The crystal structure of di-μ-bromobis(μ-tetraphenyl-cyclobutadiene)tetracarbonyldimolybdenum(I)

Abstract

The crystal structure of di-μ-bromobis(μ-tetraphenylcyclobutadiene)tetracarbonyldimolybdenum(I) has been determined by X-ray diffraction techniques using diffractometer data. The red crystals are triclinic with a = 11.306(4), b = 13.681(4), c = 17.561(10) Å and α 105.58(1), β 91.14(2) and γ 108.50(5)°. The space group indicated by the intensity statistics is P 1 and, with two dimer molecules per cell, no molecular symmetry is required ( D m 1.59 g/cm 3 and D c 1.585 g/cm 3). The structure was solved by the heavy atom method and refined by least-squares methods to a final R of 0.056 for 8089 observed reflections (2θ limit of 135° with copper radiation) used in the analyses. The average MoBr distance in the bromine bridged dimer is 2.637 Å, with a MoMo distance of 2.954 Å. The mean MoC (cyclobutadiene ring) is 2.253 Å and the MoC (carbonyl) is 2.008 Å. The average CC distance in the planar cyclobutadiene rings is 1.469 Å.