N-Heterocyclic carbene complexes of palladium(II) and rhodium(I) with pendant ferrocenylmethyl groups: synthesis and electrochemistry

Abstract

1-Ferrocenylmethyl-3-benzylimidazolidinium iodide and 1-ferrocenylmethyl-3-( 2,4,6-trimethylbenzyl) imidazolidinium iodide were prepared in good yields by boiling, under reflux, a solution of (ferrocenylmethyl)trimethylammonium iodide and the appropriate N-alkyl-2-imidazoline in MeCN. From the 1-ferrocenylmethyl-3-ben-zylimidazolidinium iodide salt, N-heterocylic carbene complexes of Pd-II and Rh-I were synthesized by in situ deprotonation and subsequent trapping. The new compounds were characterized by C, H, N analyses, H-1- n. m. r., C-13-n.m.r. and by cyclic voltammetry. The n. m. r. properties of the complexes are compared with those of nonferrocenylated carbene derivatives. The c. v.'s of these compounds show a number of resolved redox processes, indicating that CH(2)Fc substituents are electronically isolated from the remaining molecular framework.