Formation of B-P bonds through the reaction of nido-monophosphinocarboranes with palladium(II) complexes. The first example of a chelating R2P-C-B-PR2 diphosphine

Reaction of [NMe4][7-PPh2-8-R-7,8-C2B9H10] (R = Me, H, Ph) with cis-[PdCl2( PPh3)(2)] in ethanol yielded [PdCl(7-PPh2-8-R-11-PPh2-7,8-C2B9H9)(PPh3)] (R = Me, H, Ph). The Pd(II) is in a square-planar arrangement. The carborane ligand chelates the Pd through two phosphorus atoms, one from C-PPh2 and th e second from the generated B(11)-PPh2. The remaining two positions are fil led by a PPh3 and one chloride. In the complexation process, a previously n onexistent B(11)-P bond is generated in the ligand. This is unambiguously d emonstrated by a doublet in the B-11{H-1} NMR spectrum and a 1:1:1:1 quarte t in the P-31-{H-1} spectrum. The structure was fully elucidated by a cryst al diffraction analysis of [PdCl(7-PPh2-8-Me-11-PPh2-7,8-C2B9H9)(PPh3)]. C7 H8. By this reaction the hitherto unknown R2P-C-B-PPh2 chelating unit has b een formed.