Structural and reactivity studies on 4,4'-dimethyl-2,2'- bipyridine acetylacetonate copper(II) nitrate (CASIOPEINA III-ia®) with methionine, by UV-visible and EPR techniques
Por:
Tovar-Tovar A., Ruiz-Ramírez L., Campero A., Romerosa A., Moreno-Esparza R., Rosales-Hoz M.J.
Publicada:
1 ene 2004
Resumen:
When the nitrate form of [(4,4?-dimethyl-2,2 ?-bipyridine)(acetylacetonate) copper(II)] nitrate (Casiopeína III ia) was reacted with methionine under two different reaction conditions: room temperature and reflux in methanol, it was found that substitution of acetylacetonate (acac) occurred and this process was monitored by UV-Vis spectrophotometry. Electron paramagnetic resonance (EPR) spectroscopy was used to analyse changes in the electronic environment of Cu(II) in the initial and final compounds. Both compounds showed axial geometry with g ||>g?. A detailed study of the iono-covalent features of the Cu(II) ligand bonds was made, showing that in-plane ? and ? bonds were relatively more weakly covalent than ?-out-of-plane bonds. Additionally, it was possible to obtain suitable crystals for X-ray analysis. Suitable crystals of 4,4?-dimethyl-2,2?- bipyridine acetylacetonate copper(II) perchlorate (Cas III ia ClO 4)Casiopeína III ia ClO4.1 and 4,4 ?-dimethyl-2,2?-bipyridine methionine copper(II) nitrate (Cas IV met)Casiopeína IV met.2 were obtained and structure solved by X-ray diffraction. The crystallographic data for (Cas III ia ClO4) space group P21/c, a=7.3310(10) Å, ?=90°, b=13.669(3) Å, ?=95.23(3)°, c=18.973(4) Å, ?=90°, V=1893.3(6) Å3, z=4, are presented. For Cas IV met it was found a space group P21, a=1.982(2) Å, ?=90°, b=6.952(10) Å, ?=112.11(3)°, c=13.299(3) Å, ?=90°, V=1026.3(3) Å3, z=2. © 2004 Elsevier Inc. All rights reserved.
Filiaciones:
Facultad de Química, Depto. Quim. Inorg. Y Nucl., Ciudad Universitaria, Mexico, DF 04510, Mexico
Universidad Autonoma Metropolitana, Depto. de Quím. Inorg., Mexico
Universidad de Almería, Spain
Departamento de Química, CINVESTAV, Mexico
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