(Phosphacyclopentadienyl)indium(I) Derivatives:  Synthesis and X-ray Crystal Structure of [In(η⁵-P₃C₂But₂)]

Co-condensation of indium vapor and tert -butylphosphaethyne at 77 K yields two new, volatile In(I) complexes: [In(η 5 -P 3 C 2 Bu t 2 )] ( 1 ) and [In(η 5 -P 2 C 3 Bu t 3 )] ( 2 ). A single-crystal X-ray diffraction experiment on 1 reveals a discrete molecular structure, involving half-sandwich coordination of the P 3 C 2 Bu t 2 ring around the indium center. 1 may be independently prepared by treating InI with the newly synthesized, base-free ligand salt K(P 3 C 2 Bu t 2 ).