Synthesis,Structure and Quantum Mechanical Calculations of Methyl 2-(5-((Quinolin-8-yloxy)-methyl)-1,3,4-oxadiazol-2-ylthio)-acetate

The title compound was synthesized by the base catalyzed reaction of 5-((quinolin-8-yloxy)methyl)-1,3,4-oxadiazole-2(3H)-thione with methyl chloroacetate.The structure was supported by the spectroscopic data and unambiguously confirmed by single-crystal X-ray diffraction studies.It crystallizes from a methanol solution in the triclinic space group P1with unit cell dimensions a=7.4509(9),b=10.2389(12),c=12.2299(15),α=74.771(2),β=77.956(2),γ=69.263(2)°,V=834.98(17)?3 and Z=2.In order to gain some valuable insights into the molecular structure,the quantum mechanical calculations were performed using both HF and time-dependent density functional theory at the B3LYP/6-31G(d,p)level.The molecular geometry from X-ray determination of the title compound in the ground state has been compared using the Hartree-Fock(HF)and density functional theory(DFT)with the 6-31G(d)basis set.The calculated results show that the DFT and HF can well reproduce the structure of the title compound.The energetic behavior of the title compound was examined using the B3LYP method with the 6-31G(d)basis set.The harmonic vibrational frequencies calculated have been compared with the experimental FTIR and FT-Raman spectra.The restricted Hartree-Fock and density functional theory-based nuclear magnetic resonance(NMR)calculation procedure was also performed,and it was used for assigning the13C and1H NMR chemical shifts of the title compound.Moreover,molecular electrostatic potential and thermodynamic parameters of the title compound were investigated by theoretical calculations.     

Tert-butyl N-(2-bromocyclohex-2-enyl)-N-(2-furylmethyl)carbamate的结构和振动光谱

The molecular structure, conformafional stability, and vibrational frequencies of ten-butyl N-（2- bromocyclohex-2-enyl）-N-（2-furylmethyl）carbamate （TBBFC） were investigated by utilizing the Hartree-Fock （HF） and density functional theory （DFT） ab initio calculations with 6-31G ^＊ and 6-31G^＊ ＊ basis sets. The optimized bond length and angle values obtained by HF method showed the best agreement with the experimental values. Comparison of the observed and calculated fundamental vibrational frequencies indicated that B3LYP was superior to the scaled HF approach for molecular problems. Optimal uniform scaling factors calculated for the title compound are 0.899/0.904, 0.958/0.961, and 0.988/0.989 for HF, B3LYP, and BLYP （6-31G ^＊/6-31G ^＊ ＊）, respectively.     

Crystal Structure and DFT Studies of a Triazole Derivative： 4- （ 2-Hydrobenzylideneamino ） -3- （ 1,2,4-triazol-4-ylmethyl） 1H-1, 2,4-triazole-5 （4H） -thione

A novel triazole derivative 4-(2-hydrobenzylideneamino)-3-(1,2,4-triazol-4-ylmethyl)-1H-1,2,4-triazole-5(4H)-thione(1) was synthesized and characterized using elemental analysis, FTIR, and 1H NMR, and its crystal structure was determined via X-ray single crystal diffraction analysis. Crystal data: monoclinic, P2(1)/c, a=0.83335(9) nm, b=1.49777(16) nm, c=1.14724(12) nm, β =107.990(2)°, D=1.470 Mg/m3, and Z=4. The geometries and the vibrational frequencies were determined using the density functional theory(DFT) method at the B3LYP/ 6-31G level. To demonstrate the accuracy of the reaction route of compound 1, one of the important intermediates was also tested using the same method. The structural parameters of the two compounds calculated using the DFT study are close to those of the crystals, and the harmonic vibrations of the two compounds computed via the DFT method are in good agreement with those in the observed IR spectral data. The thermodynamic properties of the title compound were calculated, and the compound shows a good structural stability at normal temperature. The test results of biological activities show that it has a certain bactericidal ability.     

