Theoretical modeling of hydrogen bond infrared spectra in molecular crystals of 2-thiopheneacetic acid : Fermi resonance and Davydov coupling effects

A quantum theoretical approach, within the adiabatic approximation and taking into account a strong non-adiabatic correction via the resonant exchange between the fast mode excited states of the two moieties of the dimer. The intrinsic anharmonicity of the low-frequency mode through a Morse potential, direct and indirect damping, and a selection rule breaking mechanism for forbidden transitions, is applied to reproduce the υX-H IR line shape of cyclic dimers of moderately H-bonded species in the crystalline phase. The results are used to gain an insight into the experimental spectral line shapes obtained by the transmission method. This approach fits satisfactorily the experimental line shape of 2-thiopheneacetic acid and predicts their evolution with isotopic substitution. Numerical calculations show that mixing of all these effects allows one to reproduce the main features of the experimental IR line shapes

COMPUTATIONAL MATERIALS SCIENCE

In this work, a structural and electronic properties of 4-methoxybenzaldehyde (4MBA) have been presented. The density functional theory (DFT) along with B3LYP hybrid functional is employed. The optimized structure was found to be in well consistent with the X-ray diffraction geometry. The 4MBA crystal is stabilized by C-H center dot center dot center dot O intermolecular interactions along with pi center dot center dot center dot pi interactions. Various intermolecular interactions involved in 4MBA crystal have been analyzed deeply through topological atom-in-molecules (AIM) analysis and noncovalent interactions (NCI) method. Besides, Hirshfeld surface (HS) analysis and fingerprint plots are performed to determine the contribution of intermolecular contacts in 4MBA crystal packing. The electronic properties of the title compound have been investigated. Nonlinear optic (NLO) properties of 4MBA have been interpreted through the calculated first hyperpolarizability value. 4-substituted benzaldehydes, including 4MBA, are known with their competitive inhibitory activity on Tyrosinase, which also known as polyphenol oxidase (PPO). This enzyme is a rate limiting enzyme that controls the production of melamine and brown coloring of foods. Thus, molecular docking behaviors of 4MBA are presented in comparison with that of benzaldehyde (BA), 4-ethylBA, 4-tertbutylBA, 4-isoprophylBA, 4-propoxyBA, 4-butoxyBA, and Hexylresorcinol on four selected PPOs from sweet potato, grape, and mushroom

Synthesis and characterization of a new cyanato-N cadmium(II) Meso-arylporphyrin complex by X-ray diffraction analysis, IR, UV/vis, 1H MNR spectroscopies and TDDFT calculations, optical and electrical properties

International audienceHerein, we have presented a new cadmium(II) pentacoordinate porphyrin complex obtained by the reaction of the [(meso‑tetra(para-methoxyphenyl)porphyrinato]cadmium(II) starting material ([Cd(TMPP)]) with an excess of potassium thiocyanate (KSCN) and crystand-222 (cryst-222) in the dichloromethane solvent leading to the coordination compound with the formula: [K(crypt-222)(H2O)][Cd(TMPP)(NCO)]·2(CH2Cl2)·0.5(C6H14)·H2O (symbolized by complex I). This species was characterized by elemental analysis, UV/Vis, FT-IR, and single crystal X-ray diffraction studies. The intermolecular interactions responsible of the cohesion of the crystal lattice of complex I were investigated using the Hirshfeld surface approach. DFT/TDDFT calculations on complex I were carried out including (i) Molecular structure optimization using the DFT/B3LYP-D3/lanl2dz level of theory, (ii) the frontier molecular orbitals (FMOs) calculations, (iii) the Mulliken charges distribution calculations, (iv) the Molecular electronic potential analysis (MEP), (v) an ab initio UV/Vis and IR calculations and (vi) the QTAIM and NCI-RDG analyses. These latter DFT/B3LYP-D3/lanl2dz calculations studies confirmed, inter alia, the strong hydrogen bond linking the NCO− axial ligand and the water molecule coordinated to the potassium counterion. Furthermore, the electrical conductance and dielectric properties of complex I were investigated shown firstly that the frequency dependence of electrical conductivity, follows the Jonscher's universal dynamic law and secondly that the obtained results have been discussed in terms of the OLPT and NSPT models, which is well adapted to our Cd(II)-porphyrin-NCO semiconductor material

Preparation, Characterizations and Theoretical Calculations of a Mg(II) Porphyrin Complex with Axial O-bonded 4-Pyrrolidinopyridine

