Caffeine‐Coordinated Co, Ni and Cu Mixed‐Ligand Complexes: Synthesis, Spectroscopic Characterization, Antibacterial Investigation and Antiproliferative Activity Against Lung Cancer Cells (A549)

Mixed ligand new cobalt, nickel and copper complexes were synthesized from caffeine and pyrrolidinium ionic liquid embedded Schiff base, 1‐{2‐(5‐bromo‐2‐hydroxybenzylideneamino) ethyl}‐1‐methyl‐pyrrolidinium [BF 4 ] as the primary ligand. All the metal complexes were obtained as powders having significant bright color and analyzed by different spectroscopic methods like CHN analysis, PXRD, SEM, EDS, 13 C‐NMR, 1 H‐NMR, FT‐IR, ESI‐MS, UV‐visible and magnetic moments measurements. The obtained spectral data indicated octahedral coordination of the ligand surrounding the metal center. The synthesized metal chelates as well as the ionic liquid embedded Schiff base were examined against Bacillus cereus KTWOL4 and Escherichia coli K12 strains and very significant results were observed for the Schiff base and the nickel complex. Evaluation of antiproliferative activity of the compounds against lung cancer (A‐549) and human normal liver (WRL‐68) cell lines showed that the metal complexes had higher anticancer activity against the human lung carcinoma compared to the Schiff base, while they had significantly lower effects on normal cells.