Supramolecular NHC ligands: on the influence of Zn-II-templates on the activity of Rh-I(cod) complexes in 'carbene polymerization'

New Rh-I(cod) complexes of N-heterocyclic carbene ligands containing a pending pyridyl moiety for subsequent binding of Zn-II-templates were designed for supramolecular catalyst control in 'carbene polymerization' reactions. Zn-II-templates indeed have an influence on the yields and the polymer molecular weights (and weight distributions) produced by these 'supramolecular assemblies'. However, control experiments reveal that the effect of the Zn-II-template on the polymerization results is general and not due to the assembly formation.