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1.
Pankaj Hazarika Diganta Kalita Swapnalee Sarmah Ruli Borah Nashreen S. Islam 《Polyhedron》2006,25(18):3501-3508
Two new dinuclear oxo-bridged peroxo complexes of tungsten with coordinated dipeptides of the type, Na2[W2O3(O2)4(glycyl-glycine)2] · 3H2O (1) and Na2[W2O3(O2)4(glycyl-leucine)2] · 3H2O (2) have been synthesized from the reaction of H2WO4, 30% H2O2 and the respective dipeptide at pH ca. 2.5. Synthesis of the compounds, in addition to pH, is sensitive to reaction temperature and concentrations of the components. The compounds were characterized by elemental analysis, spectral and physico-chemical methods including thermal analysis. In the dimeric complexes the two W(VI) centres with edge bound peroxo groups are bridged by an oxo group. The dipeptides occurring as zwitterions bind the metal centers through O (carboxylate) atoms leading to hepta co-ordination around each W(VI). Thermal stability of the compounds as well as their stability in solution were determined. The compounds are highly stable toward decomposition in solutions of acidic as well as physiological pH. These compounds, besides another similar dimeric compound Na2[W2O3(O2)4(cystine)] · 4H2O (3) efficiently oxidized bromide to a bromination competent intermediate in phosphate buffer at physiological pH, a reaction in which only two of the peroxide groups of the complex species were found to be active. The complexes could also mediate bromination of organic substrate in aqueous-organic media. 相似文献
2.
钼(Ⅵ)和钨(Ⅵ)的阴离子交换性能研究——草酸-盐酸体系 总被引:2,自引:0,他引:2
本文在草酸-盐酸体系中,研究钼、钨等元素在强碱性阴离子交换树脂ZerolitFF上的阴离子交换行为,并确定其分离的最佳条件。用高仅2厘米,直径0.9厘米的交换柱可分离大量钨等元素中的微量钼;其分离比率高达1×104:1。应用于试剂级钨酸钠中钼的分离,结果满意。此外,还确定在该体系中,钼与树脂相进行交换的主要形式为MoO2(C2O4)22-。 相似文献
3.
The synthesis of the homoleptic molybdenum imido compound Li2Mo(NBut)4 is reported. The complexes M (NBut)2(NHBut)2 (M = Mo, W) can be protonated with various strong acids giving neutral species. The X-ray crystal structure of the tungsten complex W (NBut)2(NH2But)2 (SO3CF3)2 confirms the presence of O-coordinated cis- CF3SO3 groups. 相似文献
4.
Yoshitaka Yamaguchi Atsushi Fujita Noriyuki Suzuki Takashi Ito 《Journal of molecular catalysis. A, Chemical》2005,240(1-2):226-232
The ring-opening metathesis polymerization (ROMP) of norbornene catalyzed by bis(acetonitrile) molybdenum and tungsten complexes, [M(η3-C3H5)Cl(CO)2(NCMe)2] (1-Mo: M = Mo, 1-W: M = W), which have two labile acetonitrile ligands, has been investigated. These complexes catalyzed the ROMP of norbornene as a single-component initiator. The highly cis-selective polymerization proceeded in a THF solution (95% for 1-Mo and 96% for 1-W), whereas polymerization in CH2Cl2 or toluene resulted in lower cis selectivity. The polymerization of terminal acetylenes using these complexes was also examined. The tungsten complex 1-W showed a high catalytic activity for the polymerization of terminal acetylenes, such as phenyl- and tert-butylacetylene. A highly active catalytic system for the ROMP of norbornene was achieved by the activation of the tungsten complex, 1-W, with one equivalent of phenylacetylene, giving poly(norbornene) with a high molecular weight (Mn = 391 × 104) and a high cis selectivity (cis 89%). 相似文献
5.
