DFT Studies and Quantum Chemical Calculations of Benzoyl Thiourea Derivatives Linked with Morpholine and Piperidine for the Evaluation of Antifungal Activity

Herein, we report the density functional study of benzoyl thiourea derivatives linked to morpholine and piperidine to evaluate their antifungal activity. Overall six compounds BTP 1-3 and BTM 4-6 were optimized with DFT using the B3LYP method with 6-31G(d,p) basis set. The molecular geometry, bond lengths, bond angles, atomic charges and HOMO-LUMO energy gap have been investigated. The structural parameters have been compared with the reported experimental results and structure- antifungal activity relationship is explored in details. The calculated results from DFT were discussed using all Quantum chemical parameters of the compounds. Introduction: Benzoyl thiourea derivatives linked with morpholine and piperidine were reported to have good antifungal activity. Objective: To find the correlations between the quantum chemical calculations and the antifungal activity for the benzoyl thiourea derivatives linked with morpholine and piperidine. Method: Optimization was carried out with DFT using B3LYP method utilizing 6-31G(d,p) basis set. Results: A good correlation between the quantum chemical calculations and the antifungal activity for the benzoyl thiourea derivatives linked with morpholine and piperidine was found. Conclusion: The DFT study of benzoyl thiourea derivatives linked to morpholine and piperidine was evaluated for their antifungal activity and it showed good correlations of activity with the quantum chemical parameters.

Application of LFER to pKas and Dipole Moments of 1H and 2H Tautomers of Tetrazole: Mimicking Structure-Function Relation as a Chemical Education Perspective

Structure-function relation is a 155 year old concept to explain the dependence of biological activity of a drug molecule on its structure put forward by Crum-Brown and Fraser*. Similar line of interest is followed in the present work, and it stimulates the understanding of structure-activity relation (SAR) among the graduate students. An attempt is made for the first time from our laboratory to apply the Hammett and Taft equations to a five membered ring system with four nitrogens as heteroatoms viz. tetrazole to identify the aqueous medium 1H and 2H Tautomers. For this purpose experimentally determined aqueous medium pKa values of NH-acidities of a total of fifteen 5-X-1,2,3,4-tetrazoles and DFT/B3LYP method at the 6-31G* level calculated dipole moments of seven 1H and 2H tautomers of 5-X-1,2,3,4-tetrazoles are used to correlate with Hammett para and meta, and Taft _ortho^* values. Good correlations are obtained. The promising response of more abundant and more polar 1H tautomer with less susceptibility (* = -1.38 in pKa correlations and * = -0.55 in dipole moments correlation) to Taft equation and less abundant and less polar 2H tautomer with more susceptibility (para = 6.56, meta = 7.79 in pKa correlations, and para = 2.69, meta = 3.26 in dipole moments correlation) to Hammett equation of the tetrazole is well distinguished. Thus it mimics a principle of structure-function study on a chemical property like the ionization of NH proton of tetrazole and on a physical property like dipole moment for the first time. Therefore finding a way is achieved to get the equilibrium identification of 1H and 2H tautomers without using any expensive and time consuming experimental techniques.

Roboustness of Hydrogen Bonding in the Construction of Supramolecular Architechures in Protonated Perchlorate Salts

Five new multicomponent salts of perchloric acid with a series of substituted anilines and N-heterocyclic amines namely Diphenylaminium perchlorate (DPAPC) (1), 2, 5-dichloroanilinium perchlorate (25DAP) hydrate (2), 4-Methylanilinium perchlorate (4MAPC) (3), 4-diamino-6-methyl-1, 3, 5-triazin-1-ium hydrogen perchlorate (24DAMTHP) (4) and 8-hydroxyquinolinium hydrogen perchlorate (8HQP) (5) were prepared and structurally characterized. The entire complexes were subjected to FTIR and elemental analysis. A vast family of intermolecular contacts N-H…O, O-H…O, N-H…N and C-H…O were observed, which are key ingredient in the generation of privileged supramolecular self-assemblies appeared as one-dimensional chain, two-dimensional ladder and helix. Cambridge structural Database (CSD) analysis of 52 hits revealed the perchloric acid display higher propensity of ladder architectures. Molecular stability of the complexes were studied by quantum chemical calculations using DFT/B3LYP method with 6-31G(d,p) basis set. Further their relative charge distributions were identified using molecular electrostatic potential map. The use of Hirshfeld surfaces in combination with fingerprint plots was visualized in order to study the closer contacts within the molecule. The relative contribution of whole percentage of interactions associated is highlighted.

