HYPERVALENT BISMUTH ALKOXIDE DIMER COMPLEXES - SYNTHESES, STRUCTURES, AND THERMAL DECOMPOSITIONS OF [BI(OCH(CF3)2)2(MU-OCH(CF3)2)(THF)]2 AND [BI(OC6F5)2(MU-OC6F5)XN]2-CENTER-DOT-ZY (X = Y = C7H8, N = 1, Z = 1 OR 2 X = THF, Y = C6H14, N = 2, Z = 0 OR 1)

The reaction of BiCl3 With in situ generated NaOCH(CF3)2 in THF cleanly affords [Bi(OCH(CF3)2)2(mu-OCH-(CF3)2)(THF)]2 I, a dimer containing a planar Bi2(OR)2 core. A THF ligand is coordinated to each bismuth center creating hypervalent 22 electron centers. Compound I has been characterized spectroscopically and by single crystal X-ray diffraction (monoclinic space group P2(1)/n (No. 14); a = 13.738(7) angstrom, b = 10.936(7) angstrom, c = 14.389(8) angstrom, beta = 94.528(4)degrees, V = 2155(2) angstrom3, Z = 2). A similar dimer, [Bi(OC6F5)2(mu-OC6F5)(C7H8)]2.2C7H8, IIa, is obtained via the reaction of BiPh3 with HOC6F5 in toluene. Compound IIa has been characterized spectroscopically and by single-crystal X-ray diffraction (triclinic space group P1BAR (No. 2); a = 11.086(6) angstrom, b = 13.378(8) angstrom, c = 10.771(9) angstrom, alpha = 98.58(7)degrees, beta = 95.22(5)degrees, gamma = 95.20(5)degrees, V = 1564(4) angstrom3, Z = 1). A second, related crystal form of this compound which does not contain the lattice toluene molecules was also structurally characterized (IIb: monoclinic space group P2(1)/n (No. 14); a = 12.266(3) angstrom, b = 16.299(6) angstrom, c = 12.672(2) angstrom, beta = 96.32(2)degrees, V = 2518(1) angstrom3, Z = 2). Compounds IIa,b contain weakly bound eta6-toluene ligands with bismuth to ring centroid distances of 2.958(2) angstrom and 2.968 (5) angstrom, respectively. Compounds IIa,b contain 26 electron bismuth centers. A detailed variable-temperature study of II is consistent with a monomer-dimer equilibrium. Recrystallization of compounds IIa,b from THF/hexane yields [Bi(OC6F5)2(mu-OC6F5)(THF)2]2.C6H14, IIIa (triclinic space group P1BAR (No. 2); a = 11.526(7) angstrom, b = 14.12(1) angstrom, c = 10.995(8) angstrom, alpha = 109.36(6)degrees, beta = 101.63(6)degrees, gamma = 105.20(6)degrees, V = 1545(2) angstrom3, Z = 1), or [Bi(OC6F5)2(mu-OC6F5)(THF)2]2, IIIb (triclinic space group P1BAR (No. 2); a = 12.019(7) angstrom, b = 13.382(9) angstrom, c = 10.818(9) angstrom, alpha = 113.3(6)degrees, beta = 91.36(6)degrees, gamma = 111.7(5)degrees, V = 1454(2) angstrom3, Z = 1). Compounds IIIa,b contain 24 electron bismuth centers. Compounds I and IIb decompose in H2O-saturated oxygen atmospheres upon heating to 400-degrees-C to give BiOF. Prehydrolysis of IIb followed by heating at 400-degrees-C in air affords alpha-Bi2O3.