Theoretical investigation of the stability, reactivity, and the interaction of methyl-substituted peridinium-based ionic liquids

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Emmanuel A. Bisong ◽  
Hitler Louis ◽  
Tomsmith O. Unimuke ◽  
Victoria M. Bassey ◽  
John A. Agwupuye ◽  
...  
Keyword(s):  
Ionic Liquids ◽  
Electron Density ◽  
Density Functional ◽  
Natural Bond Orbital ◽  
Stabilization Energy ◽  
Basis Set ◽  
Bond Critical Point ◽  
Electronic Interaction ◽  
Donor And Acceptor ◽  
The Stability

Abstract This research work focuses on the reactivity, stability, and electronic interaction of pyridinium hydrogen nitrate (PHN)-based ionic liquids and the influence of methyl substituent on this class of ionic liquids: Ortho- (O-MPHN), meta- (M-MPHN), and para- (P-MPHN) substitution. Natural bond orbital (NBO) calculations were performed at the density functional theory (DFT) with Becke’s Lee Yang and Parr functional (B3LYP) methods and DFT/B3LYP/6-311++G(d,p) as basis set using GAUSSIAN 09W and GAUSSVIEW 6.0 software and the most important interaction between donor (Filled Lewis-type NBO’s) and the acceptor (vacant non-Lewis NBOs) were observed. From our natural bond orbital (NBO) result, it could be deduced that the higher the stabilization energy value, the greater the interaction between the donor and acceptor NBOs. The stability of the studied compounds is said to follow the order from O-MPHN > PHN > P-MPHN > M-MPHN based on the hyperconjugative interaction (stabilization energy) of the most significant interaction. The result of the highest occupied molecular orbital (HOMO), shows that PHN has the highest HOMO while the substituted derivatives have similar HOMO values between −7.70 and −7.98 eV thus PHN complex is the best electron donor while the substituted derivatives act as electron acceptors due to the presence of methyl group substituent which is observed to be electron deficient as a result of its withdrawal effect from the aromatic ring. Furthermore, the electron density, real space functions such as energy density and Laplacian of electron density at bond critical point (BCP) of the hydrogen bond interaction of the studied compounds were analyzed using Multifunctional Wavefunction analyzer software version 3.7 and it was observed that the hydrogen at position 6 and oxygen at position 11 (H6–O11) of M-methyl pyridinium nitrate with bond distance of 4.59 (Å) gave binding energy with the strongest electrostatic interaction between the cation and anion of the compounds under investigation. We also observed from our results that, substitution at the ortho position enhances the stability and strengthen the extent of charge transfer. This therefore implies that substitution at ortho position is more favorable for inter- and intramolecular interactions resulting to stabilization of the studied molecules.

Substituent effect on N–H bond dissociation enthalpies of carbamates: a theoretical study

2015 ◽  
Vol 93 (3) ◽  
pp. 279-288 ◽  
Author(s):  
Rupinder preet Kaur ◽  
Damanjit Kaur ◽  
Ritika Sharma
Keyword(s):  
Substituent Effect ◽  
Density Functional ◽  
Theoretical Study ◽  
Natural Bond Orbital ◽  
Stabilization Energy ◽  
Isodesmic Reactions ◽  
Bond Dissociation ◽  
Density Functional Methods ◽  
Functional Methods ◽  
Orbital Analysis

The present investigation deals with the study of the N–H bond dissociation enthalpies (BDEs) of the Y-substituted (NH2-C(=X)Y-R) and N-substituted ((R)(H)NC(=X)YH) carbamates (X, Y = O, S, Se; R = H, CH3, F, Cl, NH2), which have been evaluated using ab initio and density functional methods. The variations in N−H BDEs of these Y-substituted and N-substituted carbamates as the effect of substituent have been understood in terms of molecule stabilization energy (ME) and radical stabilization energy (RE), which have been calculated using the isodesmic reactions. The natural bond orbital analysis indicated that the electrodelocalization of the lone pairs of heteroatoms in the molecules and radicals affect the ME and RE values depending upon the type and site of substitution (whether N- or Y-). The variations in N−H BDEs depend upon the combined effect of molecule stabilization and radical stabilization by the various substituents.