1,3-Di（2-p-tolylvinyl）-2,4,6-trinitrobenzene： X-ray Crystallo- graphic Analysis,Thermal Decomposition and DFT Calculations

In this paper, the synthesis, crystal culturing and single-crystal X-ray crystallography of 1,3-di（2-p-tolylvingl）-2,4,6-trinitrobenzene （DTTB） were reported. FT-IR, ^1H NMR and mass spectroscopy techniques were employed to characterize this compound. The results show that this single crystal belongs to triclinic system with space group P-1. Density functional theory （DFT） B3LYP was employed to optimize structure and calculate frequencies of the title compound. The calculated geometrical parameters were close to the corresponding experiment ones. The thermal decomposition of DTTB was investigated by DSC and TG-DTG methods at the heating rate of 10 ℃/min. It was observed that the initial decomposing temperature of DTTB was higher than that of TNTM, although its melting point was lower than that of TNTM, indicating that DTTB has higher heat resistant ability.     

1,3-二甲基-2-二茂铁甲基苯并咪唑碘盐的合成、表征、晶体结构及量子化学计算

A novel benzimidazole derivative, 1,3-dimethyl-2-ferrocenylmethylbenzimidazolium iodide （1） was synthesized and characterized by elemental analysis, MS, IH NMR and IR spectra. Its crystal structure was determined by X-ray single crystal diffraction, and the title compound belongs to monoclinic system with space group P2（1）/c. According to the crystal structure, the quantum chemistry calculation was performed by Gaussian 03 program, and full geometry optimizations of the title compound were carried out with DFT method at B3LYP/6-31G level. Its structure, stability, frontier molecular orbital components and net charge distribution were discussed.     

Theoretical Investigations on the Structure,Density, Thermodynamic and Performance Properties of Bis（2,2-dinitropropyl） formal

Density functional method was used to investigate the IR spectrum,heat of formation and thermal stability of a new energetic material bis(2,2-dinitropropyl) formal(BDNPF).The detonation velocity and pressure were evaluated by using the Kamlet-Jacobs equations based on the theoretical density and heat of formation.The bond dissociation energies for the weakest bonds were analyzed to investigate the thermal stability of the title compound.The results show that the C(1)-N(1) bond is predicted to be the trigger bond during pyrolysis.The crystal structure obtained by molecular mechanics belongs to the P21 space group,with the lattice parameters to be Z = 2,a = 11.5254,b = 6.2168,c = 9.5000  and ρ= 1.66 g/cm3.     

Synthesis,Crystal Structure and Density Functional Theory Studies of 9-Hexyl-3-（（pyridin-4-yl）vinyl）-9H-carbazol

A novel pyridine derivate, 9-hexyl-3-（（pyridin-4-yl）vinyl）-9H-carbazole, was synthesized and characterized by 1H NMR spectra and X-ray diffraction analysis. The complex crystallizes in monoclinic, space group P21/n with a = 9.111（5）, b = 8.239（5）, c = 26.835（5） A, β = 95.340（5）°, Mr = 354.48, V = 2005.6（17） A3, Z = 4, Dc = 1.174 g/cm3,μ = 0.068 mm^-1, F（000） = 760, R = 0.0565 and wR = 0.1550 for 12635 observed reflections （I 〉 2σ（I））. Density functional theory （DFT） calculations were carried out to interpret its UV-Vis spectra, and the results are in agreement with the available experiments.     

Spectral and self-assembly properties of a series of asymmetrical pyrene derivatives

A series of pyrene derivatives with different asymmetrical substituents were successfully synthesized and characterized. The geometrical electronic structures of the asymmetrical pyrene derivatives were performed by density functional theory （DFT） calculations. The results of photophysical spectra and electrochemical analysis indicated that the optical or electric properties of the pyrene derivatives could be tuned by adjust the π-conjugation lengths of the substituents. Furthermore, through a phase exchange self-assembly method, the highly organized morphologies were observed by SEM.     

