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1.
The chemistry of metal-oxo compounds has been extensively and intensively studied for over a hundred years because of their theoritical importance and practical application[1]. Recent advance has afforded a study of inorganic or organometallic complexes containing metal-oxo anions[2]. Herein, the synthesis and structural characterization of two heteropolyoxomolybdnum-supported transition metal complexes (H2bpy)0.5Ni(H2O)5[Mo5P2O23]Ni(Hbpy)(H2O)4 (1) and (H2bpy)0.5Co(H2O)5[Mo5P2O23]Co(Hbpy) (H2O)4(2) are reported.  相似文献   

2.
《Liquid crystals》2000,27(6):859-863
Paramagnetic liquid crystalline complexes of the formula [LnL(LH)2][CF3SO3]2 have been synthesised, where LH is the ligand N-dodecyl-4-(3',4'-didodecyloxybenzoyloxy)salicylaldimine and Ln is a lanthanide metal. When compared with analogous nitrate complexes, the transition temperatures are rather low.  相似文献   

3.
The reaction of norbornene (NBE) and norbornadiene (NBD) in the presence of seven-coordinate tungsten(II) and molybdenum(II) complexes of the [(CO)4M(μ-Cl)3M(SnCl3)(CO)3] and [MCl(M′Cl3)(CO)3(NCMe)2] (M=W, Mo; M′=Sn, Ge) types leads to ring-opening metathesis polymerization (ROMP) and to the formation of high molecular weight polymers. The geometric structure of these polymers was determined by means of 1H- and 13C-NMR spectroscopy. The monitoring of the reaction between cyclic olefins and the metal complex by means of 1H-NMR spectroscopy allowed us to observe the coordination of NBD to metal atoms in the initiation step of the polymerization process. Compounds of the [MCl(SnCl3)(CO)34-NBD)] type prepared directly from [(CO)4M(μ-Cl)3M(SnCl3)(CO)3] or [MCl(M′Cl3)(CO)3(NCMe)2] (M=W, Mo) in the presence of an excess of NBD initiate the ROMP reaction immediately. The detection of the first-formed products in the reaction between the metal complex and cyclic olefins provides valuable information concerning the nature of the initiating species.  相似文献   

4.
A density functional theory investigation on a series of sandwich-type transition metal complexes [(CBO)n]2M (n=4–6; M=transition metals) with carbon boronyls (CBO)n as effective aromatic ligands has been presented in this work at B3LYP level. The ground-states of these complexes possess staggered Dnd symmetries, while the corresponding eclipsed Dnh structures exist as transition states with slightly higher energies (within 5.8 kJ/mol). Carbon boronyl complexes [(CBO)n]2M are confirmed to be much more stable than their boron carbonyl isomers [(BCO)n]2M, which, on the other hand, take eclipsed ground-states with Dnh symmetries. The carbon boronyl complexes [(BCO)n]2M proposed in this work parallelize the well-known sandwich-type hydrocarbon complexes [CnHn]2M in coordination chemistry with boronyl groups –BO isolobal to –H atoms in corresponding ligands.  相似文献   

5.
Studies on the syntheses, structures and properties of lanthanide-transition metal complexes are of current great interest, because they can provide good models for investigation of the nature of magnetic exchange interaction between 3d and 41metal ions in the magnetic materials containing rare earth metals. Many of such studies were focused on discrete complexes which were synthesized from the conventional self-assembly reactions in solution. Although several infinite lanthanide-transition metal complexes containing organic ligands have been obtained by conventional solution synthetic method, the polymeric complexes have been poorly explored. Recently we try to use organic ligands for designing magnetic complexes comprising lanthanide and transition metal ions, especially Gd-Cu, Gd-Zn and Gd-Ag couple,with infinite structures, and hope to provide useful messages for the modeling of the magnetic exchange in magnetic materials. Herein reported are a series of lanthanide and transition metal polymeric complexes[{Gd2M3(pydc)6(H2O)12}·4H2O]n and[{Gd4M2(pydc)8(H2O)12}·4H2O]n (M=Cu, Ag,Zn) with 1D chain and 3D wave-like structure, which were prepared from the hydrothermal reactions of Gd2O3, pyridine-2,5-dicarboxylic acid (H2pydc) and Zn(OAc)2 or MO, respectively.  相似文献   

6.
The reaction of K[ReH6(PPh3)2] with [RhCl(CO)L2] [L= PPh3, 1,2,5-triphenylphosphole (TPP), or P(OMe)3] leads to the new electronically unsaturated heterobimetallic polyhydride complexes [(CO)(PPh3)2HRe(μ-H)3RhL2] in moderate-to-good yields. The structures of these complexes have been established on the basis of spectroscopic data, especially 1H and 31P NMR. The bridging hydride ligands are fluxional but there is either a slow or nonexistent exchange between terminal and bridging hydrides. For L = PPh3 or TPP, protonation with tetrafluoroboric acid affords quantitatively the cationic complexes [(CO)(PPh3)2HRe(μ-H)3RhHL2]+, isolated as the BF4 or the BPh4 salts.  相似文献   

