Some studies in inorganic complexes. XXIII. Reactions of copper(II) with chelating heterocyclic bases

Abstract

Studies have been made of copper(II) complexes of the ligands 2- aminomethyl-pyridine, 2-methylaminomethylpyridine, 2-aminomethyl-6- methylpyridine, and 2-(2-aminoethyl)pyridine. Various hydrated and anhydrous copper(II) complexes with the anions sulphate, nitrate, halide, and perchlorate were obtained with copper(II) ion to ligand in stoicheiometric ratios of 1 : 1 and 1 : 2 and several instances of water molecule and anion attachment to the coordination sphere are reported. Certain sulphate complexes are considered to be of the bridged type, others have sulphate coordinated to the  copper(II) atom by unidentate attachment, and some of the halide complexes are thought most probably to be dimers based upon double halogen to copper bridging. But there are no instances of bridging by metal-metal bonding between adjacent copper atoms since all magnetic moment values for the copper atoms in the complexes are either normal or only very slightly lower than normal. Physical methods used in the elucidation of structures included measurements of molecular conductances in suitable organic solvents, solubility observations, infrared and visible absorption spectrophotometry, pyrolysis methods, and measurements of magnetic susceptibility. Complex cations in aqueous solution were characterized by visible spectrophotometry.     A majority of the solid complexes isolated are described for the first time; where complexes have previously been recorded additional physical investigations have been made.