Eric W. Ainscough Andrew M. Brodie Andreas Derwahl Graham H. Freeman Carl A. Otter 《Polyhedron》2007,26(18):5398-5405
The reaction of 1,2-bis(diphenylthioylphosphino)hydrazine (L) with copper(I) and mercury(II) halides affords the complexes, [{CuLX}2] (X = I, Br or Cl), [HgLX2] (X = Cl or Br) and the tetrametallic complex, [{L(HgI2)2}2]. Single crystal X-ray structures have been performed on the uncoordinated ligand, L, as well as the complexes [{CuLX}2] (X = I, Br and Cl), [HgLBr2] and [{L(HgI2)2}2. The molecules of L exist as dimers as a result of pairs of N–HS hydrogen bonds. The copper(I) complexes are centrosymmetric dimetallic species, the two copper atoms being bridged by L and the X atoms. In all cases the coordination sphere around the Cu atoms is approximately trigonal pyramidal with an ‘S2X2’ donor set. The complex, [HgLBr2], is a distorted tetrahedral monomer with an ‘S2Br2’ donor set and L acting as a bidentate thus forming a seven-membered chelate ring. The tetramercury iodo complex, [{L(HgI2)2}2], contains two ‘L(HgI2)2’ units linked centrosymmetrically via an I atom from each moiety. The geometry around the Hg atoms is distorted tetrahedral. The influence of hydrogen bonding between the hydrazine backbone hydrogens of L and the coordinated halide ions in for the structures of the metal complexes is discussed. 相似文献
6.
《Journal of molecular catalysis. A, Chemical》2002,190(1-2):131-143
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)3(η4-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
7.
As a strong reducing radical, carbon dioxide anion radical(CO2·-) can be generated by initiating sulfate radical(SO4·-) in the presence of formate anions(FA) for Cr(VI) reduction. Moreover, activated carbon(AC)-catalyzed persulfate(PS) oxidation is an economically justifiable, environmentally friendly, and easy-to-scale-up method to produce SO4·-. The complete removal of Cr(VI) was achieved within 280 min for an initial Cr(VI) concentration of 50 mg/L under the optional condition of c(AC)=1 g/L, [PS]0=10 mmol/L, [FA]0=10 mmol/L, T=30℃, and unadjusted pH. When the molar ratio of FA to PS was greater than or equal to 1, the system maintained a strong reduction state. The mechanism investigation confirmed that FA was converted to carboxyl anion radical(CO2·-) as the predominant radical for Cr(VI) reduction. This novel system may offer a potential platform technology for Cr(VI) wastewater treatment. 相似文献
8.
Since the trinuclear molybdenum cluster compound Mo3S4(DTP)3(μ-DTP)(L) (DTP=diethyldithiophosphate, L=loosely-coordinated ligand) was reported[1],a large number of monomeric trinuclear molybdenum derivatives have been synthesized from it by its diverse substitution reactions[2]. This reaction provides a useful route to design cluster complexes with specific functions. By the reaction with α, ω-dicarboxylates, we successfully synthesized the first oligomer containing two incomplete cubane-type[Mo3S4] cores formulated as[Mo3S4(DTP)3(DMF)]2[η2-μ-OOC(CH2)3COO-μ-η2]) whose molecule structure is as follows: 相似文献
9.
The binuclear molybdenum(II) complexes [Mo2(O2CCF3)4(PR3)2] (R = Ph, Et) act as templates for the self-condensation of 2-aminobenzaldehyde to give a new class of complexes in which a hydride ion bridges two molybdenum(III) centres, each of which carries a tetradentate macrocyclic ligand (C). The new hydrido complexes [Mo2(C)2 (H)(O2CCF3)3(PPh3)2] (I), [Mo2(C)2(H)2(O2CCF3)2(PPh3)2] (II), and [Mo2(C)2 (H)2(O2CCF3)2(PEt3)2]2 (V) exist in two or more isomeric forms as shown by their IR, 1H, 31P and 19F NMR spectra. Substitution with thiocyanate, nitrate and tetraphenylborate anions gives the new products [Mo2(C)2(H)(CO)(NCS)3(PPh3)2] (III), [Mo2(C)2 (H)2(O2CCF3)(NO3)(PPh3)2] (IV), [Mo2(C)2(H)(O2CCF3)(PPh3)2](BPh4)2 (VI) and [Mo2(C)2(H)2(O2CCF3)(PEt3)2](BPh4) (VII), which also exist in isomeric forms. 相似文献
10.
