Solution and solid-state photoreductive elimination of chlorine by irradiation of a [PtSb](VII) complex.

In our search for novel main-group-based redox-active platforms for solar fuel production, we have synthesized Cl2Sb(IV)Pt(III)Cl3(o-dppp)2 (2, o-dppp = o-(Ph2P)C6H4)), a complex featuring a highly oxidized [PtSb](VII) core. This thermally stable complex quickly evolves chlorine upon irradiation with a Xe lamp, leading to [Cl2Sb(IV)Pt(I)Cl(o-dppp)2] (1) as the photoproduct. This photoreduction is very efficient, with a maximum quantum yield of 13.8% when carried out in a 4.4 M solution of 2,3-dimethyl-1,3-butadiene in CH2Cl2. Remarkably, 2 also evolves chlorine when irradiated in the solid state under ambient conditions in the absence of a trap.