International audienceWe hereby report the synthesis of a new hexacoordinated magnesium(II) metalloporphyrin with the formula [Mg(TBrPP)(4-pypo-κO)2] (1) where TBrPP is the meso-tetra(para-bromophenyl)porphyrinate and (4-pypo-κO) is the O-bonded 4-pyrrolidinopyridine axial ligand. This Mg(II) coordination is considered the linking isomer of the already known N-bonded 4-pyrrolidinopyridine (4-pypo-κN) with the formula [Mg(TTP)(4-pypo-κN)2] where TTP is the meso-tetra(p-tolyl)porphyrinate. Complex 1 was characterized by elemental analysis, IR, 1H NMR, UV/Vis and fluorescence spectrometric techniques, cyclic voltammetry measurements as well as single-crystal X-ray diffraction analysis. The Wingx supported program PLATON and the Hirshfeld surface analysis were both used to elucidate the intermolecular interactions in the crystal lattice of complex 1. Computational studies at DFI/B3LYP-D3/6-31G(d,p)-LanL2DZ level of DFT were used to elucidate the minimum energy geometry, the HOMO and LUMO molecular orbitals characteristics and the reactivity of complex 1. The molecular electrostatic potential (MEP) calculations on complex 1 have been made to determine the electrophilic-nucleophilic character of our new Mg(II) metalloporphyrin. Furthermore, the quantum theory atom in molecule (QTAIM) calculations were performed to get more insights into the type of interactions between the [Mg(TBrPP)] moiety and the two 4-pyrrolidinopyridine axial ligands of complex 1. © 2023 Elsevier B.V

Copper-Catalyzed Asymmetric Hydroboration Reaction of Novel Methylene Isoindolinone Compounds through Microwave Irradiation and Their Antileishmanial and Antitoxoplasma Activities

International audienceThe aim of this study was devoted into molecular docking calculations to discover the potential antileishmania and antitoxoplasma activities of newly synthesized compounds obtained by applying a practical and simple method under microwave irradiation. All these compounds were tested in vitro for their biological activity against Leishmania major promastigotes, amastigotes, and Toxoplasma gondii tachyzoites. Compounds 2a, 5a, and 5e were the most active against both L. major promastigotes and amastigotes, with IC50 values of less than 0.4 μM mL–1. Compounds 2c, 2e, 2h, and 5d had a strong antitoxoplasma activity of less than 2.1 μM mL–1 against T. gondii. We can conclude that aromatic methyleneisoindolinones are potently active against both L. major and T. gondii. Further studies for mode of action evaluation are recommended. Compounds 5c and 5b are the best drug candidates for antileishmania and antitoxoplasma due to their SI values being over 13. The docking studies of compounds 2a-h and 5a-e against pteridine reductase 1 and T. gondii enoyl acyl carrier protein reductase reveal that compound 5e may be an effective antileishmanial and antitoxoplasma drug discovery initiative

Combined experimental and theoretical studies on the molecular structures, spectroscopy, and inhibitor activity of 3-(2-thienyl)acrylic acid through AIM, NBO,FT-IR, FT-Raman, UV and HOMO-LUMO analyses, and molecular docking

In this work, the molecular structures and vibrational spectral analyses of 3-(2-Theinyl)acrylic acid (3-2TAA) monomer and dimer structures have been reported by using density functional theory calculations at B3LYP/6-311++G(d,p) level of theory. The complete assignments of the fundamental vibrational modes were obtained using potential energy distribution. Intermolecular interactions were analyzed by orbital NBO and topological AIM approaches. The electronic properties have been carried out using TD-DFT approach. Great agreements between experimental and theoretical values were achieved throughout the analysis of structural parameters and spectroscopic features. Inhibitor characteristics on human monoamine oxidase B (MAOB) enzyme of two determined stable conformers of 3-2TAA (β and γ) along with four selective inhibitors, namely safinamide, a coumarin analogue, farnesol, and phenyethylhydrazine were investigated via molecular docking. Moreover, molecular electrostatic potential (MEP) and temperature dependency of thermodynamic functions have been reported. © 2016 Elsevier B.V

In silico exploration of O-H…X2+ (X = Cu, Ag, Hg) interaction, targeted adsorption zone, charge density iso-surface, O-H proton analysis and topographic parameters theory for calix[6]arene and calix[8]arene as model

