Indole core-based Copper(II), Cobalt(II), Nickel(II) and Zinc(II) complexes: Synthesis, spectral and biological study

Synthesis, Spectroscopic, DFT Calculation and Molecular Docking Studies of Indole Derivative

In the present work, computational and experimental work were carried out to explore the spectroscopic properties of indole derivative namely, Ethyl-5chloro-3-phenyl-1 h-indol-2carboxylate [5-CPIC] for optoelectronics applications. Redshift with increasing solvent polarity was observed indicating π → π* transition due to intramolecular charge transfer interactions. The theoretical ground and excited state dipole moments were calculated using Gaussian 16W software with basis set B3LYP/6-31 + G (d, p). The dipole moments of the derivative in-ground and excited state were determined experimentally. The excited state dipole moment is higher than the ground state, showing that excited state is more polar in nature. Specific and non-specific solute and solvent interactions were analysed using Kamlet and Catalan parameters. HOMO-LUMO energies of the molecule are determined using DFT. Chemical hardness, chemical softness and ionization potential are determined on basis of global descriptors. Molecular electrostatic potential maps are used to analyse electrophilic and nucleophilic sites. Further, Polarizability and hyperpolarizability were used to calculate Non-linear optical (NLO) properties. Natural bond orbital (NBO) analysis shows proton transfer chosen in the donor-acceptor and demonstrate high energy equilibrium for the molecule. To observe biophysical properties of the molecule, molecular docking studies performed with Cyclooxygenase-2(PDB ID-Cox-2). The physicochemical characteristics like drug-likeness and bioactivity scores of the molecule were calculated. The spectroscopic properties of the molecule studies suggest their potential use as an auspicious contender for organic light-emitting diode solar cells and sensor applications.

Exploration of newly synthesized transition metal(II) complexes for infectious diseases

Aim: In the annals of human history, infectious diseases significantly influencing the collective well-being of people worldwide. Consequently, to identify effective agents for infectious ailments, the octahedral Co(II), Ni(II), Cu(II), Zn(II) complexes of 4-(3-methoxyphenyl)pyrimidin-2-amine and 2-methoxy-1-napthaldehyde based ligand were synthesized and well characterized in the current investigation.Results & methodology: The synthesized compounds were evaluated for anti-TB, anti-inflammatory, antibacterial, antifungal activities by microplate Alamar blue, bovine serum albumin, serial dilution assays. The [Zn(L1)2(H2O)2] complex (5) demonstrates robust potency with 0.0040 ± 0.0007 and 0.0038 μmol/ml MIC value in anti-tuberculosis and antimicrobial activities, correspondingly while 06.57 ± 0.03 μM IC50 value in anti-inflammatory investigation.Conclusion: Complex (5) show promising potential as targets for pathogen deformities, supported by rigorous biological and computational investigations including pharmacophore modelling, molecular docking (binding score -121.018 and -59.8662 kcal/mol for 6H53 and 1CX2 proteins, respectively), DFT (Density functional theory), MESP (Molecular Electrostatic Potential) and ADMET (absorption, distribution, metabolism, excretion and toxicity).

Spectroscopic, theoretical and computational investigations of novel benzo[b]thiophene based ligand and its M(II) complexes: As high portentous antimicrobial and antioxidant agents

The reaction of 3-chlorobenzo[b]thiophene-2-carbohydrazide with 4-(diethylamino) salicylaldehyde gave the new ligand; 3-chloro-N'-(4-(diethylamino)-2-hydroxybenzylidene)-benzo[b]thiophene-2-carbohydrazide. The Cu(II), Co(II), Ni(II), and Zn(II) complexes have been successfully prepared. The ligand and the complexes were characterized by analytical, FT-IR, 1H NMR, mass, UV-visible spectroscopy, molar conductivity, and magnetic susceptibility measurements. The FT-IR spectral data showed that the ligand adopted a tridentate fashion when binding with the metal ions via the nitrogen atoms of the imine (C = N), carboxyl (C = O), and phenolic oxygen (O-H) donor atoms. Density Functional Theory (DFT) estimations for the ligand at the DFT/B3LYP level via 6-31G++ (d, p) replicate the structure and geometry. Finally, HOMO and LUMO analyses were used for the charge transfer interface of the structure. Furthermore, molecular docking and ADME calculations were also performed to correlate and interpret the experimental results. The antimicrobial activity study illustrated enhancement in the activity of the free ligand upon complex formation, and the Cu(II) complex (MIC 25 µg mL-1) may be considered a promising antibacterial agent, and the Ni(II) and Zn(II) complexes (MIC 25 µg mL-1) as promising antifungal agents. Also, synthesized Cu(II) and Zn(II) metal complexes (MIC 3.125 µg mL-1) showed promising anti-TB activity against M. tuberculosis. Further, benzo[b]thiophene-based ligand and its metal complexes were evaluated for in vitro antioxidant activity, and in silico docking studies were carried out against Cytochrome c Peroxidase (PDB ID: 2X08).

