New square planar complexes of rhodium and their reactions with C-H bonds

Complexes of the type RhX(P(i-Pr){sub 3}){sub 2}(CNR) (X = Cl, I; R = neopentyl, 2,6-xylyl) have been prepared and characterized. The cis derivative RhCl((i-Pr){sub 2}PCH{sub 2}CH{sub 2}P(i-Pr){sub 2})(CNneopentyl) has also been synthesized. The ability of these complexes to catalyze isocyanide insertion into aromatic C-H bonds has been examined and the rates and turnover numbers compared. The studies indicate that the iodide is slightly less reactive than the chloride analog, and that the chelating cis phosphine strongly inhibits the reaction.