Catalytic polymerization of acetylene in the presence of n5-C5H5-M-(CO)3 R (M=Mo,W;R=CH3-,C2H5-) has been studied.The results show that these complexes possess catalytic activities for the polymerization and copolymerization of monosubstituted acetylene.The catalytic mechanism has been preliminarily discussed.It is suggested that the active species be metal-car-bene.In our previous publications we reported the synthesis of some new Fischer's molybdenum and tungsten-carbene complexes and catalytic activity for alkyne polymerization.The results show that the activity of Fischer's molybdenum-carbene is higher than that of tungsten.The catalytic polymerization of alkyne by M-σ-c bond-containing complexes of molybdenum and tungsten has not been reported yet in literature.Therefore,four M-σ-C bondontaining complexes of molybdenum and tungsten were synthesized by using the method reported in the literature,and catalyst polymerization of alkyne by these complexes was examined. 相似文献
11.
Methoxyethyliron complexes [Cp(CO)(L)Fe(CH2CHROMe)] (L = CO, P(OPh)3; R = H, Me) insert SO2 into the C---O single bond wih formation of metalated sulphonic acid esters [Cp(CO)(L)Fe(CH2-CHRSO2OMe)]. the insertion is stereospecific wih retention of configuration at carbon. The complexes [Cp(CO)3M(CH2CHRSO2OMe)] (M = Mo, W; R = H, Me) are obtained analogously. Oxidation of [Cp(CO)3W(CH2CH2SO2OMe)] wih iodine gives the ionic tungsten(IV) alkyl complex [Cp(CO)3(I)W(CH2CH2SO 2OMe)]+. Triphenylphosphine converts [Cp(CO)3Mo(CH2CHRSO2OMe)] into acyl complexes [Cp(CO)2(Ph3P)Mo(C(O)CH2CHRSO 2OMe)] (R = H, Me), which upon oxidation with CeIV in MeOH yield the diesters MeOC(O)CH2CHRSO2OMe. 相似文献
12.
Jian-Fang Chai Liang-Fu Tang Wen-Li Jia Zhi-Hong Wang Ji-Tao Wang Xue-Bing Leng Hong-Gen Wang 《Polyhedron》2001,20(28):5684-3255
The reaction of bis(pyrazol-1-yl)methane tetracarbonylmolybdenum(0) or tungsten(0) complexes with RSnCl3 (R=Ph, Cl) at room temperature yielded heterobimetallic complexes CH2(Pz)2M(CO)3(Cl)(SnCl2R) (Pz represents substituted pyrazole; M=Mo or W; R=Ph or Cl) in good yields, which have been characterized by elemental analysis, 1H NMR and IR spectroscopy. The reaction of bis(3,5-dimethyl-4-halopyrazol-1-yl)methane tetracarbonyl tungsten with PhSnCl3 did not take place even in refluxing CH2Cl2. The electronic and steric characteristics of substituents on the pyrazole ring remarkably influence the structures of the products. The structures of CH2(3,5-Me2-4-BrPz)2W(CO)3(Cl)(SnCl3) (8) and CH2(4-BrPz)2Mo(CO)3(μ-Cl)(SnCl2Ph) (17) (Pz: pyrazole) determined by X-ray crystallography show that no chlorine-bridged W---Sn bond is observed in complex 8, while one chlorine-bridged Mo---Sn bond exists in complex 17. The Sn---M bond length is 2.7438(5) Å in complex 8 (W---Sn) and 2.7559(4) Å in complex 17 (Mo---Sn). 相似文献
13.
