The rate and mechanism of tetracyanoethylene addition of cycloheptatriene and related complexes of tricarbonyliron

Abstract

The rate constants for the 1,3-addition of tetracyanoethylene to a range of substituted cycloheptatriene complexes have been measured. Mechanisms are proposed for the addition reactions. The results suggest that tricarbonyliron is activating and that neither ionic nor free radical intermediates are involved. The 1-formylcycloheptatriene complex was found to undergo two parallel reactions. A rapid but reversible 1,3-addition is in competition with a much slower but irreversible 4,6-addition.