Biomedical applications of selective metal complexes of indole, benzimidazole, benzothiazole and benzoxazole: A review (From 2015 to 2022)

Indole, benzoxazole benzothiazole and benzimidazole are excellent classes of organic heterocyclic compounds. These compounds show significant application in pharmacy, industries, dyes, medicine, polymers and food packages. These compounds also form metal complexes with copper, zinc, cadmium, nickel, cobalt, platinum, gold, palladium chromium, silver, iron, and other metals that have shown to be significant applications. Recently, researchers have attracted enormous attention toward heterocyclic compounds such as indole, benzimidazole, benzothiazole, benzoxazole, and their complexes due to their excellent medicinal applications such as anti-ulcerogenic, anti-cancer, antihypertensive, antifungal, anti-inflammatory, antitubercular, antiparasitic, anti-obesity, antimalarial, antiglycation, antiviral potency, antineuropathic, analgesic antioxidant, antihistaminic, and antibacterial potentials. In this article, we summarize the medicinal applications of these compounds as well as their metal complexes. We hope this article will help researchers in designing and synthesizing novel and potent compounds with significant applications in various fields.

Synthesis, Structure and Biological Activity of Indole-Imidazole Complexes with ZnCl2: Can Coordination Enhance the Functionality of Bioactive Ligands?

The ability of the indole-imidazole hybrid ligands to coordinate with the Zn(II) ion and the resulting structures of this new class of coordination compounds were analyzed in order to determine their structural properties and biological functionalities. For this purpose, six novel Zn(II) complexes, [Zn(InIm)₂Cl₂] (1), [Zn(InMeIm)₂Cl₂] (2), [Zn(IniPrIm)₂Cl₂] (3), [Zn(InEtMeIm)₂Cl₂] (4), [Zn(InPhIm)₂Cl₂] (5) and [Zn₂(InBzIm)₂Cl₂] (6) (where InIm is 3-((1H-imidazol-1-yl)methyl)-1H-indole), were synthesized by the reactions of ZnCl₂ and the corresponding ligand in a 1:2 molar ratio in methanol solvent at an ambient temperature. The structural and spectral characterization of these complexes was performed using NMR, FT-IR and ESI-MS spectrometry and elemental analysis, and the crystal structures of 1-5 were determined using single-crystal X-ray diffraction. Complexes 1-5 form polar supramolecular aggregates by utilizing, for this purpose, the N-H(indole)∙∙∙Cl(chloride) intermolecular hydrogen bonds. The assemblies thus formed differ depending on the distinctive molecular shape, which can be either compact or extended. All complexes were screened for their hemolytic, cytoprotective, antifungal, and antibacterial activities. The results show that the cytoprotective activity of the indole/imidazole ligand significantly increases upon its complexation with ZnCl₂ up to a value comparable with the standard antioxidant Trolox, while the response of its substituted analogues is diverse and less pronounced.