7.
The catalytic activity of two manganese(III)-oxazoline complexes [Mn(phox)2(CH3OH)2]ClO4 and Mn(phox)3 (Hphox = 2-(2′-hydroxylphenyl)oxazoline), was studied in the epoxidation of various olefins. All of epoxidation reactions were carried out in (1:1) mixture of methanol:dichloromethane at room temperature using urea hydrogen peroxide (UHP) as oxidant and imidazole as co-catalyst. The epoxide yields clearly demonstrate the influence of steric and electronic properties of olefins, the catalysts and nitrogenous bases as axial ligand. [Mn(phox)2(CH3OH)2]ClO4 catalyst with low steric properties has higher catalytic activity than Mn(phox)3. The highest epoxide yield (95%) was achieved for indene at the presence of [Mn(phox)2(CH3OH)2]ClO4 within 5 min. The proximal and distal interactions of strong π-donor axial ligands such as imidazole with the active intermediate are efficiently increased activity of the catalytic system.  相似文献   

8.
Mononuclear halfsandwich transition metal complexes (Cp*M) are useful model compounds in which one hemisphere of the coordination shell is blocked by the voluminous Cp* ring. In the protected space below the Cp* ligand, one or two 1,2-dicarba-closo-dodecarborane-1,2-dichalcogenolate ligands can be accommodated, e.q. a mono-dichalcogenolate carborane halfsandwich iridium complexes Cp*Ir(E2C2B10H10)(E=S, Se)[l] and bis-dichalcogenolate carborane rhenium or tungsten complexes Cp*Re(E2C2B10H10)2(E=S, Se,Te),[Li(THF)4] [Cp*W(E2C2B10H10)2] (E=S, Se).  相似文献   

9.
A series of chromium(III) complexes [Cr(bipy)(HC2O4)2]Cl·3H2O (1), [Cr(phen)(HC2O4)2]Cl·3H2O (2), [Cr(phen)2(C2O4)]ClO4 (3), [Cr2(bipy)4(C2O4)](SO4)·(bipy)0.5·H2O (4) and [Mn(phen)2(H2O)2]2[Cr(phen)(C2O4)2]3ClO4·14H2O (5) were synthesized (bipy=4,4′-bipyridine, phen=1,10-phenanthroline), while the crystal structures of 1 and 3–5 have been determined by X-ray analysis. 1 and 3 are mononuclear complexes, 4 contains binuclear chromium(III) ions and 5 is a 3D supromolecule formed by complicated hydrogen bonding. 1–3 are potential molecular bricks of chromium(III) building blocks for synthesis heterometallic complexes. When we use these molecular bricks as ligands to react with other metal salts, unexpected complexes 4 and 5 are isolated in water solution. The synthesis conditions and reaction results are also discussed.  相似文献   

10.
Six mononuclear complexes [M(L1)2(H2O)4] (M = Co(II), 1a and M = Mn(II), 1b), [Cu(L1)2(H2O)2] (1c), [Cu(L1)2(H2O)(Py)2] (1d), [Cu(L3)(H2O)Cl] · H2O (3a) and [Co(Sal)(H2O)(Py)3] · 2ClO4 · H2O (3b) of phenoxyacetic acid derivatives and Schiff base were determined by single crystal X-ray diffraction. The Co(II) (1a) and Mn(II) (1b) complexes are isomorphous. X-ray crystal structural analyses reveal that these coordination complexes form polymeric structure via formation of different types of hydrogen bonding and π-stacking interactions in solid. Thermal analysis along with the powder X-ray diffraction data of these complexes shows the importance of the coordinated and/or crystal water molecules in stabilizing the MOF structure. Complexes 1a, 1c, 3a show marginal catalytic activity in the oxidation of olefins to epoxides in the presence of i-butyraldehyde and molecular oxygen.  相似文献   

11.
The preparation and characterization by X-ray crystallography of transition metal sulfur dioxide hexafluoroarsenates of the general formula [M(SO2)x](AsF6)2 1 (1a: M=Mn, x=2; 1c: M=Co, x=4; 1e: M=Cu, x=4) and the hexafluoroantimonate [Co(SO2)2](SbF6)2 3 is reported. The structural features of the compounds mentioned are compared with those of [Fe(SO2)4](AsF6)2 (1b) and [Ni(SO2)6](AsF6)2 (1d), reported previously. The structural diversity of transition metal sulfur dioxide complexes is discussed.  相似文献   

