Isomerism in Hexacoordinate Ti(IV) and Zr(IV) Complexes with a Tetradentate ONNO‐ <i>Schiff</i> Base Ligand

The reactions of [(thf)2TiCl4] with sodiated 2,2’-bis[2-hydroxy-3,5-di(tert-butyl)benzylideneamino]-1,1’-biphenyl (1 a) and 2,2’-bis[2-hydroxy-3,5-di(tert-butyl)benzylideneamino]-4,4’-dimethyl-1,1’-biphenyl b) yield the corresponding Ti complexes 2 a b. Similarly, 1 reacts [(thf)2ZrCl4] to Zr derivative 3. For a, mixture cis-β trans isomers were observed in solution whereas congener exclusively forms cis-α form. Quantum chemical calculations verify that these are preferred molecular structures. crystal structures isomeric 3 have been determined. Metalation Ti(NMe2)4 yields 2,2’-bis[(2-oxido-3,5-di(tert-butyl)phenyl)-dimethylaminomethylamino]-1,1’-biphenyl titanium(IV) (4) hexadentate ligand.