Structural sources of chiral discrimination in diastereoisomeric Ru(II) complexes of aromatic aminoacids and diimines

摘要

The single-crystal structure of a previously reported Ru(II) complex salt, Delta-[Ru(bPY)(2)(S-tyr)]ClO4 (.) benzene (bpy = 2,2'-bipyridyl; tyr = tyrosinato) has been refined in its correct setting. The salt contains the cation that is thermodynamically unstable in aqueous solution at 298 K with respect to the A diastereoisomer. Its stability in the solid state is ascribed to the influence of intramolecular NH-pi and CH-pi interactions involving the aromatic ring of the aminoacidate with the amine group and a pyridyl ring of one of the diimine ligands. The benzene of crystallization is involved with similar CH-pi, pi-pi and pi-facial interactions with the bpy and tyrosinato ligands, and this too may serve to stabilize the particular diastereoisomer in the lattice. (C) 2004 Published by Elsevier B.V.