Synthesis,Crystal Structure and Biological Activities of N-（4-Cyanopyrazole-3-yl）- α-（3,5-difluorophenyl）- O,O-diisopropyl- α-aminophosphonate

The title compound has been synthesized by the addition reaction of N-（4-cyanopyrazole-3-yl）-3,5-difluorophenyl-imine and diisopropyl phosphate. Its structure was confirmed by means of IR, ^1H NMR and elemental analysis. The single-crystal structure of the title compound was determined by X-ray crystallography. The compound crystallizes in monoclinic, space group C2/c with a = 18.9959（14）, b = 9.2212（7）, c = 22.1108（16）A^°, β= 90.1540（10）°, V = 3873.0（5） A^°^3, Dc = 1.366 g/cm^3, Z = 8, μ = 0.185, F（000） = 1664, and the final R = 0.0503 and wR = 0.1539 for 2996 observed reflections （I 〉 2σ（I））. The results demonstrate that the dihedral angle between the pyrazole and benzene rings is 105.5°, and there is a full delocalized pyrazole system with sp^2 hydridization of N（3）. The crystal structure is stabilized by two intermolecular hydrogen bonds of N（1）-H（1）…O（3） and N（3）-H（3A）…N（4）. The preliminary biological test shows that the title compound has a moderate antifungal activity.     

Synthesis,Crystal Structure and Theoretical Calculation of 1,1＇,5,5＇-Tetramethyl-2,2＇-diphenyl-4,4＇-[i-phenylene-bis（methylidy-nenitrilo）]di-1H-pyrazol-3（2H）-one

1,1',5,5'-Tetramethyl-2,2'-diphenyl-4,4'-[i-phenylenebis(methylidynenitrilo)]di-1H-pyrazol-3(2H)-one was synthesized and characterized by X-ray single-crystal diffraction analysis.The crystal crystallizes in monoclinic,space group P21/c with a = 6.1375(1),b = 24.6571(4),c = 17.7487(3) ,β = 94.781(1)°,V = 2676.62(8) 3,C30H28N6O2,Mr = 504.58,Z = 4,Dc = 1.252 g/cm3,F(000) = 1064,μ = 0.081 mm-1,R = 0.0463 and wR = 0.1153(I > 2σ(I)).Theoretical studies of the title compound were carried out by density functional theory(DFT) BLYP method,using ADF program package.It indicates that N(26) and N(41) are active sites of the title compound.     

Theoretical Study on the High Energy Density Compound Hexanitrohexaazatricyclotetradecanedifuroxan

Density functional theory （DFT） has been employed to study the molecular geometries, electronic structures, infrared （IR） spectra, and thermodynamic properties of the high energy density compound hexanitrohexaazatricyclotetradecanedifuroxan （HHTTD） at the B3LYP/6-31G^＊＊ level of theory. The calculated results show that there are four conformational isomers （α, β, γ and δ） for HHTTD, and the relative stabilities of four conformers were assessed based on the calculated total energies and the energy-gaps between the frontier molecular orbitals. The computed harmonic vibrational frequencies are in reasonable agreement with the available experimental data. Thermodynamic properties derived from the IR spectra on the basis of statistical thermodynamic principles are linearly correlated with the temperature. Detonation performances were evaluated by using the Kamlet-Jacobs equations based on the calculated densities and heats of formation. It was found that four HHTTD isomers with the predicted densities of ca. 2 g·cm^-3, detonation velocities near 10 km·s^-1, and detonation pressures over 45 GPa, may be novel potential candidates of high energy density materials （HEDM）. These results may provide basic information for the molecular design of HEDM.     

