Halogen to metal π-donation in metalloporphyrins

Abstract

The ¹H NMR analysis of the paramagnetic trans-dihalogeno-ruthenium(IV) and osmium(IV) porphyrins reveals that the halides have a pronounced effect on both the magnitude and the direction of charge transfer between the metal and the porphyrin, that the degree of covalency of metal–halide bonds increases in the order of Mn^III < Ru^IV < Os^IV, and that the relative strength of halogen-to-metal π-donation is Cl < Br < I.