AB INITIO STUDY OF THE MOLECULAR STRUCTURE AND THERMAL CIS–TRANS ISOMERIZATION OF 3,3′-DIAMINO-4,4′-AZOFURAZAN AND 3,3′-DIAMINO-4,4′-AZOXYFURAZAN

2009 ◽  
Vol 08 (03) ◽  
pp. 507-517 ◽  
Author(s):  
LUOXIN WANG ◽  
XINLIN TUO ◽  
HANTAO ZOU ◽  
CHANGHAI YI ◽  
XIAOGONG WANG
Keyword(s):  
Density Functional ◽  
Energy Difference ◽  
Molecular Structures ◽  
Ab Initio Study ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Azo Group ◽  
Low Sensitivity ◽  
Inversion Mechanism ◽  
Cis Isomer

In this work, we carried out the density functional theory (DFT) calculations in order to understand the molecular structures and thermal trans–cis isomerization of 3,3′-diamino-4,4′-azofurazan (DAAzF) and 3,3′-diamino-4,4′-azoxyfurazan (DAAF). We found that the azo group oxidation of DAAzF leading to the formation of DAAF induced evidently the twist of azofurazan molecule and weakened one of CN bonds connecting the furazan rings and azo group. This means that DAAzF is more stable than DAAF. In addition, the oxidation of azo group has a significant influence on the energy difference between trans- and cis-isomer of azofurazan. The energy difference between the isomers of DAAF is only about half of that of DAAzF. Furthermore, the thermal trans–cis isomerization of DAAzF and DAAF was found to follow a different mechanism: an inversion mechanism for DAAzF and a rotation mechanism for DAAF. By analyzing the reversible trans–cis isomerization process, we firstly proposed that a self-desensitization effect could be responsible for the low sensitivity of azofurazan. This new desensitization mechanism may be useful in the design of novel high energetic density material.

scholarly journals Spectroscopic Insight into Tetrahedrally Distorted Square Planar Copper(II) Complex: XRD/HSA, Physicochemical, DFT, and Thermal Investigations

Crystals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1179
Author(s):  
Ahmed Boshaala ◽  
Abrahem F. Abrahem ◽  
Abdulla Ali Almughery ◽  
Nabil Al-Zaqri ◽  
Abdelkader Zarrouk ◽  
...  
Keyword(s):  
Density Functional ◽  
Gravimetric Analysis ◽  
Perfect Agreement ◽  
Functional Theory ◽  
Square Planar ◽  
The Density Functional Theory ◽  
Thermal Investigations ◽  
Ligand Coordination ◽  
Thermal Stability Of ◽  
Cis Isomer

The reaction of bidentate N-S-thione-Schiff base, (E)-benzyl 2-(1-(4-chlorophenyl)- ethylidene)hydrazinecarbodithioate, with Cu(NO3)2·3H2O produced a cis-Cu(II) complex. The molecular structure was confirmed and characterized by CHN-EA, FAB-MS, IR, and UV-Vis analyses. The XRD supported cis-isomer of the bis anionic bidentate N (azomethine) and S (thiol) ligand coordination mode in tetrahedrally distorted square planar, rarely reported in the literature. The results of the XRD-bond lengths were in perfect agreement with the density functional theory (DFT) calculation. DFT-calculated angles around the Cu(II) center displayed slightly less distortion around the metal center from those of XRD. Additionally, the thermal stability of the complex was evaluated via thermal gravimetric analysis (TGA). Two-dimensional fingerprint (2D-FP), Hirshfeld surface analysis (HSA), and molecular electrostatic potential (MEP) support the XRD-packing results with the existence of the H⸱⸱⸱Cl and CH⸱⸱⸱π bonds as the main interactions in the crystal lattice of the desired complex.

scholarly journals Copper (IV) Stabilization in Macrocyclic Complexes with 3,7,11,15-Tetraazaporphine, Its Di[benzo]- or Tetra[benzo] Derivatives and Oxide Anion: Quantum-Chemical Research

