Reaction of p-t-butylcalix[6]arene with ethylene oxide gives a water soluble host compound with a hydrophobic cavity and it can include organic molecules and ions in aqueous solution.
The interaction of water-soluble P-(N,N-dimethylaminomethyl)-calix[8]arene(CX8)with calf thymus DNA was studied using neutral red(NR) as a probe by uv-vis spectroscopy.The effect factors such as the pH of solution and...The interaction of water-soluble P-(N,N-dimethylaminomethyl)-calix[8]arene(CX8)with calf thymus DNA was studied using neutral red(NR) as a probe by uv-vis spectroscopy.The effect factors such as the pH of solution and ionic strength on the spectra were also investigated.The interaction mechanism was proposed.The results show that the strong electrostatic interaction between DNA and CX8 existed,on the one hand,the oxyphosphate anion of DNA can be neutralized by CX8 partally,which induced the contraction of DNA and the conformational change of DNA,which led to release NR from NDA partially.On the other hand,the CX8 can also compete the electrostatic sites with NR directly.展开更多
The luminescent behavior on formation 1∶1 complex of 25,26,27,28 tetra carboxylic acid 5,11,17,23 calixarenesulfonate(L 2) and terbium(Ⅲ) ion was investigated by means of fluorescence spectra. The results showed tha...The luminescent behavior on formation 1∶1 complex of 25,26,27,28 tetra carboxylic acid 5,11,17,23 calixarenesulfonate(L 2) and terbium(Ⅲ) ion was investigated by means of fluorescence spectra. The results showed that the pH value of the solution had obviousan influence on the fluorescence intensity of L 2·Tb 3+ complex, but the fluorescence intensity was hardly changed over the pH range from 6 to 11. The complex exhibits a higher emission quantum yield( φ =0.31) in aqueous solution, which indicates energy transfer type emission. The complexation behavior of L 2 with trivalent lanthanoid ions(Tb 3+ and Eu 3+ ) was also studied in aqueous boracic acid(hydrochloric acid buffer solution(pH 8.0) at 25 ℃ by UV Vis and fluorescence measurements. The spectrophotometric titrations have been performed to give the complex stability constants( K S) for the stoichiometric 1∶1 inclusion complexation of L 2 with Tb 3+ and Eu 3+ . The complex stability for L 2·Eu 3+ was higher than that for L 2·Tb 3+ , but no characteristic fluorescence was found.展开更多
Calixarenes and pillararenes are cyclic oligomers containing repeating units of phenol and methane. The modification of ionized groups bring calixarenes and pillararenes derivates both good water solubility and strong...Calixarenes and pillararenes are cyclic oligomers containing repeating units of phenol and methane. The modification of ionized groups bring calixarenes and pillararenes derivates both good water solubility and strong binding affinities towards various organic/inorganic/biological guest molecules in both water and the solid state. Meanwhile, the pre-organized structures of these compounds are indispensable in constructing of stimuli-responsive supramolecular assembly. With these properties, the supramolecular selective binding and molecular assembly based on calixarene/pillararene are widely used in enzyme tandem assay, stimuli-responsive nanostructure, drug delivery, organelle fluorescent imaging, photo-controlled morphological change, organic and inorganic hybrid material, solid tunable photo-luminescence and so on. This review summarized the recent research progresses on the calixarene/pillararene-based supramolecular systems and discussed the expectation of the future development.展开更多
Raising cattle in feedlots is becoming more common in Argentina, but there is little information available about the effects of this practice on soil phosphorus (P) dynamics. In this study, concentrations of water and...Raising cattle in feedlots is becoming more common in Argentina, but there is little information available about the effects of this practice on soil phosphorus (P) dynamics. In this study, concentrations of water and Bray -1 extractable soil P were quantified in a feedlot (upper and lower slope positions in the feedlot pen), runoff area and pasture during 2006 - 2008. The feedlot showed higher P concentrations in all P forms, soluble reactive P, soluble nonreactive, total soluble P, and Bray-P1 when compared to runoff area and pasture. Most of the total soluble P was soluble reactive P from the soil in the feedlot and the runoff area, while soluble nonreactive P predominated in the pasture. Concentrations of total soluble P were elevated in the feedlot at the soil surface, ranging on average from 158.71 to 245.86 mg?P?kg?1, and had a rapid decrease within the first 20 cm and remained relatively low, about 25.53 - 27.33 mg?P?kg?1. The evidence that total soluble P concentration in the feedlot was significantly (p < 0.05) higher than that registered in the pasture at 20 - 40 and 40 - 60 cm soil depth suggests a potential transfer of P through the soil from the surface. Although the feedlot had a moderate increase of 23.05 to 24.55 mg?P?kg?1 from the background concentration, it may represent a long-term source of increased nutrient loading to groundwater. Soil extractable Bray-1 P in the top 0 - 2.5 cm fluctuated from 659.26 to 45.36 mg?P?kg?1 in the feedlot and pasture, respectively. The relationship between soil P extracted by test and TSP was linear, and correlation coefficient was r2 = 0.95.展开更多
文摘Reaction of p-t-butylcalix[6]arene with ethylene oxide gives a water soluble host compound with a hydrophobic cavity and it can include organic molecules and ions in aqueous solution.
