Synthesis, crystal structure, weak antiferromagnetic behavior and electronic studies of novel [((-)-sparteine) (PhCo<inf>2</inf>)(Cl)]Cu(II) complex
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[((-)-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. © 2003 Elsevier B.V. All rights reserved.
Alcántara-Flores, J. L., Vázquez-Bravo, J. J., Gutiérrez-Pérez, R., Ramírez-Rosales, D., Bernèsa, S., Ramírez Bokhimi, J. G., Zamorano-Ulloa, R., & Reyes-Ortega, Y. (2003). Synthesis, crystal structure, weak antiferromagnetic behavior and electronic studies of novel [((-)-sparteine) (PhCo<inf>2</inf>)(Cl)]Cu(II) complex. Journal of Molecular Structure, 137-143. https://doi.org/10.1016/S0022-2860(03)00413-7