SYNTHESIS AND MOLECULAR-STRUCTURE OF ([SE(CH3)3][(CH3)ALCL3])N - A NOVEL 2-DIMENSIONAL LAYERED ORGANOALUMINUM-SELENIUM POLYMER

The crystalline product {[Se(CH3)3][(CH3)AlCl3]}n was prepared from reaction of SeCl4 with A1(CH3)3 in heptane. The organo-main group polymer crystallizes in the monoclinic space group P21/c with unit cell parameters a=11.218(3) Å, b=11.119(3) Å, c=9.915(2) Å, β=107.82(2)°, V=1177.4(5) Å3, and Dcalcd=1.54 g cm-3 for Z=4. Least-squares refinement based on 1195 observed reflections I>3σ(I) in the range 3.50°<2 θ<45.0° led to a final R factor of 0.036 (Rw=0.047). The asymmetric unit contains one selenonium ion, Se(CH3)3+, and one organoaluminum anionic species, (CH3)AlCl3-. Secondary interactions (Se⋯Cl) serve to link the ions along two dimensions to form infinite layers. Thus, {[Se(CH3)3] [(CH3)A1C13]}n may be regarded as a layered organoaluminum-selenium polymer. The mean Se-C bond distance is 1.921(5) Å while the mean C-Se-C bond angle is 99.1(4)°. The independent Al-C bond distance is 1.927(8) Å while the mean Al-Cl bond distance is 2.166(7) Å. © 1990 Plenum Publishing Corporation.