Here,we designed asymmetric(m DS)and symmetrical(d DS)chiral V-shaped molecules by linking one or two dansyl groups to trans-1,2-cyclohexane diamine and investigated the solvent-regulated structural transformation and...Here,we designed asymmetric(m DS)and symmetrical(d DS)chiral V-shaped molecules by linking one or two dansyl groups to trans-1,2-cyclohexane diamine and investigated the solvent-regulated structural transformation and inversed circularly polarized luminescence(CPL)in the self-assemblies.Upon increasing water volume fraction(fw)in the mixed solvent of water/acetonitrile,asymmetric mDS selfassembled into hollow nanospheres and microtubes,while solid nanospheres and solid microplates were corresponding to symmetric d DS.During this transformation process,the emission of m DS and d DS was changed from yellow-green to blue and cyan color,which was ascribed to twisted intramolecular charge transfer(TICT)and locally excited(LE)fluorescence of V-shaped DS molecules.The conformation of N,Ndimethyl groups with respect to naphthalene ring also led to the transformation of structures.These tubular and platelike structures had stronger and reversed CPL signals in comparison with spheroidal structures.The chiral information of DS assembly could be effective transferred to achiral Nile red via co-assembly strategy,which endowed Nile red exhibiting inversed induced CPL signal regulated by water fraction.This work provides a method for achieving a variety of self-assembled structures with adjustable chiroptical properties.展开更多
Chiral separation of dansyl amino acids by capillary electrophoresis using mixed selectors of Mn(II)- L -alanine complex and β -cyclodextrin ( β -CD) was studied. Resolution was considerably superior to that obtaine...Chiral separation of dansyl amino acids by capillary electrophoresis using mixed selectors of Mn(II)- L -alanine complex and β -cyclodextrin ( β -CD) was studied. Resolution was considerably superior to that obtained by using either Mn(II)- L -alanine complex or β -CD alone. The effects of separation parameters,such as pH value of buffer solution,capillary temperature,the concentration of Mn(II)- L -alanine complex,the types of CD and ligand on the migration times and resolutions were investigated. Six different transition metal complexes, Cu(II), Zn(II),Co(II),Ni(II),Hg(II) and Cd(II)- L -alanine complexes have been employed and compared with Mn(II) complex. Differences in retention and selectivity were found. The substitution of Cu(II),Zn(II),Co(II) and Ni(II) for Mn(II) resulted in a better chiral resolution while Hg(II) and Cd(II) showed poorer resolution abilities. The chiral separation mechanism was also discussed briefly.展开更多
The aggregation of dansyl chloride (DNS-Cl) in acetone has been studied indetail by steady-state fluorescence techniques. It has been demonstrated that DNS-Cl is stable inacetone during purification and aggregation st...The aggregation of dansyl chloride (DNS-Cl) in acetone has been studied indetail by steady-state fluorescence techniques. It has been demonstrated that DNS-Cl is stable inacetone during purification and aggregation study processes. The aggregates are not solvolyzed inacetone, and do not take part in any chemical reactions either. It has been found that DNS-Cl tendsto aggregate even when its concentration is much lower than its solubility in acetone. Theaggregation is reversible, and both the aggregation and the deaggregation are very slow processes.Introduction of SDS has a positive effect upon the formation and stabilization of the aggregates.展开更多
The fluorescent spectra of two series of sulfonated polyelectrolytes respectively labeled with dansyl and pyrenyl groups were determined as a function of volume fraction φ THF of THF in DMSO/THF mixed solvents. When ...The fluorescent spectra of two series of sulfonated polyelectrolytes respectively labeled with dansyl and pyrenyl groups were determined as a function of volume fraction φ THF of THF in DMSO/THF mixed solvents. When φ THF 0.65, the maximum wavelength λ em and the intensity R F relative to that in DMSO for a band of dansylated samples, as well as I 1/I 3 for pyrene labeled samples varied slightly with increasing φ THF , indicating the capability of polyelectrolyte to maintain its chain solvation stable.As long as φ THF beyond 0.70, there was an abrupt drop in R F and λ em showing the sudden change in the chain solvation layer. I 1/I 3 decreased with an increase in the charge density of polyelectrolyte samples,suggesting the existence of aggregated structure even in pure DMSO.展开更多
