scholarly journals DFT Study of the Coordination of N-monochlorosubstituted Derivatives of the N-deprotonated Tautomer of the Biguanide

2020 ◽  
pp. 10-25
Author(s):  
Aïdote François ◽  
Kuevi Urbain Amah ◽  
Kpotin Assongba Gaston ◽  
Atohoun G. Sylvain
Keyword(s):  
Chlorine Atom ◽  
Theoretical Study ◽  
Basis Set ◽  
Imine Nitrogen ◽  
Coordination Sites ◽  
B3lyp Method ◽  
Treatment Of Diabetes ◽  
Experimental Works ◽  
Therapeutic Properties ◽  
Derivatives Of

Biguanides [HN=C(NR1R2)-NH-C(NR3R4)=NH] constitute an important family of molecules used as drugs in the treatment of diabetes. When R1=R2=R3=R4=H the molecule is named simply “biguanide”. The five nitrogen atoms are potential coordination sites. Several experimental works published in literature show that in complex state, therapeutic properties of the active molecules increase considerably. In fact, the chlorine atom, a preferred substitute in pharmacy, improves the effectiveness of these drugs by increasing their activities and also by reducing their side effects. Recent experiments with Zinc complexes on diabetic animals have been very successful. In the present work a theoretical study of the coordination of N-chlorine derivatives of N-deprotonated tautomer of biguanide has been carried out. The aim is to determine, among the five nitrogen and chlorine atoms, the site most favorable to the coordination of these ligands. This determination is based on some coordination indicators. The calculations were performed by the DFT / B3LYP method in the 6-31G (d, p) orbital basis set with the Gaussian 09 and Gaussian 03 software. The DCENT-QSAR program was also used. The results of the various calculations revealed the imine nitrogen atoms as the most favorable coordination sites in the studied N-chlorosubstituted derivatives of N-deprotonated tautomeric biguanide. Complexes of these ligands with Zn (II) were modelled. The chlorine atom proved unfavorable to coordination.

scholarly journals Theoretical Study of Reaction Between Nitrilimine and 1,4 Oxazine 2 Carboxylate by MP2 and DFT Methods

2018 ◽  
Vol 34 (6) ◽  
pp. 2992-2997
Author(s):  
H. El-Hadki ◽  
F. Hlimi ◽  
M. Salah ◽  
K. Marakchi ◽  
N. Komiha ◽  
...  
Keyword(s):  
Energy Surface ◽  
Theoretical Study ◽  
Basis Set ◽  
Dft Methods ◽  
Reactivity Indices ◽  
B3lyp Method ◽  
Transition Structures ◽  
Potential Energy Surface Calculation ◽  
Good Agreement ◽  
Surface Calculation

The regioselectivity of the reaction between phenyldiazen-1-ium-1-ylidene p-tolyl methanide and ethyl 4-benzoyl-4H-benzo [1,4]oxazine-2-carboxylate were studied by means of the DFT/B3LYP method coupled by the 6-31g(d) basis and MP2 in connection with 6-31G(d) and 6-31G+(d,p) basis set. The mechanism of this regioselectif reaction has performed by transition state optimization, evaluation of the potential energy surface, calculation of IRC and reactivity indices. Location and verification of minima and transition structures have been realized by using the Berny's algorithm. The process of formation of the two regioisomers is achieved through concerted and asynchronous mechanism. The results are in good agreement with the experimental data.

Theoretical Study of 4,10-Dinitro-2,6,8,12-tetraoxa-4,10-diaza-tetracyclododecane (TEX)

2012 ◽  
Vol 554-556 ◽  
pp. 1618-1623 ◽  
Author(s):  
Xiu Lin Zeng ◽  
Xue Hai Ju ◽  
Hong Xu Gao
Keyword(s):  
Strain Energy ◽  
Density Functional ◽  
Theoretical Study ◽  
Large Strain ◽  
Heat Of Formation ◽  
Basis Set ◽  
Isodesmic Reaction ◽  
Detonation Pressure ◽  
Functional Theory ◽  
B3lyp Method

