Synthesis, structure spectroscopy, and magnetism of two new dinuclear carbonato-bridge Cu(II) complexes

摘要

Two new dinuclear #mu#-Complexes with different coordination modes for the carbonate bridge have been obtained by fixation of atmospheric CO_2 and also directly prepared from the carbonate salt. The compounds comprise: [Cu_2(#mu#-CO_3)(dpyam)_4](ClO_4)_2(H_2O)_4 (1) , and [Cu_2(#mu#-CO_3)_2(dpyam)_2](H_2O)(2) , (in which dpyam=d-2-pyridylmine). For 1, the carbon-ate ligand acts as a bridge between two Cu(II) centres showing an anti-anti(#mu#-#eta#~1-#eta#~1-CO_3~(2-)) coordination mode with a distorted square-based pyramidal geometry for each Cu(II) environment. Complex 2 involves the di-#mu#-CO_3~(2-) bride with a novel tridentate #mu#-#eta#~1-#eta#~1-CO_3~(2-) coordination mode, The geometry around each copper atom is disptored square-based pyramidal. Susceptibility measurements for both complexes show a weak to moderately strong antiferromagnetic coupling with J values of -90.4 and -9.9 cm~(-1) for 1 and 2, respectively. The tridentate co-ordination mode of the carbonate bride in 2 has not previously been reported for dinuclear Cu(II) complexes. Also its magnetic behaviour and superexchange pathway are discussed