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

Synthesis of Some Novel Nanosized Chelates of Anchoring Bisazo Dye 5-[5-(4,6-Dioxo-2-thioxo-hexahydro-pyrimidin-5-ylazo)-naphthalen-1-ylazo]-2-mercapto-1H-pyrimidine-4,6-dione and Their Applications as Antioxidant and Antitumor Agents

“…The small size (27 nm) of the Fe­(III) complex was also a key factor in its strong antitumor efficiency. It encouraged its incorporation into the cancer cell active sites and easy destruction . Zn­(II) has a nanosize structure (42 nm) that allows it to penetrate lipid membranes and influence tumor cells but at a lower effectiveness than the Fe­(III) complex.…”

“…It encouraged its incorporation into the cancer cell active sites and easy destruction. 86 Zn(II) has a nanosize structure (42 nm) that allows it to penetrate lipid membranes and influence tumor cells but at a lower effectiveness than the Fe(III) complex. On the other hand, the amorphous Cu(II) complex showed decreased activity because its structure prevented it from penetrating the lipid membrane.…”

Tridentate Schiff base and 4,4′‐bipyridine coordinated di/polynuclear Cu (II) complexes: Synthesis, crystal structure, DNA/protein binding and catecholase activity

“…Turnover numbers are 71.81 ± 1.04 h −1 (for 1 ) and 69.45 ± 0.74 h −1 (for 2 ), respectively. Higher catalytic activity of 1 is may be due to its more distorted square pyramidal structure than complex 2 (τ 5 values for 1 and 2 are 0.445 and 0.054, respectively) . Kinetic parameters for the Cu (II) compound catalyzed catecholase oxidation are shown in Table .…”

Tetradentate iminophenolate copper complexes in rac-lactide polymerization

“…Structurally characterized (L1)CuX complexes have been reported for X -= PF 6 -, ClO 4 -, Br -, and Cl -. [57][58][59][60][61][62] We were most interested in the respective nitrate complex, (L1)Cu(NO 3 ), 1, which was prepared by reaction of copper nitrate with L1H in methanol (Scheme 3). Complex 1 crystallizes as a monomeric, cationic complex with square-pyramidal geometry.…”