Synthesis and structural characterization of some novel metalloboroxides bearing boron-bound mesityl and fluoromesityl substituents: The molecular structure of the first metallaboroxane complex

Article abstract of DOI:10.1016/S0277-5387(96)00601-8

Treatment of the new boronous acid HOB (fmes)₂ (1) (fmes = 2,4,6-(CF₃)₃C₆H₂) with n-butyllithium in diethyl ether/pentane affords after work-up the dimer [Li(thf)OB(fmes)₂]₂ (2). Reaction of [Mo₂(NMe₂)₆] with two equivalents of 1 in toluene gives the amido-boroxide complex Mo₂(NMe₂)₄[OB(fmes)₂]₂ (3). Treatment of CuBr₂ with LiOB(Mes)₂ (mes = 2,4,6-Me₃C₆H₂) in tetrahydrofuran affords after work-up and addition of excess pyridine the monomeric copper(II) boroxide {Cu[O₃B₂(mes)₂]₂[Li(CH ₃CN)(C₅H₅N)]₂} (4), containing the new ligand mesB(O)OB(O)mes, as a result of loss of mesitylene and formation of a B-O-B bond. 2 and 4 have been structurally characterized.