Five fully optimized structures of complexes between aza-calix[6]arene host monomers（Ma～Me） and complexes（a～e） have been obtained at the B3LYP/6-31G（d） level.Natural bond orbital（NBO） analysis was performed ...Five fully optimized structures of complexes between aza-calix[6]arene host monomers（Ma～Me） and complexes（a～e） have been obtained at the B3LYP/6-31G（d） level.Natural bond orbital（NBO） analysis was performed to reveal the origin of the interaction.The intermolecular interaction energy was evaluated with basis set superposition error correction（BSSE） and zero point energy correction（ZPEC）.The B3LYP/6-31G（d） calculations on the five complexes have shown that the greatest interaction（–13.98 kJ/mol） is found in the complex between HMX and hexa-aza-calix[3]-p-tri-arene[3]-2-amido-1,3,5-tri-azine.The results have indicated that intermolecular interaction energies of aza-calix[6]arenes with substituted group are stronger than those without substituted group,and those with amido are greater than with nitryl.Thus,hexa-azacalix[3]-p-tri-arene[3]-2-amido-1,3,5-tri-azine is rather equal to eliminate HMX from explosive waste water.展开更多
This paper reports that vibrational spectroscopic analysis on hYdrogen-bonding between acetone and water comprises both experimental Raman spectra and ab initio calculations on structures of various acetone/water comp...This paper reports that vibrational spectroscopic analysis on hYdrogen-bonding between acetone and water comprises both experimental Raman spectra and ab initio calculations on structures of various acetone/water complexes with changing water concentrations. The optimised geometries and wavenumbers of the neat acetone molecule and its complexes are calculated by using ab initio method at the MP2 level with 6-311＋G（d,p） basis set. Changes in wavenumber position and linewidth （fullwidth at half maximum） have been explained for neat as well as binary mixtures with different mole fractions of the reference system, acetone, in terms of intermolecular hydrogen bonding. The combination of experimental Raman data with ab initio calculation leads to a better knowledge of the concentration dependent changes in the spectral features in terms of hydrogen bonding.展开更多
The title complex Co（DMSO）2（H2O）2（SCN）2 has been prepared and structurally characterized. It crystallizes in monoclinic, space group P21/n with a= 5.1981（9）, b = 11.944（2）, c = 12.646（2） A,β = 98.686（2）...The title complex Co（DMSO）2（H2O）2（SCN）2 has been prepared and structurally characterized. It crystallizes in monoclinic, space group P21/n with a= 5.1981（9）, b = 11.944（2）, c = 12.646（2） A,β = 98.686（2）°, V = 776.2（2） A^3, C6H16CoN2O4S4, Mr = 367.38, Z = 2, De = 1.572 g/cm^3, F（000） = 378 and μ（MoKa） = 1.646 mm^-1. The structure was refined to R= 0.0232 and wR = 0.0645 for 1241 observed reflections with I 〉 2σ（I）. In the title complex, each Co（II） atom is octahedrally coordinated by four O atoms from two DMSO ligands and two water molecules as well as two N atoms from SCN^- ions. The title molecules are connected to each other through intermolecular hydrogen bonds to form a 1-D structure extended by eight-membered Co2O4H2 rings.展开更多
The structures of the complexes formed between N-methylol ethanone （model molecule of ceramide） and azacyclopentane-2-one （the model molecule of azone） have been fully optimized at the B3LYP/6-311＋＋G＊＊ level. ...The structures of the complexes formed between N-methylol ethanone （model molecule of ceramide） and azacyclopentane-2-one （the model molecule of azone） have been fully optimized at the B3LYP/6-311＋＋G＊＊ level. The intermolecular hydrogen bonding interaction energies have been calculated by using the B3LYP/6-311＋＋G＊＊, B3LYP/6-311＋＋G（2df,2p）, MP2（full）/6-311 ＋＋G＊＊ and MP2（full）/6-311 ＋＋G（2df,2p） methods, respectively. The results show that strong O-H…O=C, N-H…O=C and C-H…O=C hydrogen bonds could exist between azacyclopentane-2-one and N-methylol ethanone. The formation of the complexes might change the conformation of ceramide molecule and thus cause better percutaneous permeation for the drugs. This is perhaps the origin of the permeation enhances the activity of azone for medicament, as is in accordance with the experimental results. The hydrogen-bonding interactions follow the order of （a） 〉 （c） 〉 （b） 〉 （d） 〉 （g） ≈ （e） ≈ （i） 〉 （h） 〉 （f）. The analyses of frequency, NBO, AIM and electron density shift are used to further reveal the nature of the complex formation. In the range of 263.0- 328.0 K, the complex is formed via an exothermic reaction, and the solvent with lower temperature and dielectric constant is favorable to this process.展开更多
文摘Five fully optimized structures of complexes between aza-calix[6]arene host monomers（Ma～Me） and complexes（a～e） have been obtained at the B3LYP/6-31G（d） level.Natural bond orbital（NBO） analysis was performed to reveal the origin of the interaction.The intermolecular interaction energy was evaluated with basis set superposition error correction（BSSE） and zero point energy correction（ZPEC）.The B3LYP/6-31G（d） calculations on the five complexes have shown that the greatest interaction（–13.98 kJ/mol） is found in the complex between HMX and hexa-aza-calix[3]-p-tri-arene[3]-2-amido-1,3,5-tri-azine.The results have indicated that intermolecular interaction energies of aza-calix[6]arenes with substituted group are stronger than those without substituted group,and those with amido are greater than with nitryl.Thus,hexa-azacalix[3]-p-tri-arene[3]-2-amido-1,3,5-tri-azine is rather equal to eliminate HMX from explosive waste water.
