A bis(chlorido)-bridged linear-chain Cu(II) compound with 7-azaindole as an axial ligand; synthesis, structure, hydrogen bonding and magnetism

A novel linear bis(chlorido)-bridged Cu(II) compound with the ligand 7-azaindole (abbreviated as Haza) have been synthesized and fully characterized by spectroscopy, EPR and X-ray structure analysis. The geometry around the Cu(II) ion in the compound [Cu-μ-Cl₂(Haza)₂]_n, is distorted octahedral with the basal plane formed by two chloride anions with a Cu-Cl distance of 2.286(1) Å and two nitrogen atoms of two trans-chelating Haza ligands with a Cu-N distance of 2.042(4) Å. The apical positions is formed by two chloride anions of a neighbouring unit at a distance of 3.143(2) Å. The Cu-Cl-Cu angle is 90.09(5)°, while the Cu-Cu distance is 3.8890(8) Å.The EPR powder spectrum appears as rhombic, displaying some extra features which were assigned to the differences in orientation of chains in the lattice, as their intensity appears to decrease on powdering. The magnetic susceptibility measurements, recorded from 5 to 300 K, agree with a very weak antiferromagnetic interaction in a chain with J = −2.6 cm⁻¹.