Theoretical and experimental study of new nonlinear optical material nicotinohydrazide

Pyridine-3-carbohydrazide (NIH) crystal is grown by slow evaporation solution growth technique and the single crystal X-ray diffraction experiment confirms cell parameters and space group. The FT-IR and FT-Raman studies are used to identify the functional groups in the compound Nicotinohydrazide. The thermal studies are conducted using thermogravimetric analysis and differential thermal analysis, the UV–Visible transmission spectrum of NIH is recorded within the range of 400–800[Formula: see text]nm. Besides, in order to know the optical properties of the material at molecular level, density functional theory (DFT) has been employed using B3LYP method at 6-[Formula: see text] (d,p). The electric dipole moment and first-order hyperpolarizability are calculated and found to be high. The second-order NLO studies for NIH crystal are done and it is compared with KDP.

Synthesis, characterization, DFT, and TD-DFT studies of (E)-5-((4,6-dichloro-1,3,5-triazin-2-yl)amino)-4-hydroxy-3-(phenyldiazenyl)naphthalene-2,7-diylbis(hydrogen sulfite)

In this study, (E)-5-((4,6-dichloro-1,3,5-triazin-2-yl)amino)-4-hydroxy-3-(phenyldiazenyl)naphthalene-2,7-diylbis(hydrogen sulfite), a cyanurated H-acid (CHA) azo dye, was synthesized and characterized using FT-IR spectrophotometer and GC-MS spectroscopy. A density functional theory (DFT) based B3LYP and CAM-B3LYP method with 6–311 + G (d,p) basis set analysis was computed for HOMO-LUMO, natural bonding orbitals (NBO), UV-Vis absorptions and excitation interactions, in order to understand its molecular orbital excitation properties. A low Energy gap (Eg) of 2.947 eV was obtained from the molecular orbital analysis, which showed that HOMO to LUMO transition is highly feasible; hence CHA is adequate for diverse electronic and optic applications. Studies of the first five excitations (S0 → S1/S2/S3/S4/S5) of CHA revealed that S0 → S1 and S0 → S3 are π → π* type local excitations distributed around the –N=N– group; S0 → S2, a Rydberg type local excitation; S0 → S4, a highly localized π → π* excitation; while S0 → S5 is an n → π* charge transfer from a benzene ring to –N=N– group. From NBO analysis, we obtained the various donor–acceptor orbital interactions contributing to the stabilization of the studied compound. Most significantly, some strong hyper-conjugations (n → n*) within fragments, and non-bondingand anti-bonding intermolecular (n → n*/π* and π → n*/π*) interactions were observed to contribute appreciable energies. This study is valuable for understanding the molecular properties of the azo dyes compounds and for synthesizing new ones in the future.

Synthesis, Characterization, and DFT Studies of N-(3,5-Bis(trifluoromethyl)benzyl)stearamide

The novel N-(3,5-bis(trifluoromethyl)benzyl)stearamide 3 was prepared in moderate yield by a solventless direct amidation reaction of stearic acid 1 with 3,5-bis(trifluoromethyl)benzylamine 2 at 140 °C for 24 h under metal- and catalyst-free conditions. This practical method was conducted in air without any special treatment or activation. The fatty acid amide 3 was fully characterized by IR, UV–Vis, 1D and 2D NMR spectroscopy, mass spectrometry, and elemental analysis. Moreover, molecular electrostatic potential studies, determination of quantum descriptors, fundamental vibrational frequencies, and intensity of vibrational bands were computed by density functional theory (DFT) using the B3LYP method with 6-311+G(d,p) basis set in gas phase. Simulation of the infrared spectrum using the results of these calculations led to good agreement with the observed spectral patterns.

ELECTRON DENSITY DISTRIBUTION IN 15-CROWN-5 AND ITS THIOANALOGS

Методом B3LYP получено распределение электронной плотности ρ(r) 15-краун-5 и его серосодержащих аналогов: 1-тио-15-краун-5, 1,4-дитио-15-краун-5, 1,4,7-тритио-15-краун-5, 1,4,7,10-тетратио-15-краун-5, 1,4,7,10,13-пентатио-15-краун-5. Вычислены групповые интегральные характеристики распределения ρ(r) соединений в рамках «квантовой теории атомов в молекулах» QTAIM. Рассмотрены внутримолекулярные слабые взаимодействия в 1,4-дитио-15-краун-5, 1,4,7-тритио-15-краун-5, 1,4,7,10-тетратио-15-краун-5, 1,4,7,10,13-пентатио-15-краун-5 и отмечено образование клеточной структуры в 1,4,7-тритио-15-краун-5. Electron density distribution of 15-crown-5 and its sulfur-containing analogs: 1-thio-15-crown-5, 1,4-dithio-15-crown-5, 1,4,7-threetio-15-crown-5, 1,4,7,10-tetratio-15-crown-5, 1,4,7,10,13-pentatio-15-crown-5 by the B3LYP method was obtained. The charges, volumes and electronic energies of the compounds are calculated in the postulates of the «quantum theory of atoms in molecules» (QTAIM). Intramolecular weak interactions are found in the 1,4-dithio-15-crown-5, 1,4,7-threetio-15-crown-5, 1,4,7,10-tetratio-15-crown-5, 1,4,7,10,13-pentatio-15-crown-5. The cell structure is formed in 1,4,7-threetio-15-crown-5.