Thermal Degradation Kinetics of N,N＇-Di（diethoxythiophosphoryl）-1,4-phenylenediamine

The non-isothermal degradation kinetics of N,N＇-di（diethoxythiophosphoryl）-1,4-phenylenediamine in N2 was studied by TG-DTG techniques.The kinetic parameters,including the activation energy and pre-exponential factor of the degradation process for the title compound were calculated by means of the Kissinger and Flynn-Wall-Ozawa（FWO）method and the thermal degradation mechanism of the title compound was also studied with the Satava-Sestak methods.The results indicate that the activation energy and pre-exponential factor are 152.61 kJ/mol and 9.06×101 4s -1with the Kissinger method and 154.08 kJ/mol with the Flynn-Wall-Ozawa method,respectively.It has been shown that the degradation of the title compound follows a kinetic model of one-dimensional diffusion or parabolic law,the kinetic function is G（α）=α2and the reaction order is n=2.     

Crystal Structure, Photoluminescence and Theoretical Studies of Diethyl 4,5-di（thienyl）- 3,6-bis（trimethylsilyl）phthalate

The crystal structure of the title compound, diethyl 4,5-di（thienyl）-3,6-bis（trime- thylsilyl）phthalate （C26H3404S2Si2, Mr = 530.83）, has been determined by single-crystal X-ray diffraction. The crystal belongs to the orthorhombic system, space group Pccn with a = 43.008（5）, b = 10.9000（12）, c = 11.9357（14） A, V= 5595.3（11） A3, Z = 8, F（000） = 2256, Dc= 1.260 mg/m3, p = 0.305 mm-1, T = 113（2） K, S = 1.090, R = 0.0413 and wR = 0.0969 for 5952 observed reflections with 1 〉 2o（/）. The benzene ring system is planar and makes dihedral angles of 63.7（2） and 72.5（4） with the two thienyl rings A （C（23）-C（26）, S（2）） and B （C（19）-C（22）, S（1））, respectively. The UV-vis absorption and fluorescence of the title compound were discussed. The molecular structure of the title compound has been optimized using DFT method at the B3LYP/6-31G（d） level. The computational results showed that the optimized geometer parameters are consistent well with the experiment data. The vertical ionization potential, vertical electron affinity and frontier orbitals were also discussed.     

Stable Structure and Characteristic Spectroscopy of （CH3COCH3）n （n = 1-7） Clusters

The stable acetone molecule clusters have been studied by using Becke＇s threeparameter （B3LYP） density functional theory （DFT） with standard 6-31G（d） basis set. The calculated results show that the optimal structures of acetone clusters are cyclic and the cycles become larger and larger with the increase of cluster size. The strongest vibration peaks for neutral clusters are C=O stretching vibration. The C=O stretching peaks of cyclic acetone clusters split into double ones when n≥3, the frequencies are red-shifted and corresponding intensifies increase with the increase of cluster Size.     

Synthesis,Crystal Structure,Characterizationand Quantum Chemical Studies on 1N-Acetyl-3-（2,4-dichloro-5-fluorophenyl）-5-（p-methyl-phenyl）-2-pyrazoline

1N-Acetyl-3-（2,4-dichloro-5-fluoro-phenyl）-5-（p-methyl-phenyl）-2-pyrazoline has been synthesized and characterized by elemental analysis, IR, UV-Vis and X-ray single-crystal diffraction. Ab intio calculations have been carded out for the compound by using both B3LYP and HF methods at the 6-31G^＊ basis set. The calculated results show that the predicted geometry can well reproduce the structural parameters. The electronic absorption spectra calculated by B3LYP/6-31G^＊ method are approximate to the experiments and the Natural Bond Orbital （NBO） analyses suggest that the above electronic transitions are mainly assigned to n→π^＊ and π→π^＊ transitions. CIS-HF/6-31G^＊ method is not suitable to predict the electronic spectra for the title compound. The calculation of the second order optical nonlinearity was carded out, giving the value of molecular hyperpolarizability equal to 2.194^＋ 10^-30 esu. On the basis of vibrational analyses, the thermodynamic properties of the compound at different temperature have been calculated, revealing the correlation between C p, m^0, S m^0, H m^0 and temperature.     

