（E） -4-chloro-4＇ -ethoxystilbene （2a） and （E） -4, 4＇ - dichlorostilbene （2b） were synthesized by the Witting-Homer reaction. The crystals of 2a and 2b were prepared through solvent evaporation and characteri...（E） -4-chloro-4＇ -ethoxystilbene （2a） and （E） -4, 4＇ - dichlorostilbene （2b） were synthesized by the Witting-Homer reaction. The crystals of 2a and 2b were prepared through solvent evaporation and characterized by the single-crystal X- ray diffraction. Molecular structure analysis confirms the E- configuration of C=C bond. The crystal of 2a reveals an orthorhombic and space group Pna21 structure while 2b shows a monoclinic and space group P21/c structure. The electronic structures of 2a and 2b were optimized at B3LYP/6-311 ＋ ＋ G （d, p） level. The Hirshfeld surface and fingerprint plot indicate close O-H and C1-H contacts and π-π stacking in 2a and 2b. Molecular electrostatic potential shows that the O and C1 atoms of 2a and C1 atoms of 2b have the minimum energies and they are more likely to be attacked by electrophiles in reaction. Frontier molecular orbitals analysis demonstrates that the △ELuMO_HOMO of 2a and 2b are 3.85 and 3.91 eV, respectively.展开更多
The growth mechanism of spectinomycin dihydrochloride crystal in pure water and acetone-water mixture at different temperatures has been studied by induction period measurement. The induction period was measured visua...The growth mechanism of spectinomycin dihydrochloride crystal in pure water and acetone-water mixture at different temperatures has been studied by induction period measurement. The induction period was measured visually. The solid-liquid interfacial tension was determined on the basis of classical homogenous nucleation theory and the surface entropy factor was calculated. It was shown that the interfacial tension and surface entropy factor increased with the increase of acetone concentration and the decrease of temperature. It was demonstrated that the growth mechanism of spectinomycin dihydrochloride crystal was controlled by birth and spread growth in pure water or in acetone-water mixture at high temperatures and turned from birth and spread growth to spiral growth with the increase of acetone concentration in acetone-water mixture at low temperatures.展开更多
Coordination polymeric solid, {[Ag 2 (bpp) 2 (H 2 O) 2 ](chd)·9H 2 O} n (1) (bpp = 1,3-bis(4-pyridyl) propane, H 2 chd = 1,4-cyclo-hexanedicarboxylic acid), has been obtained by the solution phase ultrasonic synt...Coordination polymeric solid, {[Ag 2 (bpp) 2 (H 2 O) 2 ](chd)·9H 2 O} n (1) (bpp = 1,3-bis(4-pyridyl) propane, H 2 chd = 1,4-cyclo-hexanedicarboxylic acid), has been obtained by the solution phase ultrasonic synthesis techniques. The structure established through X-ray structural analysis shows that the compound traps an interesting 1D water tape built by the alternating "three-pointed star" cage-like pentameric and D 2h tetrameric clusters (C2/c, Z = 4; a = 30.37(2) , b = 9.271(5) , and c = 18.89(1) ; β = 128.47°; V = 4164(4) 3 ). The novelty of the present complex is the rarely crystallographic example of the cage-shaped water pentamer, which is usually ascribed to a less-stable species. A first-principle density functional theory (DFT) calculation demonstrates that the interconnectivity between cage-like pentamers and D 2h tetramers is beneficial for contribution to the structural stabilization of these less-stable water cluster species.展开更多
文摘（E） -4-chloro-4＇ -ethoxystilbene （2a） and （E） -4, 4＇ - dichlorostilbene （2b） were synthesized by the Witting-Homer reaction. The crystals of 2a and 2b were prepared through solvent evaporation and characterized by the single-crystal X- ray diffraction. Molecular structure analysis confirms the E- configuration of C=C bond. The crystal of 2a reveals an orthorhombic and space group Pna21 structure while 2b shows a monoclinic and space group P21/c structure. The electronic structures of 2a and 2b were optimized at B3LYP/6-311 ＋ ＋ G （d, p） level. The Hirshfeld surface and fingerprint plot indicate close O-H and C1-H contacts and π-π stacking in 2a and 2b. Molecular electrostatic potential shows that the O and C1 atoms of 2a and C1 atoms of 2b have the minimum energies and they are more likely to be attacked by electrophiles in reaction. Frontier molecular orbitals analysis demonstrates that the △ELuMO_HOMO of 2a and 2b are 3.85 and 3.91 eV, respectively.
文摘The growth mechanism of spectinomycin dihydrochloride crystal in pure water and acetone-water mixture at different temperatures has been studied by induction period measurement. The induction period was measured visually. The solid-liquid interfacial tension was determined on the basis of classical homogenous nucleation theory and the surface entropy factor was calculated. It was shown that the interfacial tension and surface entropy factor increased with the increase of acetone concentration and the decrease of temperature. It was demonstrated that the growth mechanism of spectinomycin dihydrochloride crystal was controlled by birth and spread growth in pure water or in acetone-water mixture at high temperatures and turned from birth and spread growth to spiral growth with the increase of acetone concentration in acetone-water mixture at low temperatures.
基金supported by the National Natural Science Foundation of China (50971063)the Natural Science Foundation of Fujian Province (2003F006, 2010J01042, 2011J01047)+1 种基金the Scientific Research Foundation for the Returned Overseas Chinese Scholars, State Education Ministry of Chinathe Startup Package Funding of Huaqiao University (10BS210) for supporting
文摘Coordination polymeric solid, {[Ag 2 (bpp) 2 (H 2 O) 2 ](chd)·9H 2 O} n (1) (bpp = 1,3-bis(4-pyridyl) propane, H 2 chd = 1,4-cyclo-hexanedicarboxylic acid), has been obtained by the solution phase ultrasonic synthesis techniques. The structure established through X-ray structural analysis shows that the compound traps an interesting 1D water tape built by the alternating "three-pointed star" cage-like pentameric and D 2h tetrameric clusters (C2/c, Z = 4; a = 30.37(2) , b = 9.271(5) , and c = 18.89(1) ; β = 128.47°; V = 4164(4) 3 ). The novelty of the present complex is the rarely crystallographic example of the cage-shaped water pentamer, which is usually ascribed to a less-stable species. A first-principle density functional theory (DFT) calculation demonstrates that the interconnectivity between cage-like pentamers and D 2h tetramers is beneficial for contribution to the structural stabilization of these less-stable water cluster species.