International audienceIn this work, the best adsorption targeted zones of the metal cations Ag2+, Cu2+ and Hg2+ at the surfaces or inside, outside the cavity of the calix[6] (CX[6]), calix[8]arene (CX[8]), NUBMOM (NUB-.) and LAYKUR (LAY-.) have been discussed. For X2+=Ag, Cu and Hg adsorbed onto the surface of CX[6,8], NUB-., and LAY-. and the morphologies of these complexes have been explained, the specific chosen surface structure has interfacial chemical properties to facilitate the stabilization of the cation in each targeted zone. The stability mechanisms have been investigated for the specific systems to understand the role of the cooperativity of the O center dot center dot center dot H (forming a donor-acceptor couple) bonding interactions for good selectivity to the cation in each host-guest in the acetonitrile solvent medium and the gas phase. For this purpose, all the host-guests chemical structures were investigated by the IR spectroscopy and O-H proton approach. The UV-visible absorption spectroscopy and the total DOS Orbital showed that all molecules possess a maximum absorption band in the range between 0.5 and 3.5 eV assigned to pi-pi* or n-pi* transitions, the minimum band is characterized for the CX[6,8]-Cu2+, NUB-.Cu2+ and LAY-.Cu2+, while the highest band is specified for the complexation with the cation Ag2+. The Hirshfeld surface and the molecular electrostatic potential topography have demonstrated the selected targeted zone for the most stable configurations. The nature and the type of interaction formed between the chosen cation and the targeted area of the CX[6,8], NUB-. and LAY-. were typically studied by the Atom in Molecules (AIM) approach via non-covalent interaction (NCI) analyses. According to theoretical calculations, Cu2+, Ag2+ and Hg2+ cations were complexed with CX[6] and CX [8]-arenes in endo and exo-type form. In the endo complexes, it has been observed that Cu2+ and Ag2+ cations enter the lower rim space where calixarene hydroxyl groups are located and form a complex in square planer geometry, as expected. This situation shows that the copper cation is planarly located in the calixarene core. These results show that the theoretical results are in good agreement with the experimental ones. In addition, our simulations point out the calix[6] arene and calix[8]arene were complexed with cations by "pinched" conformation, corresponding to best stable state. (C) 2021 Elsevier B.V. All rights reserved

In silico exploration of O-H^…X²⁺ (X = Cu, Ag, Hg) interaction, targeted adsorption zone, charge density iso-surface, O-H proton analysis and topographic parameters theory for calix[6]arene and calix[8]arene as model

In this work, the best adsorption targeted zones of the metal cations Ag2+, Cu2+ and Hg2+ at the surfaces or inside, outside the cavity of the calix[6] (CX[6]), calix[8]arene (CX[8]), NUBMOM (NUB-.) and LAYKUR (LAY-.) have been discussed. For X2+=Ag, Cu and Hg adsorbed onto the surface of CX[6,8], NUB-., and LAY-. and the morphologies of these complexes have been explained, the specific chosen surface structure has interfacial chemical properties to facilitate the stabilization of the cation in each targeted zone. The stability mechanisms have been investigated for the specific systems to understand the role of the cooperativity of the O…H (forming a donor-acceptor couple) bonding interactions for good selectivity to the cation in each host-guest in the acetonitrile solvent medium and the gas phase. For this purpose, all the host-guests chemical structures were investigated by the IR spectroscopy and O-H proton approach. The UV–visible absorption spectroscopy and the total DOS Orbital showed that all molecules possess a maximum absorption band in the range between 0.5 and 3.5 eV assigned to π–π* or n-π* transitions, the minimum band is characterized for the CX[6,8]-Cu2+, NUB-.Cu2+ and LAY-.Cu2+, while the highest band is specified for the complexation with the cation Ag2+. The Hirshfeld surface and the molecular electrostatic potential topography have demonstrated the selected targeted zone for the most stable configurations. The nature and the type of interaction formed between the chosen cation and the targeted area of the CX[6,8], NUB-. and LAY-. were typically studied by the Atom in Molecules (AIM) approach via non-covalent interaction (NCI) analyses. According to theoretical calculations, Cu2+, Ag2+ and Hg2+ cations were complexed with CX[6] and CX[8]-arenes in endo and exo-type form. In the endo complexes, it has been observed that Cu2+and Ag2+ cations enter the lower rim space where calixarene hydroxyl groups are located and form a complex in square planer geometry, as expected. This situation shows that the copper cation is planarly located in the calixarene core. These results show that the theoretical results are in good agreement with the experimental ones. In addition, our simulations point out the calix[6] arene and calix[8]arene were complexed with cations by “pinched” conformation, corresponding to best stable state