Assessment of some application potentials for copper complexes of the ligands containing siloxane moiety: Antimicrobial, antifungal, antioxidant and redox activity

•Copper complexes with ligands containing tetramethyldisiloxane moiety were studied.•Antibacterial, antifugal and antioxidant as well as redox activities for the metal complexes were evaluated.•The complexes enhance the antioxidant activity of the spirulina extract having thus application potential in biotechnology.

Four Schiff base copper (II) complexes derived from 1,3-bis(3-aminopropyl)tetramethyldisiloxane and 2-hydroxybenzaldehyde (H2L1), 3,5-di-bromo-2-hydroxybenzaldehyde (H2L2), 2-hydroxy-5-nitrobenzaldehyde (H2L3) and 5-chloro-2-hydroxybenzaldehyde (H2L4) were studied in terms of their biological and electrochemical application potentials. Thus, antimicrobial activity was evaluated against three fungi (Aspergillus flavus ATCC 20046, Penicillium chrysogenum ATCC 20044, Alternaria alternate ATCC 8741) from pure culture and two bacteria species (Pseudomonas aeruginosa ATCC 27813 and Bacillus sp. ATCC 31073). Among all the copper complexes investigated, the complex derived from 5-chlorosalicylaldehyde (CuL4) exhibit the highest biological activity. All the copper complexes have been investigated as possible active antioxidant enhancer for spirulina extract. Their redox behaviour was also investigated by running cyclic voltammetry measurements.

Graphical abstractWe present the utilization of the Schiff base metal complexes in biological and electrochemical application potentials. We report the biological activity and the redox behaviour of a special class of four tetradentate Schiff bases and their derived copper complexes which contain flexible and hydrophobic tetramethyldisiloxane spacer between the complexing groups.Figure optionsDownload full-size imageDownload as PowerPoint slide