Synthesis, characterization, in vitro antimicrobial and cytotoxic studies of Co(II), Ni(II), Cu(II), and Zn(II) complexes obtained from Schiff base ligands of 1, 2, 3, 4‐tetrahydro‐naphthalen‐1‐ylamine

Abstract

The transition metal complexes of Co(II), Ni(II), Cu(II) and Zn(II) with bidentate Schiff base ligands (HL1−5) were obtained from condensation of 1, 2, 3, 4‐tetrahydro‐naphthalen‐1‐ylamine with methanolic solution of 3‐hydroxy‐salicylaldehyde, 4‐hydroxy‐salicylaldehyde, 5‐bromo‐salicylaldehyde, 3,5‐dibromo‐salicylaldehyde, and 2‐hydroxy‐1‐napthaldehyde. The synthesized compounds were structurally elucidated by spectral and physical methods. The spectral characterization emphasized bidentate nature (NO) of Schiff base ligands which gets chelated with metal via nitrogen atom of imine group and deprotonated oxygen of salicylaldehyde/2‐hydroxy‐1‐napthaldehyde group to form octahedral geometry around metal atom. Thermal results supported that the complexes are stable upto 200°C leaving metal oxide as an end products. The reported compounds (1–25) in this series were screened against the bacterial strains, that is, two Gram positive: Bacillus subtilis and Staphylococcus aureus, two Gram negative: Pseudomonas aeruginosa and Escherichia coli, and two fungal strains: Candida albicans and Aspergillus niger and their results that indicated moderate to good activity with compounds 20 and 21 having good antimicrobial activity (minimum inhibitory concentration [MIC] value 0.0269–0.0067 μmol/ml) as compared with control drugs ciprofloxacine and fluconazole. Furthermore, cytotoxic studies of synthesized compounds were carried out against three human cancer cell lines: HCT‐116 (colon), A549 (alveolar), and MCF‐7 (breast) using standard drug paclitaxel. The results demonstrated that compounds 1 (IC50 values = 12.93, 15.13, 17.24), 3 (11.9, 9.29, 12.64), 9 (17.06, 20.06, 22.87), 14 (16.21, 18.47, 20.00), and 25 (17.54, 17.21, 20.23) for three cancer cell lines were found to be most potent candidates among the synthesized compounds.

Synthesis, spectral properties and antibacterial studies of new hetrocyclic schiff-azo ligand derived from 5-amino 2-phenyl.4h-pyrazol-3-one with some transition metal complexes

“…The physical properties and elemental microanalysis as well as metal content of complexes are described in Table (2). The (C.H.N.S) analysis and mass spectra have been done to all o complexes as examples of mononuclear complexes (11) . The atomic absorption technique helps us in determining the metal ion percentage at complex, so by which we can determine the (M : L) ratio in addition to mole ratio method.…”

“…There are many methods used to produce the best structure of complexes formed in solution without isolation (11). The most familiar one is the mole ratio method.…”

“…The (UV-Vis.) spectrum of ligand, Figure (11), in ethanol exhibited first high intensity absorption peak at (241 nm), (270 nm) and (320 nm) assigned to (π→π*) transitions. The absorption band at (400 nm) which attributed to (n→π*) transitions a result from presence of lone pairs of electrons (25) .…”

Zn(II), Mn(III), and Co(III) complexes of Schiff base derived from 2‐hydroxy‐1‐naphthaldehyde: Synthesis, spectral surveys, single crystal structure studies, Hirshfeld surface analysis, density functional theory calculation, molecular electrostatic potential, and molecular docking evaluations

“…Non-specific targeting, toxicity, and limited spectrum of activity and cumulative side effects of these drugs have led researchers to investigate new compounds with better properties. [1][2][3] Schiff bases are the most prevalent compounds in coordination chemistry, which have been the subject of interest due to their ease of synthesis and coordination with various transition metals and wide applications. [4][5][6] Schiff bases and their metal complexes have been able to show high efficiency in preventing the growth of cancer cells and suppressing it.…”

“…Also, the Mn center in complex (3) is ligated by two azomethine nitrogen atoms, two ligand oxygen atoms, and one Cl atom of metal salt forming five coordinated tetragonal pyramid geometry around the Mn atoms. The cyclic voltammetry of the complexes specifies an irreversible redox behavior for all complexes (1)(2)(3)(4). Next, DFT/B3LYP theoretical method was used to determine the optimal geometrical configurations and comparison between experimental and theoretical data, as well as for calculations of molecular electrostatic potential, highest-occupied molecular orbital (HOMO)-lowest-unoccupied molecular orbital (LUMO) energy values of selected compounds.…”