scholarly journals Stability Analysis and Frontier Orbital Study of Different Glycol and Water Complex

2013 ◽  
Vol 2013 ◽  
pp. 1-16 ◽  
Author(s):  
Snehanshu Pal ◽  
T. K. Kundu
Keyword(s):  
Hydrogen Bond ◽  
Density Functional ◽  
Bond Formation ◽  
Proton Donor ◽  
Basis Set ◽  
Geometrical Parameters ◽  
Hydrogen Bond Interaction ◽  
Hydrogen Bond Formation ◽  
Water Complex ◽  
Hartree Fock

A detailed theoretical study of hydrogen-bond formation in different polyethylene glycol + water complex and dipropylene glycol + water have been performed by Hartree Fock (HF) method, second-order Møller-Plesset perturbation theory (MP2), and density functional theory (DFT) using 6-31++G(d,p) basis set. B3LYP DFT-D, WB97XD, M06, and M06-2X functionals have been used to describe highly dispersive hydrogen-bond formation appropriately. Geometrical parameters, interaction energies, deformation energies, deviation of potential energy curves of hydrogen bonded O–H from that of free O–H, frontier orbitals, and charge transfer have been studied to analyze stability and nature of hydrogen bond formation of various glycol and water complexes. It is found that WB97XD is best among all the applied DFT functionals to describe hydrogen bond interaction, and intermolecular hydrogen bonds have higher covalent character and accordingly higher strength when glycol acts as proton donor for glycol + 1 water complex system.

scholarly journals Theoretical Study of Hydrogen Bond Formation in Trimethylene Glycol-Water Complex

2012 ◽  
Vol 2012 ◽  
pp. 1-12 ◽  
Author(s):  
Snehanshu Pal ◽  
T. K. Kundu
Keyword(s):  
Density Functional Theory ◽  
Hydrogen Bond ◽  
Density Functional ◽  
Bond Formation ◽  
Proton Donor ◽  
Basis Set ◽  
Functional Theory ◽  
Hydrogen Bond Formation ◽  
Water Complex ◽  
Trimethylene Glycol

A detailed quantum chemical calculation based study of hydrogen bond formation in trimethylene glycol- (TMG-) water complex has been performed by Hatree-Fock (HF) method, second-order Møller-Plesset perturbation theory (MP2), density functional theory (DFT), and density functional theory with dispersion function (DFT-D) using 6-31++G(d,p) basis set. B3LYP DFT-D, WB97XD, M06, and M06-2X functionals are used to capture highly dispersive hydrogen bond formation. Geometrical parameters, interaction energy, deviation of potential energy curve of hydrogen-bonded O–H from that of free O–H, natural bond orbital (NBO), atom in molecule (AIM), charge transfer, and red shift are investigated. It is observed that hydrogen bond between TMG and water molecule is stronger in case of TMG acting as proton donor compared to that of water acting as proton donor, and dilute TMG solution would inhibit water cluster formation.

Theoretical analysis of the (HNO)2, (HNO···HNS), and (HNS)2 dimers — A case of red and blue shifts of N–H stretching frequency

2010 ◽  
Vol 88 (8) ◽  
pp. 849-857 ◽  
Author(s):  
Nguyen Tien Trung ◽  
Tran Thanh Hue ◽  
Minh Tho Nguyen
Keyword(s):  
Hydrogen Bond ◽  
Quantum Chemical ◽  
Bond Formation ◽  
Blue Shift ◽  
Proton Donor ◽  
Basis Sets ◽  
Coupled Cluster ◽  
Hydrogen Bond Formation ◽  
Length Contraction ◽  
Moller Plesset

The hydrogen-bonded interactions in the simple (HNZ)2 dimers, with Z = O and S, were investigated using quantum chemical calculations with the second-order Møller–Plesset perturbation (MP2), coupled-cluster with single, double (CCSD), and triple excitations (CCSD(T)) methods in conjunction with the 6-311++G(2d,2p), aug-cc-pVDZ, and aug-cc-pVTZ basis sets. Six-membered cyclic structures were found to be stable complexes for the dimers (HNO)2, (HNS)2, and (HNO–HNS). The pair (HNS)2 has the largest complexation energy (–11 kJ/mol), and (HNO)2 the smallest one (–9 kJ/mol). A bond length contraction and a frequency blue shift of the N–H bond simultaneously occur upon hydrogen bond formation of the N–H···S type, which has rarely been observed before. The stronger the intramolecular hyperconjugation and the lower the polarization of the X–H bond involved as proton donor in the hydrogen bond, the more predominant is the formation of a blue-shifting hydrogen bond.