The heat of formation (HOF) for a caged owurtzitane analogue compound of 4,10-dinitro-2,6,8,12-tetraoxa-4,10-diaza-tetracyclododecane (TEX) was obtained by density functional theory B3LYP method with 6-31+G** basis set. The isodesmic reaction, instead of atomization reaction, makes good use of the available experimental data of HOFs and thus ensures the credibility of the result. The value of HOF of TEX is –448.37 kJ/mol. The predicted detonation velocity is about 8.2 km/s and detonation pressure is 31.44 GPa. The dissociation energy for the N-NO2 bond of TEX is 165.43 kJ/mol. There is large strain in TEX with strain energy of 62.47 kJ/mol. The nitro group interaction in TEX is small.

Theoretical Study on the Isomerization Reaction Mechanism of the Chain-Isomers of N9H9

2014 ◽  
Vol 887-888 ◽  
pp. 677-683
Author(s):  
Shu Zhang ◽  
Xiao Lan Wang ◽  
Wan Fei Cai ◽  
Lai Cai Li ◽  
An Min Tian
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Theoretical Study ◽  
Basis Set ◽  
Isomerization Reaction ◽  
Thermochemical Properties ◽  
Reaction Energy ◽  
Functional Theory ◽  
B3lyp Method ◽  
Isomerization Processes

Density functional theory B3LYP method with 6-311++G** basis set has been used to optimize Chain-isomers of N9H9. Sixteen species are found, the structures, stabilities, thermochemical properties, and their tautomerism are studied and discussed. The ten corresponding transition states have been found. The experimental results indicated that the reaction energy barriers of isomerization of these isomers were between 139.56 kJ/mol and 236.67kJ/mol. The activation energies is higher, the isomerization of these isomers is relatively difficult. The isomerization processes of these chain-isomers of N9H9 are all completed by the H transfer.

Quantum Mechanical Investigation of Geometrical Structure and Dynamic Behavior of h-BNNT (9,9-5) and h-AlNNT (9,9-5)Single-Walled Nanotubes: NBO Analysis

2019 ◽  
Vol 16 (9) ◽  
pp. 705-717
Author(s):  
Mehrnoosh Khaleghian ◽  
Fatemeh Azarakhshi
Keyword(s):  
Carbon Nanotubes ◽  
Density Functional ◽  
Structural Parameters ◽  
Energy Levels ◽  
Nbo Analysis ◽  
Electronic Energy ◽  
Boron Nitride Nanotubes ◽  
Basis Set ◽  
B3lyp Method ◽  
Mechanical Investigation

In the present research, B45H36N45 Born Nitride (9,9) nanotube (BNNT) and Al45H36N45 Aluminum nitride (9,9) nanotube (AlNNT) have been studied, both having the same length of 5 angstroms. The main reason for choosing boron nitride nanotubes is their interesting properties compared with carbon nanotubes. For example, resistance to oxidation at high temperatures, chemical and thermal stability higher rather than carbon nanotubes and conductivity in these nanotubes, unlike carbon nanotubes, does not depend on the type of nanotube chirality. The method used in this study is the density functional theory (DFT) at Becke3, Lee-Yang-Parr (B3LYP) method and 6-31G* basis set for all the calculations. At first, the samples were simulated and then the optimized structure was obtained using Gaussian 09 software. The structural parameters of each nanotube were determined in 5 layers. Frequency calculations in order to extract the thermodynamic parameters and natural bond orbital (NBO) calculations have been performed to evaluate the electron density and electrostatic environment of different layers, energy levels and related parameters, such as ionization energy and electronic energy, bond gap energy and the share of hybrid orbitals of different layers.

