Two lanthanide-oxo-cluster polymers were synthesized by hydrothermal reaction using Ln_2O_3 as initial lanthanide materials:[Ln_4(SO_4)_4(OH)_4(H_2O)_7]·_4H_2O(Ln = Er 1,Ho 2),and characterized by PXRD,I...Two lanthanide-oxo-cluster polymers were synthesized by hydrothermal reaction using Ln_2O_3 as initial lanthanide materials:[Ln_4(SO_4)_4(OH)_4(H_2O)_7]·_4H_2O(Ln = Er 1,Ho 2),and characterized by PXRD,IR spectra,X-ray single-crystal diffraction,2D IR correlation spectra and UV-visible absorption spectra.Single-crystal X-ray analyses reveal that compounds 1 and 2 are isostructural,and they are both crystallized in the orthorhombic system Pccn space group.Compound 1 is a 3D lanthanide cluster polymer based on tetranuclear cubane-like [Er_4(μ_3-OH)_4]^8+ cations and SO_4^2- anions.The overall structure of 1 can be assigned to 6-connected pcu-type topology with the point symbol of(4^12.6^3).展开更多
A novel bis(guanidiniums) receptor for the catalytic cleavage of phosphosdiester was prepared and self-assembly architecture through hydrogen bonds and electrostatic interactions among the bis(guanidiniums) receptor, ...A novel bis(guanidiniums) receptor for the catalytic cleavage of phosphosdiester was prepared and self-assembly architecture through hydrogen bonds and electrostatic interactions among the bis(guanidiniums) receptor, the sulfate anion and water molecule was revealed by X-ray crystallographic analysis.展开更多
An intramolecular nucleophilic substitution of carbon anion to cyclic sulfate was first employed in asymmetric synthesis of (+)-(3R, 4S, 5R, 7S)-neoclausenamide 1 which is a novel hepatoprotective lactam isolated from...An intramolecular nucleophilic substitution of carbon anion to cyclic sulfate was first employed in asymmetric synthesis of (+)-(3R, 4S, 5R, 7S)-neoclausenamide 1 which is a novel hepatoprotective lactam isolated from the dry leaves of Chinese folk medicine Clausena lansium (Lour) Skeel. The regioselectivity of beta-attack to this cyclic sulfate, just like its epoxide counterpart was attributed to the increased reactivity of beta-position by the phenyl group.展开更多
Batch experiments were conducted to evaluate fluoride removal by Al,Fe,and Ti-based coagulants and adsorbents,as well as the effects of coexisting ions and formation of aluminum–fluoride complexes on fluoride removal...Batch experiments were conducted to evaluate fluoride removal by Al,Fe,and Ti-based coagulants and adsorbents,as well as the effects of coexisting ions and formation of aluminum–fluoride complexes on fluoride removal by co-precipitation with alum(Al_2(SO_4)_3·18H_2O).Aluminum sulfate was more efficient than the other coagulants for fluoride removal in the pH range between 6 and 8.Nano-crystalline TiO_2 was more effective for fluoride removal than Al and Fe hydroxides in a pH range of 3–5.Coexisting anions in water decreased the removal of fluoride in the order:phosphate(2.5 mg/L) 〉 arsenate(0.1 mg/L) 〉 bicarbonate(200 mg/L) 〉sulfate(100 mg/L) = nitrate(100 mg/L) 〉 silicate(10 mg/L) at a pH of 6.0.The effect of silicate became more significant at pH 〉 7.0.Calcium and magnesium improved the removal of fluoride.Zeta-potential measurements determined that the adsorption of fluoride shifted the PZC of Al(OH)_3 precipitates from 8.9 to 8.4,indicating the chemical adsorption of fluoride at the surface.The presence of fluoride in solution significantly increased the soluble aluminum concentration at pH 〈 6.5.A Visual MINTEQ modeling study indicated that the increased aluminum solubility was caused by the formation of AlF^(2+),AlF^(+2),and AlF_3complexes.The AlF_x complexes decreased the removal of fluoride during co-precipitation with aluminum sulfate.展开更多
基金supported by the National Natural Science Foundation of China(No.21473030)the Natural Science Foundation of Fujian Province(No.2013J01041)the Foundation of State Key Laboratory of Structural Chemistry(No.20130012)
文摘Two lanthanide-oxo-cluster polymers were synthesized by hydrothermal reaction using Ln_2O_3 as initial lanthanide materials:[Ln_4(SO_4)_4(OH)_4(H_2O)_7]·_4H_2O(Ln = Er 1,Ho 2),and characterized by PXRD,IR spectra,X-ray single-crystal diffraction,2D IR correlation spectra and UV-visible absorption spectra.Single-crystal X-ray analyses reveal that compounds 1 and 2 are isostructural,and they are both crystallized in the orthorhombic system Pccn space group.Compound 1 is a 3D lanthanide cluster polymer based on tetranuclear cubane-like [Er_4(μ_3-OH)_4]^8+ cations and SO_4^2- anions.The overall structure of 1 can be assigned to 6-connected pcu-type topology with the point symbol of(4^12.6^3).
基金Project supported by the National Science Foundation of China (No. 29872014)
文摘A novel bis(guanidiniums) receptor for the catalytic cleavage of phosphosdiester was prepared and self-assembly architecture through hydrogen bonds and electrostatic interactions among the bis(guanidiniums) receptor, the sulfate anion and water molecule was revealed by X-ray crystallographic analysis.
文摘An intramolecular nucleophilic substitution of carbon anion to cyclic sulfate was first employed in asymmetric synthesis of (+)-(3R, 4S, 5R, 7S)-neoclausenamide 1 which is a novel hepatoprotective lactam isolated from the dry leaves of Chinese folk medicine Clausena lansium (Lour) Skeel. The regioselectivity of beta-attack to this cyclic sulfate, just like its epoxide counterpart was attributed to the increased reactivity of beta-position by the phenyl group.
文摘Batch experiments were conducted to evaluate fluoride removal by Al,Fe,and Ti-based coagulants and adsorbents,as well as the effects of coexisting ions and formation of aluminum–fluoride complexes on fluoride removal by co-precipitation with alum(Al_2(SO_4)_3·18H_2O).Aluminum sulfate was more efficient than the other coagulants for fluoride removal in the pH range between 6 and 8.Nano-crystalline TiO_2 was more effective for fluoride removal than Al and Fe hydroxides in a pH range of 3–5.Coexisting anions in water decreased the removal of fluoride in the order:phosphate(2.5 mg/L) 〉 arsenate(0.1 mg/L) 〉 bicarbonate(200 mg/L) 〉sulfate(100 mg/L) = nitrate(100 mg/L) 〉 silicate(10 mg/L) at a pH of 6.0.The effect of silicate became more significant at pH 〉 7.0.Calcium and magnesium improved the removal of fluoride.Zeta-potential measurements determined that the adsorption of fluoride shifted the PZC of Al(OH)_3 precipitates from 8.9 to 8.4,indicating the chemical adsorption of fluoride at the surface.The presence of fluoride in solution significantly increased the soluble aluminum concentration at pH 〈 6.5.A Visual MINTEQ modeling study indicated that the increased aluminum solubility was caused by the formation of AlF^(2+),AlF^(+2),and AlF_3complexes.The AlF_x complexes decreased the removal of fluoride during co-precipitation with aluminum sulfate.