COMPOUNDS WITH M3SE3 (M = LI, ZN) RINGS - SYNTHESIS AND CHARACTERIZATION OF [ZN(CH2SIME3)SE-2,4,6-T-BU3C6H2]3.0.5C6H14 AND [LI(THF)SE-2,4,6-T-BU3C6H2]3.PHME

The synthesis and structural characterization of two six-membered ring species containing selenium are described. The compound [Zn(CH2SiMe3) SeMes]3.0.5 C6H14 (Mes* = 2,4,6-t-Bu3C6H2), (1) was synthesized by th e reaction Zn(CH2SiMe3)2 with 1 equiv of HSeMes in hexane whereas [Li (THF)SeMes13.PhMe (2) was obtained by the lithiation of HSeMes* with n-BuLi in the presence of 1 equiv of THF. Each molecule has an M3Se3 c ore (M = Li, Zn) structure. Unlike the corresponding sulfur species, 1 has a nonplanar Zn3Se3 array and represents the first structure of th is type for a selenium compound. The nonplanar Li3Se3 core in 2 involv es pyramidal coordination at selenium and almost planar lithium coordi nation. Both species were characterized by H-1 NMR and IR spectroscopy and X-ray crystallography. Crystal data with Mo Kalpha (lambda = 0.71 0 69 angstrom) at 130 K are as follows: 1, a = 10.355(5) angstrom, b = 18.850(8) angstrom, c = 20.885(8) angstrom, alpha = 83.67(3)-degrees, beta = 86.92(4)-degrees, gamma = 77.62(4)-degrees, V = 3956(3) angstr om3, Z = 2, space group P1BAR, 7550 (I > 3sigma(I)) data, R = 0.077; 2 , alpha = 9.973(5) angstrom, b = 18.466(7) angstrom, c = 21.735(9) ang strom, alpha = 74.26(3)-degrees, beta = 79.45(4)-degrees, gamma = 78.2 1(2), V = 3725(3) angstrom3, Z = 2, space group P1BAR, 5357 (I > 2sigm a(I)) data, R = 0.069.