AlN Nanotubes: A DFT Study of Al-27 and N-14 Electric Field Gradient Tensors

2007 ◽  
Vol 62 (12) ◽  
pp. 711-715 ◽  
Author(s):  
Ahmad Seif ◽  
Mahmoud Mirzaei ◽  
Mehran Aghaie ◽  
Asadollah Boshra
Keyword(s):  
Electric Field ◽  
Electric Field Gradient ◽  
Field Gradient ◽  
Density Functional ◽  
Quadrupole Coupling Constant ◽  
Basis Set ◽  
Basis Sets ◽  
B3lyp Method ◽  
Package Program ◽  
Nqr Parameters

Density functional theory (DFT) calculations were performed to calculate the electric field gradient (EFG) tensors at the sites of aliminium (27Al) and nitrogen (14N) nuclei in an 1 nm of length (6,0) single-walled aliminium nitride nanotube (AlNNT) in three forms of the tubes, i. e. hydrogencapped, aliminium-terminated and nitrogen-terminated as representatives of zigzag AlNNTs. At first, each form was optimized at the level of the Becke3,Lee-Yang-Parr (B3LYP) method, 6-311G∗∗ basis set. After, the EFG tensors were calculated at the level of the B3LYP method, 6-311++G∗∗ and individual gauge for localized orbitals (IGLO-II and IGLO-III) types of basis sets in each of the three optimized forms and were converted to experimentally measurable nuclear quadrupole resonance (NQR) parameters, i. e. quadrupole coupling constant (qcc) and asymmetry parameter (ηQ). The evaluated NQR parameters revealed that the considered model of AlNNT can be divided into four equivalent layers with similar electrostatic properties.With the exception of Al-1, all of the three other Al layers have almost the same properties, however, N layers show significant differences in the magnitudes of the NQR parameters in the length of the nanotube. Furthermore, the evaluated NQR parameters of Al-1 in the Al-terminated form and N-1 in the N-terminated form revealed the different roles of Al (base agent) and of N (acid agent) in AlNNT. All the calculations were carried out using the GAUSSIAN 98 package program.

Synthesis, Characterization and Biological Activity Evaluation of Novel Pd(II) and Pt(II) Complexes with Heterocyclic Hydrazone Ligands

2007 ◽  
Vol 555 ◽  
pp. 423-427 ◽  
Author(s):  
Nenad R. Filipović ◽  
Tamara R. Todorović ◽  
D.M. Sladić ◽  
Irena T. Novaković ◽  
D.A. Jeremić ◽  
...  
Keyword(s):  
Biological Activity ◽  
13C Nmr Spectroscopy ◽  
Chloride Ions ◽  
Planar Geometry ◽  
Moderate Activity ◽  
Coordination Sites ◽  
Ligand Type ◽  
Square Planar ◽  
Derivatives Of ◽  
Hydrazone Ligands

New complexes of Pt(II) with condensation derivatives of ethyl hydrazinoacetate and either 2-acetylpyridine or 2-quinolinecarboxaldehyde, and of Pd(II) with the condensation derivative of ethyl hydrazinoacetate and 2-quinolinecarboxaldehyde were synthesized and characterized by elemental analysis, IR, 1H- and 13C-NMR spectroscopy, and molar conductivity measurements. The complexes have a square planar geometry, ligands binding as bidentates in the neutral form, and the remaining two coordination sites being occupied by chloride ions. Biological activity of new complexes, and of previously synthesized Pd(II), Cd(II), Co(III) and Zn(II) complexes with this ligand type was evaluated by the brine shrimp test. All the complexes showed a moderate activity.

Liquid Crystalline Properties of 4,4and#39;-methylenebis(N-(4-Alkanoxybenzylidene)aniline): Synthesis, Characterization, and Theoretical study

2019 ◽  
Vol 41 (6) ◽  
pp. 1107-1107
Author(s):  
Mohammed Taha Yaseen and Abdullah Hussein Kshash Mohammed Taha Yaseen and Abdullah Hussein Kshash
Keyword(s):  
Liquid Crystalline ◽  
Theoretical Study ◽  
Basis Set ◽  
Spectroscopic Techniques ◽  
Benzene Nucleus ◽  
Crystal Properties ◽  
Ft Ir ◽  
Alkoxy Groups ◽  
Gaussian Program ◽  
Mesomorphic Properties

