1,3,2-Diselenaphospholanes with an anellated dicarba-closo-dodecaborane(12) unit

The reaction of the 1,2-diselenido-1,2-dicarba-closo-do-decaborane dianion (1) with dichloro(phenyl)phosphane affords the 1,3,2-discienaphospholane (2) containing an anellated dicarbacloso-docecaborane(12) unit. The phospholane 2 was oxidised by reactions with the elements to the sulfide 3 and the selenide 4, and partial hydrolysis gave a selenophosphonic acid derivative 5 along with the bis(diselane) 6 and decomposition. The reaction of 2 with (ethene)bis(triphenylphosphane)platinum(0) displaces ethene and is accompanied by oxidative addition and rearrangement into the bis(triphenylphosphane)platinum(I I) complex 9, in which the chelating unit is linked to platinum via Pt-Se and Pt-P(Se) bonds, a rare example of a metallophosphane selenide. The molecular structures of 2 and 3 were determined by X-ray analysis. The solution-state structures of the new compounds follow from consistent multinuclear magnetic resonance data (H-1, B-11, C-13, P-31, Se-77, Pt-195 NMR).