Global Chemical Reactivity Descriptors Research Articles

Experimental and Theoretical Investigations of Tetrakis (Thiourea) Palladium Chloride Semi-Organic Non-Linear Optical Crystal: An Approach to NLO Application

Semi-organic non-linear optical crystals of tetrakis (thiourea) palladium chloride (TTPC) were synthesized by a slow evaporation method. X-ray diffraction analysis performed on the title crystal established its orthorhombic structure and Pna2 1 space group. The crystalline perfection was investigated by means of high resolution X-ray diffraction (HRXRD) measurements. The values of transmittance, cutoff wavelength, refractive index and single oscillator parameters were computed through ultraviolet (UV) transmittance analysis. The second harmonic generation efficiency (SHG) of the TTPC crystals was verified by the Kurtz Perry technique. The potential of TTPC to act as a NLO material was further envisaged by the hyperpolarizability studies which resulted in higher values of dipoles and polarizability. To shed light on the pattern of charge distribution and donor-acceptor interactions prevailing in TTPC crystals, natural bond orbital (NBO) analysis was performed. Laser damage threshold (LDT) analysis on TTPC resulted in a LDT value of 5.1 GW/cm 2. The low birefringence value calculated from birefringence patterns attested the to suitability of the crystal to be used in harmonic generation devices. Using the HOMO-LUMO approach the values of significant global chemical molecular reactivity descriptors were determined.

Density functional computational and X-ray studies on pharmaceutical compound 1-{3-[4-(4-fluorophenyl)piperazin-1-yl]propyl}-1H-indole

The crystal and molecular structure of 1-{3-[4-(4-fluorophenyl)piperazin-1-yl]propyl}-1 H -indole (I) has been determined by single-crystal X-ray diffraction. Molecular geometry of compound I in the ground state has been calculated using the density functional method (DFT) with B3LYP/6-31G(d,p) basis set and compared with the experimental data. In addition, density functional calculations of the structure, molecular electrostatic potential map, frontier molecular orbitals, atomic charges, thermodynamic functions and global chemical reactivity descriptors of compound I were performed.

Molecular structure, vibrational, factor group, optical and second order polarizability analysis of the l-prolinium trichloroacetate: A computational approach

For the first time the molecular structure, vibrational, optical and nonlinear optical properties of the l-prolinium trichloroacetate (LPTCA) have been determined by B3LYP/6-31++G** level of theory and the obtained properties are well correlated with the experimental report. The factor group investigation was also made and discussed. In the continuation of theoretical studies the TD-DFT approach is applied to study the various key properties. The calculated absorption wavelength value is found at λexc=174nm (7eV). The dipole moment and first order hyperpolarizability were also calculated and found to be comparable with urea. Further, global chemical reactivity descriptors (GCRD), frontier molecular orbitals and molecular electrostatic potential (MEP) are discussed. All the properties suggest that the present material may be a good contender for optoelectronic devices.

Bis (thiourea) strontium chloride as promising NLO material: An experimental and theoretical study

Single crystals of pure bis (thiourea) strontium chloride (BTSC) have been grown from aqueous solution by slow evaporation method. The results from single crystal X-ray diffraction studies indicated the orthorhombic structure and Pna21 space group of the crystals. 77% transmittance measured by the Ultra violet transmittance studies and a band gap of 4.7 eV indicated the high optical transparency. From Kurtz and Perry powder method, the second Harmonic Generation (SHG) efficiency of the BTSC has been found to be 1.54 times as that of KDP and the phase matching nature of the crystal has been confirmed. Hyper polarizability studies showed that the synthesized BTSC crystal has higher polarisability and dipole values and hence can be used as potential NLO material. The frontier orbital HOMO-LUMO gap has been determined to understand the chemical reactivity and kinetic stability of the title crystal. The values of various global chemical molecular reactivity descriptors like chemical hardness (η) and electrophilicity index (ω) have been calculated. Natural bond orbital (NBO) analysis has been carried out to study the charge distribution and to understand various donor–acceptor interactions taking place in the BTSC crystal.

