SAW sensors using five different types of polymer to detect of chemical agents(DMMP,CH_3CN,CH_2Cl_2,DCP) have been fabricated and its gas response characteristics were extensively investigated.The polymers used as the...SAW sensors using five different types of polymer to detect of chemical agents(DMMP,CH_3CN,CH_2Cl_2,DCP) have been fabricated and its gas response characteristics were extensively investigated.The polymers used as the sensing material are polyisobutylene(PIB),polyepichlorohydrin(PECH),polydimethylsiloxane(PDMS),polyisoprene(PIP)and polybutadiene(PBD).Their thin films were coated on quartz substrate by spin coating technique.Three types of simulants gases,dimethylmethylphosphonate(DMMP),acetonitrile(CH_3CN)and dichloromethane(CH_2Cl_2),dichloropentane(DCP)were used as target gases,instead of the real nerve,blood,choking and vesicant agents.After spin coating of PIB and PECH,the substrates were heated to 65℃with N_2 flow for 1 h to remove the cyclohexane and ethylacetate which was used as solvent. PDMS was heated to 75℃with N_2 flow for 2 h to remove the ethylacetate which was used as solvent.PBD and PIP on the substrate were heated to 60℃with N_2 flow for 1 h to remove the benzen which was used as solvent.The sensing characteristics of the SAW sensors were measured by using E-5061A network analyzer.展开更多
A cleaner and eco-friendly method was developed for the preparation of tetrakis(aminomethyl)calix-[4]-resorcinarene via a synthetic pathway of five steps starting from methylresorcinol. This alternative methodology is...A cleaner and eco-friendly method was developed for the preparation of tetrakis(aminomethyl)calix-[4]-resorcinarene via a synthetic pathway of five steps starting from methylresorcinol. This alternative methodology is firstly based on avoiding the use of CH2BrCl, which is a non-eco-friendly substance with high ozone depletion potential, and on replacing it by CH2Cl2 as a readily available reagent with much less dangerous effects. Secondly, this method engages acetone or CH2Cl2 as the solvent of the bromination step in the place of the very toxic CCl4, leading to tetrakis(bromomethyl)calix-[4]-resorcinarene. The brominated intermediate has been reacted with sodium azide in acetone instead of the high-boiling solvent DMSO to produce tetrakis(azidomethyl) calix-[4]-resorcinarene without the need of tedious purification. Lastly, this work reports an efficient hydrogenation method of the versatile azido adduct employing Pt/C (5%) as the catalyst for the preparation of the amino cavitand as an alternative route with high atom economy that can replace the classical methods used currently.展开更多
Desorption energies of dichloromethane （CH2C12） and water （H20） in a metal-organic framework, MIL-53（A1）, were investi- gated by the combination of experimental （differential scanning calorimeter, DSC） and com...Desorption energies of dichloromethane （CH2C12） and water （H20） in a metal-organic framework, MIL-53（A1）, were investi- gated by the combination of experimental （differential scanning calorimeter, DSC） and computational （ab-initio calculations） methods. The differences of desorption energy and natural log of the frequency factor of CH2C12 and H20 in MIL-53（A1） were analyzed by a thermo active process using DSC measurements. The interaction energy of guest molecules with MIL-53（A1）, which corresponds to the desorption in the thermal active process, was explored using ab-initio calculation. As a result of the difference in the interaction energies of H20 and CH2C12 in MIL-53（A1）, the site near the p2-OH groups has two potential wells Both experimentally and computationally, MIL-53 presents the preferential adsorption of CH2C12 than H20.展开更多
Infrared absorption spectra of gaseous CH2Cl2 in the regions of 1200-12000 cm^-1 were measured using a Bruker IFS 120HR Fourier transform spectrometer in conjunction with a nmltipass cell. 47 vibrational levels of ove...Infrared absorption spectra of gaseous CH2Cl2 in the regions of 1200-12000 cm^-1 were measured using a Bruker IFS 120HR Fourier transform spectrometer in conjunction with a nmltipass cell. 47 vibrational levels of overtone and combinational spectral lines of the CH stretching （v1, v6）, bending （v2）, and rocking （v8） modes were analyzed and assigned. Utilizing the normal mode model and considering the coupling among CH stretching, bending and rocking vibrations, values of the harmonic frequency wi, the anharmonic constant xij, and the coefficients of Fermi and the Darling-Dennison resonances of v1, v6, v2 and v8 modes were also determined from experimental spectral data with nonlinear least-square fitting. These spectral constants reproduced the experimental levels very well. These results showed that Fermi resonance between CH stretching and rocking vibrations （kiss=-254.63 cm^-1） is stronger than that between CH stretching and bending vibrations （k122 = 54.87 cm^-1 ）; and that Darling-Dennison resonances between CH stretching and bending vibrations （k166=-215.28 cm^-1） is also much stronger than that between CH bending and rocking vibrations （k2288=5.72 cm^-1）.展开更多