Adsorption of 1-chloro-1,2,2,2-tetrafluoroethane on pristine, Al, Ga-doped boron nitride nanotubes: a study involving PBC-DFT, NBO analysis, and QTAIM

2021 ◽  
Vol 99 (1) ◽  
pp. 51-62
Author(s):  
Mohsen Doust Mohammadi ◽  
Hewa Y. Abdullah
Keyword(s):  
Boron Nitride ◽  
Electronic Properties ◽  
Intermolecular Interactions ◽  
Density Functional ◽  
Natural Bond Orbital ◽  
Boron Nitride Nanotubes ◽  
Basis Set ◽  
Total Density ◽  
Electron Configuration ◽  
Gas Molecule

In the present investigation, the feasibility of detecting the 1-chloro-1,2,2,2-tetrafluoroethane gas molecule on the outer surface of pristine single-walled boron nitride nanotube, as well as its aluminium- and gallium-doped structures, was carefully evaluated. For achieving this goal, a periodic boundary condition density functional theory level of study using both HSE06 and B3LYP-D3 functionals together with a 6-311G(d) basis set has been used. Subsequently, the CAM-B3LYP, ωB97XD, and M06-2X functionals with a 6-311G(d) basis set were also employed to consider the single point energies. Natural bond orbital and quantum theory of atoms in molecules were implemented by using the HSE06/6-311G(d) method and the results were compatible with the electronic properties. In this regard, the total density of state, the Wiberg bond index, natural charge, natural electron configuration, donor–acceptor natural bond orbital interactions, and the second-order perturbation energies are performed to explore the nature of the intermolecular interactions. All of the energy calculations and population analyses show that by adsorbing of the gas molecule onto the surface of the considered nanostructures, the intermolecular interactions are of the type of strong chemical adsorption. Between the doped nanotubes, aluminium-doped nanotube has very high adsorption energy compared with gallium. Generally, it was revealed that the sensitivity of the adsorption will be increased when the gas molecule interacts with decorated nanotubes and decrease the HOMO–LUMO band gap; therefore, the change of electronic properties can be used to design suitable nanosensors.

Binding Energies of Organic Charge-Transfer Complexes Calculated by First-Principles Methods

1998 ◽  
Vol 63 (8) ◽  
pp. 1223-1244 ◽  
Author(s):  
Cordula Rauwolf ◽  
Achim Mehlhorn ◽  
Jürgen Fabian
Keyword(s):  
Density Functional Theory ◽  
Charge Transfer ◽  
Ground State ◽  
Density Functional ◽  
Binding Energies ◽  
Basis Set ◽  
Dispersion Energy ◽  
Functional Theory ◽  
Basis Set Superposition Error ◽  
Donor And Acceptor

Weak interactions between organic donor and acceptor molecules resulting in cofacially-stacked aggregates ("CT complexes") were studied by second-order many-body perturbation theory (MP2) and by gradient-corrected hybrid Hartree-Fock/density functional theory (B3LYP exchange-correlation functional). The complexes consist of tetrathiafulvalene (TTF) and related compounds and tetracyanoethylene (TCNE). Density functional theory (DFT) and MP2 molecular equilibrium geometries of the component structures are calculated by means of 6-31G*, 6-31G*(0.25), 6-31++G**, 6-31++G(3df,2p) and 6-311G** basis sets. Reliable molecular geometries are obtained for the donor and acceptor compounds considered. The geometries of the compounds were kept frozen in optimizing aggregate structures with respect to the intermolecular distance. The basis set superposition error (BSSE) was considered (counterpoise correction). According to the DFT and MP2 calculations laterally-displaced stacks are more stable than vertical stacks. The charge transfer from the donor to the acceptor is small in the ground state of the isolated complexes. The cp-corrected binding energies of TTF/TCNE amount to -1.7 and -6.3 kcal/mol at the DFT(B3LYP) and MP2(frozen) level of theory, respectively (6-31G* basis set). Larger binding energies were obtained by Hobza's 6-31G*(0.25) basis set. The larger MP2 binding energies suggest that the dispersion energy is underestimated or not considered by the B3LYP functional. The energy increases when S in TTF/TCNE is replaced by O or NH but decreases with substitution by Se. The charge-transferred complexes in the triplet state are favored in the vertical arrangement. Self-consistent-reaction-field (SCRF) calculations predicted a gain in binding energy with solvation for the ground-state complex. The ground-state charge transfer between the components is increased up to 0.8 e in polar solvents.

scholarly journals Charge Density Analysis and Transport Properties of TTF Based Molecular Nanowires: A DFT Approach

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Karuppannan Selvaraju ◽  
Poomani Kumaradhas
Keyword(s):  
Density Distribution ◽  
Charge Density ◽  
Electron Density ◽  
Quantum Chemical ◽  
Molecular Conformation ◽  
Topological Analysis ◽  
Basis Set ◽  
Bond Critical Point ◽  
Chemical Calculation ◽  
Energy Density Distribution

