The structures of the complexes generated by hexamethylenetetramine and nitric acid have been fully optimized by B3LYP method at the 6-311＋＋G＊＊ and aug-cc-pVTZ levels. The intermolecular hydrogen-bonding interacti...The structures of the complexes generated by hexamethylenetetramine and nitric acid have been fully optimized by B3LYP method at the 6-311＋＋G＊＊ and aug-cc-pVTZ levels. The intermolecular hydrogen-bonding interactions have been calculated by the B3LYP/6-311＋＋G＊＊, B3LYP/aug-cc-pVTZ, MP2（full）/6-311＋＋G＊＊ and CCSD（T）/6-311＋＋G＊＊ methods, respectively. The NBO （nature bond orbital）, AIM （atom in molecule）, temperature effect and solvation effect have been analyzed to reveal the origin of the interactions. The results indicate that the stable hydrogen-bonded complexes could be generated by hexamethylenetetramine and nitric acid. The interactions follow the order of （a）（e）（b）（c）（d）（f）（g）. The C–N bonds which are adjacent to the methylene involving the hydrogen bonds tend to break in the chemical reaction. Due to the exothermic process, low temperature is conducive to the formation of the composition, which tallies with the experimental result.展开更多
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
Molecular dynamics method was employed to study the binding energies of the selected crystal planes of the 1,3,5,7-tetranitro-1,3,5,7-tetrazacyclooctane（HMX）/1,3-dimethyl-2-imidazolidinone（DMI） cocrystal in differ...Molecular dynamics method was employed to study the binding energies of the selected crystal planes of the 1,3,5,7-tetranitro-1,3,5,7-tetrazacyclooctane（HMX）/1,3-dimethyl-2-imidazolidinone（DMI） cocrystal in different molecular molar ratios. The mechanical properties were estimated in different molar ratios. Solvent effects were evaluated and the cooperativity effects were discussed in the HMX···HF···DMI ternary by using the M06-2x/6-311＋G（2df,2p） and MP2（full）/6-311＋G（2df,2p） methods. The results indicate that the substituted patterns（020） and（100） own the highest binding energies. The stabilities of cocrystals in the 1：1 and 2：1 ratios are the greatest, and thus the HMX/DMI cocrystals prefer cocrystallizing in the 1：1 and 2：1 molar ratios, which have good mechanical properties. The sensitivity change of cocrystal originates from not only the formation of intermolecular interaction but also the increment of bond dissociation energy of the N–NO2 bond. The cooperativity effect appears in the linear complex while the anti-cooperativity effect is found in the cyclic system. DMI binding to HMX is not energetically and structurally favored in the presence of HF. This is perhaps the reason that the solvent with large dielectric constant weakens the stability of the HMX/DMI cocrystals. Therefore, the solvents with low dielectric constants should be chosen in the preparation of HMX/DMI cocrystals.展开更多
Six fully optimized geometries of urea nitrate cation and RDX complexes have been obtained with DFT-B3LYP and MP2 methods at the 6-311＋＋G＊＊ level. The intermolecular interaction energies have been calculated with ...Six fully optimized geometries of urea nitrate cation and RDX complexes have been obtained with DFT-B3LYP and MP2 methods at the 6-311＋＋G＊＊ level. The intermolecular interaction energies have been calculated with basis set superposition error （BSSE） and zero point energy （ZPE） correction. The nature of intermolecular interaction has been revealed by the analysis of AIM and NBO. The results indicate that the greatest binding energy of urea nitrate with RDX is –82.47kJ/mol. The O–H…O and N–H…O hydrogen bonds are important intermolecular interactions of urea nitrate cation with RDX, and the origin of hydrogen bonds is the oxygen atom offering its lone-pair electrons to the σ（O-H）＊ or σ（O-H）＊ antibonding orbital. The intermolecular interactions strengthen the N–NO2 bond, leading to the reduced sensitivity of urea nitrate and RDX mixture explosive.展开更多
The permeation enhancing activity of Azone for ketoprofen through excised cavia skins was investigated using Franz diffusion cell. The possible hydrogen-bonded complexes formed between ketoprofen and the model molecul...The permeation enhancing activity of Azone for ketoprofen through excised cavia skins was investigated using Franz diffusion cell. The possible hydrogen-bonded complexes formed between ketoprofen and the model molecule of Azone as azacyclopentane-2-one were fully optimized at the B3LYP/6-311＋＋G＊＊ level. The intermolecular hydrogen-bonding interactions were calculated 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 the steady-state permeation rate of ketoprofen through excised cavia skins enhances over 9 times in the solvent with 2% Azone as compared with the solvent without Azone. The stable O–H…O=C and N–H…O=C hydrogen-bonded complexes could exist between azacyclopentane and ketoprofen. The hydrogen-bonding interaction energy follows the order of（a） 〉（b） 〉（c） 〉（d） 〉（g）〉（e） 〉（h） 〉（f）. The formation of the complexes leads to the change of the conformation and molecular polarity of ketoprofen, and thus causes a better percutaneous permeation for the drug. The analyses of AIM（atom in molecule） and shift of electron density were used to further reveal the nature of the enhancing permeation activity of Azone for ketoprofen. The investigations of the temperature and solvent effects confirm that ketoprofen might enter into the skin by means of the Azone complex.展开更多
