INTEC   05402
INSTITUTO DE DESARROLLO TECNOLOGICO PARA LA INDUSTRIA QUIMICA
Unidad Ejecutora - UE
artículos
Título:
Structure and magnetism of catena-poly[copper(II)-µ-dichloro-L-lysine]hemihydrate. Copper chains with monochloride bridges
Autor/es:
SANTANA, R. C.; FERREIRA, B.; SABINO, J.R.; CARVALHO, J. F.; PEÑA, O.; CALVO, RAFAEL
Revista:
POLYHEDRON
Editorial:
PERGAMON-ELSEVIER SCIENCE LTD
Referencias:
Lugar: New York; Año: 2012 vol. 47 p. 53 - 59
ISSN:
0277-5387
Resumen:
We report the
preparation and characterization by elemental analysis, infrared (IR),
single crystal X-ray diffraction, magnetic measurements and electron
paramagnetic resonance (EPR) of the new compound
catena-poly[copper(II)-μ-dichloro-l-lysine]hemihydrate, with formula C6H14Cl2CuN2O2·(H2O)0.5, here after called [Cu(lys)Cl2].
The compound crystallizes in the space group C2 with copper ions in a
square pyramidal coordination, and the structure consists of zigzag
chains along the b axis
bridged by equatorial-apical chlorine bonds with CuCu distance of
3.5414(4) Å, and a small CuClCu angle of 85.47(6)°. Magnetic
susceptibility and isothermal magnetization curves reveals a weak
antiferromagnetic interaction 2J = −0.30(2) cm−1 supported by the CuClCu bridge connecting CuII neighbors in the chains. EPR spectra at 34.0 GHz were obtained in powdered samples and in a single crystal with B0 in three orthogonal planes. Assuming an axially symmetric molecular g-matrix, we obtained principal g-values g// = 2.2794(9) and g⊥=2.0489(3) from the crystal g-matrix
calculated using the observed angular variation of the EPR line
position. The angular variation of the line width, largest along the
chain direction, is attributed to dipolar couplings between CuII ions in the lattice. The magnetic and EPR results are discussed in terms of the exchange couplings.