SYNTHESIS AND CHARACTERIZATION OF CHIRAL BIMETALLIC COMPLEXES BEARING HARD AND SOFT LEWIS ACIDIC SITES

A new class of optically active heterobimetallic complexes is described. The complexes L*MCl2 (M = Pt(II), Pd(II), L* = C2-symmetric boron-containing bisphosphine ligand) and [Rh(cod)(L*)]ClO4 (Cod = eta2, eta2-1,5-cyclooctadiene) were synthesized as possible templates for asymmetric catalytic reactions that involve substrate precoordination to a Lewis acidic site remote from the transition metal reaction site. Primary amines were found to bind reversibly via a B-N interaction to the free ligands L*. H-1 NMR measurements revealed that the binding constant of representative primary amines to L* could be tuned through variation of the electronic properties of the substituents covalently bound to boron.