Six fully optimized structures of the aza-calix[2]arene[2]-triazines/RDX supramo-lecular complexes have been obtained at the DFT-B3LYP/6-311＋＋G＊＊ level,and the corresponding intermolecular interactions have been i...Six fully optimized structures of the aza-calix[2]arene[2]-triazines/RDX supramo-lecular complexes have been obtained at the DFT-B3LYP/6-311＋＋G＊＊ level,and the corresponding intermolecular interactions have been investigated using the B3LYP,mPWPW91 and MP2 methods at the 6-311＋＋G＊＊ level,respectively.The natural bond orbital（NBO） and atoms in molecules（AIM） analyses have been performed to reveal the origin of interactions.To our interest,the result indicates that the strongest interaction is up to-22.34 kJ/mol after basis set superposition error（BSSE） and zero point energy（ZPE） correction at the MP2/6-311＋＋G＊＊ level.Furthermore,the intermolecular interactions between aza-calix[2]arene[2]-triazines with the substituted amidos and RDX are stronger than those of other complexes.Thus,the complexes with amidos can be used as the candidates to increase the stability of explosive and eliminate the explosive wastewater.展开更多
The structures and energies of the side-on complexes B2（N2）2 and monocyclic Bn（N2）nm （n = 3～6,m = -1～＋2） between N2 （1∑＋g） and B （2P） have been investigated by the DFT-B3LYP and MP2 methods at the 6-311...The structures and energies of the side-on complexes B2（N2）2 and monocyclic Bn（N2）nm （n = 3～6,m = -1～＋2） between N2 （1∑＋g） and B （2P） have been investigated by the DFT-B3LYP and MP2 methods at the 6-311＋G（2d） and aug-cc-pVTZ levels. The analyses of NICS （Nucleus Independent Chemical Shifts）,NBO （nature bond orbital）,AIM （atoms in molecules） and frontal orbitals have been used to reveal the origin of coordination bond between the π-electron donor N2 group and B atom,accompanied by the comparison with the end-on complexes. The results have indicated that the side-on coordination complexes can be formed due to the relative strong fluidity of the π-electrons,and the nature of the coordination bond has been exposed to be that the N2 group offers 1πu electron to the 2p orbital of boron. The coordinate energies of the side-on complexes are less than those of the end-on complexes. Furthermore,the aromaticity of side-on coordination complex is weaker than that of the corresponding end-on coordination complex.展开更多
基金supported from the Natural Science Foundation of Shanxi Province(2009011014)
文摘The structures of the complexes generated by hexamethylenetetramine and nitric acid have been fully optimized by B3LYP method at the 6-311＋＋G＊＊ and aug-cc-pVTZ levels. The intermolecular hydrogen-bonding interactions have been calculated by the B3LYP/6-311＋＋G＊＊, B3LYP/aug-cc-pVTZ, MP2（full）/6-311＋＋G＊＊ and CCSD（T）/6-311＋＋G＊＊ methods, respectively. The NBO （nature bond orbital）, AIM （atom in molecule）, temperature effect and solvation effect have been analyzed to reveal the origin of the interactions. The results indicate that the stable hydrogen-bonded complexes could be generated by hexamethylenetetramine and nitric acid. The interactions follow the order of （a）（e）（b）（c）（d）（f）（g）. The C–N bonds which are adjacent to the methylene involving the hydrogen bonds tend to break in the chemical reaction. Due to the exothermic process, low temperature is conducive to the formation of the composition, which tallies with the experimental result.
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.
文摘Molecular dynamics method was employed to study the binding energies of the selected crystal planes of the 1,3,5,7-tetranitro-1,3,5,7-tetrazacyclooctane（HMX）/1,3-dimethyl-2-imidazolidinone（DMI） cocrystal in different molecular molar ratios. The mechanical properties were estimated in different molar ratios. Solvent effects were evaluated and the cooperativity effects were discussed in the HMX···HF···DMI ternary by using the M06-2x/6-311＋G（2df,2p） and MP2（full）/6-311＋G（2df,2p） methods. The results indicate that the substituted patterns（020） and（100） own the highest binding energies. The stabilities of cocrystals in the 1：1 and 2：1 ratios are the greatest, and thus the HMX/DMI cocrystals prefer cocrystallizing in the 1：1 and 2：1 molar ratios, which have good mechanical properties. The sensitivity change of cocrystal originates from not only the formation of intermolecular interaction but also the increment of bond dissociation energy of the N–NO2 bond. The cooperativity effect appears in the linear complex while the anti-cooperativity effect is found in the cyclic system. DMI binding to HMX is not energetically and structurally favored in the presence of HF. This is perhaps the reason that the solvent with large dielectric constant weakens the stability of the HMX/DMI cocrystals. Therefore, the solvents with low dielectric constants should be chosen in the preparation of HMX/DMI cocrystals.
