Syn/anti rotamer interconversion as the rate-determining initiation step in ring-opening metathesis polymerisations using well-defined molybdenum alkylidene complexes

Abstract

The kinetics of initiation of metathesis polymerisation of methyl-substituted norbornenes initiated by complexes of the type [Mo(CHR¹)(NC₆H₃Prⁱ ₂-2,6)(OR²)₂][R¹= Bu^t, CMe₂Ph; OR²= OCMe₃, OCMe(CF₃)₂] reveal a zero-order dependence on monomer concentration in some cases; syn→anti alkylidene conversion of the initiator is proposed as the rate-limiting step.