CRYSTAL AND MOLECULAR-STRUCTURE OF DIPHENYLTHALLIUM(III) TETRAPHENYLDITHIOIMIDODIPHOSPHINATE, [TIPH(2)((SPPH(2))(2)N)], CONTAINING A NEW INORGANIC (CARBON-FREE) TIS2P2N METALLOCYCLE

Reacting potassium tetraphenyldithioimidodiphosphinate (KL) with diphe nylthalium(III) bromide in methanol yielded the compound [TIPh(2)(L)], the structure of which was determined by X-ray diffraction. The unit cell contains two independent molecules with small structural differen ces. In both, the thallium atom is coordinated to two phenyl carbons a nd to two sulphurs belonging to a roughly isobidentate chelate ligand. The diphenylthallium(III) moiety bends back from the bite of the liga nd (average C-Tl-C bond angle for the two molecules = 149.5 degrees) g iving, together with the narrow S-Tl-S angle (average value for the tw o molecules = 97.7 degrees), a thallium environment which can be descr ibed as intermediate between tetrahedral and psi-trigonal bipyramidal.