Kinetic Studies of the Inversion of η2-trans-2-Butene in Platinum(II) Complexes Containing Various Amino Carboxylates

Abstract

Abstract Platinum(II) complexes containing S,S- or R,R-trans-2-butene and various l-amino carboxylate, i.e. cis(N,olefin)[PtCl(l-prolinate)(S,S-trans-2-butene)] and trans(N,olefin)[PtCl(l-am)(S,S- or R,R-trans-2-butene)], were synthesized (l-am=l-prolinate, N-methyl-l-prolinate, N-benzyl-l-prolinate, l-alaninate and l-valinate). The kinetics of the inversion reaction of the coordinated S,S- or R,R-trans-2-butene was investigated in acetone in the presence of an excess of trans-2-butene at 8.0 °C. Second order rate law was obeyed with respect to the concentrations of the complex and free olefin, and no solvent path was observed. In the trans (N,olefin) complexes, interactions steric around the coordinated nitrogen atoms seems to be responsible in determining the ease of inversion via an associative mechanism. On the other hand, smaller rate for the cis(N,olefin) complex than the corresponding trans isomer seems to be due to the trans effect.