The reactions of MoOCl4 with neutral group 15 and 16 ligands and a re-investigation of some N-donor ligand complexes of MoOCl3

The reaction of molybdenum(VI) oxide tetrachloride, MoOCl4, with neutral ligands including MeCN, Ph3PO, SMe2, MeS(CH2)(3)SMe, SeMe2, PMe3, 2,2'-bipyridyl and 1,10-phenanthroline, results in reduction to form oxomolybdenum(V) complexes, identified by microanalysis, IR and UV/visible spectroscopy and via X-ray crystal structure analyses of several examples. Unexpectedly, the product formed with SeMe2 was [SeMe3](2)[Mo2O2Cl6(mu-Cl)(2)] and with SMe2, [SMe2Cl](2)[Mo2O2Cl6(mu-Cl)(2)]. X-ray crystal structures are reported for mer-[MoOCl3(MeCN)(2)], [{MoOCl2(MeCN)}(2)(mu-Cl)(2)], [MoOCl3{MeS(CH2)(3)SMe}], [SeMe3][MoOCl4(H2O)], [SMe2Cl](2)[Mo2O2Cl6(mu-Cl)(2)] and [PMe3H][MoOCl4(PMe3)]. The reaction of MoOCl4 with [Et4N]Cl forms the dinuclear Mo(V) species, [Et4N](2)[Mo2O2Cl6(l-Cl)(2)]. The red mer-[MoOCl3(diimine)] (diimine = 2,2'-bipyridyl, 1,10-phenathroline) complexes were prepared from [MoOCl3(thf)(2)] and the diimine and fully characterised by spectroscopy and by X-ray crystallography. The long-known 'green isomers' of [MoOCl3(diimine)] obtained from MoOCl4 and the diimines (and in other ways), are suggested to be the red isomers co-crystallised with another lower oxidation state molybdenum complex. (C) 2021 Elsevier Ltd. All rights reserved.