Synthesis of a novel methyl(2E)-2-{[N-(2-formylphenyl)(4-methylbenzene) sulfonamido]methyl}-3-(2-methoxyphenyl)prop-2-enoate: Molecular structure, spectral, antimicrobial, molecular docking and DFT computational approaches

The title compound methyl(2E)-2-{[N-(2-formylphenyl)(4-methylbenzene)sulfonamido] methyl}-3-(2-methoxyphenyl)prop-2-enoate (MFMSM) has been synthesized and single crystals were grown by slow evaporation solution growth technique at room temperature. XRD, FT-IR and NMR spectra of MFMSM in the solid phase were recorded and analyzed. The optimized geometry and vibrational wave numbers were computed using DFT method. The NLO, Mulliken, MEP, HOMO-LUMO energy gap and thermodynamic properties were theoretically predicted. The NBO analysis explained the intramolecular hydrogen bonding. The global chemical reactivity descriptors are calculated for MFMSM and used to predict their relative stability and reactivity. All the calculations were carried out by B3LYP/6-311G (d,p) method. MFMSM has been screened for its antimicrobial activity and found to exhibit antifungal and antibacterial effects. Docking simulation has been performed.

Synthesis, crystal structure investigation, spectroscopic characterizations and DFT computations on a novel 1-(2-chloro-4-phenylquinolin-3-yl)ethanone

The title compound 1-(2-chloro-4-phenylquinolin-3-yl)ethanone (CPQE) was synthesised effectively by chlorination of 3-acetyl-4-phenylquinolin-2(1H)-one (APQ) using POCl3 reagent. Structural and vibrational spectroscopic studies were performed by utilizing single crystal X-ray diffraction, FTIR and NMR spectral analysis along with DFT method utilizing GAUSSIAN′ 03 software. Veda program has been employed to perform a detailed interpretation of vibrational spectra. Mulliken population analyses on atomic charges, MEP, HOMO-LUMO, NBO, Global chemical reactivity descriptors and thermodynamic properties have been examined by (DFT/B3LYP) method with the 6-311G(d,p) basis set level.

A new oxorhenium(V) complex with benzothiazole derived ligand: Relative stability and global chemical reactivity indices

A new rhenium complex, cis-[ReO(btmp)PPh3Cl2] (2a) with 2-benzothiazolyl-5-methoxyphenol (Hbtmp) has been synthesized and characterized by means of FT-IR, UV–Vis, 1H NMR and elemental analyses. The structural parameters of 2a as obtained from XRD studies have been compared with the calculated [PBEPBE/STMIDI] values. The observed results are in good agreement. The vibrational frequencies, electronic transitions of 2a have been calculated and compared with the experimental results. The global chemical reactivity descriptors based on conceptual density functional theory have also been calculated for a set of analogous systems derived from 2a varying the central metal center (Re or Tc) and substituted phosphine moieties. A good relationship between the calculated hardness (η) and Tolman’s cone angle (θ) of phosphines is observed both for Re and Tc complexes. Similar harmony between electronic chemical potential (μ) and Tolman’s electronic parameter (ν) of phosphines is also noted.

Experimental and computational approaches of a novel methyl (2E)-2-{[N-(2-formylphenyl)(4-methylbenzene)sulfonamido]methyl}-3-(4-chlorophenyl)prop-2-enoate: A potential antimicrobial agent and an inhibition of penicillin-binding protein

The title compound methyl(2E)-2-{[N-(2-formylphenyl) (4-methylbenzene)sulfonamido]methyl}-3-(4-chlorophenyl) prop-2-enoate (MFMSC) has been synthesized and single crystals were grown by slow evaporation solution growth technique at room temperature. Structural and vibrational spectroscopic studies were carried out by using single crystal X-ray diffraction, FT-IR and NMR spectral analysis together with DFT method using Gaussian'03 software. The detailed interpretation of the vibrational spectra has been carried out by VEDA program. NBO analysis, Mulliken charge analysis, HOMO-LUMO, MEP, Global chemical reactivity descriptors and thermodynamic properties have been analyzed. The hyperpolarisability calculation reveals the present material has a reasonably good propensity for nonlinear optical activity. The obtained antimicrobial activity results indicate that the compound shows good to moderate activity against all tested bacterial and fungal pathogens. A computational study was also carried out to predict the drug-likeness and ADMET properties of the title compound. Due to the different potential biological activity of the title compound, molecular docking study is also reported and the compound might exhibit inhibitory activity against penicillin-binding protein PBP-2X.