The dynamic transformations of conformations and aromatic properties of [32]octaphyrins（1.0.1.0.1.0.1.0） through rotating the pyrrolic ring of the macrocycles are demonstrated by theoretical simulations in CH2Cl2 so...The dynamic transformations of conformations and aromatic properties of [32]octaphyrins（1.0.1.0.1.0.1.0） through rotating the pyrrolic ring of the macrocycles are demonstrated by theoretical simulations in CH2Cl2 solution. Facile multistep isomeriza- tions involving antiaromatic-Htickel and aromatic-Mobius topologies were also predicted by density functional theory （DFT）. The understanding of changes in topologies and aromaticities of free-base expanded porphrins may provide useful information to build new macrocycles with unique properties.展开更多
The crystal structure of the title complex, [Cu(C23H26N2)Cl2]2·2CH2Cl2, has been determined by single-crystal, X-ray diffraction techniques. The compound crystallizes as dark-green prisms in space group P21/c of ...The crystal structure of the title complex, [Cu(C23H26N2)Cl2]2·2CH2Cl2, has been determined by single-crystal, X-ray diffraction techniques. The compound crystallizes as dark-green prisms in space group P21/c of the monoclinic system, with Z=4 and unit cell dimensions a=1.710 9(7) nm, b=2.395 2(11) nm, c=1.348 9(6) nm and β=110.651(8)°. The complex consists of two similar but crystallographically independent dimers, of which Cu(Ⅱ) centers display five-coordinated trigonal-bipyramidal geometry with Cu-Cu separations in two centrosymmetric dimers are 0.345 1 and 0.347 8 nm, respectively, and in each dimer the two copper centers share a common edge formed by two bridging chloride ions, each being equatorial. Solvent molecules of CH2Cl2 are packed together in the crystal lattice. CCDC: 253299.展开更多
文摘SAW sensors using five different types of polymer to detect of chemical agents(DMMP,CH_3CN,CH_2Cl_2,DCP) have been fabricated and its gas response characteristics were extensively investigated.The polymers used as the sensing material are polyisobutylene(PIB),polyepichlorohydrin(PECH),polydimethylsiloxane(PDMS),polyisoprene(PIP)and polybutadiene(PBD).Their thin films were coated on quartz substrate by spin coating technique.Three types of simulants gases,dimethylmethylphosphonate(DMMP),acetonitrile(CH_3CN)and dichloromethane(CH_2Cl_2),dichloropentane(DCP)were used as target gases,instead of the real nerve,blood,choking and vesicant agents.After spin coating of PIB and PECH,the substrates were heated to 65℃with N_2 flow for 1 h to remove the cyclohexane and ethylacetate which was used as solvent. PDMS was heated to 75℃with N_2 flow for 2 h to remove the ethylacetate which was used as solvent.PBD and PIP on the substrate were heated to 60℃with N_2 flow for 1 h to remove the benzen which was used as solvent.The sensing characteristics of the SAW sensors were measured by using E-5061A network analyzer.
文摘A cleaner and eco-friendly method was developed for the preparation of tetrakis(aminomethyl)calix-[4]-resorcinarene via a synthetic pathway of five steps starting from methylresorcinol. This alternative methodology is firstly based on avoiding the use of CH2BrCl, which is a non-eco-friendly substance with high ozone depletion potential, and on replacing it by CH2Cl2 as a readily available reagent with much less dangerous effects. Secondly, this method engages acetone or CH2Cl2 as the solvent of the bromination step in the place of the very toxic CCl4, leading to tetrakis(bromomethyl)calix-[4]-resorcinarene. The brominated intermediate has been reacted with sodium azide in acetone instead of the high-boiling solvent DMSO to produce tetrakis(azidomethyl) calix-[4]-resorcinarene without the need of tedious purification. Lastly, this work reports an efficient hydrogenation method of the versatile azido adduct employing Pt/C (5%) as the catalyst for the preparation of the amino cavitand as an alternative route with high atom economy that can replace the classical methods used currently.
