REACTIONS OF ALPHA-PHENYLALANINE AND BETA-PHENYLALANINE WITH TRANSIENT PT(III) COMPLEXES

Laser pulse photolysis was used to show that the intermediate three-va lent platinum complexes, PtCl63- and PtCl52- appearing from photoreduc tion of the PtCl62- complex, coordinate alpha- and beta-phenylalanines (alpha H and beta H) with high rate constants. Spectroscopic and kine tic parameters of transient species are determined. At the first stage of irradiation of the three-valent platinum complex, Pt(LH)(2)Cl-4(-) is formed, which at long-time photolysis converts to the diaminoacid Pt(II) complexes, in which aminoacid (LH) is bound to platinum through the COO- group. The conclusion is drawn from laser flash photolysis d ata and the comparison of electronic and proton magnetic resonance (PM R) spectra of photolysis products with the spectra of free alpha H and beta H, and the known Pt(II) complexes involving these aminoacids, ob tained by a thermal method. (C) 1997 Elsevier Science S.A.