Issue 83, 2015

Synthesis, characterization, TDDFT calculation and biological activity of tetradentate ligand based square pyramidal Cu(ii) complexes

Abstract

Distorted square pyramidal complexes [Cu(L1)(H2O)]·ClO4 (1), [Cu(L2)(H2O)]·ClO4 (2) and [Cu(L3)(H2O)]·ClO4 (3) (HL1 = o-{[2-(2-aminoethylamino)ethylimino]methyl}phenol; HL2 = 2-{[2-(2-aminoethylamino)ethylimino]methyl}-6-methoxyphenol; HL3 = o-{1-[2-(2-aminoethylamino)ethylimino]ethyl}phenol) have been synthesized, and characterized by X-ray crystallography and spectroscopic analysis. All the complexes exhibit fluorescence at room temperature [λex = 267 nm, λem = 312, 329 and 357 nm, φ = 0.52 for 1; λex = 272 nm, λem = 312, 329 and 355 nm, φ = 0.46 for 2; λex = 265 nm, λem = 312, 356 and 377 nm, φ = 0.33 for 3]. The electronic structure and photophysical properties of the ligands and complexes were calculated by density functional theory (DFT) and time-dependent density functional theory (TD-DFT) methods using the B3LYP, B3PW91 and MPW1PW91 functionals, with 6-31G (d-p) and LanL2DZ basis sets. The results of TD-DFT calculations are functional-dependent and among the functionals, B3LYP was able to best reproduce the experimental results. Catecholase activity of 1–3 has been investigated using 3,5-di-tert butyl catechol (3,5-DTBC) as the model substrate and found that complexes are active for catalyzing the aerobic oxidation of 3,5-DTBC to 3,5-di-tert butyl benzoquinone (3,5-DTBQ). The compound with more distorted square pyramidal geometry shows a higher rate of catalytic activity. All the complexes have been tested for their anticancer activities in human breast (MCF7) cancer cell lines. Complexes show dose dependent suppression of cell viability with IC50 values 30, 68 and >100 μM for 1, 2 and 3, respectively. Anticancer activities of 1–3 and cisplatin were compared, and found that 1–3 were relatively less active than cisplatin.

Graphical abstract: Synthesis, characterization, TDDFT calculation and biological activity of tetradentate ligand based square pyramidal Cu(ii) complexes

Supplementary files

Article information

Article type
Paper
Submitted
25 Jun 2015
Accepted
24 Jul 2015
First published
24 Jul 2015

RSC Adv., 2015,5, 67727-67737

Author version available

Synthesis, characterization, TDDFT calculation and biological activity of tetradentate ligand based square pyramidal Cu(II) complexes

A. Bhunia, S. Manna, S. Mistri, A. Paul, R. K. Manne, M. K. Santra, V. Bertolasi and S. Chandra Manna, RSC Adv., 2015, 5, 67727 DOI: 10.1039/C5RA12324K

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