TY - JOUR
T1 - Crystal structure, ferromagnetostructural behavior and evidence of cooperative Jahn-Teller interactions of the complex [CuL] CL·H2O (L = N-glycyl-2(aminomethyl)benzimidazol), synthesized by a novel simple method of peptide bond formation
AU - García-Orozco, Ivan
AU - Tapia-Benavides, Antonio Rafael
AU - Alvarez-Toledano, Cecilio
AU - Toscano, Ruben A.
AU - Ramírez-Rosales, Daniel
AU - Zamorano-Ulloa, Rafael
AU - Reyes-Ortega, Yasmi
PY - 2002/1/23
Y1 - 2002/1/23
N2 - [CuL] Cl·H2O 1 (L = N-glycyl-2(aminomethyl)benzimidazol) compound crystallizes in the orthorhombic space group Pna21 with unit cell parameters a = 7.140(5) Å, b = 17.621(5) Å, c = 9.941(5) Å. Its structure shows that the copper(II) ion is tetra coordinated with a square planar geometry. The ligand acts as a tridentate and the chloride ion is the fourth ligand. Symmetry related units stack into helicoidal columns along the ā direction producing weakly bonded strips with dihedral angles of 2.6° between two consecutive molecular planes. UV/VIS spectrum of 1 shows one broad and weak band at 622 nm, characteristic of d-d transitions, indicative of low local Cu(II) symmetry. X band ESR spectra of 1 at 300 and 77 K are axial exchange narrow lines with g∥ = 2.135 and g⊥ = 2.028. However, the axial spectrum at 6.4 K shows an increment Δg∥ = 0.076(6) and Δg⊥ = 0.028(4) which suggests a cooperative Jahn-Teller interactions between complexes via the hydrogen-bonding network. Magnetic susceptibility data at 18-300 K and fitted to the modified Bleany-Bowers equation indicate a weak ferromagnetic coupling with 2J ≅ +17 cm-1, which is compatible with the helium temperature ESR results and with the helicoidal stacking into columns of the molecules along the a-axis with 78.9° Cu′-Cl′-Cu and 81.2° Cu′-N(1)-Cu bonds angles. The synthesis is a novel, simple and efficient method: in aqueous conditions and heterogeneous phase with basic copper(II) carbonate, which carries out the formation of the stable peptide bond.
AB - [CuL] Cl·H2O 1 (L = N-glycyl-2(aminomethyl)benzimidazol) compound crystallizes in the orthorhombic space group Pna21 with unit cell parameters a = 7.140(5) Å, b = 17.621(5) Å, c = 9.941(5) Å. Its structure shows that the copper(II) ion is tetra coordinated with a square planar geometry. The ligand acts as a tridentate and the chloride ion is the fourth ligand. Symmetry related units stack into helicoidal columns along the ā direction producing weakly bonded strips with dihedral angles of 2.6° between two consecutive molecular planes. UV/VIS spectrum of 1 shows one broad and weak band at 622 nm, characteristic of d-d transitions, indicative of low local Cu(II) symmetry. X band ESR spectra of 1 at 300 and 77 K are axial exchange narrow lines with g∥ = 2.135 and g⊥ = 2.028. However, the axial spectrum at 6.4 K shows an increment Δg∥ = 0.076(6) and Δg⊥ = 0.028(4) which suggests a cooperative Jahn-Teller interactions between complexes via the hydrogen-bonding network. Magnetic susceptibility data at 18-300 K and fitted to the modified Bleany-Bowers equation indicate a weak ferromagnetic coupling with 2J ≅ +17 cm-1, which is compatible with the helium temperature ESR results and with the helicoidal stacking into columns of the molecules along the a-axis with 78.9° Cu′-Cl′-Cu and 81.2° Cu′-N(1)-Cu bonds angles. The synthesis is a novel, simple and efficient method: in aqueous conditions and heterogeneous phase with basic copper(II) carbonate, which carries out the formation of the stable peptide bond.
KW - Complexes-Cu(II)
KW - Paramagnetic interactions
KW - Synthesis
UR - http://www.scopus.com/inward/record.url?scp=0037160336&partnerID=8YFLogxK
U2 - 10.1016/S0022-2860(01)00649-4
DO - 10.1016/S0022-2860(01)00649-4
M3 - Artículo
SN - 0022-2860
VL - 604
SP - 57
EP - 64
JO - Journal of Molecular Structure
JF - Journal of Molecular Structure
IS - 1
ER -