基金supported by the National Natural Science Foundation of China(21376026)the Fundamental Research Funds for the Central Universities(2015YJS172)
文摘Desorption energies of dichloromethane （CH2C12） and water （H20） in a metal-organic framework, MIL-53（A1）, were investi- gated by the combination of experimental （differential scanning calorimeter, DSC） and computational （ab-initio calculations） methods. The differences of desorption energy and natural log of the frequency factor of CH2C12 and H20 in MIL-53（A1） were analyzed by a thermo active process using DSC measurements. The interaction energy of guest molecules with MIL-53（A1）, which corresponds to the desorption in the thermal active process, was explored using ab-initio calculation. As a result of the difference in the interaction energies of H20 and CH2C12 in MIL-53（A1）, the site near the p2-OH groups has two potential wells Both experimentally and computationally, MIL-53 presents the preferential adsorption of CH2C12 than H20.
基金This work was supported by National Natural Science Foundation of China （Grant No. 10274077, 20103007 and 29703007）. The authors would like to thank Wei Chu, Yong-qiang Xu and Guo-sheng Cheng for their kind help.
文摘Infrared absorption spectra of gaseous CH2Cl2 in the regions of 1200-12000 cm^-1 were measured using a Bruker IFS 120HR Fourier transform spectrometer in conjunction with a nmltipass cell. 47 vibrational levels of overtone and combinational spectral lines of the CH stretching （v1, v6）, bending （v2）, and rocking （v8） modes were analyzed and assigned. Utilizing the normal mode model and considering the coupling among CH stretching, bending and rocking vibrations, values of the harmonic frequency wi, the anharmonic constant xij, and the coefficients of Fermi and the Darling-Dennison resonances of v1, v6, v2 and v8 modes were also determined from experimental spectral data with nonlinear least-square fitting. These spectral constants reproduced the experimental levels very well. These results showed that Fermi resonance between CH stretching and rocking vibrations （kiss=-254.63 cm^-1） is stronger than that between CH stretching and bending vibrations （k122 = 54.87 cm^-1 ）; and that Darling-Dennison resonances between CH stretching and bending vibrations （k166=-215.28 cm^-1） is also much stronger than that between CH bending and rocking vibrations （k2288=5.72 cm^-1）.
基金supported by the National Basic Research Program of China(2011CB808600)the National Natural Science Foundation of China(21273102)
文摘The dynamic transformations of conformations and aromatic properties of [32]octaphyrins（1.0.1.0.1.0.1.0） through rotating the pyrrolic ring of the macrocycles are demonstrated by theoretical simulations in CH2Cl2 solution. Facile multistep isomeriza- tions involving antiaromatic-Htickel and aromatic-Mobius topologies were also predicted by density functional theory （DFT）. The understanding of changes in topologies and aromaticities of free-base expanded porphrins may provide useful information to build new macrocycles with unique properties.
文摘The crystal structure of the title complex, [Cu(C23H26N2)Cl2]2·2CH2Cl2, has been determined by single-crystal, X-ray diffraction techniques. The compound crystallizes as dark-green prisms in space group P21/c of the monoclinic system, with Z=4 and unit cell dimensions a=1.710 9(7) nm, b=2.395 2(11) nm, c=1.348 9(6) nm and β=110.651(8)°. The complex consists of two similar but crystallographically independent dimers, of which Cu(Ⅱ) centers display five-coordinated trigonal-bipyramidal geometry with Cu-Cu separations in two centrosymmetric dimers are 0.345 1 and 0.347 8 nm, respectively, and in each dimer the two copper centers share a common edge formed by two bridging chloride ions, each being equatorial. Solvent molecules of CH2Cl2 are packed together in the crystal lattice. CCDC: 253299.
