Synthesis and characterization of zirconium pentafluorophenyl complexes: X-ray crystal structures of [ZrCl2(C6F5)(4)(2-)] and [ZrF2(C6F5)(5)(3-)]

Treatment of ZrCl4 with LiC6F5, followed by addition of 1,4,7,10-tetraoxacy clododecane (12-crown-4) or N,N,N',N'-tetramethylethylenediamine (tmed), le ads to the isolation of two pentafluorophenylzirconate complexes: [Li(12-cr own-4)(2)](2)[ZrCl2(C6F5)(4)] (1) and [Li(tmed)(2)][Li(tmed)](2)[ZrF2(C6F5) (5)] (2). The presence of Zr-F groups in the latter compound shows that C-F bond activation has occurred. The anion in the former complex adopts an oc tahedral structure owing to the pi-donor character of the chloride ligands, whereas the anion in the latter adopts a regular pentagonal bipyramidal st ructure. The lithium atoms in 1 are not interacting with the anion, whereas two of the lithium atoms in 2 are involved in Li ... F interactions with f luorine atoms in the anion. Selected bond distances and angles for 1: Zr-C = 2.478(5)-2.510(5), Zr-Cl = 2.409(5), 2.435(5) Angstrom, C-Zr-C(cis) = 77. 9-106.9(2), C-Zr-C(trans) = 161.1, 169.1(2), Cl-Zr-Cl = 166.7(2)degrees. Se lected bond distances and angles for 2: Zr-C = 2.432-2.449(8), Zr-F = 1.986 (4), Li ... F = 1.73(2)-2.50(2) Angstrom, C-Zr-C(cis) = 69.6-73.3, F-Zr-F = 178.8(2)degrees. Crystal data for 1: monoclinic, space group P2(1)/n, a = 15.2288(14), b = 17.328(2), c = 24.013(2) Angstrom, beta = 91.936(3)degrees , V = 6333(1) Angstrom(3), Z = 4, wR(2) = 0.2985 for 7801 reflections and 7 22 parameters. Crystal data for 2: monoclinic, space group P2(1)/n, a = 11. 6143(5), b = 29.6561(9), c = 20.4427(8) Angstrom, beta = 103.266(1)degrees, V = 6853.3(4) Angstrom(3), Z = 4, wR(2) = 0.1822 for 8762 reflections and 759 parameters. (C) 1999 Elsevier Science S.A. All rights reserved.