Copper–acetanilide complexes: synthesis, characterization, crystal structure, computational analysis and their application as heterogeneous catalysts for biodiesel synthesis from frying waste oils

Novel copper complexes were prepared from acetanilide derivatives and deliberately characterized. The molar ratio obtained was 1:1 through neutral bi-dentate mode of bonding for ligands. Square-planer and distorted octahedral were the geometries proposed based on UV–Vis and EPR spectra. Isotropic and anisotropic parameters were estimated for well hyperfine splitting curves. Through applying crystal explorer 3.1 software package, Hirshfeld surface analysis was carried out. The dnorm as well as 2D fingerprint plots were demonstrated for molecule within crystal packing system. Conformational analysis was executed for all tested compounds. Frontier orbital patterns, iso-surface maps and ESP array plots were built upon optimized structures. QSAR parameters suggest the successful catalytic uses for new complexes, which may be evidenced for their calcination oxides. After calcination for complexes, the CuO was yielded and fully characterized. XRD patterns and SEM images signify the superior properties of the oxide obtained from Cu(II) to HL3 complex. Such oxide was used to synthesize biodiesel from suitable frying waste oils. Its physical features appeared match strongly with ASTM-D6751-02-standards (American Society for Testing and Materials) for detailed standards and specifications for biodiesel mixed with middle distilled fuels.