S. Youngme et al., Synthesis, structure, spectroscopy, and magnetism of two new dinuclear carbonato-bridged Cu(II) complexes, INORG CHIM, 324(1-2), 2001, pp. 232-240
Two new dinuclear mu -CO32- Cu(II) complexes with different coordination mo
des for the carbonato bridge have been obtained by fixation of atmospheric
CO2 and also directly prepared from the carbonate salt. The compounds compr
ise: [Cu-2(mu -CO3)(dpyam)(4)](ClO4)(2)(H2O)(4) (1), and [Cu-2(mu -CO3)(2)(
dpyam)(2)](H2O) (2), (in which dpyam = di-2-pyridylamine). For 1, the carbo
nate ligand acts as a bridge between two Cu(II) centres showing an anti-ant
i (mu-eta (1)-eta (1)-CO32-) coordination mode with a distorted square-base
d pyramidal geometry for each Cu(II) environment. Complex 2 involves the di
-mu -CO32- bridge with a novel tridentate mu-eta (1)-eta (2)-CO32- coordina
tion mode. The geometry around each copper atom is distorted square-based p
yramidal. Susceptibility measurements for both complexes show a weak to mod
erately strong antiferromagnetic coupling with J values of -90.4 and -9.9 c
m (-1) for 1 and 2, respectively. The tridentate co-ordination mode of the
carbonate bridge in 2 has not previously been reported for dinuclear Cu(II)
complexes. Also its magnetic behaviour and superexchange pathway are discu
ssed. (C) 2001 Elsevier Science B.V. All rights reserved.