基金financial support from the National Key R&D Program of China(No.2021YFA1200301)the National Natural Science Foundation of China(Nos.21890734,92156018,and 21972150)CAS Project for Young Scientists in Basic Research(No.YSBR-027)。
文摘Here,we designed asymmetric(m DS)and symmetrical(d DS)chiral V-shaped molecules by linking one or two dansyl groups to trans-1,2-cyclohexane diamine and investigated the solvent-regulated structural transformation and inversed circularly polarized luminescence(CPL)in the self-assemblies.Upon increasing water volume fraction(fw)in the mixed solvent of water/acetonitrile,asymmetric mDS selfassembled into hollow nanospheres and microtubes,while solid nanospheres and solid microplates were corresponding to symmetric d DS.During this transformation process,the emission of m DS and d DS was changed from yellow-green to blue and cyan color,which was ascribed to twisted intramolecular charge transfer(TICT)and locally excited(LE)fluorescence of V-shaped DS molecules.The conformation of N,Ndimethyl groups with respect to naphthalene ring also led to the transformation of structures.These tubular and platelike structures had stronger and reversed CPL signals in comparison with spheroidal structures.The chiral information of DS assembly could be effective transferred to achiral Nile red via co-assembly strategy,which endowed Nile red exhibiting inversed induced CPL signal regulated by water fraction.This work provides a method for achieving a variety of self-assembled structures with adjustable chiroptical properties.
文摘Chiral separation of dansyl amino acids by capillary electrophoresis using mixed selectors of Mn(II)- L -alanine complex and β -cyclodextrin ( β -CD) was studied. Resolution was considerably superior to that obtained by using either Mn(II)- L -alanine complex or β -CD alone. The effects of separation parameters,such as pH value of buffer solution,capillary temperature,the concentration of Mn(II)- L -alanine complex,the types of CD and ligand on the migration times and resolutions were investigated. Six different transition metal complexes, Cu(II), Zn(II),Co(II),Ni(II),Hg(II) and Cd(II)- L -alanine complexes have been employed and compared with Mn(II) complex. Differences in retention and selectivity were found. The substitution of Cu(II),Zn(II),Co(II) and Ni(II) for Mn(II) resulted in a better chiral resolution while Hg(II) and Cd(II) showed poorer resolution abilities. The chiral separation mechanism was also discussed briefly.
基金theNationalNaturalScienceFoundationofChina (Nos.2 99730 2 4and 2 0 1730 35 ) ,theUniversityKeyTeacher’sFoundingProgramoftheMinistryofEducationofChina (No .30 0 6 )andtheNaturalScienceFoundationofShaanxiProvince (No .99H13)
文摘The aggregation of dansyl chloride (DNS-Cl) in acetone has been studied indetail by steady-state fluorescence techniques. It has been demonstrated that DNS-Cl is stable inacetone during purification and aggregation study processes. The aggregates are not solvolyzed inacetone, and do not take part in any chemical reactions either. It has been found that DNS-Cl tendsto aggregate even when its concentration is much lower than its solubility in acetone. Theaggregation is reversible, and both the aggregation and the deaggregation are very slow processes.Introduction of SDS has a positive effect upon the formation and stabilization of the aggregates.
文摘The fluorescent spectra of two series of sulfonated polyelectrolytes respectively labeled with dansyl and pyrenyl groups were determined as a function of volume fraction φ THF of THF in DMSO/THF mixed solvents. When φ THF 0.65, the maximum wavelength λ em and the intensity R F relative to that in DMSO for a band of dansylated samples, as well as I 1/I 3 for pyrene labeled samples varied slightly with increasing φ THF , indicating the capability of polyelectrolyte to maintain its chain solvation stable.As long as φ THF beyond 0.70, there was an abrupt drop in R F and λ em showing the sudden change in the chain solvation layer. I 1/I 3 decreased with an increase in the charge density of polyelectrolyte samples,suggesting the existence of aggregated structure even in pure DMSO.
