MULTIDENTATE LEWIS-ACIDS - SYNTHESIS, STRUCTURE, AND REACTIONS OF COMPLEXES OF BIDENTATE ZIRCONIUM TRICHLORIDE ALKOXIDES

The 1:2 tetrahydrofuran adduct 5 of zirconium trichloride isopropoxide adopts a mer octahedral geometry in solution. Partial redistribution occuss to give the 1:2 tetrahydrofuran adduct 3 of ZrCl4. A bidentate zirconium trichloride alkoxides 8 could be prepared by treating the bis(trimethylsilyl) ether 7 of racemic trans-1,2-cyclohexanediol with 2 equiv of the 1:2 tetrahydrofuran adduct 3 of ZrCl4. An X-ray crystallographic study of the tetrahydrofuran adduct of bidentate Lewis acid 8 showed that the electrophilic sites are trans-diaxially oriented and independently bind two molecules of tetrahydrofuran to give mer octahedral complexes. In solution, the adduct decomposes by a redistribution that produces the 1:2 tetrahydrofuran adduct 3 of ZrCl4. The adduct crystallizes in the monoclinic space group P21/c with a = 16.111 (9) Å, b = 10.868 (6) Å, c = 25.178 (13) Å, β = 121.32 (4)°, V = 3766.1 Å3, and Z = 4. Refinement of 3699 reflections yielded R = 0.042 and Rw = 0.042. © 1990, American Chemical Society. All rights reserved.