Molecular conformational stability and Spectroscopic analysis of Parared with experimental techniques and quantum chemical calculations

Synthesis, Ligating Properties, Thermal Behavior, Computational and Biological Studies of Some Azo-transition Metal Complexes

Synthesis of new Fe(III), Co(II), Ni(II), and Cu(II) complexes of two azo ligands; 1-(phenyldiazenyl) naphthalene-2-ol (sudan orange R, HL1), and sodium 2-hydroxy-5-[(E)-(4-nitrophenyl) diazenyl]benzoate (alizarin yellow GG, HL2) have been reported. Stoichiometries of 1:2 and 1:3 (M:L) of the synthesized complexes were approved by total-reflection X-ray fluorescence technique (TXRF) and by elemental analyses. The geometry of complexes (octahedral and square planar) was typified by various spectroscopic, thermal, and magnetic techniques. The ESR spectroscopy showed that Cu(II) complexes are of different isotropic and rhombic symmetries with the existence of Cu–Cu ions interaction. TGA, DTA, and DSC analyses supported the multi-stage thermal decomposition mechanisms, where the thermal breakdown is ended by the formation of metal oxide in most cases. Moreover, chemical reactivity modeling using the density functional theory (DFT) method with the B3LYP/6–31 basis set, showed that metal complexes are more biologically active than their precursor ligands. The calculated lipophilicity character for metal complexes is in the range of 33.8–37.5 eV. Docking results revealed high scoring energy for [Fe(HL2)3].H2O complex and moderate inhibition strength of [Cu(L1)2].H2O complex versus 1bqb, 3t88, and 4esw proteins. Ultimately, the extent of biological effectiveness was endorsed experimentally against four microbial strains. The results are guidelines for toxicological investigations.

Graphical Abstract

Unveiling the role of 2D monolayer Mn-doped MoS2 material: toward an efficient electrocatalyst for H2 evolution reaction

Two-dimensional (2D) monolayer pristine MoS₂ transition metal dichalcogenide (TMD) is the most studied material because of its potential applications as nonprecious electrocatalyst for the hydrogen evolution reaction (HER). Previous studies have shown that the basal planes of 2D MoS₂ are catalytically inert, and hence it cannot be used directly in desired applications such as electrochemical HER in industry. Here, we thoroughly studied a defect-engineered Mn-doped 2D monolayer MoS₂ (Mn-MoS₂) material, where Mn was doped in pristine MoS₂ to activate its inert basal planes. Using the density functional theory (DFT) method, we performed rigorous inspection of the electronic structures and properties of the 2D monolayer Mn-MoS₂ as a promising alternative to noble metal-free catalyst for effective HER. A periodic 2D slab of monolayer Mn-MoS₂ was created to study the electronic properties (such as band gap, band structures and total density of states (DOS)) and the reaction pathways occurring on the surface of this material. The detailed HER mechanism was explored by creating an Mn₁Mo₉S₂₁ non-periodic finite molecular cluster model system using the M06-L DFT method including solvation effects to determine the reaction barriers and kinetics. Our study revealed that the 2D Mn-MoS₂ follows the most favorable Volmer-Heyrovsky reaction mechanism with a very low energy barrier during H₂ evolution. It was found that the change in the free energy barrier (ΔG) during the H˙-migration (i.e., Volmer) and Heyrovsky reactions is about 10.34-10.79 kcal mol^-1 (computed in the solvent phase), indicating that this material is an exceptional electrocatalyst for the HER. The Tafel slope (y) was lower in the case of the 2D monolayer Mn-MoS₂ material due to the overlap of the s-orbital of hydrogen and d-orbitals of the Mn atoms in the HOMO and LUMO transition states (TS1 and TS2) of both the Volmer and Heyrovsky reaction steps, respectively. The better stabilization of the atomic orbitals in the HER rate-limiting step Heyrovsky TS2 is the key for reducing the reaction barrier, and thus the overall catalysis, indicating a better electrocatalytic performance for H₂ evolution. This study focused on designing low-cost and efficient electrocatalysts for the HER using earth abundant transition metal dichalcogenides (TMDs) and decreasing the activation energy barriers by scrutinizing the kinetics of the reaction to achieve high reactivity.

Molecular structure interpretation, spectroscopic (FT-IR, FT-Raman), electronic solvation (UV-Vis, HOMO-LUMO and NLO) properties and biological evaluation of (2E)-3-(biphenyl-4-yl)-1-(4-bromophenyl)prop-2-en-1-one: Experimental and computational modeling approach

In this present work, a molecule (2E)-3-(biphenyl-4-yl)-1-(4-bromophenyl) prop-2-en-1-one (3BPO) was synthesized and the structure has been characterized by using spectroscopic techniques. The most stable conformational structure of title compound has been calculated using HF-6-31G(d,p) basis set. DFT method were used through B3LYP/6-311++G(d,p) basis set to optimize the structure of the title compound. The geometrical parameters, vibrational wavenumbers and electronic properties have also been performed. The electronic properties for HOMO-LUMO, UV-Vis and MEP maps were contemplated by IEFPCM model with various solvation impacts which depends on TD-DFT ((M062X for UV and B3LYP for HOMO-LUMO, MEP)/6-311++G(d,p)) strategies. The NLO activity of title compound has been examined by solvation DFT/B3LYP technique with 6-311++G(d,p) premise set. Mean while, lone pair of donor-acceptor interactions and H bond donor/acceptor surface has been obtained by which a charge transfer mechanism can be explained. Molecular docking has been explored to comprehend the coupling transportation of the examined ligand with human folate receptor alpha in complex with folic corrosive protein (4LRH).