BIS(2-DIPHENYLPHOSPHINOETHYL)PHENYLPHOSPHINERUTHENIUM(II) COMPLEXES OF AMINO-ACIDS AND DIPEPTIDES

The monomeric complexes [RuCl(aa)(triphos)] (aaH=L-alaH (2), L-valH (3)), in which the bioligands display a kappa2N,O Coordination, may be prepared by the reaction of [Ru2(mu-Cl),(triphoS)2]Cl (1) (triphos=bis(2-diphenyl-phosphinoethyl)phenylphosphine) with the appropriate amino acid in methanol. An X-ray analysis on 3 established an OC-6-35 geometry with the triphosphine ligand in a facial position. This is also the case for triphos in [Ru(glyglyH-1)(triphos)] (4) and [Ru(metglyH-1)(triphos)] (5) prepared by cleavage of chloro bridges in 1 by the appropriate dipeptides, which, therefore, require pyramidal metallated peptide nitrogen atoms. The dipeptides display a kappa3N,N',O Coordination in both complexes with an angle sum of 344-degrees at the peptide nitrogen in 5 as determined by X-ray analysis.