Tautomerization, molecular structure, transition state structure, and vibrational spectra of 2-aminopyridines: a combined computational and experimental study

Synthesis and structural investigation of salts of 2-amino-3-methylpyridine with carboxylic acid derivatives: an experimental and theoretical study

The salts bis(2-amino-3-methylpyridinium) fumarate dihydrate, 2C6H9N2+·C4H2O22-·2H2O (I), and 2-amino-3-methylpyridinium 5-chlorosalicylate, C6H9N2+·C7H4ClO3- (II), were synthesized from 2-amino-3-methylpyridine with fumaric acid and 5-chlorosalicylic acid, respectively. The crystal structures of these salts were characterized by single-crystal X-ray diffraction, revealing protonation in I and II by the transfer of a H atom from the acid to the pyridine base. In the crystals of both I and II, N-H...O interactions form an R22(8) ring motif. Hirshfeld surface analysis distinguishes the interactions present in the crystal structures of I and II, and the two-dimensional (2D) fingerprint plot analysis shows the percentage contribution of each type of interaction in the crystal packing. The volumes of the crystal voids of I (39.65 Å3) and II (118.10 Å3) have been calculated and reveal that the crystal of I is more mechanically stable than II. Frontier molecular orbital (FMO) analysis predicts that the band gap energy of II (2.6577 eV) is lower compared to I (4.0035 eV). The Quantum Theory of Atoms In Molecules (QTAIM) analysis shows that the pyridinium-carboxylate N-H...O interaction present in I is stronger than the other interactions, whereas in II, the hydroxy-carboxylate O-H...O interaction is stronger than the pyridinium-carboxylate N-H...O interaction; the bond dissociation energies also confirm these results. The positive Laplacian [∇2ρ(r) > 0] of these interactions shows that the interactions are of the closed shell type. An in-silico ADME (Absorption, Distribution, Metabolism and Excretion) study predicts that both salts will exhibit good pharmacokinetic properties and druglikeness.

Speculative assessment, molecular composition, PDOS, topology exploration (ELF, LOL, RDG), ligand-protein interactions, on 5-bromo-3-nitropyridine-2-carbonitrile

Computational calculations of 5-bromo-3-nitropyridine-2-carbonitrile (5B3N2C) on molecular structure and on energy are implemented using the 6-311++G(d,p) basis set by DFT/B3LYP method. The UV-Vis spectrum of 5B3N2C was obtained by TD-DFT with chloroform as a solvent. The analysis of molecular electrostatic potential (MEP) and frontier molecular orbital (FMO) were used to evaluate, the entire electron density and organic reactive sites of 5B3N2C. The electron-hole conversions were conjointly deliberated. Donor-acceptor interactions (NBO) analysis examines the intra-and intermolecular charge transfer, hyper conjugate interaction of the compound. The orbital molecular contributions are evaluated by density of states (DOS and PDOS). To discern the reactivity of the molecule, topology analyses were done. The biological prominence of the 5B3N2C molecule was investigated in a pertinent study of molecular docking with target protein 3CEJ exhibiting the centromere associated protein inhibitor property. Molecular Dynamics simulations were done to assess the stability of the complex. 5B3N2C physiochemical parameters were also compared to those of widely viable medications Ispinesib and Lonafarnib.

The structural, spectral, frontier molecular orbital and thermodynamic analysis of 2-hydroxy 2-methyl propiophenone by MP2 and B3LYP methods

In the present work, we have studied the 2-hydroxy 2-methyl propiophenone (2H2MPP) theoretically as well as experimentally. The optimized molecular structure has been obtained by the density functional theory (DFT), second-order Moller–Plesset perturbation theory (MP2) and Hartree Fock (HF) in the gas phase as well as in different media like ethanol, DMSO and heptane. FT-IR and FT-Raman spectra were computed as well as recorded and fundamental vibrational wavenumbers were assigned. The electronic absorption spectra were calculated by employing the time-dependent density functional theory (TD-DFT) to get the information about excitation energies, oscillator strength and excited state geometries in gas phase and in different solvent media. Chemical activity and chemical stability obtained by HOMO-LUMO studies using a HF/6-31[Formula: see text]G and MP2/6-311[Formula: see text]G calculations. The chemical interpretation of hyperconjugation interactions obtained by the Natural Bond Orbital (NBO) analysis. Moreover, electrostatic potential (ESP) calculations performed to get the visual representation of relative polarity of molecule. Thermodynamic parameters like enthalpy, entropy, heat capacity, and Gibbs free energy computed with varying temperature from 10[Formula: see text]K to 500[Formula: see text]K. The aim of the current investigation is to find out the quantum chemical properties of the title compound which show an active role in the pharmaceutical and printing industries.

Review for chiral-at-metal complexes and metal-organic framework enantiomorphs

This review discusses chiral-at-metal complexes and introduces enantiomorphs from assembly structure. Owing to the diverse coordination number and activity of metal ions as chiral centers, abundant structures for chiral selectivity, catalysis, and polarized light-response are the notable advantages of the chiral-at-metal complexes. The rational design and preparation of linear multi-dentate ligands is a good choice to improve the stability of chiral complexes, such as multi-bonding structure for high stability as a self-limiting system. The bio-significance and potential application of chiral-at-metal complexes are discussed, such as the synergistic effect of catalysis and chiral selectivity of the metal center in enzymes. Enzyme could be remolded to replace the original central metal ions with highly active rare earth or precious metal ions to form artificial metalloenzyme or to remove the "redundant" part around the metal center to improve the accessibility of substrate. The polarized light-response mechanism of chiral opsin is introduced in relation to its role in animal migration. Metal-organic frameworks (MOFs) are crystalline and porous materials built from metal nodes or clusters and organic linkers and provide the possibility to prepare artificial enantiomorphs. The preparations, applications, and characterization methods of MOF enatiomorphs are therefore introduced. We hope this review inspires researchers at all levels of their career to consider the title topic in their own research in terms of its application and potential value.