Theoretical calculations were carried out using the DFT/B3LYP/6-31+G(d) methodology in an attempt to predict the preferred interaction site of a polyfunctional heterocyclic base 3-methyl-4- pyrimidone molecule with a ...Theoretical calculations were carried out using the DFT/B3LYP/6-31+G(d) methodology in an attempt to predict the preferred interaction site of a polyfunctional heterocyclic base 3-methyl-4- pyrimidone molecule with a series of proton donors of different acidic strength, i.e. water, methanol, phenol, 1-naphtol, 2,4,5 trichlorophenol, pentachlorophenol, picric acid and hydrogen chlordide. Computed H-bond interaction energies (ΔEc), internuclear and intermolecular distances r(O…H) and r(O…O), infrared frequency shifts Δv(C=O) and (Δv(OH) are proved to be reliable parameters for predicting the preferred interaction site of 3-methyl-4-pyrimidone. These computational data suggest that the O-H…O=C complex is preferred with water, methanol, phenol, 1-naphtol, 2,4,5 trichlorophenol and pentachlorophenol. However, for H-bonding with stronger acids such as picric acid or hydrochloric acid, the computational data suggest that the H-bonding occurs at the N1 ring atom of 3-methyl-4-pyrimidone. In the O-H…O=C com- plex, where the H-bond at the carbonyl O-atom can be oriented “anti” (Ha) and “syn” (Hb) with respect to the N3 atom, the same computational data suggest a higher stability of the “anti-O” compared to the “syn-O” orientation.展开更多
The ammonia adsorption on the GaN (0001) surface has been investigated by using DFT/B3LYP method combined with the cluster model approach. The dissociative adsorp- tion of NH2 and H is found thermodynamically favored ...The ammonia adsorption on the GaN (0001) surface has been investigated by using DFT/B3LYP method combined with the cluster model approach. The dissociative adsorp- tion of NH2 and H is found thermodynamically favored relative to the molecular NH3 adsorption by decreasing the total energy of 0.95 eV. The adsorption geometries of the molecular and dis- sociative NH3 are given in detail, among which the molecular NH3 bonds to the surface Ga with its lone electronic pair, and the N atom of NH2 adspecies forms the four-fold coordinated N by bridging two surface Ga atoms.展开更多
The novel carbenoid H2Ge=CLiF was studied by using the DFT B3LYP and QCISD methods. Geometry optimization calculations indicate that H2Ge=CLiF has three equilibrium configurations, in which the three-membered structur...The novel carbenoid H2Ge=CLiF was studied by using the DFT B3LYP and QCISD methods. Geometry optimization calculations indicate that H2Ge=CLiF has three equilibrium configurations, in which the three-membered structure is the lowest in energy and thus the most stable. Two transition states for isomerization reactions of H2Ge=CLiF were located and the energy barriers were calculated. For the most stable one, the vibrational frequencies and infrared intensities were predicted.展开更多
The unsaturated germylenoid H2C=GeLiF has been studied by using DFT method at the B3LYP/6-311＋G （d, p） level. Geometry optimization calculations indicate that H2C=GeLiF has three equilibrium configurations, in whic...The unsaturated germylenoid H2C=GeLiF has been studied by using DFT method at the B3LYP/6-311＋G （d, p） level. Geometry optimization calculations indicate that H2C=GeLiF has three equilibrium configurations, in which the p-complex is the lowest in energy and the most stable structure. Two transition states for isomerization reactions of H2C=GeLiF are located and the energy barriers are calculated. For the most stable one, vibrational frequencies and infrared intensities have been predicted.展开更多
1,2-Benzothiazine derivatives methyl 3-methoxy-4-oxo-3,4-dihydro-2H-benzo[e] [1,2]thiazine-3-carboxylate 1,1-dioxide（1） and methyl 2-ethyl-3-hydroxy-4-oxo-3,4-dihydro-2Hbenzo[e][1,2]thiazine-3-carboxylate 1,1-dioxid...1,2-Benzothiazine derivatives methyl 3-methoxy-4-oxo-3,4-dihydro-2H-benzo[e] [1,2]thiazine-3-carboxylate 1,1-dioxide（1） and methyl 2-ethyl-3-hydroxy-4-oxo-3,4-dihydro-2Hbenzo[e][1,2]thiazine-3-carboxylate 1,1-dioxide（2） were synthesized, and characterized by spectroscopic techniques; 1H-NMR and infrared（IR） spectroscopy. Crystals of 1 and 2 were grown by slow evaporation of methanol and ethyl acetate, respectively and their crystal structures were investigated by single-crystal X-ray diffraction analysis. Geometric properties were calculated by the B3 LYP method of density functional theory（DFT） at the 6-31G＋（d） basis set to compare with the experimental data. Simulated properties were found in strong agreement with the experimental ones. Intermolecular forces have also been modeled in order to investigate the strength of packing and strong hydrogen bonding was observed in both compounds 1 and 2. Electronic properties such as Ionization Potential（IP）, Electron Affinities（EA） and coefficients of the highest occupied molecular orbital（HOMO） and the lowest unoccupied molecular orbital（LUMO） of com- pounds 1 and 2 were simulated for the first time.展开更多
