Intermediates formed by laser flash photolysis of [PtCl(6)](2-) in aqueous solutions

• Published in: Photochemical & photobiological sciences 2005-11, Vol.4 (11), p.897
• Main Authors: Znakovskaya, Irene V, Sosedova, Yulia A, Glebov, Evgeni M, Grivin, Vjacheslav P, Plyusnin, Victor F
• Format: Article
• Language: English
• Subjects: Chlorine - chemistry; Cisplatin - analogs & derivatives; Cisplatin - chemistry; Kinetics; Lasers; Photolysis; Platinum - chemistry; Platinum Compounds - chemistry; Platinum Compounds - metabolism; Solutions; Water - chemistry
• ISSN: 1474-905X
• DOI: 10.1039/b509587e

The stationary photolysis of [PtCl(6)](2-) in aqueous solutions (10(-5)-10(-4) M) at the region of 313 nm leads to its photoaquation with a quantum yield of 0.19. Laser flash photolysis experiments (308 nm) provided evidence of the formation of Pt(iii) intermediates, namely [PtCl(4)(OH)(H(2)O)](2-) and [PtCl(4)](-), and Cl(2) (-) radical anions. The Pt(iii) complexes formed as a result of an intrasphere electron transfer from Cl(-) ligands to the excited Pt(iv) ion. However, the main ( approximately 90%) photolysis channel was not accompanied by the transfer of Cl atoms to the solvent bulk. The photoaquation of [PtCl(6)](2-) results from the back electron transfer in the secondary geminate pair, [PtCl(5)(H(2)O)](2-)-Cl. The relative yield of Pt(iii) intermediates, recorded after the completion of all processes in the geminate pair, was less than 10% of the number of disappearing initial [PtCl(6)](2-) complexes.