Materials ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3162 ◽  
Author(s):  
Oleg V. Mikhailov ◽  
Denis V. Chachkov
Keyword(s):  
Quantum Chemical ◽  
Density Functional ◽  
Nbo Analysis ◽  
Macrocyclic Complexes ◽  
Molecular Structures ◽  
Chemical Research ◽  
Functional Theory ◽  
Chemical Modeling ◽  
The Density Functional Theory ◽  
Oxidation State Of Copper

Using the data of a quantum chemical modeling of molecular structures obtained by the density functional theory (DFT), the possibility of the existence of a copper macrocyclic complexes with 3,7,11,15-tetraazaaporphine, trans-di[benzo] 3,7,11,15-tetraazaaporphine or tetra[benzo] 3,7,11,15-tetraazaaporphine and oxide anion where oxidation state of copper is IV, was shown. The values of the parameters of molecular structures and NBO analysis for such complexes were presented, too.

scholarly journals Магнитострикция в сплавах Fe-=SUB=-75-=/SUB=-Ga-=SUB=-25-x-=/SUB=-Z-=SUB=-x-=/SUB=- (Z=Al, Ge, Si): расчет методом магнитного вращающего момента

2021 ◽  
Vol 63 (11) ◽  
pp. 1745
Author(s):  
М.В. Матюнина ◽  
М.А. Загребин ◽  
В.В. Соколовский ◽  
В.Д. Бучельников
Keyword(s):  
Elastic Modulus ◽  
Density Functional ◽  
Ternary Alloys ◽  
Ab Initio Study ◽  
Magnetic Torque ◽  
Functional Theory ◽  
Cubic Crystal ◽  
Lattice Constants ◽  
Magnetoelastic Properties ◽  
The Density Functional Theory

This work presents an ab initio study of the effect of a small addition of the third element of III and IV groups on the elastic and magnetoelastic properties of Fe75Ga25 alloy. The dependencies of the tetragonal elastic modulus C', magnetoelastic constant –b1, and the tetragonal magnetostrictive constant λ001 on the concentration of the Z-element in the cubic crystal structures A2 and D03 were obtained with the help of the density functional theory and the magnetic torque method in Fe75Ga25-xZx (Z = Al, Ge, Si) alloys (0≤x≤6 at.%). It is shown that the addition of Al and Si atoms leads to an increase in the tetragonal elastic modulus compared to the Fe75Ga25 binary alloy. A correlation was established in the dependence equilibrium lattice constants a0(x) and λ001(x) in the studied ternary alloys for the A2 structure.

Ab Initio Study of Hydrogen Desorption from Hydrogenated Diamond (100) Surface

2007 ◽  
Vol 121-123 ◽  
pp. 1119-1124
Author(s):  
Feng Bin Liu ◽  
Jia Dao Wang ◽  
Da Rong Chen ◽  
Bing Liu
Keyword(s):  
Density Functional ◽  
Hydrogen Desorption ◽  
Stable Structure ◽  
Ab Initio Study ◽  
Generalized Gradient ◽  
Reaction Heat ◽  
Functional Theory ◽  
Desorption Process ◽  
Generalized Gradient Approximation ◽  
The Density Functional Theory

By means of the density functional theory on the basis of generalized gradient approximation, the reaction paths of the dehydrogenation from the diamond (100) surface was deduced due to the reaction heat. Moreover, the most stable structure of the hydride diamond (100) surface was obtained. The results indicate that the dehydrogenation is easier to take place at the same C-C dimer and forms the parallel geometries. The parallel 1×1:1.5H, 2×1:H and parallel 2×1:0.5H are the intermediate products during the hydrogen desorption process, while, 2×1:H is the most stable structure of the hydride diamond (100) surfaces. The calculated reaction heat is in accordance with the experimental results.