Benzothiazole (BTH) and its derivatives are organic molecules with biologic actions. Because of their many applications, they are produced on a massive scale and used in a number of environmental compartments. Their d...Benzothiazole (BTH) and its derivatives are organic molecules with biologic actions. Because of their many applications, they are produced on a massive scale and used in a number of environmental compartments. Their discharge into water produces environmental problems, exposing our environment to public health problems. A solution that can contribute to their deterioration is becoming a necessity. For this reason, a conceptual analysis of the reactivity of benzothiazole and four of its compounds was undertaken in order to investigate certain aspects of their biodegradability. A theoretical investigations of the compounds studied were conducted in the gas and water phases with the most widely used density functional theory method, Becke-3-Parameter-Lee-Yang-Parr (B3LYP) with 6-31G+ (d, p) basis. Reactivity study calculated global indices of reactivity revealed that 2-SCH3_BTH is the most reactive. Dipole moment values analysis reveals that 2-NH2_BTH is the most soluble in water, while the lipophilicity shows that 2-NH2_BTH is the most hydrophilic compound. Thermodynamic parameters values reflect that reactions are respectively exothermic and spontaneous. By analyzing an Electrostatic Molecular Potential (EMP) map, researchers can pinpoint reactive sites on a molecule and anticipate its reactivity. This assessment is further enhanced by incorporating global and local reactivity descriptors. Additionally, an exploration of frontier molecular orbitals offers valuable insights into the molecule’s charge transfer characteristics. Moreover, a combined examination of internal and external molecular interactions unveils hyperconjugative interactions arising from charge delocalization, as elucidated through natural bond orbital (NBO) analysis.展开更多
A novel interesting d^（10） metal hybrid, [1,2-C_6H_（10）（NH_3）_2]ZnCl_4; 1,2-diammoniumcyclohexane tetrachlorozincate（II） was grown, structurally characterized and their vibrational as well as thermal and diele...A novel interesting d^（10） metal hybrid, [1,2-C_6H_（10）（NH_3）_2]ZnCl_4; 1,2-diammoniumcyclohexane tetrachlorozincate（II） was grown, structurally characterized and their vibrational as well as thermal and dielectric proprieties were studied. A preliminary single crystal X-ray diffraction structural analysis has revealed that the latter crystallizes in the monoclinic system（space group C2/c）. Its unit cell dimensions are a = 32.394（9） ？, b = 12.217（4） ？, c = 10.175（3） ？, β = 97.852（13）° with Z = 12 and the refinement converged to R = 0.034 and ωR = 0.065. Hirshfeld surface analyses, especially d_（norm）surface and fingerprint plots were used for decoding intermolecular interactions in the crystal network. The optimized geometric parameters, normal mode frequencies and corresponding vibrational assignments of the present compound were theoretically examined by the DFT/B3 LYP method with the Lan L2 DZ basis set. The thermal and dielectric analyses suggested the presence of ferroelectric phase transition at 314 K.展开更多
The complexation of BDHTD （4-benzylidenamino-4,5-dihydro-lH-l,2,4-triazol-5-one derivatives） by divalent doubly charged metal ions M2＋ （M = Mg, Ca, Fe and Cu） has been investigated using the density functional me...The complexation of BDHTD （4-benzylidenamino-4,5-dihydro-lH-l,2,4-triazol-5-one derivatives） by divalent doubly charged metal ions M2＋ （M = Mg, Ca, Fe and Cu） has been investigated using the density functional method B3LYP. Two distinct coordination modes （k2-O,O and k2-O,N） have been taken into account. Geometry optimizations have been performed in gas-phase and solution-phase： acetonitrile and DMF （N,N-dimethylformamide） with the basis set 6-31G（d,p）. The B3LYP method was also used to calculate the stability and free energies of the 24 complexes of BDHTD with metal ions M2＋ （M = Mg, Ca, Fe and Cu） respectively in gas-phase and solution-phase： acetonitrile and DMF. Results indicate that k2-O,N structures are most stable in gas-phase. The influence of substitution on the stability is sensitive in solution-phase. The interaction energies of complexation process in various media have been calculated at B3LYP/6-31G（d,p） and CCSD（T） level. The MIA （metal ion affinity） of BDHTD with M2＋ （M = Mg, Ca, Fe and Cu） in various media has been explored. The results show that the M1A highly varies with the coordination mode and substitution effect. From the calculated Gibb energies of complexation in various media, it is revealed that the complexation is possible in gas in acetonitrile. The ligand＇s affinity toward individual cation M2＋ （M = Mg, Ca, Fe and Cu） has been analysed. A significant reduce of BDEs observed confirms the decrease of the antioxidant activity by the metal chelation. The charge transfer induced by metal chelation is examined using the NBO analysis.展开更多
