Interactions of nitric oxide with copper(II) dithiocarbamates in aqueous solution

Abstract

This is the first report on the formation of air-stable copper nitrosyl complexes. The interaction of nitric oxide, NO, with Cu(DTC) 2.3H 2O (DTC: dithiocarbamate) and was studied in aqueous solution at pH 7.4 and 293 K. The stability constants were determined from UV–Vis data, using LETAGROP program. The high values obtained, log β 1=9.743(5) and log β 2=15.44(2) for Cu(ProDTC) 2–NO , (ProDTC= l-prolinedithiocarbamate) and log β 1=8.723(5) and log β 2=11.45(2) for Cu(MorDTC) 2–NO system, (MorDTC=morpholyldithiocarbamate), indicate the formation of two stable nitrosyl complexes, Cu(DTC) 2NO and Cu(DTC) 2(NO) 2 . Coordinated NO is neither affected by the presence of air nor when the solution is purged with Ar. Cu(MorDTC) 2NO.3H 2O was isolated in the solid state and its νNO (IR) band at 1682 cm −1, but affected by temperature variations over 333 K.