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Neutron diffraction analysis of the structure of H/sub 3/Ni/sub 4/(C/sub 5/H/sub 5/)/sub 4/

Journal Article · · J. Am. Chem. Soc.; (United States)
DOI:https://doi.org/10.1021/ja00513a030· OSTI ID:5844278
The structure of H/sub 3/Ni/sub 4/Cp/sub 4/ (Cp=n/sup 5/-C/sub 5/H/sub 5/), an unusual paramagnetic metal cluster complex, has been analyzed by single-crystal neutron diffraction techniques at low temperature (81 K). As predicted from an earlier x-ray diffraction study, the hydrogen atoms bridge three faces of the Ni/sub 4/ tetrahedral core. Although the Ni/sub 4/ cluster itself is an essentially undistorted tetrahedron (with Ni-Ni edges of 2.469 (6) A), the individual Ni/sub 3/H linkages are unsymmetrical. The H atoms are slightly displaced away from the unique apical Ni atom: Ni-H distances involving the apical Ni atom average to 1.716 (3) A, while those involving the basal Ni atoms average to 1.678 (6) A. The overall mean Ni-H distance is 1.691 (8) A, and the H atoms are situated an average of 0.907 (6) A above the Ni/sub 3/ faces. Other average distances and angles in the molecule follow: H-H = 2.316 (6) A, Ni-C = 2.132 (5) A, Ni-H-Ni = 93.9 (3)/sup 0/, H-Ni-H = 86.1 (6)/sup 0/. The title compound crystallizes in space group C2/c with the following cell parameters at 81 K: a = 28.312 (13) A, b = 9.234 (5) A, c = 14.783 (7) A, BETA = 103.35 (2)/sup 0/, V = 3760 (3) A/sup 3/, Z = 8. The structure has been refined to yield final agreement factors of R/sub f/ reverse arrow 0.107 and R/sub wf/ = 0.067 for 2616 reflections having I > 1.5 sigma (I). (5 tables, 4 figures)
Research Organization:
Univ. of Southern California, Los Angeles
OSTI ID:
5844278
Journal Information:
J. Am. Chem. Soc.; (United States), Journal Name: J. Am. Chem. Soc.; (United States) Vol. 101:19; ISSN JACSA
Country of Publication:
United States
Language:
English