文摘Theoretical calculations were carried out using the DFT/B3LYP/6-31+G(d) methodology in an attempt to predict the preferred interaction site of a polyfunctional heterocyclic base 3-methyl-4- pyrimidone molecule with a series of proton donors of different acidic strength, i.e. water, methanol, phenol, 1-naphtol, 2,4,5 trichlorophenol, pentachlorophenol, picric acid and hydrogen chlordide. Computed H-bond interaction energies (ΔEc), internuclear and intermolecular distances r(O…H) and r(O…O), infrared frequency shifts Δv(C=O) and (Δv(OH) are proved to be reliable parameters for predicting the preferred interaction site of 3-methyl-4-pyrimidone. These computational data suggest that the O-H…O=C complex is preferred with water, methanol, phenol, 1-naphtol, 2,4,5 trichlorophenol and pentachlorophenol. However, for H-bonding with stronger acids such as picric acid or hydrochloric acid, the computational data suggest that the H-bonding occurs at the N1 ring atom of 3-methyl-4-pyrimidone. In the O-H…O=C com- plex, where the H-bond at the carbonyl O-atom can be oriented “anti” (Ha) and “syn” (Hb) with respect to the N3 atom, the same computational data suggest a higher stability of the “anti-O” compared to the “syn-O” orientation.
基金Supported by the National Natural Science Foundation of China (202730313)
文摘The ammonia adsorption on the GaN (0001) surface has been investigated by using DFT/B3LYP method combined with the cluster model approach. The dissociative adsorp- tion of NH2 and H is found thermodynamically favored relative to the molecular NH3 adsorption by decreasing the total energy of 0.95 eV. The adsorption geometries of the molecular and dis- sociative NH3 are given in detail, among which the molecular NH3 bonds to the surface Ga with its lone electronic pair, and the N atom of NH2 adspecies forms the four-fold coordinated N by bridging two surface Ga atoms.
文摘The novel carbenoid H2Ge=CLiF was studied by using the DFT B3LYP and QCISD methods. Geometry optimization calculations indicate that H2Ge=CLiF has three equilibrium configurations, in which the three-membered structure is the lowest in energy and thus the most stable. Two transition states for isomerization reactions of H2Ge=CLiF were located and the energy barriers were calculated. For the most stable one, the vibrational frequencies and infrared intensities were predicted.
基金Supported by NNSFC (20473029)the Fund for Doctor of Yantai University (HY05B30)the Open Project Program of Key Laboratory for Supramolecular Structure and Materials of Ministry of Education, Jilin University
文摘The unsaturated germylenoid H2C=GeLiF has been studied by using DFT method at the B3LYP/6-311＋G （d, p） level. Geometry optimization calculations indicate that H2C=GeLiF has three equilibrium configurations, in which the p-complex is the lowest in energy and the most stable structure. Two transition states for isomerization reactions of H2C=GeLiF are located and the energy barriers are calculated. For the most stable one, vibrational frequencies and infrared intensities have been predicted.
基金funded by the Saudi Basic Industries Corporation(SABIC) and the Deanship of Scientific Research(DSR),King Abdulaziz University,Jeddah,under grant no.(MS/15/396/1434)
文摘1,2-Benzothiazine derivatives methyl 3-methoxy-4-oxo-3,4-dihydro-2H-benzo[e] [1,2]thiazine-3-carboxylate 1,1-dioxide（1） and methyl 2-ethyl-3-hydroxy-4-oxo-3,4-dihydro-2Hbenzo[e][1,2]thiazine-3-carboxylate 1,1-dioxide（2） were synthesized, and characterized by spectroscopic techniques; 1H-NMR and infrared（IR） spectroscopy. Crystals of 1 and 2 were grown by slow evaporation of methanol and ethyl acetate, respectively and their crystal structures were investigated by single-crystal X-ray diffraction analysis. Geometric properties were calculated by the B3 LYP method of density functional theory（DFT） at the 6-31G＋（d） basis set to compare with the experimental data. Simulated properties were found in strong agreement with the experimental ones. Intermolecular forces have also been modeled in order to investigate the strength of packing and strong hydrogen bonding was observed in both compounds 1 and 2. Electronic properties such as Ionization Potential（IP）, Electron Affinities（EA） and coefficients of the highest occupied molecular orbital（HOMO） and the lowest unoccupied molecular orbital（LUMO） of com- pounds 1 and 2 were simulated for the first time.
