Rhodium(I) and iridium(I) phosphaferrocene complexes

The synthesis of 3,4-dimethylphosphaferrocene (1) complexes of rhodium ([Rh (1)(3)Cl] 2, and [Rh(1)(4)][BF4], 3) and iridium ([lr(1)(3)(COD)][BF4], 4) are reported. An X-ray crystal structure analysis of the homoleptic derivat ive 3 reveals that ligands arrange around the rhodium center without appare nt steric congestion. Complex 4, which was also structurally characterized, adopts a trigonal bipyramid geometry in the solid state. The reaction. of 4 with H-2 under pressure yields the [Ir(1)(4)H-2](+) complex.