The present study has been performed to understand the charge density distribution and the electrical characteristics of Au and thiol substituted tetrathiafulvalene (TTF) based molecular nanowire. A quantum chemical calculation has been carried out using DFT method (B3LYP) with the LANL2DZ basis set under various applied electric fields (EFs). The bond topological analysis characterizes the terminal Au–S and S–C bonds as well as all the bonds of central TTF unit of the molecule. The variation of electron density and Laplacian of electron density at the bond critical point of bonds for zero and different applied fields reveal the electron density distribution of the molecule. The molecular conformation, the variation of atomic charges and energy density distribution of the molecule have been analyzed for the various levels of applied EFs. The HOMO-LUMO gap calculated from quantum chemical calculations has been compared with the value calculated from the density of states. The variation of dipole moment due to the polarization effect and the I-V characteristics of the molecule for the various applied EFs have been well discussed.

scholarly journals The difference in stability between 5′R and 5′S diastereomers of 5′,8-cyclopurine-2′-deoxynucleosides. DFT study in gaseous and aqueous phase

2010 ◽  
Vol 8 (1) ◽  
pp. 134-141 ◽  
Author(s):  
Boleslaw Karwowski
Keyword(s):  
Density Functional ◽  
Bond Cleavage ◽  
Basis Set ◽  
Small Range ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Formic Acid Hydrolysis ◽  
The Difference ◽  
The Stability ◽  
First Time

AbstractOxidatively generated damage to DNA frequently appears in the human genome as an effect of aerobic metabolism or as the result of exposure to exogenous oxidizing agents. Due to these facts it has been decided to calculate the stability of 5′,8-cyclo-2′-deoxyadenosine/guanosine (cdA, cdG) in their 5′R and 5′S diastereomeric forms. For all points of quantum mechanics studies presented, the density functional theory (DFT) with B3LYP parameters on 6-311++G** basis set level was used. The calculations showed a significant negative enthalpy for glycosidic bond cleavage reaction for cationic forms and slightly negative for neutral ones. The preliminary study of the discussed process has shown the nature of stepwise nucleophilic substitution DN*AD type mechanism. Surprisingly, the different values in free energy, between short-lived oxacarbenium ion intermediates, have been found to lie over a relatively small range, around 1 and 2.8 kcal mol−1. For anions, the decomposition enthalpies were found as positive in aqueous phases. These theoretical results are supported by the formic acid hydrolysis experiments of both diastereomers of cdA, for the first time. (5′S)cdA exhibited higher stability than (5′R)cdA.

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.

Evaluation of N—H...S and N—H...π interactions inO,O′-diethylN-(2,4,6-trimethylphenyl)thiophosphate: a combination of X-ray crystallographic and theoretical studies

2018 ◽  
Vol 74 (7) ◽  
pp. 847-855 ◽  
Author(s):  
Elham Torabi Farkhani ◽  
Mehrdad Pourayoubi ◽  
Mohammad Izadyar ◽  
Pavel V. Andreev ◽  
Ekaterina S. Shchegravina
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Density Functional ◽  
Natural Bond Orbital ◽  
Crystal Packing ◽  
Hirshfeld Surface ◽  
Basis Set ◽  
Theoretical Studies ◽  
Functional Theory ◽  
X Ray

In the crystal structure ofO,O′-diethylN-(2,4,6-trimethylphenyl)thiophosphate, C13H22NO2PS, two symmetrically independent thiophosphoramide molecules are linked through N—H...S and N—H...π hydrogen bonds to form a noncentrosymmetric dimer, withZ′ = 2. The strengths of the hydrogen bonds were evaluated using density functional theory (DFT) at the M06-2X level within the 6-311++G(d,p) basis set, and by considering the quantum theory of atoms in molecules (QTAIM). It was found that the N—H...S hydrogen bond is slightly stronger than the N—H...π hydrogen bond. This is reflected in differences between the calculated N—H stretching frequencies of the isolated molecules and the frequencies of the same N—H units involved in the different hydrogen bonds of the hydrogen-bonded dimer. For these hydrogen bonds, the corresponding charge transfers,i.e.lp (or π)→σ*, were studied, according to the second-order perturbation theory in natural bond orbital (NBO) methodology. Hirshfeld surface analysis was applied for a detailed investigation of all the contacts participating in the crystal packing.

scholarly journals Free Radical Scavenging Activity of Dihydrocaffeic Acid: A Quantum Chemical Approach

2021 ◽  
Vol 33 (4) ◽  
pp. 937-944
Author(s):  
K. Senthilkumar ◽  
S.S. Naina Mohammed ◽  
S. Kalaiselvan
Keyword(s):  
Electron Transfer ◽  
Quantum Chemical ◽  
Density Functional ◽  
Radical Scavenging ◽  
Hydrogen Atom Transfer ◽  
Basis Set ◽  
Published Data ◽  
Chemical Calculation ◽  
Neutral Radical ◽  
Donor And Acceptor