文摘Six fully optimized geometries of urea nitrate cation and RDX complexes have been obtained with DFT-B3LYP and MP2 methods at the 6-311＋＋G＊＊ level. The intermolecular interaction energies have been calculated with basis set superposition error （BSSE） and zero point energy （ZPE） correction. The nature of intermolecular interaction has been revealed by the analysis of AIM and NBO. The results indicate that the greatest binding energy of urea nitrate with RDX is –82.47kJ/mol. The O–H…O and N–H…O hydrogen bonds are important intermolecular interactions of urea nitrate cation with RDX, and the origin of hydrogen bonds is the oxygen atom offering its lone-pair electrons to the σ（O-H）＊ or σ（O-H）＊ antibonding orbital. The intermolecular interactions strengthen the N–NO2 bond, leading to the reduced sensitivity of urea nitrate and RDX mixture explosive.
基金Supported by Natural Science Foundation of Shanxi Province(No.2012011007-5)the application and innovation project in police(No.2011YYCXSXST016)
文摘The permeation enhancing activity of Azone for ketoprofen through excised cavia skins was investigated using Franz diffusion cell. The possible hydrogen-bonded complexes formed between ketoprofen and the model molecule of Azone as azacyclopentane-2-one were fully optimized at the B3LYP/6-311＋＋G＊＊ level. The intermolecular hydrogen-bonding interactions were calculated 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 the steady-state permeation rate of ketoprofen through excised cavia skins enhances over 9 times in the solvent with 2% Azone as compared with the solvent without Azone. The stable O–H…O=C and N–H…O=C hydrogen-bonded complexes could exist between azacyclopentane and ketoprofen. The hydrogen-bonding interaction energy follows the order of（a） 〉（b） 〉（c） 〉（d） 〉（g）〉（e） 〉（h） 〉（f）. The formation of the complexes leads to the change of the conformation and molecular polarity of ketoprofen, and thus causes a better percutaneous permeation for the drug. The analyses of AIM（atom in molecule） and shift of electron density were used to further reveal the nature of the enhancing permeation activity of Azone for ketoprofen. The investigations of the temperature and solvent effects confirm that ketoprofen might enter into the skin by means of the Azone complex.
文摘Six fully optimized structures of the aza-calix[2]arene[2]-triazines/RDX supramo-lecular complexes have been obtained at the DFT-B3LYP/6-311＋＋G＊＊ level,and the corresponding intermolecular interactions have been investigated using the B3LYP,mPWPW91 and MP2 methods at the 6-311＋＋G＊＊ level,respectively.The natural bond orbital（NBO） and atoms in molecules（AIM） analyses have been performed to reveal the origin of interactions.To our interest,the result indicates that the strongest interaction is up to-22.34 kJ/mol after basis set superposition error（BSSE） and zero point energy（ZPE） correction at the MP2/6-311＋＋G＊＊ level.Furthermore,the intermolecular interactions between aza-calix[2]arene[2]-triazines with the substituted amidos and RDX are stronger than those of other complexes.Thus,the complexes with amidos can be used as the candidates to increase the stability of explosive and eliminate the explosive wastewater.
文摘The structures and energies of the side-on complexes B2（N2）2 and monocyclic Bn（N2）nm （n = 3～6,m = -1～＋2） between N2 （1∑＋g） and B （2P） have been investigated by the DFT-B3LYP and MP2 methods at the 6-311＋G（2d） and aug-cc-pVTZ levels. The analyses of NICS （Nucleus Independent Chemical Shifts）,NBO （nature bond orbital）,AIM （atoms in molecules） and frontal orbitals have been used to reveal the origin of coordination bond between the π-electron donor N2 group and B atom,accompanied by the comparison with the end-on complexes. The results have indicated that the side-on coordination complexes can be formed due to the relative strong fluidity of the π-electrons,and the nature of the coordination bond has been exposed to be that the N2 group offers 1πu electron to the 2p orbital of boron. The coordinate energies of the side-on complexes are less than those of the end-on complexes. Furthermore,the aromaticity of side-on coordination complex is weaker than that of the corresponding end-on coordination complex.
