Alkoxo, chlorido, and methyl derivatives of oxidomolybdenum(VI) complexes with tetradentate [O3N]-type ligands

Dioxomolybdenum(VI) complex [MoO2(Heg)2] (H2eg = 1,2-ethanediol) reacts with phenolic ligand precursors tris(2-hydroxy-3,5-dimethylbenzyl)amine (H3LMe) and tris(2-hydroxy-3,5-di-tert-butylbenzyl)amine (H3LtBu) to form oxomolybdenum(VI) complexes of type [MoO(LR) (Heg)]. The Heg ligand can be replaced by other alcohols (i.e. 2-aminoethanol, 2-amino-2-methylpropan-1-ol, 2-(dimethylamino)ethanol or allyl alcohol) in the reaction at refluxing toluene or at neat alcohol. Treatment of [MoO(LR)(Heg)] with Me3SiCl yields corresponding chlorido complexes [MoO(LR)Cl]. These are also formed in the reaction of H3LR with [MoO2Cl2(dmf)2]. The reaction of [MoO(LR)Cl] with MeMgI yields air-stable monomethyl derivatives [MoO(LR)(Me)]. X-ray analyses of [MoO(LtBu)X] (X = Heg, 2-methyl-2-aminopropanolate anion or Cl) reveal that the ligand LR has a tetradentate coordination through three oxygen donors and one nitrogen donor, which is located trans to the terminal oxo group. The sixth coordination site is occupied by an oxygen donor, a chlorido ligand or a methyl group.

Dioxomolybdenum(VI) complex [MoO2(Heg)2] (Heg = ethanediolato monoanion) reacts with phenolic ligand precursors tris(2-hydroxy-3,5-dialkylbenzyl)amine H3LR (R = Me, tert-Bu) to form complexes [MoO(LR)(Heg)]. These compounds react further with alcohols or Me3SiCl to form corresponding alkoxides [MoO(LR)(OR′)] or chlorides [MoO(LR)Cl], respectively. The reaction of [MoO(LR)Cl] with MeMgI yields air-stable monomethyl derivatives [MoO(LR)(Me)].Figure optionsDownload as PowerPoint slide