12.
The acid–base chemistry of some ruthenium ethyne-1,2-diyl complexes, [{Ru(CO)2(η-C5H4R)}22-CC)] (R=H, Me) has been investigated. Initial protonation of [{Ru(CO)2{η-C5H4R}}22-CC)] gave the unexpected complex cation, crystallised as the BF4 salt, [{Ru(CO)2(η-C5H4R}}33-CC)][BF4] (R=Me structurally characterised). This synthesis proved to be unreliable but subsequent, careful protonation experiments gave excellent yields of the protonated ethyne-1,2-diyl complexes, [{Ru(CO)2{η-C5H4R)}2212-CCH)](BF4) (R=Me structurally characterised) which could be deprotonated in high yield to return the starting ethyne-1,2-diyl complexes.  相似文献   

13.
通过水热方法合成了2个由多铌酸盐和过渡金属配合物形成的有机-无机杂化配合物[Cu(TETA)]4[VNb12(VO)4O40][OH]·10H2O(1)和[Cu(TETA)]4[VNb12(VO)6O40][OH]5·5H2O(2)(TETA=三亚乙基四胺). 化合物1和2的多阴离子分别是由4个{VO5}帽和6个{VO5}帽加盖在Keggin型多铌酸盐的方形缺口上形成的, 它们通过多酸阴离子中Nb-Ot (Ot =端氧)与[Cu(TETA)]2+配合物的金属中心配位构筑形成三维结构. 价键计算结果表明, Keggin中心的钒为+5价, 帽位的钒为+4价, X射线光电子能谱分析(XPS)结果也证实了这一结论. 通过单晶X射线衍射分析、红外光谱(IR)、粉末X射线衍射(PXRD)、热重(TG)分析和元素分析对这2个化合物的结构和性质进行了表征.  相似文献   

14.
Five inorganic–organic hybrid vanadates based on tetravanadate cores, transition metals and N-donor ligands have been designed and synthesized under hydrothermal conditions, namely, [Zn(eIM)_3]_2V_4O_(12)(1), [Zn(pIM)_3]_2V_4O_(12)H_2O(2), [Zn(ipIM)_3]_2V_4O_(12)(3), [Co(e IM)_3]_2V_4O_(12)H_2O(4), [Cu(eIM)_2(H+2O)]_2V_4O_(12)(_5)(eIM = 1-ethylimidazole, p IM = 1-propylimidazole, ip IM = isopropylimidazole). All compounds were fully characterized by single-crystal XRD, powder XRD, elemental analysis, TGA, and FT-IR spectroscopy.The hybrid zinc vanadates(1–3) and cobalt vanadate(4) exhibit interesting 2D folded structures and the hybrid copper vanadate(5) presents a 1D chain configuration. All compounds can catalyze olefin epoxidation reactions when using TBHP(TBHP = tert-butyl hydroperoxide) as an oxidant in acetonitrile.The introduction of transition metal ions into tetravanadate cores not only improved the catalytic activity but also fulfilled the heterogeneous catalytic behavior. 1–5 all exhibit extraordinary efficiency in converting olefins to the corresponding epoxides with high conversion and selectivity(particularly,conv. up to 97.1%, sele. up to 100% for 1). Leaching test was also carried out to prove the heterogeneous behavior.  相似文献   

15.
Improved syntheses for the dimeric compounds [Pd2(μ-X)2(PBut3)2] (X = Br, I) have been developed and the X-ray crystal structure for the dimer with X = 1 is reported. The reactions of these dimers with CNR (R = 2,6-dimethylphenyl), H2 and a series of terminal and substituted alkynes are also reported. The dimer with X = Br is an initiator for the catalytic polymerisation of phenylacetylene. The product of the dimers with disubstituted alkynes results in the synthesis of trimeric species with formula [Pd3(μ-X){ν2-C4(CO2R)4}2][PBut3)Me]2 (X = Br, I; R = Me, Et). The X-ray crystal structure of one of these compounds (when R = Et and X = I) is presented, demonstrating that the palladium dimers assist the C---C coupling of the alkynes.  相似文献   

16.
4-Vinyl pyridine (4-Vp) reacts with RuHClCO(PPh3)3 (I) in THF to give RuHClCO(PPh3)2(4-Vp) (II, which reacts with sodium derivatives of bidentate chelating ligands to afford substitution products, [RuH(CO)(PPh3)2(L)]. The bindentate ligands used are 2-hydroxybenzaldehyde, 2-hydroxy-3-methoxybenzaldehyde, trifluorothenoylacetone and 8-hydroxyquinoline. Insertion reactions of the Ru---H bond of II with activated olefins such as acrylonitrile [giving RuCl(CO)(CH3CHCN)(PPh3)2(4-Vp)], 2-vinyl pyridine, dimethyl fumarate and monobromodiethyl fumarate have been carried out to obtain chelated Ru---C bonded complexes. RuCl2(PPh3)3 reacts with an excess of 4-Vp to give an octahedral ruthenium addition complex containing two vinyl pyridine ligands. The dimer [RuClCO(CH3CHCN)(PPh3)(4-Vp)]2 is obtained by the reaction of [RuClCO(CH3CHCN)(PPh3)2]2 with an excess of 4-Vp. Stereochemical assignments have been made for these new complexes on the basis of IR and 1H NMR data.  相似文献   