Study on vibrational spectroscopy, molecular property, UV-VIS, HOMO-LUMO energies and MEP analysis of N-[2-(4-Bromo-benzoyl)-benzofuran-3-yl]-acrylamide monomer by DFT method

Purpose This study aimed the synthesis and theoretical/experimental characterization of novel benzofuran-based acrylamide monomer. Design/methodology/approach Novel N-substituted acrylamide monomer, i.e. N-[2–(4-Bromo-benzoyl)-benzofuran-3-yl]-acrylamide (BBFA), was synthesized by reacting (3-Amino-benzofuran-2-yl)-(4-bromophenyl) methanone with acryloylchloride at 0–5oC. Nuclear magnetic resonance (1H-NMR), infrared (FT-IR) and UV-Visible spectrophotometer were used to elucidate the chemical structure of BBFA. Computational studies were performed using the DFT (B3LYP) method on the basis of 6-31 + G (d, p) using Gaussian 09 W and Gauss View 5.0 package in addition to the VEDA program, gauge-independent atomic orbital (GIAO) and time-dependent density functional theory (TD-DFT) methods. Findings Molecular geometry and vibration assignments of the BBFA monomer were calculated. The molecular structure of the monomer was examined. Both longest and shortest bonds were determined in the structure. The nucleophilic and electrophilic regions of the monomer were determined. The theoretical spectroscopic data of the monomer were compared with the experimental data; both were consistent with each other. The chemical reactivity of the monomer was also determined. Originality/value The synthesized BBFA monomer can be evaluated in many areas; from medicine to industry (such as textiles) owing to the presence of various active functional groups. Indeed, acrylamide copolymers are remarkable materials for polymer science and industry. The data produced in this study is original and adds to the scientific community.

Theoretical study of OH− nucleophilic attack on cobalt(II)-verdoheme complex

OH[Formula: see text] attack on a four, five and six-coordinated cobalt(II)-verdoheme-coordinated with imidazole (1 M) while the axial ligand was studied using B3LYP method. Different spin multiplicities were considered, namely doublet, quartet, and sextet. Results show the most positive charge to be concentrated at the cobalt and carbon atoms adjacent to the oxygen in the cobalt(II)-verdoheme complex. Data obtained show that a stable intermediate was formed by a nucleophilic attack on one of the latter carbon atoms. The intermediate is initially formed by a nucleophilic attack on one of the aforementioned carbon atoms. This intermediate is then directly converted to a helical open-ring complex by passing it through a transition state. It is specified that if every nucleophilic attack is considered separately, then the OH[Formula: see text] attack on cobalt(II)-verdoheme occurred at all spin multiplicity and coordination states, from a thermodynamics and kinetics point of view, all except an OH[Formula: see text] attack on five-coordinated cobalt(II)-verdoheme at quartet state. However, comparison of reaction paths with different spin in the same coordination show that such a nucleophilic attack is not proceeded, while the reactant is a four and six-coordinated cobalt(II)-verdoheme because the latter reaction spin state is not conserved. It is clear that OH[Formula: see text] attack on five-inatedcoordinated Co(II)-verdoheme at doublet spin multiplicity is the most stable reaction path. Moreover, these findings were confirmed by NBO analysis and molecular orbital calculations.

Fused Thiazine Tethered Metal-Free Dyes for Dye Sensitized Solar Cells: A Computational Investigation

Three novel cyanoacetamide decorated phenothiazines (1a-c) have been designed. Structural and photo-physical properties of the molecules 1a-c have been investigated. To better realize the charge transport process involved in the dye-sensitized solar cells (DSSCs), computational studies have been performed using B3LYP and CAM-B3LYP method for the dyes 1a-c. Theoretical findings for DSSCs include LHE (light-harvesting efficiency) and driving forces such as electron injection (ΔGinject) and dye regeneration have been calculated to envisage the most appropriate dyes for the application of DSSC.