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Linear and nonlinear optical (NLO) properties of triphenyl fused rhodamine analogues were estimated by spectroscopic based mathematical calculations and compared with computed values using density functional theory (DFT) calculations. Various Global hybrids (GHs) and range separated hybrids (RSHs) were utilized for reliable estimations of NLO properties. Spectroscopic based mathematical calculations of polarizability (α CT ), first order hyperpolarizability (β CT ) and second order hyperpolarizability (γ) were performed in varying polarity solvents. Spectroscopic based mathematical calculted α CT , β CT and γ values are found to have much closer agreement with the DFT computed values obtained by using RSHs. Comparative analysis of α CT , β CT and γ values suggested that these values increases with the increase of triphenylamine substitutions. Moreover, α CT , β CT and γ values increase with decreasing HOMO-LUMO band gap for all the dyes. N-[9-(isobenzofuran-1(3H)-one)-6-(dipnenylamino)-xanthene]-N-diphenyl amine having bis-triphenylamine substituent showed the largest NLO response among all analogues dyes. [ABSTRACT FROM AUTHOR]

A density functional theory study was performed on the [3+2] cycloaddition (32CA) reaction of 1 H -phosphorinium-3-olate and 1-methylphosphorinium-3-olate with methyl acrylate. The thermodynamic and kinetic parameters were analysed by considering the regio- and stereoisomeric pathways in gas phase and solvents. The geometries indicate that the transition states are slightly more advanced and asynchronous in ethanol. Electron localisation function topological analysis of the bonding changes along the most favourable reaction pathway associated with the 32CA reaction of 1 H -phosphorinium-3-olate with methyl acrylate indicates that the reaction takes place through a two-stage one-step mechanism. Non-covalent interactions analysis of TS6x-H reveals the existence of weak hydrogen bonding explaining the regioselectivity found in this low-polar zw-type 32CA reaction. On comparing these theoretical findings with the nitrogen analogues of the 32CA reactions, it is found that the regioselectivity is affected and the pathways are kinetically and thermodynamically enhanced. Therefore, a priori , the phosphorus cycloadducts could be synthesised. [ABSTRACT FROM AUTHOR]

Effective adsorption of pyridine (Py)- a major pollutant present in various industrial wastewaters onto silica derived from de-oiled mustard cake (DOMC ) was evaluated. Fourier transform infrared spectroscopy (FT-IR) and SEM were used to characterized the adsorbent. The paper describes data on the chemical composition of the DOMC, kinetics and equilibrium adsorption of Py as well as the effect of different operational parameters (temperature, pH, ionic strength and effect of urea) on the effective removal of Py from its aqueous solution. Adsorption data were modeled with the Freundlich, Langmuir, Redlich–Peterson (R–P) and Temkin isotherm. The adsorption data are found suitable for the studied models quite reasonably. However, the results describe the best representation of the Langmuir isotherm model (non-linear R 2 = 0.99). The adsorption process followed Lagergren first order kinetics. The experimental findings were complemented using density functional theory (DFT) to have more understanding at atomistic level. The possible adsorption interactions were discussed. The effects of process parameters such as pH, urea and ionic strength on the adsorption suggested that the adsorption of Py was attributed to hydrogen bonding; however, hydrophobic interactions and charge transfer interactions are also believed to be responsible for the observed adsorption in the present case. The experimental data were subsentiated by employing a silica model based on DFT. Experimental and theoretical modeling of the adsorption phenomenon suggest hydrogen bonding to be a dominant force for Py adsorption onto silica. [ABSTRACT FROM AUTHOR]

Fullerenes have received attentions due to their versatile properties. Molecular structures and electronic properties namely binding energy, band gap, electrophilicity index and molecular topological analysis were studied for undoped and silicon doped C20 fullerenes and favipiravir in order to search for possible application of the systems as drug delivery vehicles. Density functional theory (DFT) and quantum theory of atoms in molecules (QTAIM) were used for the research. Molecular structures having the interaction edges of SiC19… OH in water and SiC19…C=O in gas phase were found as those most stable with binding energies of -57.28 kcal/mol and -43.46 kcal/mol correspondingly. The results and parameters found in this research may provide additional insights into drug delivery systems.

Fullerenes, with their extensive application potentials, have been receiving attention for their possible usage as drug delivery vehicles and devices for sensor technologies. In this work, the optimized molecular geometries, some diagnostic geometric parameters, electronic characteristics, natural bond orbital examinations and the interaction phenomena between C60, Si- or Al-doped C60 and phenylalanine amino acid molecule were investigated by the quantum mechanical calculations. It is observed that the impurity addition and using water as the solvent intensify the interaction between fullerene and amino acid system. These lead to various alterations in the electronic properties and NH stretching values of the clusters studied.

1-(3-trifluoromethylphenyl)piperazine (TFMPP) is one of the commonly abused drugs in the illicit drug market. Its detection or identification is important to investigate. In this work, density function theory (DFT) approach was used to analyse silicon or aluminium doped C60 fullerenes and TFMPP interactions for possible sensor applications. Stabilities of the investigated systems were examined in terms of the adsorption energies of TFMPP onto Si and Al decorated fullerenes. It was found that AlC59+TFMPP resulted in higher adsorption energies compared to SiC59+TFMPP. We also considered the band gap energy and concluded that Si and Al decorated fullerenes are sensitive to the presence of TFMPP in both the gas phase and aqueous medium.

