Ruthenium(II) carbonyl complexes of P,P and P,O donor diphosphine ligands,Ph2P(CH2)nPPh2 and Ph2P(CH2)nP(O)Ph2, n = 2, 3 and their activities in catalytic transfer hydrogenation reactions

The polymeric precursor [RuCl₂(CO)₂]_n reacts with the ligands, P∩P (a, b) and P∩O (c, d), in 1:1 M ratio to generate six-coordinate complexes [RuCl₂(CO)₂(?²-P∩P)] (1a, 1b) and [RuCl₂(CO)₂(?²-P∩O)] (1c, 1d), where P∩P: Ph₂P(CH₂)_nPPh₂, n = 2(a), 3(b); P∩O: Ph₂P(CH₂)_nP(O)Ph₂, n = 2(c), 3(d). The complexes are characterized by elemental analyses, mass spectrometry, thermal studies, IR, and NMR spectroscopy. 1a–1d are active in catalyzed transfer hydrogenation of acetophenone and its derivatives to corresponding alcohols with turnover frequency (TOF) of 75–290 h^?1. The complexes exhibit higher yield of hydrogenation products than catalyzed by RuCl₃ itself. Among 1a–1d, the Ru(II) complexes of bidentate phosphine (1a, 1b) show higher efficiency than their monoxide analogs (1c, 1d). However, the recycling experiments with the catalysts for hydrogenation of 4-nitroacetophenone exhibit a different trend in which the catalytic activities of 1a, 1b, and 1d decrease considerably, while 1c shows similar activity during the second run.     

Vibrational spectrum of CF<Subscript>4</Subscript> isotopes in an algebraic model

In this paper the stretching vibrational modes of CF₄ isotopes are calculated up to first overtone using the one-dimensional vibron model for the first time. The model Hamiltonian so constructed seems to describe the C-F stretching modes accurately using a relatively small set of well-defined parameters.     

A comparative study of the vibrational spectra of OCS and HCP using the Lie algebraic method

Using the Lie algebraic method the vibrational energy levels of OCS and HCP are calculated for 58 vibrational bands each using the local Hamiltonian. A comparative study is made between the two.     

丙二酰二腙衍生的二氧化二钼(Ⅵ)配合物的合成、表征和晶体结构

本文报道了二氧杂钼(Ⅵ)配合物[MoO₂(H₂L)(H₂O)]的合成、表征和分子结构。该配合物是由马来酰二腙配体双(2-羟基-1-萘醛)丙二酰二腙(H₄L)与双(乙酰丙酮)二氧钼(Ⅵ)在甲醇中以1∶1的物质的量之比反应得到的。通过各种光谱(如IR、MS和NMR)对该配合物进行了表征。通过单晶X射线晶体学确定了配合物的结构。该配合物属于单斜晶系P2₁/c空间群。金属中心具有扭曲的八面体配位环境,与H₂L^2-的1个甲亚胺氮原子、2个末端氧基团、H₂L^2-的2个氧原子和配位水分子的1个氧原子相连。     

Vibrational spectroscopy of Cm–H,C β –C β stretching vibrations of Nickel metalloporphyrins: An algebraic approach

An algebraic model of coupled anharmonic oscillators is introduced, capable of describing the stretching vibrations of medium and large polyatomic molecules. This model is applied to the calculation of C_m–H and C _β –C _β vibrational modes of nickel octaethyl porphyrins and nickel porphyrins molecules. The model appears to describe the data accurately.     

An algebraic approach to the study of the vibrational spectra of HCN

Using Lie algebra the vibrational energy levels of HCN were calculated using the local Hamiltonian for 35 vibrational bands. A comparative study was made with earlier results.     

Phase transition and some physical properties of binary mixtures of two nematogenic compounds showing induced smectic phase

The binary mixtures of nematogenic compounds 4-n-pentyl phenyl 4-n′-hexyloxy benzoate (ME6O.5) and 4-cyanophenyl 4-pentyl benzoate (CPPB) show the presence of induced smectic phase. In this article, we report the phase diagram and the results of refractive index, density, static dielectric permittivity and X-ray diffraction measurements of different binary mixtures of (ME6O.5?+?CPPB) throughout the entire composition range. The density and refractive index values have been analysed to obtain orientational order parameters. The various physical properties of the system have been discussed on the basis of the phase diagram.     

Synthesis,electrochemistry and thermal studies of fluoro and imidazole complexes of copper(II)

Complexes of the (H2Im)4[CuF6], (H2Im)2[CuF4(H2O)2] type (H2Im=imidazolium cation) and Cu(HIm)4X2 (X=Cl or Br; HIm=imidazole) have been prepared in aqueous solution by the interaction of CuO·nH2O with the respective halide in the presence of imidazole. Formation of a particular complex species has been shown to be dependent on the reaction solution pH and also on the nature of the halide. The complexes were characterised on the basis of FT-i.r., u.v.–vis. and e.s.r. spectroscopy and by measurement of magnetic susceptibilities and solution electrical conductivities. Cyclic voltammetry revealed a two-peak quasi-reversible response for [Cu(HIm)4Br2], while other complexes produced overall irreversible voltammographs. Thermal decomposition profiles are consistent with the proposed formulations.     

Pentamethylcyclopentadienyl ruthenium(II) complexes of para-substituted N-(pyrid-2-ylmethylene)-phenylamine ligands: syntheses,spectral and structural studies

The reaction of [(η⁵-C₅Me₅)Ru(PPh₃)₂Cl] (1) with acetonitrile in the presence of excess NH₄PF₆ leads to the formation of the cationic ruthenium(II) complex [(η⁵-C₅Me₅)Ru(PPh₃)₂(CH₃CN)]PF₆ (2). The complex (2) reacts with a series of N,N′ donor Schiff base ligands viz. para-substituted N-(pyrid-2-ylmethylene)-phenylamines (ppa) in methanol to yield pentamethylcylopentadienyl ruthenium(II) Schiff base complexes of the formulation [(η⁵-C₅Me₅)Ru(PPh₃)(C₅H₄N-2-CHN-C₆H₄-p-X)]PF₆ [3a]PF₆–[3f]PF₆, where C₅Me₅ = pentamethylcylopentadienyl, X = H, [3a]PF₆, Me, [3b]PF₆, OMe, [3c]PF₆, NO₂, [3d]PF₆, Cl, [3e]PF₆, COOH, [3f]PF₆. The complexes were isolated as their hexafluorophosphate salts. The complexes were fully characterized on the basis of elemental analyses and NMR spectroscopy. The molecular structure of a representative complex, [(η⁵-C₅Me₅)Ru(PPh₃)(C₅H₄N-2-CHN-C₆H₄-p-Cl)]PF₆ [3e]PF₆, has been established by X-ray crystallography.