基金supported by National Natural Science Foundation of China (Grant Nos.10774057 and 10974067)
文摘This paper reports that vibrational spectroscopic analysis on hYdrogen-bonding between acetone and water comprises both experimental Raman spectra and ab initio calculations on structures of various acetone/water complexes with changing water concentrations. The optimised geometries and wavenumbers of the neat acetone molecule and its complexes are calculated by using ab initio method at the MP2 level with 6-311＋G（d,p） basis set. Changes in wavenumber position and linewidth （fullwidth at half maximum） have been explained for neat as well as binary mixtures with different mole fractions of the reference system, acetone, in terms of intermolecular hydrogen bonding. The combination of experimental Raman data with ab initio calculation leads to a better knowledge of the concentration dependent changes in the spectral features in terms of hydrogen bonding.
基金This work was supported by the National Natural Science Foundation of China (No. 50572040)
文摘The title complex Co（DMSO）2（H2O）2（SCN）2 has been prepared and structurally characterized. It crystallizes in monoclinic, space group P21/n with a= 5.1981（9）, b = 11.944（2）, c = 12.646（2） A,β = 98.686（2）°, V = 776.2（2） A^3, C6H16CoN2O4S4, Mr = 367.38, Z = 2, De = 1.572 g/cm^3, F（000） = 378 and μ（MoKa） = 1.646 mm^-1. The structure was refined to R= 0.0232 and wR = 0.0645 for 1241 observed reflections with I 〉 2σ（I）. In the title complex, each Co（II） atom is octahedrally coordinated by four O atoms from two DMSO ligands and two water molecules as well as two N atoms from SCN^- ions. The title molecules are connected to each other through intermolecular hydrogen bonds to form a 1-D structure extended by eight-membered Co2O4H2 rings.
文摘The structures of the complexes formed between N-methylol ethanone （model molecule of ceramide） and azacyclopentane-2-one （the model molecule of azone） have been fully optimized at the B3LYP/6-311＋＋G＊＊ level. The intermolecular hydrogen bonding interaction energies have been calculated by using the B3LYP/6-311＋＋G＊＊, B3LYP/6-311＋＋G（2df,2p）, MP2（full）/6-311 ＋＋G＊＊ and MP2（full）/6-311 ＋＋G（2df,2p） methods, respectively. The results show that strong O-H…O=C, N-H…O=C and C-H…O=C hydrogen bonds could exist between azacyclopentane-2-one and N-methylol ethanone. The formation of the complexes might change the conformation of ceramide molecule and thus cause better percutaneous permeation for the drugs. This is perhaps the origin of the permeation enhances the activity of azone for medicament, as is in accordance with the experimental results. The hydrogen-bonding interactions follow the order of （a） 〉 （c） 〉 （b） 〉 （d） 〉 （g） ≈ （e） ≈ （i） 〉 （h） 〉 （f）. The analyses of frequency, NBO, AIM and electron density shift are used to further reveal the nature of the complex formation. In the range of 263.0- 328.0 K, the complex is formed via an exothermic reaction, and the solvent with lower temperature and dielectric constant is favorable to this process.
