Synthesis, structure, and theoretical studies of bis(five-coordinate) μ–O–[CuL₂]₂: predicting distortion toward trigonality

An oxo-bridged binuclear Cu(II) complex, [CuL₂]₂, has been synthesized and characterized by microanalysis, spectra (infrared and electronic), and X-ray diffraction crystallography. The theoretical properties of the complex were studied using the semi-empirical PM3 method. The optimized geometries, dipole moment, thermodynamic parameters, and vibrational frequencies were investigated. The crystal structure revealed that each Cu(II) was five-coordinate with a distorted square pyramidal geometry (τ = 0.324 and 0.307). The two units of the complex were bridged by phenolic oxygens to give a binuclear Cu(II) complex with the average bridging angle and Cu…Cu distance being 98.49° and 3.413 Å, respectively. Theoretical studies revealed that the geometric parameters are in agreement with the experimental data. The compound was stable and has good non-linear optical properties.