Syntheses, Crystal Structures, Spectroscopic Characterization, and Electrochemical Studies of the Ditungsten(III) Complexes Cl3W(μ-L)3WCl3 and [Cl3W(μ-L)2(μ-Cl)WCl3]- (L = 1,4-Dithiane, 1,4-Thioxane, pms = Pentamethylene Sulfide). C−S Bond Cleavage of the Bridging Thioether(s) in Cl3W(μ-L)3WCl3

Abstract

Reduction of WCl(4) with 1 equiv of sodium amalgam, in the presence of either a refluxing toluene or neat solution of the desired thioether, produces a mixture of Cl(3)W(&mgr;-L)(3)WCl(3) (L = 1,4-dithiane (1), 1,4-thioxane (2), pms = pentamethylene sulfide (3)) and [Na][Cl(3)W(&mgr;-L)(2)(&mgr;-Cl)WCl(3)] (L = 1,4-dithiane (4), 1,4-thioxane (5), pms (6)). 4 and 5 could be converted to 1 and 2, respectively, in the presence of excess L in refluxing toluene. The structures of 1, 2, 3, 7, and 8 have been solved. 1, 2, and 3 are the first reported crystal structures for ditungsten(III) tris-bridged cyclic thioether complexes. Crystal data are as follows: for an acetone solvate of 1, monoclinic space group P2(1)/n (No. 14), a = 12.518(3) Å, b = 9.475(2) Å, c = 27.408(3) Å, beta = 93.34(1) degrees, Z = 4; for an acetone solvate of 2, tetragonal space group P4/ncc (No. 130), a = 25.7603(3) Å, b = 25.7603(3) Å, c = 18.6771(2) Å, Z = 16; for a hexane solvate of 3, monoclinic space group P2(1)/n (No. 14), a = 11.874(4) Å, b = 21.823(3) Å, c = 12.545(3) Å, beta = 100.46(3) degrees, Z = 4; for an acetonitrile solvate of 7, monoclinic space group P2(1)/c (No. 14), a = 9.704(5) Å, b = 28.241(7) Å, c = 15.480(5) Å, beta = 98.55(4) degrees, Z = 4; for a chloroform solvate of 8, monoclinic space group P2(1)/a (No. 14), a = 13.531(4) Å, b = 25.207(5) Å, c = 14.083(3) Å, beta = 115.57(2) degrees, Z = 4. 1, 2, and 3 were all shown to undergo C-S bond cleavage of a bridging thioether by reaction with [PPh(4)][Sptol] (ptol = 4-methyl phenyl) to afford the anionic complexes [PPh(4)][Cl(3)W(&mgr;-S(CH(2)CH(2))(2)E)(2)(&mgr;-SCH(2)CH(2)ECH(2)CH(2)Sptol)WCl(3)] (E = S (9), O (10), CH(2) (12)). 1, 2, 7, and 8 undergo reversible one-electron reductions.