−260 and J2=−205 cm−1 (g=2.122). Compound 2 is the first ferromagnetically coupled trinuclear nickel(II) complex with JA=16.4 and JB=11.0 cm−1 (g1,2=2.183, g3=2.247). For the high-spin nickel(II) centers a zero-field splitting of D1,2=3.7 cm−1 and D3=1.8 cm−1 is observed. The S=3 ground state of complex 2 is consistent with magnetization measurements at low temperatures. 相似文献
7.
Treatment of molybdenum(II) chloride with the difunctional silylamide Li2Me2Si(NPh)2 led to the formation of the tetranuclear cluster compound [Mo4{Me2Si(NPh)2}4]. According to the X-ray crystal structure determination, the central core of the cluster consists of four molybdenum atoms in a nearly rectangular arrangement. There are two μ4-κ-N,N,N',N'-Me2Si(NPh)22– ligands capping the Mo4 rectangle and two μ2-Me2Si(NPh)22– ligands located at opposite edges. The alternating Mo–Mo distances of 218.1(1) and 279.5(1) pm indicate the presence of a cyclobutadiyne type cluster with alternating Mo–Mo triple and single bonds. 相似文献
8.
Songsong Wang Changliang Han Liuqi Ye Guiling Zhang Yangyang Hu Weiqi Li Yongyuan Jiang 《Molecules (Basel, Switzerland)》2021,26(4)
The electronic structures and transition properties of three types of triangle MoS2 clusters, A (Mo edge passivated with two S atoms), B (Mo edge passivated with one S atom), and C (S edge) have been explored using quantum chemistry methods. The highest occupied molecular orbital (HOMO)–lowest unoccupied molecular orbital (LUMO) gap of B and C is larger than that of A, due to the absence of the dangling of edge S atoms. The frontier orbitals (FMOs) of A can be divided into two categories, edge states from S3p at the edge and hybrid states of Mo4d and S3p covering the whole cluster. Due to edge/corner states appearing in the FMOs of triangle MoS2 clusters, their absorption spectra show unique characteristics along with the edge structure and size. 相似文献
9.
Dr. Inderpal Yadav Dr. Ved Prakash Ram R. Kaswan Prof. Dr. Mannar R. Maurya Prof. Dr. Muniappan Sankar 《欧洲无机化学杂志》2023,26(34):e202300459
Two new β-functionalized oxidomolybdenum(V) corroles, oxido[3-formyl-5,10,15-triphenylcorrolato]molybdenum(V) ( Mo-1 ) and oxido[3-dicyanovinyl-5,10,15-triphenylcorrolato]molybdenum(V) ( Mo-2 ) were synthesized and characterized by various spectroscopic techniques and electrochemical studies. Mo-2 manifests splitted B bands due to x and y polarizations and highly red shifted longest B and Q bands due to the electron-deficient nature of the dicyanovinyl group. EPR data showed that these complexes exhibit an axial compression with dxy1 configuration. DFT studies revealed that HOMO and LUMO orbitals are stabilized in Mo-2 relative to Mo-1 . Mo-1 exhibits two successive reversible reductions and two oxidation potentials in cyclic voltammetry. Surprisingly, Mo-2 exhibits three successive reversible reductions and two oxidations; the one extra reduction could possibly be due to the reduction of the dicyanovinyl moiety. The catalytic activities of Mo-1 and Mo-2 for the oxidative bromination of various phenols using H2O2-KBr-HClO4 mixture in water have been explored and exhibited excellent activity at a very low catalyst loading of 0.0030 and 0.0028 mol%, respectively. Both synthesized β-functionalized Mo(V) corroles manifest much higher conversion and TOF (59801–71174 h−1) for oxidative bromination of phenols relative to earlier reported meso-functionalized Mo(V) corroles (20781–61646 h−1). Hence, Mo-1 and Mo-2 mimic vanadium bromoperoxidase (VBPO) and act as functional models for these catalytic applications. These catalysts were reused upto 3 cycles and showed conversion rate upto 82 % indicating their excellent thermal and chemical stabilities. 相似文献
10.
《International journal of quantum chemistry》2018,118(16)
Mo‐based catalysts are commonly used in the direct methanation of CO; however, no integrated mechanism has been proposed due to limits in characterizing the nano‐sized active structures of MoS2. Thus, we report our investigation into the mechanism of CO methanation over pure MoS2 through density functional theory simulations, considering that only MoS2 edge sites exhibit catalytic activity. Simulations revealed the presence of (010) and (110) surfaces on the MoS2 edges. Both surfaces are reconstructed by the redistribution of surface sulfur atoms upon exposure to H2/H2S, and after sulfur coverage redistribution, S vacancies are generated for CO hydrogenation. The reaction mechanisms on both surfaces are discussed, with the S‐edge being better suited to CO methanation than Mo‐edge on the (010) surface. The rate‐controlling step differs between surfaces, and corresponds to the initial activation reaction, which was achieved more easily on the (110) surface. 相似文献
11.