Exploration of Indolo[3,2c]isoquinoline derived triazoles as potential antimicrobial and DNA cleavage agents: Synthesis, DFT calculations, and molecular modeling studies

Indole and its derivatives are well-known assorted motif in drug design and development. We here in reporting synthesis of new 9-chloro-1-(4-substituted phenyl)-12H-indolo[2,3-c][1,2,4]triazolo[3,4-a]isoquinolines 7 (a-h). Structures of the newly synthesized compounds were confirmed by making use of spectroscopic techniques like IR, NMR and Mass. The DFT calculations were taken for the selected molecules using CAM-B3LYP hybrid functional with a 6-31 + g(d) all-electron basis set using the Gaussian 09 package. The drug-likeness predictions were described for the synthesized derivatives. The In vitro antimicrobial and DNA cleavage activities were reported for all compounds 7 (a-h). The compounds 7a, 7b, and 7h showed excellent microbial inhibition and DNA cleavage activity as compared to standard drugs. Furthermore, the docking studies for the newly synthesized molecules were carried out by Auto dock software with two molecular targets Epidermal Growth Factor Receptor tyrosine kinase (1 M17) and C-kit Tyrosine Kinase (1 T46) exhibited better binding affinity of all synthesized compounds. In addition, the docking results were observed to be in full agreement with the in vitro DNA cleavage assay suggesting the potential of synthesized metal complexes in biological applications. Lastly, the protein stability, fluctuations of APO-Protein, and protein-ligand complexes were investigated through Molecular Dynamics (MD) simulations studies using Desmond Maestro 11.3 and potential lead molecules were identified.

Copper(II) and Cobalt(II) Complexes Based on Abietate Ligands from Pinus Resin: Synthesis, Characterization and Their Antibacterial and Antiviral Activity against SARS-CoV-2

Co-abietate and Cu-abietate complexes were obtained by a low-cost and eco-friendly route. The synthesis process used Pinus elliottii resin and an aqueous solution of CuSO₄/CoSO₄ at a mild temperature (80 °C) without organic solvents. The obtained complexes are functional pigments for commercial architectural paints with antipathogenic activity. The pigments were characterized by Fourier-transform infrared spectroscopy (FTIR), mass spectrometry (MS), thermogravimetry (TG), near-edge X-ray absorption fine structure (NEXAFS), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and colorimetric analysis. In addition, the antibacterial efficiency was evaluated using the minimum inhibitory concentration (MIC) test, and the antiviral tests followed an adaptation of the ISO 21702:2019 guideline. Finally, virus inactivation was measured using the RT-PCR protocol using 10% (w/w) of abietate complex in commercial white paint. The Co-abietate and Cu-abietate showed inactivation of >4 log against SARS-CoV-2 and a MIC value of 4.50 µg·mL^-1 against both bacteria Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). The results suggest that the obtained Co-abietate and Cu-abietate complexes could be applied as pigments in architectural paints for healthcare centers, homes, and public places.

Synthesis, spectral analysis, DFT calculations, biological potential and molecular docking studies of indole appended pyrazolo-triazine

A series of novel 5-(3,5-disubstituted-1H-indol-2-yl)-2,3-dimethyl-1-phenyl-2,6-dihydro-1H-pyrazolo[4,3-e][1,2,4]triazines (3a-l) were synthesized in single step from 3,5-disubstituted indole-2-carbohydrazide and 4-aminoantipyrine under acidic conditions with excellent yields. The various spectroscopic methods were used to prove the formation of all these products. The compounds 3a, 3b, 3e, 3f, 3i and 3j exhibited excellent antibacterial and antifungal activities with an MIC value of 3.125 µg/ml against the tested pathogens and anti-tuberculosis inhibitory potential against M. tuberculosis which is equivalent to standard drug. The antidiabetic activity of the compounds 3a and 3b showed the maximum potential as glucosidase inhibitors with IC₅₀ = 47.21 μg/ml and IC₅₀ = 48.36 μg/ml, respectively. The physicochemical characteristics like ADMET, drug-likeness and bioactivity scores for these molecules were also disclosed. To comprehend the electronic behavior of compound 3a, density functional theory estimations at the DFT/B3LYP level via 6-31G++ (d, p) have been carried out to replicate the structure and geometry. The first-order hyperpolarizability calculation was used to calculate the nonlinear visual feature of compound 3a. The charge transfer interface among the structure is elucidated by the estimated HOMO-LUMO analysis. Further, molecular docking studies were carried out for synthesized compounds with human maltase-glucoamylase (PDB: 2QMJ).