17.
We reported here four structures of lanthanide–amino acid complexes obtained under near physiological pH conditions and their individual formula can be described as [Tb2(dl-Cys)4(H2O)8]Cl2 (1), [Eu43-OH)4(l-Asp)2(l-HAsp)3(H2O)7] Cl · 11.5H2O (2), [Eu8(l-HVal)16(H2O)32]Cl24 · 12.5H2O (3), and [Tb2(dl-HVal)4(H2O)8]Cl6 · 2H2O (4). These complexes showed diverse structures and have shown potential application in DNA detection. We studied the interactions of the complexes with five single-stranded DNA and found different fluorescence enhancement, binding affinity and binding stoichiometry when the complexes are bound to DNA.  相似文献   

18.
Copper(II) complex with -piperidine-3-carboxylic acid ( -Hpipe-3):[Cu( -pipe-3)2(H2O)] and cobalt(II) and nickel(II) complexes with piperidine-4-carboxylic acid (Hpipe-4):[M(Hpipe-4)2(H2O)4]Cl2 (M: Co, Ni) have been prepared and characterized by means of IR and powder diffuse reflection spectra, thermal analysis, and magnetic susceptibility. The crystal structures of these complexes have been determined by X-ray diffraction. The crystal of [Cu( -pipe-3)2(H2O)] is orthorhombic with the space group Pbcn. The copper atom is in a square pyramidal geometry, ligated by two carboxylato oxygen atoms, two nitrogen atoms, and a water molecule. One molecule of this complex consists of either -piperidine-3-carboxylic acid or -piperidine-3-carboxylic acid. The crystals of [M(Hpipe-4)2(H2O)4]Cl2 are monoclinic with space group P21/n. In these complexes the metal atom is in an octahedral geometry ligated by two carboxylato oxygen atoms and four water molecules.  相似文献   

19.
Three new metal complexes, Cu(4-Hcba)2(4-cba)2(Py)2 (4-Hcba=4-cyanobenzoic acid) 1 and M[H(4-cba)2]2(Py)2 (M=Ni 2, Co 3), have been prepared by the treatment of 4-Hcba with the respective metal nitrate M(NO3)2 (M=Cu, Ni, Co) in the presence of pyridine (Py). Single-crystal X-ray diffraction analyses (3 is isostructural to 2) show that the obtained complexes are of isolated mononuclear and the metal atoms have distorted octahedral coordination environment. Two different types of intramolecular hydrogen bonds exist: asymmetrical O–HO for 1 and symmetrical OHO for 2 and 3. The crystal packing between the molecular complexes is controlled mainly by T-shaped C–Hπ interactions between pyridine and phenyl rings. Preliminary discussions on IR, UV–VIS and fluorescent spectra have also been carried out.  相似文献   

20.
Photodynamic properties of series of metal complexes having the general formula [M(diars)2X2]ClO4 or BF4 where M = Co3+, Cr3+, Rh3+; X = Cl, Br, I, diars = o-phenylene bis(dimethylarsine) are studied. Photogeneration of singlet oxygen is monitored by both optical and EPR methods. In comparison with rose bengal ((1O2) for RB = 0.76), singlet oxygen generating efficiencies of these complexes are determined. Rate of N,N-dimethyl-4-nitrosoaniline (RNO) bleaching is found to be retarded by specific 1O2 quencher NaN3, confirming the involvement of 1O2 as an active intermediate. Photolysis of these complexes in the presence of spin trap 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) generates 12-line EPR spectra, characteristic of O2 adduct. Photogeneration of O2 is also monitored by optical spectroscopy using superoxide dismutase (SOD) inhibitable cytochrome c reduction assay. The results indicate that the [Co(diars)2Br2]ClO4 complex possesses high ability to generate reactive oxygen species (ROS). Both Type I and II paths are involved in the photosensitisation of the metal complexes. The antimicrobial activity of the complexes against selected bacteria is estimated. The relationship between the enzymatic production of ROS and antimicrobial activity of the complexes is examined and a good correlation between two factors is found. The [CoBr2(diars)2]ClO4 complex investigated in this study effect photo cleavage of the plasmid DNA (pUC18).  相似文献   

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