aeH(3), 9.9 G (H(l) is cis to the a H). The calculation confirms the large -proton interaction and small /3-proton interaction, as the /3-proton coupling would be the same for all ß protons in a freely rotating methyl group, and hence the calculation yields extremes.

The thermally stable phosphinocopper(I) hydride cluster H8Cu8(PPh3)8 has been prepared from the reaction of (PPh3CuCl)4 and sodium trimethoxyborohydride in dimethylformamide (DMF). It crystallizes from DMF as H8Cue(PPh3)8• DMF in the centrosymmetric orthorhombic space group Pbca (Zk/,15; No. 61) with a = 40.10 ± 0.04, b = 22.46 ± 0.02, c ~21.86 ± 0.02 Á, and Z = 8. Observed and calculated densities are 1.367 ± 0.005 and 1.368 g cm-3, respectively. A single-crystal X-ray diffraction study based on counter data (sin 9max = 0.65, Cu Ka radiation) has led to the location of all 125 nonhydrogen atoms, the final discrepancy index being Rf = 9.2% for 3180 independent nonzero reflections. The crystal consists of discrete molecular units of H8Cu8(PPh3)8 and DMF, mutually separated by normal van der Waals distances. The H6Cue(PPh3)6 molecule contains a (slightly distorted) octahedral cluster of copper atoms. Two mutually trans faces of this octahedron are enlarged with their copper-copper distances ranging from 2.632 (6) to 2.674 (5) and averaging 2.655 ± 0,017 Á, while the remaining six copper-copper bond lengths range from 2.494 (6) to 2.595 (5), averaging 2.542 ± 0.044 Á. Each copper atom is apically bonded to a triphenylphosphine ligand with copper-phosphorus distances varying from 2.217 (7) to 2.262 (7), averaging 2.240 ± 0.017 A. Decomposition of the complex with CeHsCChD yields Ha and HD (but no D2) in varying proportions. An assay of liberated [ ]hydrogen indicates that the cluster is associated with six hydride ligands.Possible sites for these ligands (which were not located from the diffraction study) are discussed.

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Pentacoordinate Transition Metal Complexes molecular contacts are collected in Table VI. The individual molecules of (C7Fl6CH2)Fe(CO)3 are separated by normal van der Waals distances, closest approaches (of each type) being as follows: oxygen• Oxygen, 3.374 (4) carbon, 3.261 (4) A; oxygen• • -hydrogen, 2.50 (3) A; carbon• • -hydrogen, 3.02 (5) A; hydrogen• • -hydrogen, 2.81 (6) A.

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