Crystal structure and molecular geometry of tetraphenylphosphonium π-cyclopentadienylbis-(1,2-dicyanoethylene-1,2-dithiolato)molybdenum, [Ph4P+][(π-C5H5)Mo{S2C2(CN)2}2–]

Abstract

The crystal and molecular structure of tetraphenylphosphonium π-cyclopentadienylbis-(1,2-dicyanoethylene-1,2-dithiolato)molybdenum, [Ph₄P⁺][(π-C₅H₅)Mo{S₂C₂(CN)₂}₂^–], has been determined by X-ray diffraction studies. The complex crystallizes in the centrosymmetric triclinic space group P(C_i¹, No. 2) with a= 19·151 ± 0·016, b= 7·246 ± 0·006, c= 12·907 ± 0·010 Å, α= 88·87 ± 0·05°, β= 93·69 ± 0·05°, γ= 100·15 ± 0·05°, Z= 2. A full three-dimensional X-ray diffraction study, based on data to sin θ= 0·86 (Cu-K_α radiation) collected with a 0·01°-incrementing Buerger automated diffractometer, has led to the location of all 47 non-hydrogen atoms. The structure was refined by least-squares methods to R 8·6% for 3657 independent non-zero reflections. The [(π-C₅H₅)Mo{S₂C₂(CN)₂}₂^–] anion has approximate C_s symmetry. The molybdenum atom may be considered seven-co-ordinate, being linked to two bidentate dithiolate ligands and a formally tridentate π-cyclopentadienyl ligand. Mo–S distances average 2·407 Å. Carbon–sulphur and carbon–carbon distances within the dithiolate ligands are compared with those in other transition-metal dithiolates.