Fullerenes and heteroatom doped fullerenes exhibit high potential as drug delivery agents in sensor technology and medical applications. We investigated, using density functional theory, the possible interaction sites and the nature of interaction, adsorption energy assessments, band gap energy evaluations, charge transfer analyses, and some diagnostic vibrational band assignments for valproic acid (VPA) and aluminum, silicon, and boron decorated fullerene systems. The present research shows that VPA has strong interaction with the doped fullerene cages particularly at its carbonyl edge. Therefore, these doped fullerenes can be suggested as possible drug delivery agents.

Piperazine and tetraone-related compounds are widely used in the drug industry. Heteroatom-doped fullerenes are studied as new types of sensor devices, and medical applications are studied as drug delivery vehicles. In this work, Si- or Al-doped C60 fullerenes and their interactions with piperazine-2,3,5,6-tetraone (ppto) molecule and some important structural or electronic properties were examined using the density functional theory (DFT). Results indicate that doped C60 fullerenes might be used to diagnose the presence of ppto as delivery vehicle and sensor because of their high adsorption energies and change of band gap energies.

Abstract: We report the results of computational studies performed on the lowest doublet and quartet states of GaO4. Using density functional theory (DFT) and coupled cluster approach with 6-311+G(2df) basis set, the Cs end-on bonded superoxo complex proposed earlier for GaO4, from matrix experiments and computational studies, is thermodynamically unstable with respect to GaO4(2A′)→OGaO(2Πg) + O2() reaction. A kite-like C2v ground state geometry has been computed for GaO4. The energies of the low-lying states, harmonic vibrational frequencies and isotopic frequency ratios are reported for the GaO4 molecule. The adiabatic electron affinity of GaO4 is computed to be 3.74eV and 3.81eV at the B3LYP and CCSD(T)//B3LYP levels, respectively. [ABSTRACT FROM AUTHOR]

Piperazines and fullerene nanocages are versatile compounds. These are discussed in a wide range of academic work, especially in the field of medicine, and considered for various applications by the pharmaceutical industry. In the present research, the potential interaction mechanisms between B-, Si-doped C60 and 1-formylpiperazine (1-fp) were examined within the framework of density functional theory, along with their optimized molecular structures and electronic properties. The calculated binding energies and various other physical and chemical parameters of 1-fp found in this work in comparison with the Si- and B-doped fullerenes suggest that doping of fullerene nanocage leads to a strong interaction mechanism that alters the chemical and electronic properties of the investigated compounds. This finding can be used as a guide for their further applications.

The Schiff base, 4-[3-(4-methoxy-phenyl)-allylideneamino]-1,5-dimethyl-2-phenyl-1,2-dihydro-pyrazol-3-one (TPMC/AAP) was synthesized by the condensation of 4-aminoantipyrine (4-amino-1,5-dimethyl-2-phenylpyrazole-3-one) and trans-para-methoxycinnamaldehyde (trans-3,4-methoxyphenyl-2-propenal) in dry methanol at 75 °C. The compound was characterized using elemental microanalysis, IR, NMR, UV spectroscopies and single-crystal X-ray crystallography. The X-ray structure determination shows that the Schiff base, (TPMC/AAP) is orthorhombic with the Pbca space group. The anti-microbial screening of the compound was carried out with Escherichia coli, Bacillus subtillis, Staphylococcus aureus, Pseudemonas aeruginosa, Candida albicans and Aspergillus niger using agar well diffusion method. The Schiff base possesses significant antimicrobial activity. The minimum inhibitory concentration (MIC) of the compound was also determined and the activity was compared with that of conventional drugs ciprofloxacin and ketoconazole. The compound (TPMC/AAP) showed varying activity against the cultured bacteria and fungi used. To complement the experimental data, density functional theory (DFT) was used to have deeper understanding into the molecular parameters and infrared spectra of the compound. [ABSTRACT FROM AUTHOR]

The reaction of the rhenium(V) complex cis-[ReO2I(PPh3)2] with 2-aminothiophenol (H2atp), benzene-1,2-dithiol (H2tdt) and 2-hydroxybenzenethiol (H2otp) led to the formation of the rhenium(III) complexes [Re(Hatp)(ibsq)2]·OPPh3, [Re(sbsq)3]·OPPh3 and [Re(obsq)3]·OPPh3 (ibsq=2-iminothiobenzosemiquinonate, sbsq=1,2-dithiobenzosemiquinonate, obsq=2-hydroxothiobenzosemiquinonate) respectively. These paramagnetic complexes were characterized by single crystal X-ray crystallography, 1H NMR spectrometry, IR and electronic spectroscopy, and cyclic voltammetry. To complement the experimental data, density functional theory (DFT) and time-dependent DFT were successfully used to investigate the structural, molecular, infrared and electronic spectra of these three complexes. [ABSTRACT FROM AUTHOR]

[Display omitted] • All possible tautomers of hydantoin interconversions were investigated. • DFT B3LYP-D3(BJ)/aug-cc-pVTZ method was used to account for dispersion corrections. • Explicit water and ethanol have a catalytic effect on specific energy barriers. • Binding energies for hydantoin bound to water or ethanol were calculated. Hydantoin exhibits tautomerism and the interconversion among the tautomers was studied using theoretical methods in the gas phase and solvents (water or ethanol). The implicit solvation as well as one explicit solvent molecule with water or ethanol were investigated. The functional used was B3LYP-D3(BJ) and the basis set for all atoms was aug-cc-pVTZ. The results indicate that the electronic energy barriers in the gas phase and implicit solvation are in the range 50–90 kcal mol−1. However, explicit water is found to have a catalytic effect as the electronic energy barriers are lowered to 18–30 kcal mol−1. Explicit ethanol lowers the electronic energy barriers further by about 2 kcal mol−1. This study should be beneficial for the rational design and experiments involving hydantoin and water or ethanol as solvents. [ABSTRACT FROM AUTHOR]