The paper presents six homologues series of Schiff bases ether compounds distinguished by the length of terminal alkoxy groups which substituted on a side benzene nucleus. The above structures were demonstrated through the use of spectroscopic techniques, like FT- IR and 1H-NMR. Polarized hot stage optical microscopy was used to study both mesomorphic properties and phase transitions. The results showed that out of the six compounds only three (B2, B3 and B4) were pure (marble) nematic mesophase, while no liquid crystal properties for (B5, B6 and B7) compounds. The theoretical study for the electronic structures was intended to study the effects of alkyl chain length on the electronic structure by using Gaussian program, DFT and 6-31G as basis set. The theoretical results indicate that there is no effect to the terminal substituted alkoxy groups on the HOMO energies but there is an effect on LUMO energies through decreasing energy for the prepared compounds.

scholarly journals Experimental and Theoretical Study of the Enthalpy of Formation of 3,6-Diphenyl-1,2,4,5-Tetroxane Molecule

2002 ◽  
Vol 2 ◽  
pp. 455-460 ◽  
Author(s):  
N.L. Jorge ◽  
L.C.A. Leiva ◽  
M.G. Castellanos ◽  
M.E. Gomez Vara ◽  
L.F.R. Cafferata ◽  
...  
Keyword(s):  
Vapor Pressure ◽  
Enthalpy Of Formation ◽  
Vapor Phase ◽  
Theoretical Study ◽  
Theoretical Calculations ◽  
Basis Set ◽  
Sublimation Enthalpy ◽  
Combustion Heat ◽  
Different Temperatures ◽  
The Enthalpy Of Formation

We report the results obtained for the experimental determination and the theoretical calculation of the enthalpy of formation of 3,6-diphenyl-1,2,4,5-tetroxane molecule. The experimental work was performed using a macrocalorimeter to measure the combustion heat, and the sublimation enthalpy was determined via the measurement of the vapor pressure at equilibrium with the vapor phase at different temperatures resorting to the Clapeyron-Claussius equation. Theoretical calculations were performed using semiempirical AM1 and PM3 methods as well asab initiotechniques at the 3-21, 6-31G(d,p), and 6-311G(d,p) basis set levels.

scholarly journals Theoretical Study of Solvent Effects on the Electronic and Thermodynamic Properties of Tetrathiafulvalene (TTF) Molecule Based on DFT

2021 ◽  
pp. 42-54
Author(s):  
Rabiu Nuhu Muhammad ◽  
N. M. Mahraz ◽  
A. S Gidado ◽  
A. Musa
Keyword(s):  
Thermodynamic Properties ◽  
Bond Length ◽  
Density Functional ◽  
Theoretical Study ◽  
Energy Gap ◽  
Basis Set ◽  
Basis Sets ◽  
Frontier Molecular Orbital ◽  
Orbital Energy ◽  
Chemical Hardness

Tetrathiafulvalene () is an organosulfur compound used in the production of molecular devices such as switches, sensors, nonlinear optical devices and rectifiers. In this work, a theoretical study on the effects of solvent on TTF molecule was investigated and reported based on Density Functional Theory (DFT) as implemented in Gaussian 03 package using B3LYP/6-31++G(d,p) basis set. Different solvents were introduced as a bridge to investigate their effects on the electronic structure. The HUMO, LUMO, energy gap, global chemical index, thermodynamic properties, NLO and DOS analysis of the TTF molecule in order to determine the reactivity and stability of the molecule were obtained. The results obtained showed that the solvents have effects on the electronic and non-linear-optical properties of the molecule. The optimized bond length revealed that the molecule has strong bond in gas phase with smallest bond length of about 1.0834Å than in the rest of the solvents. It was observed that the molecule is more stable in acetonitrile with HOMO-LUMO gap and chemical hardness of 3.6373eV and 1.8187eV respectively. This indicates that the energy gap and chemical hardness of TTF molecule increases with the increase in polarity and dielectric constant of the solvents. The computed results agreed with the results in the literature. The thermodynamics and NLO properties calculation also indicated that TTF molecule has highest value of specific heat capacity (Cv), total dipole moment () and first order hyperpolarizability () in acetonitrile, while acetone has the highest value of entropy and toluene has a slightly higher value of zero point vibrational energy (ZPVE) than the rest of the solvents. The results show that careful selection of the solvents and basis sets can tune the frontier molecular orbital energy gap of the molecule and can be used for molecular device applications.

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