Displacement kinetics of 1,5-cyclooctadiene from M(CO)(4)(eta(2:2)-1.5-cyclooctadiene) (M=Cr, Mo, W) by bis(diphenylphosphino)alkane

Kayran, C
Okan, E
Özkar, Saim
Ozturk, O
Saldamli, S
Tekkaya, A
Kreiter, CG
The thermal substitution kinetics of 1,5-cyclooctadiene (COD) from M(CO)(4)(eta(2:2)-COD) (M = Cr, Mo, W) by bis(diphenylphosphino)alkane, (C6H5)(2)P(CH2)(n)-P(C6H5)(2) (n = 1, 2, 3), was studied by quantitative FT-IR spectroscopy. The reaction rate exhibits first-order dependence on the concentration of starting complex and the observed rate constant depends on the concentrations of both the leaving COD and entering diphosphine ligand. In the proposed mechanism the rate determining step is the cleavage of one of two metal-olefin bonds. A rate-law is derived from the proposed mechanism. The evaluation of the kinetic data gives the activation parameters which tend to suggest an associative mechanism for the molybdenum and tungsten complexes, and a dissociative mechanism for the chromium complexes in transition states. The observed rate constant is found to be dependent on the concentration and the nature of the entering diphosphine ligand.


TEKKAYA, A; KAYRAN, C; Özkar, Saim; KREITER, CG (American Chemical Society (ACS), 1994-05-25)
The kinetics of the thermal substitution of 1,5-cyclooctadiene (COD) from [Mo(CO)4(eta2:2-COD)] (1) by bis-(diphenylphosphino)methane (DPPM) and the formation of [Mo(CO)4(DPPM)] (6) was studied by quantitative FT-IR spectroscopy. The reaction rate exhibits first-order dependence on the concentration of 1, and the observed rate constant, k(obs), depends on the concentrations of both leaving COD and entering DPPM ligand. From the evaluation of data collected, one can propose a mechanism in which the rate-dete...
Orbey, H.; Orbey, N. (Informa UK Limited, 1989-3)
A data reduction technique is introduced for the evaluation of second virial coefficients of gases at subcritical temperatures. The method makes use of the vapor-liquid equilibrium data, i.e., temperature, saturation pressure, liquid and vapor molar volumes and can be used to obtain second virial coefficients of a wide variety of fluids including polar, associating and quantum gases. The calculated second virial coefficients are in good agreement with their counterparts from literature, which are obtained f...
Kinetic analysis of DSC and thermogravimetric data on combustion of lignite
Kök, Mustafa Verşan (Springer Science and Business Media LLC, 1996-06-01)
Thermal analysis increasingly being used to obtain kinetic data relating to sample decomposition. This work involves a comparative study of several methods used to analyse DSC and TG/DTG data obtained on the oxidation of Beypazari lignite. A general computer program was developed and the methods are compared with regard to their accuracy and the ease of interpretation of the kinetics of thermal decomposition. For this study, the ratio method was regarded as the preferred method, because it permits the estim...
Thermal behaviour of some metal complexes of N,N-diethyl-N'-benzoyl thiourea
Merdivan, M; Aygün, Rüveyde Sezer; Kulcu, N (Springer Science and Business Media LLC, 1997-06-01)
The thermal behaviour of the complexes of N,N-diethyl-N'-benzoylthiourea (DEBT) with NI(II), Cu(II), Pt(II), Pd(II) and Ru(III) was studied using differential thermal analysis (DTA) and thermogravimetry (TG). These complexes undergo only a pyrolytic decomposition process. A gas chromatography-mass spectrometry combined system was used for the verification of the first decomposition product and X-ray diffraction method for the characterization of the final products of pyrolysis.
Critical behaviour of the specific heat and the thermal expansion close to the melting point in ammonia solid III
Yurtseven, Hasan Hamit (Periodica Polytechnica Budapest University of Technology and Economics, 2009-01-01)
A linear correlation between the specific heat C(P) and the thermal expansion alpha(p) is established here for constant temperatures close to the melting pressure in ammonia solid III. For this correlation, the experimental data for the isothermal compressibility kappa(T) is analysed according to a power-law formula with the critical exponent gamma and, the C(P) and alpha(p) are calculated as a function of pressure near the melting point in ammonia solid III.
Citation Formats
C. Kayran et al., “Displacement kinetics of 1,5-cyclooctadiene from M(CO)(4)(eta(2:2)-1.5-cyclooctadiene) (M=Cr, Mo, W) by bis(diphenylphosphino)alkane,” PURE AND APPLIED CHEMISTRY, pp. 193–198, 1997, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/37740.