摘要:
The single-crystal X-ray structures of two new linear trinuclear copper(II) complexes of 3,5-pyrazoledicarboxylic acid (H3L) are reported, viz. [Cu-3(L)(2)(Me(2)en)(2)(H2O)(2)].(H2O)(8) (1) and [Cu-3(L)(2)(MeOH)(6)(H2O)(4)](2), with Me(2)en is N,N-dimethylethylenediamine. Both complexes are trinuclear and have been obtained from a precursor ligand, through copper-induced amide hydrolysis. In 1, the central copper ion is in a distorted square-planar environment and the two outer copper ions are in a distorted square-pyramidal environment. All three copper ions in 2 are six-coordinated in an elongated octahedral environment. A weak, broad EPR signal centered around g = 3.5. indicative for an S = 3/2 state, is observed and confirms both complexes to be trinuclear. Magnetic susceptibility measurements of 1 and 2 from 4 to 300 K indicate a weak anti-ferromagnetic exchange coupling, with J values of - 15 and - 19 cm - 1, respectively. (C) 2002 Elsevier Science B.V. All rights reserved.