Pseudo-oxocarbon complexes - crystal structure of a copper(II) complex with 2,4-bis(dicyanomethylene)cyclobutane-1,3-dione

The reaction of copper(II) ions with the 2,4-bis(dicyanomethylene)cyclobuta ne-1,3-dione dianion (2,d-dcms(2-)), a pseudo-oxocarbon derived from squari c acid in which two carbonyl oxygen atoms have been substituted by dicyanom ethylene groups C(CN)(2), leads to many complexes according to the preparat ive scheme. The complex [Cu(2,4-dcmsq)(H2O)(4)](n) has been synthesized and characterized by single-crystal X-ray diffraction. The structure consists of a chain of copper atoms bridged by the ligand with short Cu-N bonds. Spe ctroscopic and structural characterizations of the product are compared wit h those of the previously described [Cu(2,4-dcmsq)(H2O)(4). 2H2O](n). (C) 2 001 Elsevier Science B.V. All rights reserved.