SELECTIVE OXIDATIVE ADDITION AT SINGLE CENTERS IN TRIIRIDIUM CLUSTERS- CRYSTAL AND MOLECULAR-STRUCTURES OF ONE-FRAGMENT AND 2-FRAGMENT ADDITION-PRODUCTS, [IR3(MU-PPH2)3(CO)4(T-BUNC)3(CH3)]I AND [IR3(MU-PPH2)3(CO)3(DPPM)I(OH)].CH2CL2

Oxidative addition to the 46- and 50-electron clusters [Ir3(mu-PPh2)3( CO)3(dppm)] and [Ir3(mu-PPh2)3-(CO)4(t-BuNC)3] in both cases gives rea ction at a single, formally 16-electron, iridium center. The products are [Ir3(mu-PPh2)3(CO)3(dppm)XY] (X = I, Y = I, OH, X = H, Y = Cl) and [Ir3(mu-PPh2)3(CO)4(t-BUNC)3(R)]X (RX = MeI, BzBr, HCI, I2, HgCl2), r espectively. The latter complexes contain unusual complex cations, [Ir 3(mu-PPh2)3(CO)4(t-BUNC)3(R)]+, in which R+ has added to a formally 16 -electron iridium center to give a 16-electron iridium(III) cation.