摘要 : The coordination chemistry of tetradentate Salophan ligands with titanium and zirconium alkoxides is described for the first time. Three new Salophan ligand precursors featuring different phenolate substituents (ortho-Me, ortho,pa... 展开 The coordination chemistry of tetradentate Salophan ligands with titanium and zirconium alkoxides is described for the first time. Three new Salophan ligand precursors featuring different phenolate substituents (ortho-Me, ortho,para-di-Cl, ortho,para-di-tBu) were synthesized in addition to the known prototypical Salophan precursor, by a sequence of condensation and reduction. All ligand precursors were reacted with the metal alkoxides Ti(OiPr)(4) and Zr(OiBu)(4). The unsubstituted Salophan led to a complex product mixture for both titanium and zirconium. The methyl-substituted ligand led to a clean complex only with zirconium, and the other ligands gave well-defined coordination chemistry with both metals. NMR analysis indicated that these Salophans acted as dianionic ligands, giving rise to hexa-coordinate complexes of C-2-symmetry. X-ray analysis of three complexes supported this view, and revealed that the ligands wrapping mode was fac-fac and that the orientation of the labile groups was cis. A partial hydrolysis of one of the titanium complexes led to a dinuclear bridging oxo complex in which the ligand wrapping mode had changed to fac-mer, as revealed from its crystal structure. 收起