N-2-[3-methylpyridyl]-N'-phenylthiourea transition metal complexes

New complexes of N-2-[3-methylpyridyl]-N'-phenylthiourea (HMPyPT) have been prepared from Ni-II, Cu-II, Zn-II, Pd-II, Pt-IV and Au-III chlorides. Thre e types, containing 1:1, 1:2 and 1:3 metal-ligand ratios, were isolated and characterized. In every case the ligand behaves in a monodentate manner co ordinating via the pyridyl nitrogen. Attempts to isolate complexes containi ng the deprotonated ligand by raising the pH of the reaction mixture from 1 .6-5.5 to 8.5 were unsuccessful. The bonding modes and the stereochemistry of the metal complexes have been determined from spectral (i.r., u.v.-vis., H-1-n.m.r.) and magnetic measurements. The results suggest a square-planar structure for the Pd-II and Au-III complexes, but octahedral geometry for the other metal complexes. Thermal analysis (d.t.a., t.g.a.) measurements o n the solid complexes have also been conducted.