Synthesis of new Schiff base and its Ni(II), Cu(II), Zn(II) and Co(II) complexes; photophysical, fluorescence quenching and thermal studies

Synthesis, characterization, and biological activities of novel organometallic compounds of rhenium(I) with 2-(2-benzylidenehydrazinyl) benzothiazole Schiff-base derivatives: Molecular docking, ADME, and DFT studies

A series of substituted 2-(2-benzylidenehydrazinyl)benzothiazole Schiff-base derivatives and complexes containing Re(I) were synthesized and analyzed using various characterization techniques, including elemental analysis, conductance measurement, 1H-NMR, FT-IR, and LC-MS. The biological activities of the compounds were evaluated. Binding affinity between the complexes and calf thymus DNA (CT-DNA) was conducted using UV-visible spectroscopy, viscosity measurement, fluorescence spectroscopy, and molecular docking studies, indicating intercalation binding mode. The broth dilution method evaluated antibacterial activity against two Gram-positive and three Gram-negative bacteria. The results demonstrated the effectiveness of each complex against the tested pathogens. The MTT assay examined cytotoxic qualities on MCF-7 cell lines, demonstrating strong cytotoxic effects. The lethality of brine prawn assay was employed to assess the toxicity of the compounds. The Schiff base was optimized using the 6-31 G (d, p) basis set and B3LYP techniques. Density functional theory calculations were performed to compare the bond angles and lengths of the synthesized compounds with experimental values, showing good agreement, and to calculate the related orbital energies. The therapeutic qualities were evaluated using an in silico ADMET model, which verified that the synthesized compounds have qualities similar to those of drugs.

The synthesis of novel water-soluble zinc (II) phthalocyanine based photosensitizers and exploring of photodynamic therapy activities on the PC3 cancer cell line

In this study, Schiff base substituted phthalocyanine complexes (Zn1c, Zn2c) and their quaternized derivatives (Q-Zn1c, Q-Zn2c) were synthesized for the first time. Their structures have been characterized by FT-IR, 1H-NMR, UV-Vis, mass spectrometry and elemental analysis as well as. The photophysicochemical properties (fluorescence, singlet oxygen and photodegradation quantum yield) of these novel complexes were investigated in dimethylsulfoxide (DMSO) for both non-ionic and quaternized cationic phthalocyanine complexes and in aqueous solution for quaternized cationic phthalocyanine complexes. Water soluble cationic phthalocyanine compounds gave good singlet oxygen quantum yield (0.65 for Q-Zn1c, 0.66 for Q-Zn2c in DMSO; 0.65 for Q-Zn2c in aqueous solution). The binding of Q-Zn1c and Q-Zn2c to BSA/DNA was studied by using UV-Vis and fluorescence spectroscopy and these. Studies indicate that the mechanism of BSA quenching by quaternized zinc(II) phthalocyanines was static quenching. Quaternized zinc(II) phthalocyanines interacted with ct-DNA by intercalation. Quaternized zinc(II) phthalocyanines caused a decrease in cell viability and triggered apoptotic cell death after PDT was applied at a concentration that did not have a toxic effect on their own. Q-Zn1c and Q-Zn2c mediated PDT reduced the activity of SOD, CAT, GSH while increased MDA level in the prostate cancer cells. Furthermore, expression of apoptotic proteins after PDT was examined. The results revealed that the synthesized water soluble quaternized zinc(II) phthalocyanine complexes (Q-Zn1c and Q-Zn2c) are promising potential photosensitizers for PDT.

Synthesis, Structural Characterization, Hirshfeld Surface Analysis, and Antibacterial Study of Pd(II) and Ni(II) Schiff Base Complexes Derived from Aliphatic Diamine

A Schiff base bearing two methyl substituents, namely, 6,6'-((1E,1'E)-((2,2-dimethylpropane-1,3-diyl) bis(azanylylidene)) bis(methanylylidene)) bis(2-methylphenol) [H₂AD1Me] was synthesized and characterized through physicochemical and spectroscopic analyses. Then, the Schiff base was complexed with Pd(II) and Ni(II) to form [Pd(AD1Me)] and [Ni(AD1Me)], respectively. Both metal complexes were successfully obtained and characterized through several analyses, viz., melting point, elemental analysis, molar conductivity, magnetic susceptibility, FTIR, ¹H NMR, UV-vis, and single crystal X-ray diffraction. A quantitative analysis of the intermolecular interactions in the crystal structures has been performed using Hirshfeld surface analysis. Both metal complexes were crystallized in a monoclinic crystal system with the space group of P2₁/c. Additionally, the deprotonated phenolic oxygen atom (O1/O2) and azomethine nitrogen atom (N1/N2) of the ligand chelate the Pd(II) and Ni(II) ions, forming a slightly distorted square-planar complex containing three six-membered rings encircling the metal core with dsp² hybridization. The shift of ν(C=N) to a higher frequency in FTIR by 26-28 cm^-1 indicated that the complexation to Pd(II) and Ni(II) through the azomethine N was established. It was further supported through the shifting of the azomethine proton signal to higher or lower chemical shifts with Δδ = 0.43-1.15 ppm in ¹H NMR. In addition, the shifting of the n-π*(C=N) band in UV-vis spectra with Δλ = 24-40 nm indicated the involvement of azomethine nitrogen in the complexation. All the compounds showed no significant antibacterial activity against three bacterial strains, namely, Staphylococcus aureus subsp. aureus Rosenbach (ATCC 6538), Streptococcus mutans Clarke (ATCC 700,610), and Proteus vulgaris (ATCC 6380), as the percent growth inhibition calculated was less than 90%.

Synthesis, Structural Characterization of a New Ni(II) Complex and Its Catalytic Activity for Oxidation of Benzyl Alcohol

In ethanol-water (v:v = 1:1), a new Ni(II) complex, [Ni(L)2(H2O)2] (1) (HL = 6-phenylpyridine-2-carboxylic acid) was synthesized using 6-phenylpyridine-2-carboxylic acid, NaOH and Ni(CH3COO)2.4H2O. The structure of complex 1 has been determined by elemental analysis and single crystal X-ray diffraction. The single crystal analysis shows that complex 1 contains one Ni(II) ion, two L ligands and  two coordinated water molecules. In 1, the Ni(II) ion is six-coordinated to two O atoms and two N atoms from L ligands and two O atoms from coordinated water molecules, respectively, which form a distorted octahedral coordination geometry. The whole unit of complex 1 is interconnected to each other through intermolecular N−H•••O hydrogen bonds involving oxygen atom of coordinated water molecule and the oxygen atoms of  L ligand to form 1D molecular architecture. The catalytic activity of complex 1 for oxidation of benzyl alcohol with O2 was investigated. The complex 1 shows good catalytic performance for the oxidation of benzyl alcohol, the benzyl alcohol conversion, benzaldehyde selectivity, and benzaldehyde yield were 49.1%, 92.0%, and 45.2%, respectively, at 90 °C under 0.7 Mpa O2 for 2 h. Moreover, complex 1 could be recovered easily by centrifugation and used repetitively for at least four times. Copyright © 2022 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).