Theoretical Study on the Structures and Properties of Hydrogen Bonding Complexes between Diazines and Water

Density functional theory B3LYP method and second-order Moller-Plesset perturbation theory MP2 method were employed to obtain the optimized geometries of the ground state and interaction energy for diazines and water complexes. The results show that the ground state complexes have strong hydrogen bonding interaction with -20.99, -16.73 and -15.31 kJ/mol after basis set superposition error and zero-point vibration energy correction for pyridazine-water, pyrimidine-water and pyrazine-water, respectively, and large red-shift for the symmetric H-O stretching vibration frequencies due to the formation of N…H-O hydrogen bond in the diazine-water complexes. The NBO analysis indicates that intermolecular charge transfer are 0.0316, 0.0255 and 0.0265 e respectively. In addition, the first singlet （n,n＊） vertical excitation energy of the monomer and the hydrogen bonding complexes between diazines and water was investigated by time-dependent density functional theory.     

A Theoretical Study on the Photochromic Mechanism of 1-Phenyl-3-methyl-4-（6-hydro-4-amino-5-sulfo-2,3-pyrazine）-pyrazole-5-one

The photochromic mechanism of 1-phenyl-3-methyl-4-（6-hydro-4-amino-5-sulfo-2,3- pyrazine）-pyrazole-5-one has been investigated using the density functional theory（DFT）. The solvent effect is simulated using the polarizable continuum model（PCM） of the self-consistent reaction field theory. According to the crystal structure of the title compound, an intramolecular proton transfer mechanism from enol to keto form was proposed to interpret its photochromism. Bader＇s atom-in-molecule（AIM） theory is used to investigate the nature of hydrogen bonds and ring structures. Time-dependent density functional theory（TDDFT） calculation results show that the photochromic process from enol to keto form is reasonable. The conformation and molecular orbital analysis of enol and keto forms explain why only intramolecular proton transfer is possible. The results from analyzing the energy and dipole moments of enol form, transition state and keto form in the gas phase and in different solvents have been used to assess the stability of the title compound.     

Synthesis,Crystal Structure,DFT Studies and Antifungal Activity of 5-(4-Cyclopropyl-5-((3-fluorobenzyl)sulfonyl)-4H-1,2,4-triazol-3-yl)-4-methyl-1,2,3-thiadiazole

5-(4-Cyclopropyl-5-((3-fluorobenzyl)sulfonyl)-4H-1,2,4-triazol-3-yl)-4-methyl-1,2,3-thiadiazole was synthesized and recrystallized from Et OH. The compound was characterized by ~1H NMR,MS,elemental analysis and X-ray diffraction. The structure-active relationship and the antifungal activity based on density functional theory calculation(DFT) and antifungal activities were investigated. The compound crystallizes in the monoclinic space group P121/n1 with a = 8.929(3),b=12.715(4),c=15.161(5) ?,β = 106.142(3)o,V = 1653.3(9) ?~3,Z = 4 and R = 0.0393 for 3930 observed reflections with I 2σ(I). Theoretical calculation of the title compound was carried out with B3LYP/6-31G(d,p). The full geometry optimization was carried out using the 6-31G(d,p) basis set.The frontier orbital energy and atomic net charges were discussed. The observed results of the compound have been compared with theoretical results and the experimental data show good agreement with the calculated values. The compound exhibits good antifungal activity.     

Theoretical Studies on Reaction Mechanisms of HNCS with NH （ X^3∑）

The reaction mechanisms of HNCS with NH（X^3∑ ） were theoretically investigated. The minimum energy paths （MEP） of the reaction were calculated by using the density functional theory（DFT） at the B3LYP/6-311 ＋ ＋ G^＊＊ level. The equilibrium structural parameters, the harmonic vibrational frequencies, the total energies, and the zeropoint energies（ZPE） of all the species were calculated. The single-point energies along the MEP were further refined at the QCISD（T）/6-311 ＋ ＋ G^＊ ＊ level. It was found that the mechanisms of the HNCS ＋ NH（X^3∑） reaction involve two channels producing the HNC ＋ HNS and the N2H2 ＋ CS products. Channel 1 plays a dominant role and the HNC ＋ HNS are the main preduets. The reaction is exothermie.