Complexes of tungsten(IV,VI) derived from linked aryloxide ligands

Biphenoxo complexes of tungsten(VI), [WCl4{CHR[C6H2(Bu')(2)O](2))] R = H (1), Me (2) are reduced by Na/Hg in the presence of PMe3 to give cis, tranS-WCl2(PMe3)(2){CHR[C6H2(Bu)(2)O](2)} R = H (3), Me (4). Reaction of [WOCl4] with the biphenols 2,2'-CHR[C6H2(Bu-t)(2)OH](2) in diethyl ether gives [WOCl2{CHR[C6H2(Bu)(2)O-12)] R = H (5), Me (6). Similar treatment of [W(NPh)Cl-4(Et2O)] gives the complex [W(NPh)Cl-3{(1,1'-O,OH)(2,2'-CH3CH)[4,6-(Bu-t)(2)C6H2](2)}] (7) containing the monoanionic ligand {(1,1'-O,OH)(2,2'-CH3CH)[4,6-(Bu-t)(2)C6H2](2)}(-). Reaction Of [WOCl4] with the linear triphenol 2,6-bis(3,5-di-t-butyl-2-hydroxybenzyl)-4-methylphenol, HOArCH2Ar1(OH)CH2ArOH (Ar = 4,6-di-t-butylphenol; Ar-1 = 4-methylphenyl), in refluxing toluene affords the centrosymmetric complex (WOCl[OArCH2Ar1(O)CH2ArO]}(2) (8), in which the mer-tridentate ligands adopt the U-conformation. The related complex {WOCl[(OArCH2Ar3)-C-2(O)(CH2ArO)-O-2]) (9) has been isolated as a hydrolysis product from the reaction of [W(NPh)Cl-4(Et2O)] and 2,6(3-t-butyl-5-methyl-2-hydroxybenzyl)-4-t-butylphenol, (HOArCHAr3)-C-2(OH)(CHArOH)-O-2 (Ar-2 = 4-methyl-6-t-butylphenol; Ar-3 = 4-tbutylphenyl), and is also available via [WOCl4]. Reaction Of [W(eg)31 (eg = 1,2-ethanediolato) with 2,6-bis(3,5-methyl-2-hydroxybenzyl)-4-t-butylphenol, (HOArCHAr3)-C-4 (OH)(CH2ArOH)-O-4(Ar-4 =4,6-di-methylphenol) affords [W(eg)(2)((OArCH2Ar3)-C-4(0)(CH2ArOH)-O-4)] (10), containing a chelating biphenolate ligand with a pendant phenolic group. Crystal structures of complexes 1, 3, 5, 8, 9 and 10 are reported. (c) 2006 Elsevier Ltd. All rights reserved.