Weak ferromagnetic behavior, crystal structure, and electronic studies of novel [Cu(II)(Br)(PhCO<inf>2</inf>)(Sp)] (Sp=(-)-sparteine) complex

Yasmi Reyes-Ortega, José Luis Alcántara-Flores, María del Carmen Hernández-Galindo, René Gutiérrez-Pérez, Daniel Ramírez-Rosales, Sylvain Bernès, Blanca Martha Cabrera-Vivas, Alejandro Durán-Hernández, Rafael Zamorano-Ulloa

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Abstract

Complex [Cu(II)(Br)(PhCO2)(Sp)] 1 is obtained starting from copper(0), (-)-sparteine (sp) and benzoyl bromide. 1 Crystallizes in the monoclinic space group P21 with a=14.8857(11), b=8.9257(9), c=17.4456(14) Å, β=111.689(5)°, and Z=4. The UV-vis spectrum is characteristic of Cu(II) complexes with tetragonally distorted square pyramidal geometry. The far IR spectrum of 1 shows characteristic vibrations of Cu-Br (239 cm-1), Cu-N (437 cm-1) and Cu-O (466 cm-1) bonds. The 1H NMR broad chemical shifts of 1 integrated for a total of 31 protons and are typical of Cu(II) complexes. ESR spectra of polycrystalline 1 at 77 and 300 K show axial spectra with areas in the ratio A77/A300=4.02, suggesting a very weak Cu-Cu ferromagnetic interaction. Complex 1-doped with Zn(II) gives hfs with hyperfine interaction constant value A∥=112.45×10-4 cm-1. The magnetization vs temperature data in the 2-299 K range, show that cupric ion pairs interact through a small antiferromagnetic Heisenberg exchange energy-JS1·S2 with a ground singlet state S=0, separated by J=-1.3 cm-1 from the excited triplet state S=1. The sign of the very weak interchange interaction constant, J, does not agree with the ESR spectra areas ratio of 1 at 77 and 300 K, which is a more accurate quantification of the weak ferromagnetic interaction Cu-Cu through the space. © 2005 Elsevier B.V. All rights reserved.
Original languageAmerican English
Pages (from-to)145-151
Number of pages129
JournalJournal of Molecular Structure
DOIs
StatePublished - 8 May 2006

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Reyes-Ortega, Y., Alcántara-Flores, J. L., Hernández-Galindo, M. D. C., Gutiérrez-Pérez, R., Ramírez-Rosales, D., Bernès, S., Cabrera-Vivas, B. M., Durán-Hernández, A., & Zamorano-Ulloa, R. (2006). Weak ferromagnetic behavior, crystal structure, and electronic studies of novel [Cu(II)(Br)(PhCO<inf>2</inf>)(Sp)] (Sp=(-)-sparteine) complex. Journal of Molecular Structure, 145-151. https://doi.org/10.1016/j.molstruc.2005.11.030