Synthesis, structure, computational, antimicrobial and in vitro anticancer studies of copper(II) complexes with N,N,N′,N′-tetrakis(2-hydroxyethyl)ethylenediamine and tris(2-hydroxyethyl)amine

Abstract

The present work consists of synthesis, structural characterization, spectral, density functional theory (DFT), antimicrobial, and anticancer studies of two copper(II) complexes, [Cu(THEEN)(DNB)](DNB) (1) and [Cu(TEAH₃)₂](DNB)₂ (2). In these complexes, THEEN is N,N,N′,N′-tetrakis(2-hydroxyethyl)ethylenediamine, a tetrapodal ligand, and TEAH₃ is tris(2-hydroxyethyl)amine, a tripodal ligand, and the counter-anion is 3,5-dinitrobenzoate (DNB⁻). X-ray crystallography studies reveal that both complexes have distorted octahedron geometries. DFT studies have been performed to calculate structural parameters, vibrational bands, and energy gaps of frontier orbital (HOMO-LUMO) with B3LYP/6–31G*/LANL2DZ level of theory using DMSO as solvent. The theoretical and crystallographic analyses are consistent. Antimicrobial studies have been performed with new copper(II) complexes against Gram(+) bacteria (Staphylococcus aureus), Gram(−) bacteria (Serratia marcescens, Sphingobium japonicum, and Stenotrophomonas maltophilia) and fungal species (Candida albicans, Aspergillus niger, and Saccharomyces cerevisiae). The copper(II) complexes have also shown in vitro cytotoxicity on MCF-7, HCT-116, and HL-60 human cell lines. This study demonstrates that 2 was active against MCF-7 cell lines with IC₅₀ of 23 μg/mL.

The present work consists of synthesis, crystal structure, DFT studies, antimicrobial, and anticancer activities of [Cu(THEEN)(DNB)](DNB) (1) and [Cu(TEAH₃)₂](DNB)₂ (2). Both complexes have distorted octahedron geometries with Jahn–Teller distortion. The theoretical and crystallographic analyses are consistent with each other.

Keywords:

• Crystal structure
• DFT studies
• Jahn-Teller distortion
• Hydrogen bonding
• HOMO-LUMO
• Antimicrobial and anticancer activity

Acknowledgements

We are highly thankful to Ministry of Human Resource and Development (MHRD), New Delhi for providing research assistantship to Mr Rakesh Kumar, one of the authors, and Dr B. R. Ambedkar National Institute of Technology, Jalandhar for providing research infrastructure. Rakesh Kumar is also thankful to Ms Isha for their valuable help to carrying out the UV-vis spectral studies.

Disclosure statement

No potential conflict of interest was reported by the authors.