Ligand displacement reactions. Part II. Kinetics of the reaction between trimethyl phosphite and the tricarbonyl(cycloheptatriene) complexes of chromium, molybdenum, and tungsten

Abstract

Reaction of an excess of trimethyl phosphite with complexes of the type [(C₇H₈)M(CO)₃](M = Cr, Mo, and W), in methylcyclohexane yields cis-[M(CO)₃{(CH₃O)₃P}₃] quantitatively, and the kinetics are first order in each reactant. Activation parameters for the range 30–50° are discussed in terms of S_N2 mechanism. A new method for the preparation of [(C₇H₈)W(CO)₃] is described.