Synthesis and structural, electrochemical and NMR analysis of the [{Pt(PEt3)2}2Te2]nseries (n= 0,2 +) and the bicapped triplatinum [{Pt(PEt3)2}3(µ3-Te)2]2+dication: Te–Te bond formation in a cyclo-Pt2Te2core upon a chemically reversible two-electron oxidation

Abstract

Room-temperature reactions of three [Pt3(CO)6]n2– dianions (n= 3, 4, 5) with TePEt3 in tetrahydrofuran (containing [AsPh4]+Cl–) give rise to the 32-electron [{Pt(PEt3)2}2(µ2-Te)2]1, the 30-electron [{Pt(PEt3)2}2(µ2-Te2)]2+ dication 2 and the 48-electron [{Pt(PEt3)2}3(µ3-Te)2]2+ dication 3 which were characterized by X-ray diffraction, electrochemical and multinuclear (1H, 13C, 19F, 31P, 195Pt) NMR measurements; a chemical two-electron oxidation of 1, which has a planar cyclo-Pt2Te2 core, quantitatively produces 2 with a highly bent bicyclo-Pt2Te2 core due to the formation of an electron-pair Te–Te bond (which can be reversibly cleaved upon chemical reduction to reconvert 2 into 1).