Remote control: stereoselective coordination of electron-deficient 2,2′-bipyridine ligands to Re(i) and Ir(iii) cores

Abstract

Highly diastereoselective coordination of unsymmetrical cationic 2,2′-bipyridine ligands bearing a chiral amidinium substituent to [Re(CO)₃Cl] and [Ir(PhPy)₂]⁺ cores is reported. Binding strength and stereoselectivity have been correlated with the position of the amidinium group on the bipy. The 4-, 5- and 6-substituted ligands all produce C-[Re(CO)₃(LH)Cl]X selectively, while only the 4-derivative gives preferred formation of Δ-[Ir(Phpy)₂(4-LH)](BF₄)₂.