The physical properties of cupric nitrosyl complexes.

Abstract

The reaction between cupric chloride and nitric oxide in methanol has been studied by measuring the absorption of nitric oxide per mole copper as a function of initial cupric chloride concentration. The results were interpreted by the equilibria: CuCl2+NO&rlhar2;CuCl2NO CuCl2NO&rlhar2;CuCl2- +NO+ NO++CH3OH&rlhar2;CH3 NO2+H+ Over the concentration range 0.016--0.2 M, dissociation of the nitrosyl to NO-containing species is estimated to be 35%. As the concentration is decreased further, this dissociation tends to completion. The nitrosyl of salicylal o-hydroxybenzylamine copper (II) was prepared, and the number of molecules of associated solvent determined by the mole ratio method.* The nitrosyl complexes of cupric iodide, cyanide, thiocyanate and pyridine thiocyanate have been prepared in solution. The nitrosyls of cupric iodide, cyanide and thiocyanate are extremely unstable, with a lifetime of the order of two minutes. The nitrosyl of cupric pyridine thiocyanate is stable in solution for several hours. Spectrophotometric evidence is presented for their existence. Further investigations covered cupric nitrate, hydroxide, iodate, aslicyaldoximate and dithio-oxamide. None of these compounds were observed to form nitrosyls. Consideration of the conditions under which nitrosyls may be formed has led to the suggestion that NO requires to be able to attack the fourth co-planar position. The solid nitrosyls of cupric bromide and chloride have been isolated by precipitation with petroleum ether. On drying, the solid loses associated solvent, and it is suggested that dimerization could be expected to (CuCl 2NO)2. Analysis of the solid shows that it may be isolated with one molecule of solvent attached. Solvation determination by I.R. spectra on CuCl2NO shows that one molecule of solvent is attached, with some indication of a second less strongly held. *Please refer to dissertation for diagrams.