SYNTHESIS AND STRUCTURAL CHARACTERIZATION OF ETA-6-ARENE-RUTHENIUM(II) COMPLEXES OF ALANINE AND GUANINE DERIVATIVES

The η6-arene-ruthenium(II) complexes of L-alanine (L-alaH) and L-alanine methyl ester (L-alaMe), [(η6C6H6)Ru(L-ala)Cl] (1) and [(η6 C6H6)Ru(L-alaMe)Cl2] (2) have been prepared and their structures established by X-ray structural analysis. The crystal lattice of 1 contains two diastereomers with opposite chiralities at the metal centre. Epimerization of these species is relatively slow in aqueous solution. Reaction of 1 with 9-ethylguanine (9Etgua) yields [(η6C6H6)Ru(L-ala)(9-Etgua)] Cl (3) for which two diastereomers are observed in solution and in the solid state. In contrast L-alanine methyl ester in 2 may be replaced by 9-ethylguanine leading to the formation of [(η6C6H6)Ru(9Etgua)Cl2] (4). N7 coordination of the nucleobase is exhibited by both 3 and 4. © 1990.