TY - JOUR
T1 - Weak ferromagnetic behavior, crystal structure, and electronic studies of novel [Cu(II)(Br)(PhCO2)(Sp)] (Sp=(-)-sparteine) complex
AU - Reyes-Ortega, Yasmi
AU - Alcántara-Flores, José Luis
AU - Hernández-Galindo, María del Carmen
AU - Gutiérrez-Pérez, René
AU - Ramírez-Rosales, Daniel
AU - Bernès, Sylvain
AU - Cabrera-Vivas, Blanca Martha
AU - Durán-Hernández, Alejandro
AU - Zamorano-Ulloa, Rafael
N1 - Funding Information:
The present work has been supported by Secretaría de Educación Pública and Sub-Secretaría de Educación Superior and Vicerrectoría de Investigación y Estudios de Posgrado from BUAP. Proyect No. II 163-04/NAT/G.
PY - 2006/5/8
Y1 - 2006/5/8
N2 - 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.
AB - 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.
KW - Cu(II)-complexes
KW - Weak ferromagnetic exchange
UR - http://www.scopus.com/inward/record.url?scp=33747109878&partnerID=8YFLogxK
U2 - 10.1016/j.molstruc.2005.11.030
DO - 10.1016/j.molstruc.2005.11.030
M3 - Artículo
SN - 0022-2860
VL - 788
SP - 145
EP - 151
JO - Journal of Molecular Structure
JF - Journal of Molecular Structure
IS - 1-3
ER -