Synthesis, crystal structure analysis, spectral investigations, DFT computations, Biological activities and molecular docking of methyl(2E)-2-{[N-(2-formylphenyl)(4-methylbenzene) sulfonamido]methyl}-3-(4-fluorophenyl)prop-2-enoate, a potential bioactive agent

The title compound methyl(2E)-2-{[N-(2-formylphenyl) (4-methylbenzene)sulfonamido]methyl}-3-(4-fluorophenyl) prop-2-enoate (MFMSF) has been synthesized and single crystals were grown by slow evaporation solution growth technique at room temperature. The grown crystals were characterized by FTIR, 1H NMR, 13C NMR, and single crystal X-ray diffraction. In the crystal, molecules are linked by intermolecular C–H…O hydrogen bonds forming a two-dimensional supramolecular network along [110] direction. The molecular geometry was also optimized using density functional theory (DFT/B3LYP) method with the 6-311G (d,p) basis set in ground state and compared with the experimental data. The entire vibrational assignments of wave numbers were made on the basis of potential energy distribution (PED) by VEDA 4 programme. Stability of the molecule arising from hyper conjugative interactions, charge delocalization has been analyzed using natural bond orbital (NBO) analysis. In addition, NLO, MEP, Mulliken, thermodynamic properties, HOMO and LUMO energy gap were theoretically predicted. The global chemical reactivity descriptors are calculated for MFMSF and used to predict their relative stability and reactivity. The antibacterial activity of the compound was also tested against various pathogens. The molecular docking studies concede that title compound may exhibit PBP-2X inhibitor activity.

Synthesis, structural, conformational and DFT studies of N-3 and O-4 alkylated regioisomers of 5-(hydroxypropyl)pyrimidine

Because of the great pharmacological potential of the pyrimidine motif, novel C-5 substituted N-3 acyclic and O-4 acyclic pyrimidine derivatives were prepared as an interesting class of compounds for biological evaluation. Introduction of the 2,3-dihydroxypropyl (DHP) and penciclovir (PCV)-like side chains to 2-methoxypyrimidin-4-one (2) afforded a mixture of N- and O-acyclic pyrimidine nucleosides in the ratio of 54: 29 (3:4) and 57:21 (5:6) with N-3 isomer being dominant. Distinction between N- and O-alkylated pyrimidine moiety was deduced from extensive experimental FT-IR, HPLC-MS and 1D (1H, 13C) and 2D (COSY, HMQC and HMBC) NMR analyses. The N-, O-regioisomers were also examined by computational method at density functional theory (DFT) RB3LYP/6-31G(d), 6-31G∗∗ and 6-31+G∗ levels. DFT global chemical reactivity descriptors (total energy, chemical hardness, electronic chemical potential and electrophilicity) were calculated for the isomers and used to predict and describe their relative stability and reactivity. The chemical reactivity indices were related to the C2N3C4 bond angle. Theoretical predictions can be used to compare chemical reactivity and stability with future biological evaluation and behaviour of these compounds.

Density functional study of spectroscopy, electronic structure, linear and nonlinear optical properties of l-proline lithium chloride and l-proline lithium bromide monohydrate: For laser applications

Using density functional theory (DFT), a systematic study of structure, bonding, vibration, excitation energies and non-linear optical properties has been carried out for noncentrosymmetric l-proline lithium chloride monohydrate and l-proline lithium bromide monohydrate for the first time. The calculated vibrational frequencies and the S0→S1 transition energy were compared with the earlier reported experimental results and found in good agreement. HOMO–LUMO energy gap was calculated by CIS, B3LYP and CISD using 6-31G(d,p), 3-21G, 6-31++G respectively and the obtained results are compared. For the calculation of excitation energies we used time dependent DFT (TDDFT). Both the molecules show the considerably lower dipole moment in excited state in comparison with the ground state. Mulliken charge and molecular electrostatic potential were studied. The first order hyperpolarizability for LPLCM and LPLBM are 2.15675×10−30esu and 3.78984×10−30esu respectively which are 5 and 10 times higher than prototype urea (0.3728×10−30esu) molecule. The global chemical reactivity descriptors were also calculated. The calculated results of polarizability, first and second hyperpolarizability confirm that these molecules are good non-linear optical materials and can be used for laser device fabrications.

