Benign synthesis of carboxamide ligands,H2Me2bqb and H2Me2bpb. Preparation,characterization and electrochemistry of Ni(II) complexes: The crystal structure of [Ni(Me2bqb)]

A novel and highly efficient approach for the synthesis of H₂Me₂bqb and H₂Me₂bpb using ionic liquid as an environmentally benign reaction medium has been developed, eliminating the need for the pyridine as a toxic solvent. The Ni(II) complex of the dianionic ligand Me₂bqb²⁻, [Me₂bqb²⁻ = 1,2-bis(quinoline-2-carboxamide)-4,5-dimethyl-benzene dianion], has been synthesized and characterized by elemental analyses and spectroscopic methods, and the crystal and molecular structure of [Ni(Me₂bqb)] (1), has been determined by X-ray crystallography. The complex exhibits distorted square-planar NiN₄ coordination geometry with two short and two long Ni–N bonds (Ni–N ∼1.85 and ∼1.96 Å, respectively). The electrochemical behavior of [Ni(Me₂bqb)] (1), has been studied by cyclic voltammetry and compared with the analogous complex, [Ni(Me₂bpb)] (2).