Molecular Structures, Rotational Barriers, and Density Functional Theory Studies on 3,5-Diamino-6-(2,3-Dichlorophenyl)-1,2,4-Triazine

2019 ◽  
Vol 892 ◽  
pp. 185-192
Author(s):  
Pek Lan Toh ◽  
Suh Miin Wang

In this report, different hybrid Density Functional Theory (DFT) methods were utilized to determine the geometries, total energies, Frontier molecular orbitals, atomic charges, and rotational barriers of 3,5-Diamino-6-(2,3-Dichlorophenyl)-1,2,4-Triazine, C9H7Cl2N5 molecular system. All optimized geometrical parameters (i.e. bond lengths, bond angles, and dihedral angles) were then compared with the experimental data, which reported by Sridhar and Ravikumar in 2009 [5]. Also, the results of electronic structures (i.e. total energies, Frontier molecular orbitals, atomic charges, and others) obtained by different DFT methods were compared and discussed.

2009 ◽  
Vol 08 (06) ◽  
pp. 1185-1195 ◽  
Author(s):  
R. L. PRASAD ◽  
A. KUSHWAHA ◽  
RAJENDRA PRASAD ◽  
S. JAISWAL ◽  
R. A. YADAV

Computations were carried out employing the restricted Hartree–Fock (RHF) and density functional theory (DFT) methods to investigate the geometries and energies for the 1,3-dithiole-2-thione (DTT), 1,3-dithiole-2-one (DTO), 1,3-dioxole-2-thione (DOT), and 1,3-dioxole-2-one (DOO) molecules and their radical cations. The geometrical parameters of all the four molecules suggest a finite extent of extended conjugation across the molecules. The radical cations of the DTT and DOT molecules exhibit increased extent of conjugation compared to their neutral analogues. However, on going from the neutral DOO and DTO molecules to their radical cations, the extent of conjugation across the ions decreases and two unsaturated sites become isolated from each other. Requirement of the relaxation energy for the formation of radical cation is much lower for the DTT and DOT molecules compared to that for the DOO and DTO molecules. Smaller relaxation energy requirement favors minimal resistance to charge transport along the molecular stacking. Therefore, it is speculated that the DTT and DOT molecules are better molecular conductors as compared to the DOO and DTO molecules.


2009 ◽  
Vol 08 (04) ◽  
pp. 773-781 ◽  
Author(s):  
YANLING SI ◽  
WEILIN CHEN ◽  
ZHIMING ZHANG ◽  
ENBO WANG

The electronic structures of [ CpTi · SiW 9 V 3 O 40]4- constructed from Keggin–type polyoxometalates functionalized by CpTi 3+ group have been investigated by Density Functional Theory (DFT) methods. We discuss the relative stability affected by incorporating the CpTi 3+ group into the different sites of the [ SiW 9 V 3 O 40]7- framework on the basis of geometrical parameters, total bonding energies, fragment analysis and frontier molecular orbitals analysis. The calculated results indicated that the structure of the CpTi 3+ group coordinating to one terminal oxygen and two bridging oxygen atoms of the Keggin–type polyoxoanion (system a) is more stable than that to three bridging oxygen atoms (system b). In system a, Ti -Ob1, Ti -Ob2 and Ti - Ot1 are relatively shorter, and as result, it exhibits a more compact and nearly spherical structure of the well-known Keggin–type [ SiW 9 V 3 O 40]7-. Fragment analysis elucidates that there is deviation of ΔE B in systems a and b, which makes a significant contribution to the stability of system a. The stability of different isomeric forms of polyoxoanions appears to be a balance between the stabilizing ΔE O and ΔE E terms and the destabilizing ΔE P term. The relatively small energy differences (ΔE B = 4.26 eV ) between systems a and b arise directly from this balance. Frontier molecular orbitals analysis further confirms the stability order of systems a > b by the difference of the HOMO-LUMO energy gap.


2018 ◽  
Vol 73 (11) ◽  
pp. 1037-1045 ◽  
Author(s):  
Aijaz Rasool Chaudhry ◽  
Shabbir Muhammad ◽  
Ahmad Irfan ◽  
Abdullah G. Al-Sehemi ◽  
Bakhtiar Ul Haq ◽  
...  

AbstractUsing density functional theory (DFT) methods, we shed light on the structural, optical, electronic, and nonlinear optical (NLO) properties of three derivatives of 9,12-diiodo-1,2-dicarba-closo-dodecaborane(12) (C2H10B10I2). The DFT and time-dependent DFT methods are considered very precise and practical to optimize the ground and excited state geometries, respectively. A vibrant intramolecular charge transfer from highest occupied molecular orbitals (HOMOs) to the lowest unoccupied molecular orbitals (LUMOs) was observed in all compounds. The geometrical parameters of the experimental crystal structure, i.e. bond lengths/angles, have been successfully reproduced. The HOMO and LUMO energies, as well as their energy gaps (Eg), were also calculated and compared with each other for all derivatives. The effect of attached groups on electronic, optical, and NLO properties along with detailed structure-property relationship was discussed. For NLO response, the CAM-B3LYP functional along with relatively larger basis set 6-31+G** (for hydrogen, carbon, boron, and oxygen atoms) and LANL2DZ (for iodine atoms) have been used to optimize the compounds at ground states. The calculation of second-order NLO polarizabilities (βtot) shows that compounds 2 and 3 possess the βtot amplitudes of 3029 and 4069 a.u., respectively, with CAM-B3LYP method that are reasonably larger than similar prototype molecules. Owing to their unique V-shapes, the nonlinear anisotropy values are found to be 0.63, 0.34, and 0.44 for compounds 1–3, respectively, which show the significant two-dimensional character of these compounds. Thus, the NLO amplitudes as well as the nonlinear anisotropies indicate that the above-entitled compounds are good contenders for optical and NLO applications.