Dimeric [Mo2S12]2− Cluster: A Molecular Analogue of MoS2 Edges for Superior Hydrogen‐Evolution Electrocatalysis
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Zhongjie Huang Wenjia Luo Lu Ma Mingzhe Yu Xiaodi Ren Mingfu He Shane Polen Kevin Click Benjamin Garrett Prof. Jun Lu Prof. Khalil Amine Prof. Christopher Hadad Prof. Weilin Chen Prof. Aravind Asthagiri Prof. Yiying Wu 《Angewandte Chemie (International ed. in English)》2015,54(50):15181-15185
Proton reduction is one of the most fundamental and important reactions in nature. MoS2 edges have been identified as the active sites for hydrogen evolution reaction (HER) electrocatalysis. Designing molecular mimics of MoS2 edge sites is an attractive strategy to understand the underlying catalytic mechanism of different edge sites and improve their activities. Herein we report a dimeric molecular analogue [Mo2S12]2?, as the smallest unit possessing both the terminal and bridging disulfide ligands. Our electrochemical tests show that [Mo2S12]2? is a superior heterogeneous HER catalyst under acidic conditions. Computations suggest that the bridging disulfide ligand of [Mo2S12]2? exhibits a hydrogen adsorption free energy near zero (?0.05 eV). This work helps shed light on the rational design of HER catalysts and biomimetics of hydrogen‐evolving enzymes. 相似文献
12.
Shu‐Mei Chen Can‐Zhong Lu Ya‐Qin Yu Quan‐Zheng Zhang Xiang He 《Acta Crystallographica. Section C, Structural Chemistry》2004,60(9):m437-m439
A novel chain molybdenum compound, {[Mo2O6(C6H5NO2)]·H2O}n, which was synthesized under hydrothermal conditions, consists of an infinite rail‐like chain formed by molybdenum oxide units linked by zwitterionic nicotinic acid ligands. Each Mo atom is coordinated octahedrally by six O atoms and the MoO6 octahedra are linked to one another via edge‐sharing to produce a zigzag polymeric chain, with nicotinic acid ligands located, alternately, on each side of the rail‐like chain plane. 相似文献
13.
Synthesis and characterization of molybdenum bisimido complexes featuring the extremely bulky Pr* framework [Pr* = 2,6‐bis(diphenylmethyl)‐4‐methylphenyl] are reported. The octahedral halide complex [Mo(NPr*)2Cl2(THF)2] ( 1 ) is readily available from ammonium dimolybdate and the amine Pr*NH2, and features two THF molecules in the coordination sphere of molybdenum. The chloride ligands in 1 may be exchanged with methyl or benzyl groups using Grignard reagents. The resulting complexes [Mo(NPr*)2Me2] ( 2 ) and [Mo(NPr*)2Bz2] ( 3 ) are monomeric and, in contrast to 1 , do not coordinate further neutral two‐electron donor ligands in neither the solid state nor in solution. 相似文献
14.
Pierre Braunstein Neil M. Boag 《Angewandte Chemie (International ed. in English)》2001,40(13):2427-2433
Alkyl, silyl, and phosphane ligands are amongst the most familiar and ubiquitous ligands in organometallic and coordination chemistry. The C, Si, and P donor atoms of these ligands are sp3‐hybridized and the ligands are related to each other by the isolobal analogy: (CR3)−(SiR3)−PR3. Herein, we demonstrate that although a number of unusual observations concerning the reactivity and bonding of these ligands appears unrelated at first sight, they in fact provide offer an exiting and consistent picture that may form the basis for new paradigms. The characterization of stable complexes in which alkyl, silyl, and phosphane ligands behave as symmetrical bridges confirms that there is no inherent thermodynamic instability associated with these bonding situations, and, in fact, reactivity studies suggest that these ligands should be able to bridge between metal centers in reaction intermediates or transition states. 相似文献
15.
E. P. D’yachkov I. A. Bochkov V. A. Zaluev P. N. D’yachkova 《Russian Journal of Inorganic Chemistry》2017,62(8):1048-1050
The effect of 4d-metal dopants on the densities of states of hexagonal TiO2 nanotubes has been calculated by the linearized augmented cylindrical wave method. It has been demonstrated that the substitution of Nb, Mo, Tc, or Pd atoms for a part of Ti atoms leads to a decrease in the band gap width of the material due to the formation of impurity levels in the band gap of TiO2. Doping TiO2 nanotubes with these metals is a promising way to produce materials for electrodes for electrochemical photolysis of water. Doping with Y, Rh, or Ag leads to the displacement of the absorption edge from the UV to the visible range owing to a considerable broadening of the valence and conduction band edges; Zr, Ru, and Cd have a lower disturbing effect on the electronic levels of TiO2. 相似文献
16.
