Complexation of croconate violet with copper(II). Crystal structures, spectroscopic characterizations and redox studies

摘要

The crystal structures of two copper(II) complexes of croconate violet (3,5-bis(dicyanomethylene)cyclopentane-1,2,4-trionate = L2-) have been determined by X-ray methods. Complex 1 consists of mononuclear [CuL2(H2O)(2)](2-) ions, potassium cations and two crystallisation water molecules. Complex 2 consists of mononuclear [CuL3](4-) ions, (NBu4)(+) cations and one half crystallisation water molecule. In these two complexes, the ligand is coordinated in a chelating mode by two adjacent oxygen atoms. The electrochemical behaviour of these complexes is discussed and compared to that of the free croconate violet. (C) 2001 Elsevier Science B.V. All rights reserved. [References: 62]