N-2-[4,6-dimethylpyridyl]-N '-phenylthiourea (HDMPyPT) transition metal complexes

Several types of new metal complexes of N-2-[4,6-dimethylpyridyl]-N'-phenyl thiourea (HDMPyPT) have been prepared from M(OAC)(2) [M = Cu(II), Zn(II), N i(II), Co(II), UO2(VI)], HAuCl4, Na-2[PdCl4] and metal chlorides [M=Co(II), Sm(III), Nd(III)]. HDMPyPT behaves in a monodentate fashion via the pyridy l nitrogen in all of the complexes except the Cu(II), Pd(II), and Au(III) c omplexes. The participation of the thioketo and/or thioenol groups, in addi tion to the pyridyl nitrogen, has been confirmed in the latter three comple xes. The role of the methyl groups in positions 4 and 6 as well as the pH o f the reaction mixture has been investigated. Also, the effect of anions (C l- and OAc-) attached to the metal salts on the structure of the complexes has been studied. The stereochemistry of the metal complexes has been deter mined from spectral (IR, UV-Vis., H-1 NMR and mass) and magnetic measuremen ts. The results suggest a square-planar geometry for the Pd(II) and Au(III) complexes, a tetrahedral structure for one of the Co(II) complexes and oct ahedral geometry for the other metal complexes. The amount of solvents insi de or outside the coordination sphere has been determined using TGA and DTA measurements.