Mixed ligand complex formation of 2-aminobenzamide with Cu(II) in the presence of some amino acids: Synthesis, structural, biological, pH-metric, spectrophotometric and thermodynamic studies

• Mixed ligand complexes play a vital role in medicinal & pharmaceutical chemistry.
• Synthesized complexes show moderate antimicrobial activity than free ligand.
• Cu(II) complexes have an efficient binding and cleavage ability against DNA.
• All the complexes are microcrystalline nature with uniform morphology.

Mixed ligand Cu(II) complexes of 2-aminobenzamide (2AB) and amino acids viz., glycine (gly), l-alanine (ala), l-valine (val) and l-phenylalanine (phe) have been synthesised and characterized by various physico-chemical and spectral techniques. The calculated g-tensor values for Cu(II) complexes at 77 K and 300 K, show the distorted octahedral geometry which has been confirmed from the absorption studies. Consequently, the thermal studies illustrate that the loss of water and acetate molecules in the initial stage which are followed by the decomposition of organic residues. The powder X-ray diffraction and SEM analysis reflect that all the complexes have well-defined crystallinity nature with homogeneous morphology. The binding activities of CT DNA with CuAB complexes have been examined by absorption studies. Further, the oxidative cleavage interactions of 2-aminobenzamide and CuAB complexes with DNA were studied by gel electrophoresis method in H2O2 medium. Also, the complex formation of Cu(II) involving 2-aminobenzamide and amino acids were carried out by a combined pH-metric and spectrophotometric techniques in 50% (v/v) water-ethanol mixture at 300, 310, 320 and 330 ± 0.1 K with I = 0.15 mol dm−3 (NaClO4). In solution, CuAB and CuAB2 species has been detected and the binding modes of 2-aminobenzamide and amino acids in both binary and mixed ligand complexes are same. The calculated stabilization value of Δ log K, log X and log X′ indicates higher stabilities for the mixed ligand complexes rather than their binary species. The thermodynamic parameters like ΔG, ΔH and ΔS have been determined from temperature dependence of the stability constant. In vitro biological activities of 2-aminobenzamide, CuA and CuAB complexes show remarkable activities against some bacterial and fungal strains. The percentage distribution of various binary and mixed ligand species in solution at dissimilar pH intervals were also evaluated.

Mixed ligand Cu(II) complexes of 2-aminobenzamide (2AB) and amino acids viz., glycine (gly), l-alanine (ala), l-valine (val) and l-phenylalanine (phe) have been synthesised and characterized by various physico-chemical and spectral techniques. The powder X-ray diffractogram and SEM pictogram shows all the complexes have homogeneous morphology with well-defined crystalline nature. The cleavage and binding interactions of mixed ligand complexes with calf thymus DNA under aerobic conditions show moderate activities. Also, the complex formation of Cu(II) involving 2-aminobenzamide and amino acids were carried out by a combined pH-metric and spectrophotometric techniques in 50% (v/v) water-ethanol mixture at 300, 310, 320 and 330 ± 0.1 K with I = 0.15 mol dm−3 (NaClO4). In solution, CuAB and CuAB2 species has been detected and the calculated stabilization value indicates higher stabilities for the mixed ligand complexes rather than their binary species. Thermodynamic parameters have also been determined from the temperature dependence of stability constant. In vitro biological activities of 2-aminobenzamide, CuA and CuAB complexes show remarkable activities.Figure optionsDownload as PowerPoint slide