53232-00-1Relevant academic research and scientific papers
A kinetic study of the 1,2-hydrogen shift in a bis(η-cyclopentadienyl)tungsten system
Green, Jennifer C.,Green, Malcolm L. H.,Morley, Christopher P.
, p. 1302 - 1305 (2008/10/08)
The rate of the thermal isomerization of [W(η-C5H5)2(H)(CH2PMe 2Ph)]+ (A) to [W(η-C5H5)2(CH3)-(PMe 2Ph)]+ (B) in acetone solution with hexafluorophosphate as counterion has been measured under a variety of conditions. The rate is found to be first order in A (k70°C = (3.2 ± 0.08) × 10-6 s-1), strongly temperature dependent (EA = 144.7 ± 3.6 kJ mol-1), essentially independent of free phosphine concentration, and enhanced by deuteration of the active methyl group (kH/kD(70°C) = 0.80 ± 0.02). Hydrogen migration is involved in the rate-determining transition state of the reaction, and simple reversible phosphine dissociation to a cationic metal carbene intermediate is too simple a mechanism to account for all the results. Two alternative mechanisms are proposed, one involves the formation of an agostic methyl intermediate, [W(η-C5H5)2(CH2)(μ-H)] +, and the other an equilibrium between a carbene hydride. [W(η-C5H5)2(CH2)(H)] +, and a methyl cation. [W(η-C5H5)2(CH3)]+.
Further Evidence for 1,2-Hydrogen Shift Equilibra in the Bis(η-cyclopentadienyl)methyltungsten System
Canestrari, Massimo,Green, Malcolm L. H.
, p. 1789 - 1794 (2007/10/02)
Trimethylphosphine reacts with PF6 (1) to give PF6 (8) which decomposes thermally to PF6 (9).Thermal equilibrum between (9) and PF6 (11) has been demonstrated.Methyldiphenylphosphine with PF6 (1) gives the complex PF6 (10), then PF6 (12).The products of the reaction of a 1:1 mixture of PF6 (1) and the CD3 analogue with PMe2Ph show that intermolecular hydrogen/deuterium scrambling does not occur.Exchange of the PMe2Ph group by PMe3 has been show in PF6 (10).A mechanism for the reactions involving reversible 1,2-hydrogen shift equilibria of the tungsten-methyl system is discussed.
Photosubstitution Reactions of : Some Evidence for an α-Elimination Mechanism
Costa, Silvia M. B.,Dias, Alberto R.,Pina, Fernando J. S.
, p. 314 - 316 (2007/10/02)
Irradiation of in the presence of L led to the isolation of the following products: , (when L = PMe2Ph), and , (when L = py or MeCN).An α-elimination mechanism is proposed for these reactions.In a study of the related thermal reactions the products were the same as in the photochemical reactions for L = PMe2Ph; for L = py the sole product isolated was ; and no reaction was observed with L = MeCN.