WANG Dun-jia** FANG Zheng-dong HAN De-yan Department of Chemistry Environmental Engineering Hubei Normal University Huangshi P. R. China 《高等学校化学研究》2005,21(3):258-263
Four polyoxometalate complexes, (CPFX·HCl)3H4SiW12O40, (CPFX·HCl)3H3PW12O40, (CPFX·HCl)3H3PMo12O40 and (CPFX·HCl)4H4SiMo12O40, were prepared from ciprofloxacin hydrochloride(CPFX·HCl) reacting with HnXM12O40·nH2O(X=P,Si; M=W,Mo) in an aqueous solution, and characterized by elemental analysis, IR spectrometry and TG-DTA. The IR spectrum confirms the presence of Keggin-type anions of heteropoly acids and the characteristic functional groups of ciprofloxacin. The TG/DTA curves show that their thermal decomposition is a multi-step process including simultaneous collapse of the Keggin-type structure. At first, these compounds had a mass loss of water molecules, then several other mass losses occurred due to the decomposition of ciprofloxacin hydrochloride and its fragments with the degradation of Keggin anions. The end product of decomposition is the mixture of WO3(or MoO3) and SiO2(or P2O5), identified by X-ray diffraction and IR spectroscopy. The possible thermal decomposition mechanisms of these complexes are proposed. This study exemplified that the thermal stability of the complexes containing tungsten is much better than that of the complexes containing molybdenum. 相似文献
14.
有关相络合物极谱催化波的报导颇多,但研究钼与PAR络合物极谱行为的工作尚未见报导。在稀硫酸(pH1.7)介质中,我们观察到,钼与PAR共存时产生一极谱还原波,再引入NaClO3时,此波灵敏度增加,示波极谱导数波波形尖锐而又对称。本文研究钼(Ⅵ)-PAR-NaClO5体系极谱催化波产生的条件,应用该体系测定了矿样中的痕量钼。 相似文献
15.
Barbara A. Fir Hlne P. A. Mercier Jeremy C. P. Sanders David A. Dixon Gary J. Schrobilgen 《Journal of fluorine chemistry》2001,110(2):89-107
The XeOSeF5+ cation has been synthesized for the first time and characterized in solution by 19F, 77Se and 129Xe NMR spectroscopy and in the solid state by X-ray crystallography and Raman spectroscopy with AsF6− as its counter anion. The X-ray crystal structures of the tellurium analogue and of the Xe(OChF5)2 derivatives have also been determined: [XeOChF5][AsF6] crystallize in tetragonal systems, P4/n, a=6.1356(1) Å, c=13.8232(2) Å, V=520.383(14) Å3, Z=2 and R1=0.0453 at −60°C (Te) and a=6.1195(7) Å, c=13.0315(2) Å, V=488.01(8) Å3, Z=2 and R1=0.0730 at −113°C (Se); Xe(OTeF5)2 crystallizes in a monoclinic system, P21/c, a=10.289(2) Å, b=9.605(2) Å, c=10.478(2) Å, β=106.599(4)°, V=992.3(3) Å3, Z=4 and R1=0.0680 at −127°C; Xe(OSeF5)2 crystallizes in a triclinic system,
, a=8.3859(6) Å, c=12.0355(13) Å, V=732.98(11) Å3, Z=3 and R1=0.0504 at −45°C. The energy minimized geometries and vibrational frequencies of the XeOChF5+ cations and Xe(OChF5)2 were calculated using density functional theory, allowing for definitive assignments of their experimental vibrational spectra. 相似文献
16.
Pablo Espinet Paloma Gomez-Elipe Fernando Villafae 《Journal of organometallic chemistry》1993,450(1-2):145-150
The first carbonyl molybdenum-(O) and -(II) complexes with phenylbis(2-pyridyl)phosphine (PPhpy2) have been synthesized. PPhpy2 reacts with [Mo(CO)5(NCMe)] to give [Mo(CO)5(PPhpy2-P)]. With [Mo(CO)4(NBD)] (NBD = norbornadiene) it gives [Mo(CO)4(PPhpy2-P)2] when a 2 : 1 ratio is used, or [MO(CO)4(py2PhP---N,N′)] for a 1 : 1 ratio. Decarbonylation of any of these pyridylphosphine complexes leads to an oligomer of formula {MO(CO)3(μ-PPhpy2)}n, which is also obtained after heating [MO(CO)6] in solution with an equimolar amount of PPhpy2. The oligomer undergoes oxidative addition by iodine or allylbromide to give [MoI2(CO)3(py2PhP---N,N′)], or [MoBr(η3-CH2CHCH2)(CO)2(py2PhP---N,N′)], respectively. These complexes are also obtained by addition of equimolar amounts of PPhpy2 to solutions of [MoI2(CO)3(NCMe)2] and MoBr(η3-CH2CH CH2)(CO)2(NCMe)2, respectively. The ligand tends to act as a P-donor towards molybdenum(O) substrates, and as a chelating N,N′-donor in molybdenum (II) complexes. 相似文献
17.
