Novel Rhodate and Iridate Complexes containing C,N Chelating Arylamine Ligand Systems

Abstract

The synthesis is described of a series of new iridate and rhodate complexes Li(L-C, N){2}M(cod) (M = Rh, Ir; cod = cycloocta-1,5-diene) containing the ortho-chelating, mono-anionic, arylamine ligands L = C{6}H{4}CH{2}NR{2}-2 (R = Me, Et), C{6}H{3}CH{2}NMe{2}- 2-Me-5, C{6}H{4}CH(Me)NMe{2}-(R)-2 or C{6}H{4}CH{2}NMe(}t{Bu)-2. The synthetic procedure for the -ate complexes from [MCl(cod)] {2} depends on the solubility of the starting aryllithium compound in benzene-an indirect effect of the bulky organic group on the N-donor atom. All the -ate complexes are formed diastereoselectively (and in the case of C{6}H{4}CH(Me)NMe{2}-(R)-2, enantioselectively). }1{H and }1{}3{C NMR spectroscopies show the -ate complexes to be monomeric, heterobimetallic species. The }1{}3{C NMR data show clearly that C{i}{p}{s}{o} is bridging between the late transition metal and the lithium centre. Consequently, this C{i}{p}{s}{o} atom is chiral, and its configuration is stabilized by intramolecular coordination of the N-donor atom of the ortho-amine substituent. The -ate complexes are fluxional with differences in fluxionality (which involve N-dissociation/association, pyramidal inversion at N and rotation around the C{b}{e}{n}{z}{y}{l}-N bond) that can be attributed to differences in the bulk of the groups on the nitrogen atom.