TY - JOUR
T1 - Synthesis, crystal structure, weak antiferromagnetic behavior and electronic studies of novel [((-)-sparteine) (PhCo2)(Cl)]Cu(II) complex
AU - Alcántara-Flores, José Luis
AU - Vázquez-Bravo, José Jaime
AU - Gutiérrez-Pérez, René
AU - Ramírez-Rosales, Daniel
AU - Bernèsa, Sylvain
AU - Ramírez Bokhimi, José Guadalupe
AU - Zamorano-Ulloa, Rafael
AU - Reyes-Ortega, Yasmi
PY - 2003/9/10
Y1 - 2003/9/10
N2 - [((-)-Sparteine)(PhCO2)(Cl)]Cu(II) 1 complex is obtained by direct synthesis using copper(0). 1 crystallizes in the monoclinic space group P21 with a = 14.7355(12), b = 8.9768(5), c = 17.2810(10) Å, β = 111.916(5)°, and Z = 4. The electronic spectrum of 1 shows a broad band with λmax ∼ 841 nm (ε = 0.261 mM-1 cm-6) characteristic of a low symmetry and tetragonally distorted square pyramidal local Cu geometry. The far IR spectrum of 1 shows characteristic vibrations of Cu-Cl (260, 267 cm-1), Cu-N (436, 467 cm-1) and Cu-O (457 cm-1) bonds. The 1H NMR spectrum of 1 is typical of magnetic Cu(II) complexes with line broadening due to efficient nuclear relaxation from the metal center. ESR spectra of polycrystalline 1 at 77 K show an axial spectrum with linewidth of 58.6 G and at 300 K of 89.0 G, with areas in the ratio A77/A300 = 2.79, indicative of antiferromagnetic order. The linewidth is reduced by 34% on going from 300 to 77 K. Standard magnetization measurements at low temperatures show an Curie-Weiss behavior with θ = -21.67 K, suggesting a weak exchange coupling interaction. The crystalline structure of 1 shows that the lattice is arranged so that the space between molecules is smaller than 40 Å3, not enough to accommodate solvent molecules. However, the shortest Cu-Cu contact is 7.5912(8) Å.
AB - [((-)-Sparteine)(PhCO2)(Cl)]Cu(II) 1 complex is obtained by direct synthesis using copper(0). 1 crystallizes in the monoclinic space group P21 with a = 14.7355(12), b = 8.9768(5), c = 17.2810(10) Å, β = 111.916(5)°, and Z = 4. The electronic spectrum of 1 shows a broad band with λmax ∼ 841 nm (ε = 0.261 mM-1 cm-6) characteristic of a low symmetry and tetragonally distorted square pyramidal local Cu geometry. The far IR spectrum of 1 shows characteristic vibrations of Cu-Cl (260, 267 cm-1), Cu-N (436, 467 cm-1) and Cu-O (457 cm-1) bonds. The 1H NMR spectrum of 1 is typical of magnetic Cu(II) complexes with line broadening due to efficient nuclear relaxation from the metal center. ESR spectra of polycrystalline 1 at 77 K show an axial spectrum with linewidth of 58.6 G and at 300 K of 89.0 G, with areas in the ratio A77/A300 = 2.79, indicative of antiferromagnetic order. The linewidth is reduced by 34% on going from 300 to 77 K. Standard magnetization measurements at low temperatures show an Curie-Weiss behavior with θ = -21.67 K, suggesting a weak exchange coupling interaction. The crystalline structure of 1 shows that the lattice is arranged so that the space between molecules is smaller than 40 Å3, not enough to accommodate solvent molecules. However, the shortest Cu-Cu contact is 7.5912(8) Å.
KW - Cu(II)-Complexes
KW - Small antiferromagnetic exchange
UR - http://www.scopus.com/inward/record.url?scp=0041821764&partnerID=8YFLogxK
U2 - 10.1016/S0022-2860(03)00413-7
DO - 10.1016/S0022-2860(03)00413-7
M3 - Artículo
SN - 0022-2860
VL - 657
SP - 137
EP - 143
JO - Journal of Molecular Structure
JF - Journal of Molecular Structure
IS - 1-3
ER -