[TRIS(3-TERT-BUTYLPYRAZOLYL)HYDROBORATO]BERYLLIUM HYDRIDE - SYNTHESIS, STRUCTURE, AND REACTIVITY OF A TERMINAL BERYLLIUM HYDRIDE COMPLEX

The terminal beryllium hydride complex {eta(3)-HB(3-Butpz)3}BeH (3-Butpz = 3-C3N2ButH2) has been synthesized by the reactions of either {eta(3)-HB(3-Butpz)3}BeCl or {eta(3)-HB(3-Butpz)3}BeBr with LiAlH4. The molecular structure of {eta(3)-HB(3-Butpz)3}BeH has been investigated by X-ray diffraction, thus determining d(Be-H) = 1.23 (7) angstrom. H-1 NMR studies on {eta(3)-HB(3-Butpz)3}BeH have determined the magnitude of 1J9Be-H to be 28 Hz, the first report of 1J9Be-H for a terminal beryllium hydride moiety. IR studies demonstrate that the Be-H stretching frequency is observed at 1865 cm-1 and shifts to 1410 cm-1 (nu(H)/nu(D) = 1.32) upon deuterium substitution. Other half-sandwich [tris(pyrazolyl)hydroborato]beryllium complexes of the series {eta(3)-HB(3-Butpz)3}BeX (X = Cl, Br, I, SH) have also been synthesized, and the molecular structure of the bromide derivative {eta(3)-HB(3-Butpz)3}BeBr has been determined by X-ray diffraction. The series of complexes {eta(3)-HB(3-Butpz)3}BeX (X = H, Cl, Br, I, SH) have been investigated by Be-9 NMR spectroscopy and are characterized by Be-9 resonances in the range delta-1-4 ppm (relative to [Be(H2O)4]2+). {eta(3)-HB(3-Butpz)3}BeH is rhombohedral, R3m (No. 160), with a = 15.739 (3) angstrom, b = 15.739(3) angstrom, c = 8.228 (3) angstrom, alpha = 90.0-degrees, beta = 90.0-degrees, gamma = 120.0-degrees, V = 1765.3 (8) angstrom 3, {eta(3)-HB(3-Butpz)3}BeBr is monoclinic, Pn (No. 7), with a = 8.455 (1) angstrom, b = 15.242(3) angstrom, c = 9.643 (2) angstrom, beta = 100.54 (1)-degrees, V = 1221.8 (4) angstrom 3, and Z = 2.