High-precision neutron diffraction investigation of the prototype biscyclopentadienyl transition metal hydride (eta/sup 5/-C/sub 5/H/sub 5/)/sub 2/MoH/sub 2/ and resolution of the structure in terms of modern bonding theory
A high-precision single-crystal neutron diffraction determination of the crystal and molecular structure of (eta/sup 5/-C/sub 5/H/sub 5/)/sub 2/MoH/sub 2/ has been carried out in order to resolve previous x-ray and neutron diffraction studies which produced structural models which are inconsistent with modern bonding theories. The complex crystallizes in space group C2/c with cell parameters of a = 14.311 (7) A, b = 5.905 (3) A, c = 10.440 (5) A, ..beta.. = 104.15 (2)/sup 0/, and Z = 4. Intensity data were measured for two independent octants out to (sin theta)/lambda = 0.72. The structure was solved by direct methods and refinement led to final discrepancy indices of R(F/sub 0//sup 2/) = 0.074 and R/sub w/(F/sub 0//sup 2/) = 0.101. The dihedral angle between the two cyclopentadienyl planes is 34.2/sup 0/, and the C--C bond lengths within each ring are indicative of a completely delocalized ..pi.. system. The coordinates of the metal-bonded hydrogen atom have been unequivocally located and refined, and a Mo--H distance of 1.685 (3) A and a H--Mo--H' angle of 75.5 (3)/sup 0/ has been obtained. The new structural parameters determined for (eta/sup 5/-C/sub 5/H/sub 5/)/sub 2/MoH/sub 2/ are substantially different from those previously reported but are in excellent agreement with those predicted today for transition metal cyclopentadienyl hydrides.
- Research Organization:
- Argonne National Lab., IL
- OSTI ID:
- 5184414
- Journal Information:
- Inorg. Chem.; (United States), Vol. 16:12
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
CYCLOPENTADIENE
CRYSTAL STRUCTURE
MOLYBDENUM HYDRIDES
ORGANOMETALLIC COMPOUNDS
BOND LENGTHS
NEUTRON DIFFRACTION
ALKENES
COHERENT SCATTERING
CYCLOALKENES
DIENES
DIFFRACTION
HYDRIDES
HYDROCARBONS
HYDROGEN COMPOUNDS
MOLYBDENUM COMPOUNDS
ORGANIC COMPOUNDS
POLYENES
SCATTERING
TRANSITION ELEMENT COMPOUNDS
400201* - Chemical & Physicochemical Properties