文摘Benzothiazole (BTH) and its derivatives are organic molecules with biologic actions. Because of their many applications, they are produced on a massive scale and used in a number of environmental compartments. Their discharge into water produces environmental problems, exposing our environment to public health problems. A solution that can contribute to their deterioration is becoming a necessity. For this reason, a conceptual analysis of the reactivity of benzothiazole and four of its compounds was undertaken in order to investigate certain aspects of their biodegradability. A theoretical investigations of the compounds studied were conducted in the gas and water phases with the most widely used density functional theory method, Becke-3-Parameter-Lee-Yang-Parr (B3LYP) with 6-31G+ (d, p) basis. Reactivity study calculated global indices of reactivity revealed that 2-SCH3_BTH is the most reactive. Dipole moment values analysis reveals that 2-NH2_BTH is the most soluble in water, while the lipophilicity shows that 2-NH2_BTH is the most hydrophilic compound. Thermodynamic parameters values reflect that reactions are respectively exothermic and spontaneous. By analyzing an Electrostatic Molecular Potential (EMP) map, researchers can pinpoint reactive sites on a molecule and anticipate its reactivity. This assessment is further enhanced by incorporating global and local reactivity descriptors. Additionally, an exploration of frontier molecular orbitals offers valuable insights into the molecule’s charge transfer characteristics. Moreover, a combined examination of internal and external molecular interactions unveils hyperconjugative interactions arising from charge delocalization, as elucidated through natural bond orbital (NBO) analysis.
文摘A novel interesting d^（10） metal hybrid, [1,2-C_6H_（10）（NH_3）_2]ZnCl_4; 1,2-diammoniumcyclohexane tetrachlorozincate（II） was grown, structurally characterized and their vibrational as well as thermal and dielectric proprieties were studied. A preliminary single crystal X-ray diffraction structural analysis has revealed that the latter crystallizes in the monoclinic system（space group C2/c）. Its unit cell dimensions are a = 32.394（9） ？, b = 12.217（4） ？, c = 10.175（3） ？, β = 97.852（13）° with Z = 12 and the refinement converged to R = 0.034 and ωR = 0.065. Hirshfeld surface analyses, especially d_（norm）surface and fingerprint plots were used for decoding intermolecular interactions in the crystal network. The optimized geometric parameters, normal mode frequencies and corresponding vibrational assignments of the present compound were theoretically examined by the DFT/B3 LYP method with the Lan L2 DZ basis set. The thermal and dielectric analyses suggested the presence of ferroelectric phase transition at 314 K.
文摘The complexation of BDHTD （4-benzylidenamino-4,5-dihydro-lH-l,2,4-triazol-5-one derivatives） by divalent doubly charged metal ions M2＋ （M = Mg, Ca, Fe and Cu） has been investigated using the density functional method B3LYP. Two distinct coordination modes （k2-O,O and k2-O,N） have been taken into account. Geometry optimizations have been performed in gas-phase and solution-phase： acetonitrile and DMF （N,N-dimethylformamide） with the basis set 6-31G（d,p）. The B3LYP method was also used to calculate the stability and free energies of the 24 complexes of BDHTD with metal ions M2＋ （M = Mg, Ca, Fe and Cu） respectively in gas-phase and solution-phase： acetonitrile and DMF. Results indicate that k2-O,N structures are most stable in gas-phase. The influence of substitution on the stability is sensitive in solution-phase. The interaction energies of complexation process in various media have been calculated at B3LYP/6-31G（d,p） and CCSD（T） level. The MIA （metal ion affinity） of BDHTD with M2＋ （M = Mg, Ca, Fe and Cu） in various media has been explored. The results show that the M1A highly varies with the coordination mode and substitution effect. From the calculated Gibb energies of complexation in various media, it is revealed that the complexation is possible in gas in acetonitrile. The ligand＇s affinity toward individual cation M2＋ （M = Mg, Ca, Fe and Cu） has been analysed. A significant reduce of BDEs observed confirms the decrease of the antioxidant activity by the metal chelation. The charge transfer induced by metal chelation is examined using the NBO analysis.