THEORETICAL STUDIES OF HYDROGEN BONDING INTERACTION BETWEEN TRIMETHYLAMINE AND SUBSTITUTED PHENOLS, INFLUENCE OF THE SUBSTITUENTS ON THE HYDROGEN BOND PROPERTIES AND THE VIBRATIONAL SPECTRUM

2008 ◽  
Vol 07 (06) ◽  
pp. 1171-1186 ◽  
Author(s):  
SALMA PARVEEN ◽  
SUBOJIT DAS ◽  
ASIT K. CHANDRA ◽  
THERESE ZEEGERS-HUYSKENS
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Density Functional ◽  
Structural Changes ◽  
Structural Parameters ◽  
Basis Set ◽  
Bond Properties ◽  
Substituted Phenols ◽  
Hydrogen Bond Formation ◽  
Donor And Acceptor

Hydrogen bonding interactions between trimethylamine (TMA) and a series of para substituted phenols (X– C 6 H 4 OH , X = H , CH 3, NH 2, Cl , CN , and NO 2) are studied by using density functional theory with the hybrid B3LYP functional and the 6-31++G(d,p) basis set. Both electron donor and acceptor substituents (X) are chosen to study systematically the relation between the proton donor ability of the phenols and the strength of the OH … N hydrogen bond. The effect of hydrogen bonding on spectral and structural parameters and their inter relation are discussed. The natural bond orbital (NBO) analysis (occupation of σ* orbitals, hyperconjugative energies and atomic charges) is also carried out to elucidate the reason behind the spectral and structural changes due to hydrogen bond formation. Several correlations between hydrogen bond strength and bond properties are discussed.

scholarly journals Xrd, Quantum Chemical, Vibrational, Thermal and Antifungal Activity Analysis on 3-Nitroanilinium Hydrogen Oxalate

2019 ◽  
Vol 9 (1S3) ◽  
pp. 319-323
Keyword(s):  
Density Functional ◽  
Density Functional Method ◽  
Functional Method ◽  
Basis Set ◽  
Frontier Molecular Orbital ◽  
Geometrical Parameters ◽  
Vibrational Assignments ◽  
Hartree Fock ◽  
Homo Lumo ◽  
Good Agreement

3-nitroanilinium hydrogen oxalate has been crystallized successfully by solvent evaporation method. Optimized molecular geometrical parameters and the vibrational assignments of 3NAOX has been calculated by using Hartree-Fock (HF) and density functional method (B3LYP) with 6-311++G (d, p) basis set. The computational analysis showed good agreement with the experimental data. The energy and various parameters were obtained by HOMO–LUMO plot. The apparent pharmaceutical/biological activity of the salt confirmed by lower band gap value obtain from the Frontier Molecular Orbital (FMO) analysis. Thermal properties of 3NAOX were analyzed by TGA/DTA. The grown crystals were involved in an antimicrobial activity against certain potentially threatening microbes which shows that grown crystal screened the bacteria.

scholarly journals Structural, Vibrational, Quantum Chemical Calculations, Thermal and Antimicrobial Studies On Nitrate Salt Of 3-Nitroaniline

2021 ◽  
Author(s):  
Thangarasu S ◽  
Siva V ◽  
Asath Bahadur S ◽  
Athimoolam S
Keyword(s):  
Density Functional ◽  
Basis Set ◽  
Experimental Result ◽  
Frontier Molecular Orbital ◽  
Geometrical Parameters ◽  
Functional Theory ◽  
Hartree Fock ◽  
Antimicrobial Studies ◽  
Evaporation Technique ◽  
Homo Lumo

Abstract In this work, 3-nitroanilinium nitrate (3NAN) has been synthesized and crystallized successfully by solution growth combined with solvent evaporation technique. 3NAN molecular structure has been optimized with Density Functional Theory (DFT) using B3LYP function and Hartree-Fock method with a 6-311 + + G(d,p) basis set. The geometrical parameters of the title molecules have been analyzed. The computed vibrational spectra were compared with experimental result which show appreciable agreement. Thermal stability of the crystal was analyzed with TGA/DTA and the melting points of the salt identified at 209 ºC. HOMO-LUMO energy calculations have shown the charge transfer within the molecu le. The possible pharmaceutical/biological activity of the salts confirmed by the Frontier Molecular Orbital (FMO) analysis have lower band gap value. The antimicrobial activity of grown crystals were tested against certain potentially threatening microbes.

COMPARATIVE INVESTIGATION OF THE EFFECT OF TYPE OF DENSITY FUNCTIONAL IN THE DETERMINATION OF GEOMETRICAL PARAMETERS IN A Cu COMPLEX

2013 ◽  
Vol 12 (07) ◽  
pp. 1350066 ◽  
Author(s):  
JABER JAHANBIN SARDROODI ◽  
ALIREZA RASTKAR ◽  
NEGAR RAD YOUSEFNIA ◽  
JAFAR AZAMAT
Keyword(s):  
Density Functional ◽  
Comparative Investigation ◽  
Basis Set ◽  
Basis Sets ◽  
Geometrical Parameters ◽  
Teller Distortion ◽  
Hartree Fock ◽  
Jahn Teller ◽  
Jahn Teller Distortion

The effects of short-range electron correlation, long-range electron exchange, local and nonlocal parts of density, higher order gradients of density, and adding some percentage of Hartree–Fock exchange to the functional on the prediction of geometrical parameters were investigated. A copper complex namely 1,2-bis(1,4,7-triaza-1-cyclononyl) ethane copper (II) with Jahn–Teller distortion in octahedral geometry was used to evaluate the performance of 50 commonly available density functionals. The standard 3-21G basis set was used for all light elements, while pseudo potential LANL2DZ was used for the copper atom. The best bond lengths and bond angles were obtained using M05-2x and OP functionals respectively. Also in order to more accurate survey the performance of B3LYP, we used this functional with two all-electron basis sets (6-31G and 3-21G) and three basis sets involving effective core potentials (LANL2DZ/3-21G, LANL2DZ, and LACVP).

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