Synthesis, spectral analysis, structural elucidation and quantum chemical studies of (E)-methyl-4-[(2-phenylhydrazono)methyl]benzoate

The title compound, (E)-methyl-4-[(2-phenylhydrazono)methyl]benzoate, (I), (C15H14N2O2), has been synthesized by condensation reaction of methyl-4-formylbenzoate and phenylhydrazine. The compound has been characterized by elemental analysis, IR, 1H NMR, 13C NMR, UV–Vis spectroscopies and single crystal X-ray diffraction techniques. Optimized molecular structure, harmonic vibrational frequencies, 1H and 13C NMR chemical shifts have been investigated by B3LYP/6-31G(d,p) method using density functional theory (DFT). Global chemical reactivity descriptors, natural population analysis (NPA), thermodynamic and non-linear optical (NLO) properties have also been studied. The energetic behavior of the compound has been examined in solvent media using the integral equation formalism polarizable continuum model (IEF-PCM).

Synthesis, molecular structure, spectroscopic analysis, thermodynamic parameters and molecular modeling studies of (2-methoxyphenyl)oxalate

The aim of this study is to find out the molecular characteristic and structural parameters that govern the chemical behavior of a new (2-methoxyphenyl)oxalate compound and to compare predictions made from theory with experimental observations. The title compound, (2-methoxyphenyl)oxalate, (I), (C16H14O6), has been synthesized. The compound has been characterized by elemental analysis, IR, 1H NMR, 13C NMR spectroscopies and single crystal X-ray diffraction techniques. Optimized molecular structure, harmonic vibrational frequencies, 1H and 13C NMR chemical shifts have been investigated by B3LYP/6-31G(d,p) method using density functional theory (DFT). The calculated results show that the predicted geometry can well reproduce structural parameters. In addition, global chemical reactivity descriptors, molecular electrostatic potential map (MEP), frontier molecular orbitals (FMOs), Mulliken population method and natural population analysis (NPA) and thermodynamic properties have also been studied. The energetic behavior of title compound has been examined in solvent media using polarizable continuum model (PCM).

Cytotoxic activity of substituted chalcones in terms of molecular electronic properties

Global chemical reactivity descriptors and lipophilicity (logP) were evaluated via density functional theory in order to clarify the structure–cytotoxic activity relationships of substituted chalcones. Stepwise multiple regression was employed to establish correlation between descriptors and cytotoxic activity against three cancer cell lines (HL-60, NALM-6 and WM-115) for 11 compounds. Regression analysis revealed that electrophilicity index and chemical potential significantly contributed in explaining of chalcones cytotoxic potential. Moreover, the established structure–activity relationships based on electronic structure properties allow indicating the substructures responsible for their cytotoxic activity. The study has also been supported by crystallographic data of 2-chloro-2′-hydroxychalcone.

Synthesis, spectral analysis, X-ray crystal structures and evaluation of chemical reactivity of five new benzoindazole derivatives through experimental and theoretical studies

The main purpose of this study was synthesis, X-ray, DFT and spectroscopic investigations of the title compounds (I–V). Five new compounds were synthesized and the detailed experimental results are reported. The crystal and molecular structures of the title compounds have been determined by IR, 1H NMR, 13C NMR and single-crystal X-ray diffraction. Molecular geometries from X-ray experiment of I–V in the ground state have been compared using the Density Functional Theory (DFT) with B3LYP/6-31G(d,p) basis set. In addition, the molecular electrostatic potential maps and frontier molecular orbitals were performed at B3LYP/6-31G(d,p) level of theory. DFT global chemical reactivity descriptors (chemical hardness, total energy, electronic chemical potential and electrophilicity) are calculated for the title molecules and used to predict their relative stability and reactivity.

