title: NMR investigation of the spontaneous thermal- and/or photoinduced reduction of trans dihydroxido Pt(IV) derivatives.
abstract: The initial aim of the present work was the synthesis of the axial disuccinato Pt(IV) derivative of [PtCl2(cis-1,4-DACH)] (Kiteplatin, 1 in Figure 1 ) (DACH = diaminocyclohexane), which contains an isomeric form of the diamine ligand present in oxaliplatin (i.e., 1R,2R-DACH). The interest in this compound stems from its activity on several cisplatin and oxaliplatin-resistant cell lines. Oxidation of 1 with hydrogen peroxide affords cis,trans,cis-[PtCl2(OH)2(cis-1,4-DACH)] (2) which was treated with succinic anhydride in suitable solvents. To our surprise, in dimethylformamide (DMF) (50-70 °C or under light irradiation) or in dimethylsulfoxide (DMSO) (under light irradiation) the formation of the succinato complex cis,trans,cis-[PtCl2{OC(O)CH2CH2C(O)OH}2(cis-1,4-DACH)] (3) was accompanied by reduction to 1. It was found that solvolysis of 2 and formation of a μ-oxo dinuclear species (5) is the key step. The dinuclear species can then undergo reduction to a 1:1 mixture of 1 and 2 with concomitant elimination of oxygen (1/2 O2 in the form of H2O2). The whole process is fostered by heat and/or light, which could favor solvolysis of 2 as well as decomposition of hydrogen peroxide to water and oxygen so preventing the reoxidation of 1 to 2. Because of its peculiar behavior, compound 5 could be exploited also for the development of a technology for water splitting.
authors: Dipartimento di Chimica, Università degli Studi di Bari A. Moro, via E. Orabona 4, 70125 Bari, Italy.
authors: Emanuele
authors: E
authors: Petruzzella
authors: Nicola
authors: N
authors: Margiotta
authors: Mauro
authors: M
authors: Ravera
authors: Giovanni
authors: G
authors: Natile
mesh_terms: D003510:Cyclohexanes / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D009944:Organoplatinum Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D010084:Oxidation-Reduction; D055668:Photochemical Processes; D013386:Succinates / Q000737:chemistry*; D013696:Temperature
chemical_list: D003510:Cyclohexanes; D009944:Organoplatinum Compounds; D013386:Succinates