Copper Schiff base complex as a new immobilized heterogeneous catalyst: experimental, theoretical, biological and docking study

Abstract

The novel copper(II) Schiff base complex was synthesized. Density functional theory calculations at the B3LYP (6-311G**/LANL2DZ) level of theory have been carried out to investigate the structure and geometry of the Schiff base ligand and its copper complex. IR spectra data (experimental and theoretical) show that the ligand Schiff base is coordinated to the copper ion in a bi-negative tetradentate manner with NNOS donor sites. From the theoretical data, it was found that the geometrical structure of this complex is distorted square planar. In continue, a safe, efficient, and improved procedure for synthesis of 1, 2, 3-triazole derivatives by immobilized [CuL] on silica is described. Terminal alkynes reacted with organic azides in the presence of a novel copper(I) catalyst, which is prepared by in situ reduction of the copper(II) Schiff base complex with ascorbic acid, in H2O/THF at room temperature. Moreover, immobilized [CuL] on silica was approved to be a chemically and thermally stable catalyst that can be reused for several times with no significant loss in catalytic activity. The in vitro antifungal activities of title compounds were studied against Candida albicans (ATCC 10231), Candida krusei (ATCC 6258) and Aspergillus niger (ATCC 16404). Two compounds containing 2-(4-((((diphenylmethylene)amino)oxy)methyl)-1H-1,2,3-triazol-1-yl)-1-phenylethan-1-one and 2-(4-((((9H-fluoren-9-ylidene)amino)oxy)-methyl)-1H-1,2,3-triazol-1-yl)-1-phenylethan-1-one proved to have potent antifungal activity against Candida albicans and Candida krusei. A molecular docking study is also discussed for all synthesized compounds. The docking study demonstrated a significant interaction between the two most potent compounds and the active site of Mycobacterium P450DM.