Based on density functional theory (DFT), to investigate relationships between the antioxidant activity and structure of dihydrocaffeic acid, quantum chemical calculation is used. The optimized structures of the neutral, radical and ionic forms have been carried out by DFT-B3LYP method with the 6-311G(d,p) basis set. Reaction enthalpies related with the hydrogen atom transfer (HAT), single electron transfer proton transfer (SET-PT) and sequential proton loss and electron transfer (SPLET) were calculated in gas and water phase. The HOMO-LUMO energy gap, electron affinity, electronegativity, ionization energy, hardness, chemical potential, global softness and global electrophilicity were calculated by using the same level of theory. Surfaces with a molecular electrostatic potential (MEP) were studied to determine the reactive sites of dihydrocaffeic acid. The difference in energy between the donor and acceptor as well as the stabilization energy was determined through the natural bond orbital (NBO) analysis. The Fukui index (FI) based on electron density was employed to predict reaction sites. Reaction enthalpies are compared with previously published data for phenol and 3,4-dihydroxycinnamic acid.

scholarly journals Comparing Study of The Stability and spectral properties vibrations for some Tellurium (IV) compounds containing cycloctadienyl group by Quantum Mechanical Calculations

2013 ◽  
Vol 10 (3) ◽  
pp. 1041-1049
Author(s):  
Baghdad Science Journal
Keyword(s):  
Density Functional ◽  
Heat Of Formation ◽  
Basis Set ◽  
Orbital Energy ◽  
Empirical Methods ◽  
Geometrical Structures ◽  
Functional Theory ◽  
Exchange Correlation ◽  
The Stability ◽  
Semi Empirical

Density Functional Theory (DFT) with B3LYP hybrid exchange-correlation functional and 3-21G basis set and semi-empirical methods (PM3) were used to calculate the energies (total energy, binding energy (Eb), molecular orbital energy (EHOMO-ELUMO), heat of formation (?Hf)) and vibrational spectra for some Tellurium (IV) compounds containing cycloctadienyl group which can use as ligands with some transition metals or essential metals of periodic table at optimized geometrical structures.

scholarly journals Synthesis and Structure Insights of Two Novel Broad-Spectrum Antibacterial Candidates Based on (E)-N′-[(Heteroaryl)methylene]adamantane-1-carbohydrazides

Molecules ◽  
2020 ◽  
Vol 25 (8) ◽  
pp. 1934
Author(s):  
Lamya H. Al-Wahaibi ◽  
Natalia Alvarez ◽  
Olivier Blacque ◽  
Nicolás Veiga ◽  
Aamal A. Al-Mutairi ◽  
...  
Keyword(s):  
Electron Density ◽  
Broad Spectrum ◽  
Light Absorption ◽  
Density Functional ◽  
Pathogenic Fungus ◽  
Thiophene Ring ◽  
Density Functional Theory Calculations ◽  
X Ray Diffraction ◽  
Functional Theory ◽  
The Stability

Two new N′-heteroarylidene-1-carbohydrazide derivatives, namely; E-N′-[(pyridine-3-yl)methylidene]adamantane-1-carbohydrazide (1) and E-N′-[(5-nitrothiophen-2-yl)methylidene]adamantane-1-carbohydrazide (2), were produced via condensation of adamantane-1-carbohydrazide with the appropriate heterocyclic aldehyde. Both compounds were chemically and structurally characterized by 1H-NMR, 13C-NMR, infrared and UV-vis spectroscopies, and single crystal X-ray diffraction. The study was complemented with density functional theory calculations (DFT). The results show an asymmetrical charge distribution in both compounds, with the electron density accumulated around the nitrogen and oxygen atoms, leaving the positive charge surrounding the N-H and C-H bonds in the hydrazine group. Consequently, the molecules stack in an antiparallel fashion in the crystalline state, although the contribution of the polar contacts to the stability of the lattice is different for 1 (18%) and 2 (42%). This difference affects the density and symmetry of their crystal structures. Both molecules show intense UV-Vis light absorption in the range 200–350 nm (1) and 200–500 nm (2), brought about by π → π* electronic transitions. The electron density difference maps (EDDM) revealed that during light absorption, the electron density flows within the π-delocalized system, among the pyridyl/thiophene ring, the nitro group, and the N′-methyleneacetohydrazide moiety. Interestingly, compounds 1 and 2 constitute broad-spectrum antibacterial candidates, displaying potent antibacterial activity with minimal inhibitory concentration (MIC) values around 0.5–2.0 μg/mL. They also show weak or moderate antifungal activity against the yeast-like pathogenic fungus Candida albicans.

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