Kinetics of substitution reactions of olefins in trans-dichloro(.eta.2-2-methyl-2-butene)platinum(II) complexes containing pyridine or aniline derivatives

Use of a surface-acoustic-wave sensor to characterize the reaction of styrene vapor with a square-planar organoplatinum complex

“…The curves are all linear (linearregression r2 values range from 0.973 to 0.999) and from their slopes a mean thermal activation energy of 22.8 ± 0.3 kcal/mol is obtained. Studies of similar reactions in solution, where the olefins involved were substituted butenes, yielded values of 13-20 kcal/mol (22). While the agreement with these previous data is quite good, the slightly higher value measured for our system may reflect the positive temperature dependence of diffusion of the styrene (or ethylene) in the solid trapping agent.…”

“…The trapping reagent is one member of a class of squareplanar platinum-olefin ^-complexes of the general formula, frans-PtCl2(olefin)(amine), whose ligand-substitution behavior has been studied extensively (18)(19)(20)(21)(22)(23). In the case of nucleophilic attack by olefins, reversible substitution of the initially bound olefin occurs with retention of the spatial configuration of the ligands in the olefin-substituted product.…”

“…In the case of nucleophilic attack by olefins, reversible substitution of the initially bound olefin occurs with retention of the spatial configuration of the ligands in the olefin-substituted product. For complexes where the amine is pyridine or a substituted pyridine, olefin-substitution reactions proceed under mild conditions via an associative bimolecular transition state (21,22).…”

A Kinetic Study of the Competition between Carbon Monoxide and Alkenes in Chloro Complexes of Platinum(II)

“…However, to the best of our knowledge, kinetic studies concerning competitive CO/alkene substitution reactions are not available in the literature, although they are certainly relevant to processes involving both carbon monoxide and olefins, such as hydroformylation and alkene/CO copolymerization . On the other hand, the kinetics of exchange of carbon monoxide have been reported for Pt(II), Pd(II), Rh(I), and Ir(I), and a certain number of data concerning olefin exchange, 5a-d or the displacement of an olefin by another olefin, 5f,g are available in the literature.…”

“…Olefin exchange in [MCl 3 (C 2 H 4 )] - (M = Pd, Pt) shows that the second-order rate constant at 298 K ( k 2 298 ) in THF as solvent is 9 × 10 2 and 1.3 × 10 3 M -1 s -1 for platinum and palladium, respectively 5c. The CO exchange in [MCl 3 (CO)] - is considerably slower, k 2 298 values being, in CDCl 3 as solvent, 3.4 × 10 -3 and 5.70 × 10 -1 M -1 s -1 for platinum and palladium, respectively 4a.…”