Jolanta Bucher Olivier Blacque Helmut W. Schmalle Heinz Berke 《Acta Crystallographica. Section C, Structural Chemistry》2008,64(2):m87-m90
The title compounds, [Mo(C2H4NO2)2(NO)2], (I), and [Mo(C2H6NS)2(NO)2]·CH3CN, (II), contain distorted octahedral complexes in which the monoanionic N,S‐ and N,O‐bidentate ligands coordinate the molybdenum centres in different modes. The anionic O atoms of the glycinate ligands in (I) are coordinated trans to the nitrosyl ligands and the amine N atoms are located trans to each other, whereas in (II) the anionic S atoms are coordinated trans to each other and the amine N atoms are located trans to the nitrosyl ligands. Each compound has a single complete complex in the asymmetric unit on a general position. Six N—H...O contacts with N...O distances of less than 3.2 Å are observed in (I) between the amine groups and the nitrosyl and carboxylate O atoms. In the 1:1 solvate (II), the acetonitrile molecule forms short N—H...N contacts (N...N < 3.2 Å) between the solvent N atoms and one of the amine H atoms. In addition, three weak intermolecular N—H...S interactions (N...S > 3.3 Å) contribute to the stabilization of the structure of (II). 相似文献
17.
Xin Qiang Wang Wen Tao Yu Dong Xu Meng Kai Lu Duo Rong Yuan 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(6):m336-m337
The CdII ion in the title complex, [Cd(SCN)2{SC(NH2)2}2]∞, is situated at a centre of symmetry, and is bound to two N atoms belonging to thiocyanate groups and to four S atoms of bridging thiourea ligands. The structure consists of infinite chains of slightly distorted edge‐shared Cd‐centred octahedra. The bridging S atoms of two thiourea ligands comprise the common edge. Some thermal properties are described. 相似文献
18.
The synthesis and characterization of a number of cis-dioxomolybdenum(VI) coordination complexes involving tridentate (ONS) ligands is described. The Schiff base ligands were obtained by condensation of 5-substituted salicylaldehydes with o-aminobenzenethiol or 2-aminoethanethiol. The chemical properties of these molybdenum complexes are compared with those having tridentate ligands with the ONO donor atom set. Cyclic voltammetry was used to obtain cathodic reduction potentials (Epc) for the irreversible reduction of the Mo(VI) complexes. Although the reductions are irreversible, trends are observed in Epc both within each series and when different series are compared. Cathodic reduction potentials for the four series examined span the range from ?1.53 to ?1.05 V versus NHE. There are three ligand features whose effect systematically alters the Mo(VI) cathodic reduction potentials. These include (1) the X-substituent on the salicylaldehyde portion of each ligand; (2) the degree of ligand delocalization; and (3) the substitution of a sulphur donor atom for an oxygen donor atom. Each of these effects is considered separately with regard to the Mo(VI) cathodic reduction potentials and then their cumulative effect is described. 相似文献
19.
Istvan Bakk Dietrich Gudat Stefan Hp Martin Nieger Lszl Nyulaszi Lszl Szarvas 《无机化学与普通化学杂志》2005,631(1):47-54
Reactions of the phosphonio‐benzophospholide π‐complexes 3a, b[Cr] with [M(CO)5(olefin)] or of the σ‐complexes 2a, b[M] (M = Cr, Mo, W) with [M(CO)3(aren)] lead to the first binuclear complexes 4a, b[CrM] featuring phosphonoio‐benzophospholides as μ‐bridging 8e‐donor ligands to two group 6 metal atoms. The constitution of the products was determined by spectroscopic and X‐ray diffraction studies. Mixed complexes with both group 6 and 7 metals were not accessible. Mechanistic studies showed that the reactions follow a complicated mechanism whose single steps may involve transfer of either M(CO)n fragments or single CO ligands between complexes; the latter are associated with a σ/π‐coordination isomerization of the benzophospholide unit. Competition between both reaction channels can lead to the formation of product mixtures whose composition is controlled by the relative thermodynamic stabilities of the products. Computational studies suggest that in the more stable isomer of heterobimetallic complexes 4a, b[MM′] end‐on coordination to the heavier and side‐on coordination to the lighter metal atom is preferred. 相似文献
20.
Donald J. Darensbourg Floyd A. Beckford Joseph H. Reibenspies 《Journal of Cluster Science》2000,11(1):95-107
The syntheses of Ru3(CO)9(PTA)3 and Ir4(CO)7(PTA)5 were accomplished through the thermal reactions of Ru3(CO)12 or Ir4(CO)12 with the water-soluble phosphine, PTA(1,3,5-triaza-7-phosphaadamantane). The ruthenium derivative was shown by X-ray crystallography to consist of a triangular Ru3 core with three nearly equal Ru–Ru bonds, with each ruthenium atom bearing an equatorially positioned PTA ligand. In Ir4(CO)7(PTA)5 the iridium atoms define a tetrahedron which is bridged on three edges by CO ligands. One basal iridium atom contains two PTA ligands, while the other two basal and the apical iridium atoms each possess one PTA ligand in their coordination spheres. Although, Ru3(CO)9(PTA)3 is only sparingly soluble in pure water, it is very soluble in aqueous solution of pH<4. Indeed the triruthenium cluster can be extracted reversibly between an aqueous and an organic phase (e.g., CH2Cl2) by changing the pH of the aqueous phase. On the other hand the more highly PTA substituted cluster, Ir4(CO)7(PTA)5, exhibits good solubility in aqueous solution (pH 7 and below) and a variety of organic solvents. Both cluster derivatives are stable in deoxygenated, aqueous solutions for extended period of time (>24 h). 相似文献