文摘The interaction of water-soluble P-(N,N-dimethylaminomethyl)-calix[8]arene(CX8)with calf thymus DNA was studied using neutral red(NR) as a probe by uv-vis spectroscopy.The effect factors such as the pH of solution and ionic strength on the spectra were also investigated.The interaction mechanism was proposed.The results show that the strong electrostatic interaction between DNA and CX8 existed,on the one hand,the oxyphosphate anion of DNA can be neutralized by CX8 partally,which induced the contraction of DNA and the conformational change of DNA,which led to release NR from NDA partially.On the other hand,the CX8 can also compete the electrostatic sites with NR directly.
文摘The luminescent behavior on formation 1∶1 complex of 25,26,27,28 tetra carboxylic acid 5,11,17,23 calixarenesulfonate(L 2) and terbium(Ⅲ) ion was investigated by means of fluorescence spectra. The results showed that the pH value of the solution had obviousan influence on the fluorescence intensity of L 2·Tb 3+ complex, but the fluorescence intensity was hardly changed over the pH range from 6 to 11. The complex exhibits a higher emission quantum yield( φ =0.31) in aqueous solution, which indicates energy transfer type emission. The complexation behavior of L 2 with trivalent lanthanoid ions(Tb 3+ and Eu 3+ ) was also studied in aqueous boracic acid(hydrochloric acid buffer solution(pH 8.0) at 25 ℃ by UV Vis and fluorescence measurements. The spectrophotometric titrations have been performed to give the complex stability constants( K S) for the stoichiometric 1∶1 inclusion complexation of L 2 with Tb 3+ and Eu 3+ . The complex stability for L 2·Eu 3+ was higher than that for L 2·Tb 3+ , but no characteristic fluorescence was found.
基金the National Natural Science Foundation of China (Nos. 21672113, 21432004, 21772099,21861132001)
文摘Calixarenes and pillararenes are cyclic oligomers containing repeating units of phenol and methane. The modification of ionized groups bring calixarenes and pillararenes derivates both good water solubility and strong binding affinities towards various organic/inorganic/biological guest molecules in both water and the solid state. Meanwhile, the pre-organized structures of these compounds are indispensable in constructing of stimuli-responsive supramolecular assembly. With these properties, the supramolecular selective binding and molecular assembly based on calixarene/pillararene are widely used in enzyme tandem assay, stimuli-responsive nanostructure, drug delivery, organelle fluorescent imaging, photo-controlled morphological change, organic and inorganic hybrid material, solid tunable photo-luminescence and so on. This review summarized the recent research progresses on the calixarene/pillararene-based supramolecular systems and discussed the expectation of the future development.
文摘Raising cattle in feedlots is becoming more common in Argentina, but there is little information available about the effects of this practice on soil phosphorus (P) dynamics. In this study, concentrations of water and Bray -1 extractable soil P were quantified in a feedlot (upper and lower slope positions in the feedlot pen), runoff area and pasture during 2006 - 2008. The feedlot showed higher P concentrations in all P forms, soluble reactive P, soluble nonreactive, total soluble P, and Bray-P1 when compared to runoff area and pasture. Most of the total soluble P was soluble reactive P from the soil in the feedlot and the runoff area, while soluble nonreactive P predominated in the pasture. Concentrations of total soluble P were elevated in the feedlot at the soil surface, ranging on average from 158.71 to 245.86 mg?P?kg?1, and had a rapid decrease within the first 20 cm and remained relatively low, about 25.53 - 27.33 mg?P?kg?1. The evidence that total soluble P concentration in the feedlot was significantly (p < 0.05) higher than that registered in the pasture at 20 - 40 and 40 - 60 cm soil depth suggests a potential transfer of P through the soil from the surface. Although the feedlot had a moderate increase of 23.05 to 24.55 mg?P?kg?1 from the background concentration, it may represent a long-term source of increased nutrient loading to groundwater. Soil extractable Bray-1 P in the top 0 - 2.5 cm fluctuated from 659.26 to 45.36 mg?P?kg?1 in the feedlot and pasture, respectively. The relationship between soil P extracted by test and TSP was linear, and correlation coefficient was r2 = 0.95.