1999 ◽  
Vol 595 ◽  
Author(s):  
W. R. Wampler ◽  
J. C. Barbour ◽  
C. H. Seager ◽  
S. M. Myers ◽  
A. F. Wright ◽  
...  

AbstractWe have used ion channeling to examine the lattice configuration of deuterium in Mg doped GaN grown by MOCVD. The deuterium is introduced by exposure to gas phase or ECR plasmas. A density functional approach including lattice relaxation, was used to calculate total energies for various locations and charge states of hydrogen in the wurtzite Mg doped GaN lattice. Results of channeling measurements are compared with channeling simulations for hydrogen at lattice locations predicted by density functional theory.


2018 ◽  
Vol 33 (1) ◽  
pp. 71
Author(s):  
Ali Hashem Essa ◽  
A. F. Jalbout

The structural and electronic properties of 1-(5-Hydroxymethyl - 4 –[ 5 – (5-oxo-5-piperidin- 1 -yl-penta- 1,3 -dienyl)-benzo [1,3] dioxol- 2 -yl]- tetrahydro -furan-2 -yl)-5-methy l-1Hpyrimidine-2,4dione (AHE) molecule have been investigated theoretically by performing density functional theory (DFT), and semi empirical molecular orbital calculations. The geometry of the molecule is optimized at the level of Austin Model 1 (AM1), and the electronic properties and relative energies of the molecules have been calculated by density functional theory in the ground state. The resultant dipole moment of the AHE molecule is about 2.6 and 2.3 Debyes by AM1 and DFT methods respectively, This property of AHE makes it an active molecule with its environment, that is AHE molecule may interacts with its environment strongly in solution.


2004 ◽  
Vol 59 (6) ◽  
pp. 685-691 ◽  
Author(s):  
Bernd Wrackmeyer ◽  
Hans-Jörg Schanz

Deprotonation of hexaethyl-2,4-dicarba-nido-borane(8) 2 leads first to the hexaethyl-2,4-dicarbanido- borate(1−) 3, and further deprotonation, using BuLi/KOtBu, gives the hexaethyl-2,4-dicarbanido- hexaborate(2−) 4. The reaction of 3 with FeCl2 affords the commo-ferracarborane [Fe(Et6-2,4- C2B4H)2] 5, and the analogous reaction of 4 leads to the anionic sandwich complex [Fe(Et6-2,4- C2B4)2]2− 6 which can be protonated to give 5. The complex 5 contains two hydrido ligands, each bridging the iron and two boron atoms. Reactions were monitored and the products were characterised by 11B NMR spectroscopy in solution. The geometries of the carboranes, the borates (all unsubstituted and permethyl-substituted) and the iron complexes (all unsubstituted) were optimised by DFT methods [B3LYP/6-311+G(d,p) or B3LYP/6-31+G(d)], and the relevant NMR data [chemical shifts δ11B, δ13C, δ57Fe, and coupling constants 1J(13C,1H), 1J(11B,1H), 1J(57Fe,1H), 1J(57Fe,11B)] were calculated at the same level of theory.


2013 ◽  
Vol 807-809 ◽  
pp. 543-548 ◽  
Author(s):  
Yan Fei Chen ◽  
Yan Hong Cui ◽  
Dong Shun Deng ◽  
Ning Ai

The absorptions of CO2on the 1-butyl-3-methylimidazolium acetate ([Bmi [Ac]) with different substituents are calculated systematically at GGA/PW91 level. Three hydrogen bonds are formed between [A and cations of 1-n-[Bmi [A ([NBmi+) and 1-tert-[Bmi [A ([TBmi+). The interaction between CO2and the [NBmi [A by a C-O bond is much weaker than that with the [TBmi [A by forming a O...O...C...C four member-ring. The chemisorption of CO2on the ion pairs of [NBmi [A is much weaker than that on the [TBmi [A, resulted from the absorption energies analysis. The frontier molecular orbitals shows the electronic density overlap between absorbed CO2and the [A in CO2-[NBmi [A is much weaker than that in [TBmi [A. Therefore, the chemisorption of CO2on the ion pair of [NBmi [A is much weaker than that on the [TBmi [A. The ionic liquids based [NBmi+can be used repetitively, and the adsorbed CO2would be easier desorbed.


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