Synthesis and characterization of 2,6-Bis(carboxyethyl sulfanylmethyl)-4-methylphenol and its mono and binuclear complexes with Mn2+, Fe3+, Co2+, Ni2+, Cu2+ or Zn2+

After the synthesis of the ligand 2,6-bis(carboxyethyl sulfanylmethyl)-4-methyl phenol (H3L), which has two sites for metal ion coordination, we prepared mononuclear, MLH (M = Mn, Co, Ni, Cu, Zn) and FeLHCl, homobinuclear, M2LOAc (M = Mn, Co, Ni, Cu, Zn), and heterobinuclear complexes, CuM'LOAc (M' = Ni, Zn). The UV spectra in methanol show d-->d transitions for the complexes as well as pi-->pi* and n-->pi* absorptions attributed to the ligand. The absence of a free C=O vibration in the infrared spectra of the solids indicates intermolecular interactions between the complexes. In the binuclear complexes the metallic centers are linked through the phenolic oxygen and the acetate is in a syn-syn,configuration. The cyclic voltammetry studies of the binuclear complexes show that there are interactions between the metal ions. The high value of K-com (comproportionation) indicates that the complexes' are of "class III" in the Robin and Day series. This work shows interplay between the metallic centers and the absence of decomplexation.