Coordination of the new weakly coordinating anions Al(OCH(CF3)2)4-, Al(OC(CH3)(CF3)2)4-, and Al(OC(Ph)(CF3)2)4- to the monovalent metal ions Li+ and Tl+

The structures of Li+ or Tl+ salts of three new fluoroalkoxide-containing aluminate anions were determined by X-ray crystallography. For LiAl(OC(Ph)(CF3)(2))(4), monoclinic, C2/c, a = 42.297(6), b = 10.641(1), c = 19.132(2) Angstrom, beta = 114.808(9), Z = 8, T = -100 degrees C, R = 0.052; for TiAl(OC(CH3)(CF3)(2))(4), monoclinic, P2(1)/c, a = 12.650(3), b = 9.970(2), c = 21.237(4) Angstrom, beta = 94.00(3)degrees, Z = 4, T = -100 degrees C, R = 0.073; for TiAl(OCH(CF3)(2))(4), monoclinic, P2(1)/n, a = 14.261(1), b = 9.8024(9), c = 16.911(2) Angstrom, beta = 93.467(8), Z = 4, T = -130 degrees C, R = 0.053. The monatomic, monovalent cations interact with their respective anions by means of M-O and M-F bonds. The Ti+ cations in TiAl(OCH(CF3)(2))(4) and TiAl(OC(CH3)(CF3)(2))(4) interact with three different aluminate anions. The Li+ cation in LiAl(OC(Ph)(CF3)(2))(4) interacts with only one aluminate anion, forming a rare trigonal-prismatic LiO2F4 coordination unit. (C) 1998 Elsevier Science B.V.