Carbon compounds of the transition metals. Part XIX. Crystal and molecular structure of µ-(π,π-1,6-dihydroheptalene)-bis(tricarbonylmolybdenum)

Abstract

The crystal structure of µ-(π,π-1,6-dihydroheptalene)-bis(tricarbonylmolybdenum) has been elucidated by single-crystal X-ray analysis. The crystals are orthorhombic: a= 10·83, b= 12·25, c= 13·07 Å, Z= 4, space group P2₁2₁2₁(D₂⁴). The molecule comprises two Mo(CO)₃ fragments bonded together and bridged by a 1,6-dihydroheptalene molecule; the Mo–Mo distance is 3·19 Å. The Mo(CO)₃ fragments adopt a cis-configuration with respect to the organic ligand and the molecule possesses idealised two-fold symmetry with the two-fold axis passing through the mid-point of the C–C bond common to the two fused seven-membered carbon rings in the ligand, and bisecting the Mo–Mo bond. Within the Mo(CO)₃ fragments the mean Mo–C and C–O bond-lengths are 1·99 and 1·14 Å respectively.