Synthesis and characterization of ReCl(H(2))(AsMePh(2))(4), a classical hydride complex; reexamination of ReCl(H(2))(PMePh(2))(4) and theoretical calculations on model compounds.
The synthesis of ReCl(H(2))(AsMePh(2))(4) is reported and verified on the basis of (1)H NMR and FAB-MS. The minimum T(1) time for the metal-bonded hydrogen atoms was determined to be 44 ms (-78 degrees C) and 89 (-48 degrees C) ms at 200 and 400 MHz, respectively. From this minimum T(1) time, and, allowing for contributions from other nuclei to the relaxation, a metal-bonded H to H atom distance of 1.57 A can be assessed. The complex is reversibly oxidized at a potential E(1/2)(ox) = +0.07 V. The J(HD) coupling in the related ReCl(HD)(AsMePh(2))(4) compound was at 3.3 Hz. These data for ReCl(H(2))(AsMePh(2))(4) suggest that this molecule contains classical hydrides, and interpretations on T(1) and X-ray data published previously for ReCl(H(2))(PMePh(2))(4) suggest that this molecule contains a very long metal-bonded H-H interaction of 1.39 A. Theoretical calculations on model compounds ReCl(H(2))(XR(3))(4) (X = P, As; R = H, Me) give virtually identical average d(H-H) values of 1.5 (XH(3)) and 1.63 (XMe(3)) A.
Bayse
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Department of Chemistry, Michigan Technological University, 1400 Townsend Drive, Houghton, Michigan 49931, USA.
Luck
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Schelter
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