Rectification and negative differential effects of Si2C2 clusters: An ab initio study

2019 ◽  
Vol 33 (19) ◽  
pp. 1950205
Author(s):  
Qinghua Zhou ◽  
Ziqing Wei ◽  
Wei Hu ◽  
Yan Liang ◽  
Wenhua Liu ◽  
...  
Keyword(s):  
Linear Form ◽  
Negative Differential Resistance ◽  
Density Functional ◽  
Differential Resistance ◽  
Molecular Devices ◽  
Ab Initio Study ◽  
Transmission Characteristics ◽  
Functional Theory ◽  
Transmission Properties ◽  
The Density Functional Theory

By combining the density functional theory (DFT) with the nonequilibrium Green’s function, we studied the transmission properties of Si2C2 clusters (the linear form M1 and the rhombic form M2). The result shows that the I-V characteristics of the cluster are closely related to the structure of the cluster. The change in the structure of the cluster causes a change in the coupling process between the cluster and the electrode, resulting in a change in its transmission characteristics. Compared with the linear form M1 system, the rhombic form M2 system has obvious rectification and negative differential resistance (NDR) effects, which makes it more advantageous as a candidate for molecular devices.

Effect of pressure on the mechanical, electronic and optical characters of CsSnBr3 and CsSnI3: ab-initio study

2020 ◽  
pp. 2150056
Author(s):  
R. Y. Alyoubi ◽  
Bahaaudin M. Raffah ◽  
Farida Hamioud ◽  
A. A. Mubarak
Keyword(s):  
Ab Initio ◽  
Density Functional ◽  
Applied Pressure ◽  
Interatomic Bond ◽  
Semiconductor Materials ◽  
Optical Parameters ◽  
Ab Initio Study ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Electronic Parameters

A theoretical comprehensive implementing of the structural, elastic, electronic and optical properties of CsSnX3 (X = Br and I) perovskite compounds under pressures 0 and 20 GPa is performed by ab-initio calculations included within the density functional theory (DFT). The structure of crystal perovskite compounds is found to be stable under induced pressure. The compounds have shown a decrease in the structural properties such as lattice constant and interatomic bond length when the pressure was induced. Whereas, there was an increase in the thermodynamic properties such as Debye temperature and average velocities of sound when pressure was induced. Moreover, the values of mechanical parameters, such as the elastic constant, increased under applied pressure. The electronic parameters indicate that the compounds can be classified as semiconductor materials with a direct (M-M) gap. The induced pressure is found to enhance the optical parameters in the different energy regions. Our calculation predicts that the studied compounds can be the relevant candidates in optical, thermoelectric and mechanical applications.

scholarly journals Ab Initio Study of Geminal Steric Hindrance Effects on the Stability of Conformations of Cyclohexane Derivatives

2005 ◽  
Vol 2005 (8) ◽  
pp. 508-515 ◽  
Author(s):  
Davood Nori-Shargh ◽  
Mostafa Mohamadpour Amini ◽  
Maryam Jafari ◽  
Farzad Deyhimi ◽  
Saeed Jameh-Bozorghi
Keyword(s):  
Density Functional Theory ◽  
Ab Initio ◽  
Energy Barrier ◽  
Density Functional ◽  
Energy Difference ◽  
Ab Initio Study ◽  
Functional Theory ◽  
Conformational Properties ◽  
The Stability ◽  
Twist Boat

Ab initio and density functional theory methods (HF/3-21G*//HF/3-21G*, MP2/3-21G*//HF/3-21G*, B3LYP/3-21G*//HF/3-21G*, B3LYP/LANL2DZ*//HF/LANL2DZ*, MP2/LANL2DZ*//HF/LANL2DZ* and HF/LANL2DZ*//HF/LANL2DZ*) used to investigate the conformational properties of cyclohexane, 1,1-dimethylcyclohexane, 1,1-di-tert-butylcyclohexane, 1,1-bis(trimethylsilanyl)cyclohexane, 1,1-bis(trimethylgermanyl)cyclohexane and 1,1-bis(trimethylstannyl)cyclohex ane showed that the energy difference between the chair and twist-boat conformations and also the ring flipping energy barrier decreases from cyclohexane, 1,1-dimethylcyclohexane to 1,1-di-tert-butylcyclohexane, and increases from 1,1-bis(trimethylsilanyl)cyclohexane, 1,1-bis(trimethylgermanyl)cyclohexane to 1,1-bis(trimethylstannyl)cyclohexane.

Sign in / Sign up

Export Citation Format

Share Document