Coordination study of a new class of imine imidazol-2-imine ligands to titanium(IV) and palladium(II).

A new family of ligand precursors, N-(1-(2,6-dimethylphenylimino)ethyl)-1,3-bis(aryl)imidazol-2-imine hydrochloride, wherein aryl = 2,4,6-trimethylphenyl (3a) and 2,6-diisopropylphenyl (3b), was prepared and structurally characterised. Deprotonation of the salts yields molecules with delocalised pi-electrons, leading to zwitterionic mesomeric structures. Titanium(IV) (4a,b) and palladium(II) (5a,b) complexes were isolated and also structurally characterised. Two different coordination modes were observed where the ligand is either coordinated in a bidentate fashion as expected, or in a monodentate fashion through the more basic aryliminic nitrogen atom.