不对称取代双(吡唑)甲烷VIB羰基金属化合物的合成及表征 总被引:1,自引:0,他引:1
3-苯基吡唑与二溴甲烷在相转移催化下反应,得到(3-苯基吡唑-5'-苯基吡唑)甲烷(1)和双(3-苯基吡唑)甲烷(2)的混合物.当该混合配体与M(CO)6(M=Cr,Mo,W)在光照下反应时,分离得到了不对称取代的(3-苯基吡唑-5'-苯基吡唑)甲烷四羰基铬(3),钼⑷和钨(5).用X-射线衍射测定了化合物5的晶体结构.结果表明,该晶体属于单斜晶系,P2(1)/n空间群,a=1.7976(7) rnn,b=1.3210(5) nm, c=1.8681(7) nm;β=98.293(8)°, V=4.390(3) nm3, Z=8,最终结构偏离因子[I>2σ(I)]=0.0516, Rw=0.0898, GOF=0.879.两个苯基分别处于两个吡唑的3位及5'位. 相似文献
18.
Reactions among Cu(ClO4)2 · 6H2O, Cu(acac)2/VO(acac)2 and 3-methoxysalicylaldehyde Picoloylhydrazone in different solvents give three complexes, [Cu2L(acac)(H2O)2]ClO4 (1), [Cu4L2(acac)2(py)2](ClO4)2 (2) and (VO2)2L2Cu2(acac)2 (3) (acac = acetyl acetonate and py = pyridine). There is an extended 2D structure in complex 1 constructed by hydrogen bonds between the binuclear complex cation and the ClO4− anion, and an extended 1D structure in complex 2 constructed by weak ππ stacking interactions between neighboring cyclic tetranuclear complex molecules. Complex 3 is the first oxovanadium–copper complex with a bridging oxo oxygen atom between the V atom and the Cu atom. The solid-state photoluminescent properties of the three title complexes have been studied. There is an antiferromagnetic interaction in 1. 相似文献
19.
Four novel oxovanadium(IV) binuclear complexes have been synthesized, namely [(VO)2(IPHTA) (L)2SO4 (L denotes 2,2′-bipyridine (bpy); 1,10-phenanthroline (phen); 4,4′-dimethyl-2,2′-bipyridine (Me2bpy) and 5-nitro-1,10-phenanthroline (NO2-phen)), where IPHTA is the isophthalate dianon. Based on elemental analyses, molar conductivity measurements, IR and electronic spectra studies, it is proposed that these complexes have IPHTA-bridged structures and consist of two vanadium(IV) atoms in a square-pyramidal environment. The complexes [(VO)2(IPHTA)(Me2bpy)2]SO4 (1) and [(VO)2(IPHTA)(bpy)2]SO4 (2) were characterized by variable temperature magnetic susceptibility (4–300 K) and the data could be well fitted by the least-squares method to a susceptibility equation derived from the spin Hamiltonian operator,
. The exchange integral, J, was found to be −26.8 cm−1 for (1) and −31.0 cm−1 for (2). These results are commensurate with antifferomagnetic interactions between two oxovanadium(IV) ions within each molecule. The influence of different terminal ligands on magnetic interactions between the metals of this kind of complexes is also discussed. 相似文献
20.
Reaction of N,N′-butylenebis(2-pyridone) (BBP) with hydrated M(NO3)3 salts (M = Y or a lanthanide ion) affords the complexes M2(BBP)3(NO3)6. Thorium(IV) nitrate and dioxouranium(VI) nitrate give Th2(BBP)3(NO3)8·0.5Me2CO and UO2(BBP)(NO3)2, respectively. X-ray diffraction studies on the Nd complex show it to contain arrays of contiguous 66-membered macrocyclic rings arranged so as to form as unusual “bedspring”-like network structure. 相似文献