Theoretical studies on the reactivity of thiazole derivatives

The global and local quantum chemical reactivity descriptors of a series of thiazole derivatives substituted at 2, 4, and 5 positions with different groups including electron-donating and electron-withdrawing substituents, have been calculated at the B3LYP/6-311++G(d,p) and MP2/6-311++G(d,p) levels of theory. The substituents have been selected to cover a wide range of electronic effects. Considering the calculated Fukui functions, thiazole derivatives are found to be suitable nucleophilic sites in the gas-phase. For the most substituents, it was observed that the calculated Fukui function $${\mathbf{\it f}}_{k }^{ - }$$ values at the N-site are small in the case of electron-attracting substituents indicating a preferred N-site for hard reactions. In contrast, large $${\mathbf{\it f}}_{k }^{ - }$$ values in case of electron-releasing groups indicate a preferred N-site for soft reactions. These two local descriptors predicted the reactivity of the electron-rich thiazoles and sequence to be 2-substituted thiazoles >5-substituted thiazoles >4-substituted thiazoles, where reactivity toward electrophilic attack at the pyridine nitrogen atom is enhanced by electron-donor substituents elsewhere in the molecule, due to resonance effect.

First-principles DFT study of cyclic and acyclic nucleoside phosphonates

In this paper, we have studied the properties and successfully explained the effectiveness of nucleoside phosphonates as antiviral agents. Working within the framework of first-principles density functional theory (DFT) using the B3LYP functional and the 6-311+G(d,p) basis set, the structural, energetics, and electronic properties of cyclic and acyclic nucleoside phosphonates were determined. Conceptual DFT was used to determine chemical parameters. By comparing the reactivities with those of the competing natural nucleotide during diphosphorylation, we show that, as is, commonly believed, the drugs act by terminating the viral DNA chain. A good correlation has been obtained between the experimental biological activity and the computed DFT-based global chemical reactivity descriptors.

DFT study and microbiology of some coumarin-based compounds containing a chalcone moiety

In the present investigation, a series of coumarin-based compounds containing a chalcone moiety were studied for their in vitro and in silico properties. DFT global chemical reactivity descriptors (chemical hardness, total energy, electronic chemical potential and electrophilicity) are calculated for four synthesized compounds and used to predict their relative stability and reactivity. The antibacterial activities of all compounds have been screened against Bacillus subtilis (ATCC No. 6633) and Bacillus cereus (ATCC No. 11778). Quantum-chemical calculations indicate that antibacterial activity correlates well with chemical reactivity descriptors of molecules.

Theoretical studies on the reactivity of mono-substituted imidazole ligands

The global and local quantum chemical reactivity descriptors of a series of imidazole derivatives substituted at 2, 4, and 5 positions with different groups including electron-donating and electron-withdrawing substituents have been calculated using the B3LYP/6-311++G(d,p) and MP2/6-311++G(d,p) methods. The substituents have been selected to cover a wide range of electronic effects. Considering the calculated Fukui functions, both imidazole derivatives and their anions are found to be suitable nucleophilic sites in the gas phase. For the most substituents it was observed that the calculated Fukui function \(f_{\text{k}}^{ - }\) values at the N-site are small in case of electron-releasing substituents indicating a preferred N-site for hard reaction. In contrast, large \(f_{\text{k}}^{ - }\) values in case of electron-attracting groups indicate a preferred N-site for soft reaction. These two local descriptors predicted the reactivity of the electron-rich imidazole sequence to be 2-substituted imidazoles > 5-substituted imidazoles > 4-substituted imidazole where reactivity toward electrophilic attack at a pyridine nitrogen atom is enhanced by electron donor substituents elsewhere in the molecule, due to resonance effect.

Conformational, Chemical Reactivity, Thermodynamic Properties, and the SEM Study of Yohimbine Hydrochloride

We have presented a study on structural conformation of yohimbine hydrochloride using density functional theory (DFT) method. A short description about the surface morphology with scanning electron microscopy imaging has been included. Correlation between different thermodynamic properties with variation in the temperature has been given. The global and local chemical reactivity descriptors have been calculated, from which nucleophilicity and electrophilicity of the given atomic sites in the molecule can be known.