Investigating the effects of steric hindrance on the coordination of 2-aminothiazoyl based ligands

The ligands 2-(diphenylphosphino)aminothiazole (dppat) 2-(diphenylphosphino)amino-4-methylthiazole (Medppat) and 2-(diphenylphosphino)amino-4-tert-butylthiazole (Budppat) have been prepared. Reaction of these ligands with MCl2 (COD) gives [MCl(dppat-P,N)(dppat-P)][Cl], [MCl(Medppat-P,N)(Medppat-P)][Cl], and [PtCl2 (tBu-dppat-P2], respectively. The increased bulk at the 4-position limits the formation of a P, N system in Budppat. The X-ray structure of [PtCl(Medppat-P,N)(Medppat-P)][Cl] reveals that the monodentate ligand has undergone a tautomerism upon coordination.