The molecular structure of dimolybdenum tetrahyphen;acetate

摘要

The molecular structure of anhydrous dimolybdenum tetrahyphen;acetate Mo2(O2CCH3)4in the gas phase at 190thinsp;deg;C, was determined from the diffraction of 54 keV electrons. Two common refinement techniques, involving the use of constrained and unconstrained molecular geometries, were used and found to give comparable results for the major structure parameters. The structure parameters include distances for the Mondash;Mo and Mondash;O bonds of 2.079(3) and 2.108(3) Aring;, respectively, and a Mondash;Mondash;O bond angle of 92.2(2)deg;. The Mondash;Mo bond determined by xhyphen;ray diffraction on a single crystal is longer by about 0.01 Aring;, demonstrating the distorting effects on the quadruple metal bond of axial coordination in the crystal geometry. The effects of intramolecular multiple scattering were also investigated and found to depend critically on the approximation used to account for the effects of molecular vibrations on the multiple scattering corrections. This indicates that a more careful treatment of the vibrational averaging is required.