Multiple C–H Activations of Linear Alkanes by Various (η5-Cyclopentadienyl)W(NO)(CH2CMe3)2 Complexes

Abstract

As illustrated in the accompanying diagram, thermolysis of Cp*W(NO)(CH2CMe3)2 (Cp* = η5-C5Me5) at 80 °C in neat linear alkanes effects three successive C–H bond activations of the hydrocarbon substrates and forms Cp*W(NO)(H)(η3-allyl) complexes in which the allyl ligands are derived from the alkanes. These allyl hydrido compounds exist in solutions as mixtures of isomers containing monosubstituted (i.e., terminal) or 1,3-disubstituted (i.e., internal) allyl ligands which can have either an endo or exo orientation with the substituent groups being either proximal or distal to the nitrosyl ligand. Due to steric factors the most abundant isomer in all cases has a monosubstituted allyl ligand in the endo orientation with the alkyl end distal to the nitrosyl ligand. In addition, the relative abundance of Cp*W(NO)(H)(η3-allyl) isomers having monosubstituted allyl ligands decreases with increasing length of the n-alkane chain. Further thermolysis of the Cp*W(NO)(H)(η3-allyl) complexes results in the liberation o...