Synthesis, structural characterization, electronic structure calculation, molecular docking study and biological activity of triorganotin(IV) complexes of schiff base (E)-4-amino-3-(2-(2-hydroxybenzylidene)hydrazinyl)-1H-1,2,4-triazole-5(4H)-thione)

Co(II), Ni(II), and Zn(II) complexes based on new hybrid imine-pyrazole ligands: structural, spectroscopic, and electronic properties

The present work reports the theoretical investigation of Co(II), Ni(II), and Zn(II) complexes containing Schiff bases (used as ligands) derived from the reaction of 2-hydroxy-1-naphthaldehyde with N-(2-aminoethyl) pyrazoles. The spectral analyses were carried out using infrared, Raman, and UV-Vis spectroscopy. Vibrational analyses were performed in order to investigate the mechanisms involving metal-ligand and intra-ligand vibrations and indicated the possibility of charge transfer related to the transitions n[Formula: see text]* and [Formula: see text]*. Structure optimizations and normal coordinate force field calculations were performed via the density functional theory (DFT) method at the HSE06/6-311G(d,p)/LanL2DZ level. A thorough analysis was also conducted regarding the nonlinear optical (NLO) properties and the natural bond orbital (NBO) of the complexes. The results show that these complexes have prospective application as materials for NLO. Furthermore, the NBO analysis confirms the coordination between the lone pair (LP) electrons of the donor atoms (O and N) and the metal acceptors. Finally, studies were conducted regarding the electronic properties of the complexes; among the properties investigated included the frontier molecular orbitals (FMO) and the molecular electrostatic potential (MEP), allowing to determine the energy gap and charge distribution.

A review: Pharmacological aspects of metal based 1,2,4-triazole derived Schiff bases

Clinical reports have highlighted the radical increase of antibiotic resistance. As a result, multidrug resistance has emerged as a serious threat to human health. Many organic compounds commonly used as drugs in the past, no longer have pure organic mode of action rather need bio-transformation or more activation. Bulk of research has shown that they need trace amount of metal ions incorporated within the chemistry of bioactive molecules for enhancement of their potentiality to fight aggressively against resistance. The deficiency of some metal ions can also be responsible for many diseases like growth retardation, pernicious anemia and heart diseases in infants. To overcome these problems, there is a need to introduce novel strategies which have new mechanism of action along with significant spectrum of biological activity, enhanced safety and efficacy. Bioinorganic compounds have played imperative role in developing the new strategy in the form of "Metal Based Drugs". In current years there have been momentous rise of interest in the application of metal based Schiff base compounds to treat various diseases which are difficult to be treated with conventional methodologies. The unique properties of metal chelates acting as an intermediate between conventional organic and inorganic compounds provided innovative opportunities in the field of pharmaceutical chemistry. In this review, we have exclusively focused on the search of metal based 1,2,4-triazole derived Schiff base compounds (synthesized, reported and reviewed in the past ten years) that possess various biological activities such as antifungal, antibacterial, antioxidant, antidiabetic, anthelmintic, anticancer, antiproliferative, cytotoxic and DNA-intercalation activity.

In vitro antifungal activities, molecular docking, and DFT studies of 4-amine-3-hydrazino-5-mercapto-1,2,4-triazole derivatives

Six disubstituted Schiff base compounds were synthesized (A1-A6) and characterized using infrared spectroscopy (IR), elemental analyses (EA), ¹H NMR, ¹³C NMR and HRMS spectroscopic techniques. Crystal structure of A1 has been determined by single crystal X-ray diffraction. The antifungal activities against three fungi were assessed, and the results showed that compounds of A1 and A2 have good activity for Wheat gibberellic with EC₅₀ value of 15.89 and 16.99 mg/L, respectively. Compounds of A3, A4 and A6 have good bioactivity against Maize rough bacteria (the value of EC₅₀ is 8.23, 7.56 and 7.92 mg/L, respectively). According to the result of molecular docking, compounds of A1 and A2 have the smallest docking energy (-8.33, -9.00 kcal/mol). Besides, for A1 and A2, the analysis of highest occupied molecular orbital (HOMO), the lowest unoccupied molecular orbital (LUMO) analysis and molecular electrostatic potential map were to further elaborate the reason for the good activity with density functional theory (DFT)-B3LYP/6-31G.

Mn(II) complex of a vitamin B6 Schiff base as an exclusive apoptosis inducer in human MCF7 and HepG2 cancer cells: Synthesis, characterization, and biological studies

Herein, a Mn(II) complex of the N,N'-dipyridoxyl(1,4-butanediamine) (═H₂ L) Schiff base has been newly synthesized. The synthesized complex was characterized by several experimental methods. In addition, the density functional theory approaches were used for theoretical identification of the complex. A good agreement between the computed and experimental infrared frequencies demonstrates validity of the optimized geometry for the synthesized complex. In a N₂ O₂ manner, two azomethine nitrogens and two phenolate oxygens of the L^2- ligand are coordinated to the Mn²⁺ metal ion. The biological studies indicate an efficient apoptotic and antioxidant activities of the synthesized [MnL(CH₃ OH)₂ ] complex on both of the HepG2 and MCF7 cancer cells. Since it has been suggested that the complex is an exclusive potent antitumor for treatment of the human breast and liver cancers.