NMR Investigation of the Spontaneous Thermal- and/or Photoinduced Reduction of trans Dihydroxido Pt(IV) Derivatives

作者：Petruzzella Emanuele; Margiotta Nicola^*; Ravera Mauro; Natile Giovanni

来源：Inorganic Chemistry, 2013, 52(5): 2393-2403.

DOI：10.1021/ic302100x

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 cisplarin 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 degrees 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 mu-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 O-2 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.

• 出版日期2013-3-4