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
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
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
Chiral metal-organic frameworks(CMOFs)with enantiomeric subunits have been employed in chiral chemistry.In this study,a CMOF formed from 6-methoxyl-(8S,9R)-cinchonan-9-ol-3-carboxylic acid(HQA)and ZnCl_(2),{(HQA)(ZnCl...Chiral metal-organic frameworks(CMOFs)with enantiomeric subunits have been employed in chiral chemistry.In this study,a CMOF formed from 6-methoxyl-(8S,9R)-cinchonan-9-ol-3-carboxylic acid(HQA)and ZnCl_(2),{(HQA)(ZnCl_(2))(2.5H_(2)O)}n,was constructed as a chiral stationary phase(CSP)via an in situ fabrication approach and used for chiral amino acid and drug analyses for the first time.The{(HQA)(ZnCl_(2))(2.5H_(2)O)}n nanocrystal and the corresponding chiral stationary phase were systematically characterised using a series of analytical techniques including scanning electron microscopy,X-ray diffraction,Fourier transform infrared spectroscopy,circular dichroism,X-ray photoelectron spectroscopy,thermogravimetric analysis,and Brunauer-Emmett-Teller surface area measurements.In opentubular capillary electrochromatography(CEC),the novel chiral column exhibited strong and broad enantioselectivity toward a variety of chiral analytes,including 19 racemic dansyl amino acids and several model chiral drugs(both acidic and basic).The chiral CEC conditions were optimised,and the enantioseparation mechanisms are discussed.This study not only introduces a new high-efficiency member of the MOF-type CSP family but also demonstrates the potential of improving the enantioselectivities of traditional chiral recognition reagents by fully using the inherent characteristics of porous organic frameworks.展开更多
Fluorescent three-dimensional(3-D)superlattices of dansyl glutathione protected gold nanoparticles,with potential applications in molecular detection,have been synthesized at an air/water interface by controlling the ...Fluorescent three-dimensional(3-D)superlattices of dansyl glutathione protected gold nanoparticles,with potential applications in molecular detection,have been synthesized at an air/water interface by controlling the pH of the nanoparticle suspension.The number of fluorophores per nanoparticle was calculated to be~127.Morphologies of the superlattice crystals were examined using scanning electron microscopy(SEM).Most of the crystals observed were triangular in shape.High-resolution transmission electron microscopy(HRTEM)and small angle X-ray scattering(SAXS)were used to study the packing of nanoparticles in these crystals.Both these studies showed that the nanoparticles were arranged in a face-centered cubic(fcc)pattern with a particle-particle distance(center-center)of~10.5 nm.Evolution of the crystal morphologies with time was also examined.The fluorescence properties of these triangles were studied using confocal fluorescence imaging and confocal Raman mapping,which were in good agreement with the morphologies observed by SEM.The superlattice exhibits near-infrared(NIR)absorption in the range 1100-2500 nm.Easy synthesis of such functional nanoparticle-based solids makes it possible to use them in novel applications.We utilized the fluorescence of dansyl glutathione gold superlattice crystals for the selective detection of bovine serum albumin(BSA),the major protein constituent of blood plasma,based on the selective binding of the naphthalene ring of the dansyl moiety with site I of BSA.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
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.
基金This study was funded by the National Natural Science Foundation of China(Grant No.:82003705)the Shanghai Science and Technology Innovation Foundation(Grant Nos.:23010500200 and 23ZR1422700).
文摘Chiral metal-organic frameworks(CMOFs)with enantiomeric subunits have been employed in chiral chemistry.In this study,a CMOF formed from 6-methoxyl-(8S,9R)-cinchonan-9-ol-3-carboxylic acid(HQA)and ZnCl_(2),{(HQA)(ZnCl_(2))(2.5H_(2)O)}n,was constructed as a chiral stationary phase(CSP)via an in situ fabrication approach and used for chiral amino acid and drug analyses for the first time.The{(HQA)(ZnCl_(2))(2.5H_(2)O)}n nanocrystal and the corresponding chiral stationary phase were systematically characterised using a series of analytical techniques including scanning electron microscopy,X-ray diffraction,Fourier transform infrared spectroscopy,circular dichroism,X-ray photoelectron spectroscopy,thermogravimetric analysis,and Brunauer-Emmett-Teller surface area measurements.In opentubular capillary electrochromatography(CEC),the novel chiral column exhibited strong and broad enantioselectivity toward a variety of chiral analytes,including 19 racemic dansyl amino acids and several model chiral drugs(both acidic and basic).The chiral CEC conditions were optimised,and the enantioseparation mechanisms are discussed.This study not only introduces a new high-efficiency member of the MOF-type CSP family but also demonstrates the potential of improving the enantioselectivities of traditional chiral recognition reagents by fully using the inherent characteristics of porous organic frameworks.
基金The authors thank the Department of Science and Technology(DST),Government of India for constantly supporting our research program on nanomaterials.We gratefully thank Prof.C.N.R.Rao and Mr.Kanishka Biswas,JNCASR,Bangalore,India,for the SAXS measurements.Thanks are due to Prof.G.U.Kulkarni,Ms.T.Bhuvana and Ms.N.R.Selvi,JNCASR Bangalore,India,for the FESEM measurements.Thanks are due to Dr.C.Subramaniam for help in AFM measurements.We thank Mr.Mohammed Akbar Ali,Dept.of Chemistry,IIT Madras for the calculations using Gaussian-03.E.S.S.thanks the University Grants Commission(UGC)for a senior research fellowship.
文摘Fluorescent three-dimensional(3-D)superlattices of dansyl glutathione protected gold nanoparticles,with potential applications in molecular detection,have been synthesized at an air/water interface by controlling the pH of the nanoparticle suspension.The number of fluorophores per nanoparticle was calculated to be~127.Morphologies of the superlattice crystals were examined using scanning electron microscopy(SEM).Most of the crystals observed were triangular in shape.High-resolution transmission electron microscopy(HRTEM)and small angle X-ray scattering(SAXS)were used to study the packing of nanoparticles in these crystals.Both these studies showed that the nanoparticles were arranged in a face-centered cubic(fcc)pattern with a particle-particle distance(center-center)of~10.5 nm.Evolution of the crystal morphologies with time was also examined.The fluorescence properties of these triangles were studied using confocal fluorescence imaging and confocal Raman mapping,which were in good agreement with the morphologies observed by SEM.The superlattice exhibits near-infrared(NIR)absorption in the range 1100-2500 nm.Easy synthesis of such functional nanoparticle-based solids makes it possible to use them in novel applications.We utilized the fluorescence of dansyl glutathione gold superlattice crystals for the selective detection of bovine serum albumin(BSA),the major protein constituent of blood plasma,based on the selective binding of the naphthalene ring of the dansyl moiety with site I of BSA.
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.
