Metal complexes of 2-(2′-or 8′-quinolyl)benzimidazoles and benzothiazoles

Summary

The copper(II), cobalt(II) and nickel(II) chloride and bromide complexes with the ligands 2-(2′-quinolyl)-benzimidazole (qbi), 2-(4′-methyl-2′-quinolyl)benzimidazole (mqbi), 2-(4′-methyl-8′-quinolyl)benzothiazole (m'q'bt) have been prepared and characterized by analytical methods, magnetic measurements as well as by electronic absorption, e.s.r. and far i.r. spectra. Complexes of various stoichiometries have been isolated, namely MLX₂ (all cobalt complexes with exception of the bromide qbi complex; the chloride and bromide nickel m'q'bt and mq'bt complexes), ML₂X₂ (M=Co,L=qbi and X=Br; M=Ni, L=mqbi, X=Cl or Br, M=Ni, L=qbi, X=Cl) and ML₃X₂(M=Ni, L=qbi or mqbi, X=Br). The cobalt ion has a distorted tetrahedral N₂X₂ coordination in all the CoLX₂ complexes, whereas Co(qbi)₂Br₂ is six-coordinate. The following conclusions may be drawn for the nickel complexes: in those with the 1∶1 metal-to-ligand molar ratio the metal ion is four-or five-coordinate; in those with the 1∶2 and 1∶3 ratios the metal ion is hexa-coordinate, being essentially bound to four nitrogen atoms with halogens, oxygens from water or methanol or nitrogen atoms (from the third ligand) occupying the axial positions.