Crystal structure, spectroscopy and ferromagnetostructural behavior of the complex [Cu^II(L)(Cl)(L′)]·H₂O (L = 2-aminomethylbenzimidazole, L′= L-isoleucinate)

[Cu^II(L)(Cl)(L′)]·H₂O 1 (L = 2-aminomethylbenzimidazole, L′ = L-isoleucinate) compound crystallizes in the orthorhombic space group P2₁2₁2₁. A short Cu - O...Cu contact is observed between neighboring molecules in the crystal structure, with a O...Cu separation of 4.214(3) Å. Molecular structure of 1 shows that L and L′ act as bidentate ligands, forming the base of the square pyramidal geometry environment of the Cu^II ion, while the chloro is the fifth apical ligand. UV/VIS spectrum of 1 shows d-d transitions with λ_max = 603 nm, characteristic of a low symmetry. Far IR spectrum shows ν_Cu-N at 493, 404 cm^-1, ν_Cu-O at 446 cm^-1, and at 302 cm^-1 ν_Cu-Cl. ESR X-band of polycrystalline 1 at 77, 300 K show axial spectra with the ratio A₇₇/A₃₀₀ = 4.51, and a linewidth increase by 14.5 % on going from 300 K to 77 K, suggesting a incipient ferromagnetic exchange interaction. ESR axial spectrum of 1 in solution shows abundant hfs and shfc interactions. Susceptibility vs Temperature data measured from 2-300 K range, show that the magnetic ordering may be due to Cu ions linking by oxygen bridges given place to a weak ferromagnetic interaction. The very weak exchange interaction, J = 0.103 cm^-1, is in agreement with the ESR spectra results and with a Cu^II - O...Cu^II direct interaction.