Cobalt(II) and nickel(II) chloride and bromide complexes of 2-(2′-methyl-8′-quinolyl)benzoxazole and 2-(2′ or 4′-methyl 8′-quinolyl)benzimidazole

Summary

Cobalt(II) and nickel(II) halide complexes of the ligands 2-(2′-methyl-8′-quinolyl)benzoxazole (m′q′bo), 2-(2′-methyl8′quinolyl)benzimidazole (m′q′bi) and 2-(4′-methyl-8′-quinolyl)benzimidazole (mq′bi) were synthesized and characterized by analytical, thermogravimetric, conductivity and magnetic data, and i.r. and electronic spectra.

The ligands are bidentate N-donors yielding complexes where the coordination geometry depends on the metal ion and steric hindrance. All the cobalt complexes have formula [CoL₂X₂] and distorted tetrahedral geometry. Different types of nickel compounds were obtained: i) complexes of formula NiLX₂ · n H₂O (or EtOH) (L = m′q′bo or m′q′bi; n=0–1.5) which arepseudo-tetrahedral or five-coordinate and ii) complexes NiL₂X₂ · n H₂O (L = mq′bi, n=3 or 4) where the metal is bound to four nitrogen atoms and the overall coordination geometry is tetragonal. The structural changes occurring after removal of water or alcohol from the complexes are also reported.