Nickel(II) and cobalt(II) complexes of rhodanine

Abstract

Nickel(II) and cobalt(II) complexes of rhodanine (Hrd) were prepared from the metal chloride or acetate and the ligand. With an excess of NH3, the octahedral [Ni(NH3)6](Rd)2 and [Co(NH3)5Rd]Rd complexes are ob-tained; use of only two NH3 equivalents per metal ion yields the Ni(Rd)2 sd HRd · NH3 and [Co(Rd)2 ] · 1.5 H2O complexes, the first with tetragonally distorted hexacoordination and the second with polymeric octahedral coordination. By using two equivalents of NaOH per metal ion, the binuclear [Ni(Rd)2][Ni(Rd)2 · (HRd)2] · 2 H2O complex is formed having one diamagnetic planar and one high spin octahedral chromophore. Rhodanine is coordinated through the thiocarbonylic sulphur in the neutral form and through the thiocarbonylic sulphur and the deprotanated nitrogen atoms in the rhodanidato anionic form.