NMR spectroscopic study and DFT calculations of GIAO NMR shieldings and 1JCH spin-spin coupling constants of 1,9-diaminononane

1H, proton coupled and decoupled 13C, DEPT, HETCOR NMR spectra, the magnitude of one bond 1JCH coupling constants and 13C NMR spin-lattice relaxation time (T1) of 1,9-diaminononane (danon, C9H22N2) have been reported for the first time. 1H, 13C NMR chemical shifts and 1JCH coupling constants of danon have been calculated by means of B3LYP density functional method with 6-311++G(d,p) basis set. Comparison between the experimental and the theoretical results indicates that density functional B3LYP method is able to provide satisfactory results for predicting NMR properties

Infrared spectrum and STM images of cyclohexene-2-ethanamine: First principle investigation

Cataloged from PDF version of article.he vibrational properties of cyclohexene-2-ethanamine molecule are studied by both theoretically and experimentally. The theoretical calculations are performed using density functional perturbation theory (DFPT) based on plane wave pseudopotential method while the experimental technique is infrared (IR) spectroscopy. We also present the results of theoretical calculation of STM images for electron density of the cyclohexene-2-ethanamine. Our results also show that DFPT can be applied to the molecular systems in GGA approximation by comparing experimental and other commercial theoretical methods. (C) 2007 Elsevier B.V. All rights reserved

Computational study on favipiravir adsorption onto undoped- and silicon-decorated C60 fullerenes

Adsorption and interaction mechanisms of fullerene-based complex systems for possible drug delivery vehicles have been at the center of increasing attention. In the scope of this work, the interaction mechanism between an important antiviral drug favipiravir and silicon-doped/undoped C60 fullerenes have been investigated using density functional theory (DFT). Calculations were carried out in both gas phase and water media to see the possible solvent effects. The effect of adsorption of the favipiravir on the SiC59 fullerene system and the nature of interaction were examined by analyzing the band shifts in the carbonyl stretching vibrations and natural bond orbital (NBO) properties of the examined complexes. Some important structural and electronic properties were reported and discussed as well. It was observed that doping the C60 fullerene nanocages with silicon atom enhanced the adsorption mechanism and calculations performed in water media gave rise to more stable complexes for silicon-doped systems compared to the results obtained for the gas phase. Results and parameters found in the present search reveal further insights into the drug delivery systems. © 2017 World Scientific Publishing Company

fullerenes with chlorophenylpiperazine isomers

A great deal of attention has been paid recently to the fullerene based complex systems for their possible applications as drug delivery vehicles and sensor applications. In the framework of this research, Si and Al-doped C20 fullerenes and physical interaction mechanisms of doped fullerenes with ortho, meta and para chlorophenylpiperazines were examined based on the computational density functional methods. Energetically stable complexes were searched with M06-2X and B3LYP functionals with 6-31G(d) basis set and some important geometrical structures including interatomic distances and dihedral angles were reported. All calculations were carried out in the gas phase and water media. It was observed that stabilities of the investigated systems were enhanced in the water phase calculations and upon adsorption besides the changes in NH stretching values, nuclear magnetic shielding tensors of 27A1 and 29Si nuclei were considerably changed. In order to further analyse the electronic, physical and chemical properties, binding and band gap energies, electrophilicity indexes and chemical hardness values were also calculated. (C) 2017 Elsevier B.V. All rights reserved

DFT STUDY OF SOLVENT EFFECTS ON CONFORMATIONAL EQUILIBRIA AND VIBRATIONAL SPECTRA OF 4-(1-PYRROLIDINYL)PIPERAZINE

Author Institution: Physics Department, Science Faculty, Anadolu University, Eskisehir, 26470, Turkey; Faculty of Science, University of South Bohemia, Czech Republic; Department of Physics, Dumlup_nar University, Kutahya, 43100, Turkey; Physics Department, Science Faculty, Anadolu University, Eskisehir, 26470, TurkeyThe optimized structural parameters (bond lengths, bond and dihedral angles), conformational equilibria and normal mode frequencies and corresponding vibrational assignments of 4-(1-Pyrrolidinyl)piperazine (4-pypp) have been examined by means of B3LYP hybrid density functional theory (DFT) method with 6-31++G(d,p) basis set. Furthermore, reliable vibrational assignments have made on the basis of potential energy distribution (PED) calculated and the thermodynamics functions, highest occupied and lowest unoccupied molecular orbitals (HOMO and LUMO) of 4-pypp ($C_8H_{17}N_3$) have been predicted. Calculations are employed for different conformations of 4-pypp both in gas phase and in solution. Solvent effects are investigated using chloroform and dimethylsulfoxide. Results from the theoretical values are showed that the structural parameters, mole fractions of stable conformers, vibrational frequencies, IR intensities and Raman activities of 4-pypp are solvent dependent.\\ \textbf{Keywords}: 4-(1-Pyrrolidinyl)piperazine, vibrational spectra, solvent effect, DFT

DFT, FT-RAMAN AND FT-IR INVESTIGATIONS OF 1-CYCLOPENTYLPIPERAZINE

Author Institution: Physics Department, Science Faculty, Anadolu University, Eskisehir, 26470, Turkey; Department of Physics, Dumlup_nar University, Kutahya, 43100, Turkey; Department of Physics, Dumlup_nar University, Kutahya, 43100, Turkey; Physics Department, Science Faculty, Anadolu University, Eskisehir, 26470, Turkey; Physics Department, Science Faculty, Anadolu University, Eskisehir, 26470, TurkeyFT-IR and FT-Raman spectra of 1-cyclopentylpiperazine (1cppp) have been experimentally reported in the region of 4000-50 $cm^{-1}$. The optimized geometric parameters (bond lengths, bond and dihedral angles), conformational analysis, normal mode frequencies and corresponding vibrational assignments of 1cppp ($C_9H_{18}N_2$) are theoretically examined by means of B3LYP hybrid density functional theory (DFT) method together with $6-31++$G(d,p) basis set. Furthermore, reliable vibrational assignments have been made on the basis of potential energy distribution (PED) and the thermodynamics functions, highest occupied and lowest unoccupied molecular orbitals (HOMO and LUMO) of 1cppp have been predicted. Calculations are employed for four different conformations of 1cppp both in gas phase and in solution. Solvent effects are investigated using chloroform and dimethylsulfoxide. All results indicates that B3LYP method is able to provide satisfactory results for predicting vibrational frequencies and the structural parameters, mole fractions of stable conformers, vibrational frequencies and assignments, IR and Raman intensities of 1cppp are solvent dependent. \textbf{Keywords}: 1-cyclopentylpiperazine; Vibrational spectra; Solvent effect; PED; DFT; B3LY

Crystallographic, vibrational and DFT studies of 1-(2-hydroxy-4,5-dimethylphenyl)ethanone

Molecular structure and properties of 1-(2-hydroxy-4,5-dimethylphenyl)ethanone were experimentally investigated by X-ray diffraction technique and vibrational spectroscopy. Experimental results on the molecular structure of the reported compound were supported with computational studies using the density functional theory (DFT), with the Becke-3-Lee-Yang-Parr (B3LYP) functional and the 6-311+G(3df,p) basis set. Potential energy distribution (PED) and potential energy surface (PES) analyses were performed to identify characteristic frequencies and reliable conformational analysis correspondingly. The compound crystallizes in monoclinic space group C2/c with the CO up-OH down conformation. There is a good agreement between the experimentally determined geometrical parameters and vibrational frequencies of the compound to those predicted theoretically. (C) 2015 Elsevier B.V. All rights reserved