A series of cholesterol-appended quinacridone (QA) derivatives 1a-1d have been synthesized,in which 1b and 1c could form stable organogels in a wide range of organic solvents upon ultrasound irradiation.Field emission...A series of cholesterol-appended quinacridone (QA) derivatives 1a-1d have been synthesized,in which 1b and 1c could form stable organogels in a wide range of organic solvents upon ultrasound irradiation.Field emission scanning electronic microscope (FESEM) and transmission electron microscopy (TEM) of xerogels or precipitates indicated that 1b and 1c formed 1D fibrous nanostructure,while 1a assembled into 3D flower-like microstructures.The ultrasound-induced organogel process was characterized by kinetic UV-vis and photoluminescence spectroscopic methods suggesting the formation of ?-? aggregates in the gel state.Experimental results demonstrated that the ultrasound could promote molecules to contact frequently in the solution and induce semistable initial aggregates,which propagate to form nano/micro superstructures.The aggregation model was optimized by semiempirical AM1 calculation suggesting the hierarchical self-assembly process.In addition,the formed xerogel film exhibited mechanochromic property,and the phase transition process was accompanied by the fluorescence changes between yellowish green and orange.展开更多
Two novel quinacridone (QA) cyclophanes with intrinsic intramolecular dye-dye interactions have been designed and synthesized.X-ray crystal structures as well as detailed photophysical properties have been well demons...Two novel quinacridone (QA) cyclophanes with intrinsic intramolecular dye-dye interactions have been designed and synthesized.X-ray crystal structures as well as detailed photophysical properties have been well demonstrated.These two dyes have a major advantage that efficient fluorescence quenching can be observed even in their dilute solutions.A comparison of photophysical properties between the dimeric QA cyclophane and its reference monomeric counterpart indicates that the dimerization is predominant for the fluorescence quenching of QA dyes in solution.This study provided some model QA derivatives with dimeric structures for understanding the fluorescence quenching of QA dyes in solutions.展开更多
It is a great challenge to spontaneously assemble achiral molecules into twisted nanostructures in the absence of chiral substances.Here we show that two achiral centrosymmetric quinacridone(QA)derivatives,N,N’-di(n-...It is a great challenge to spontaneously assemble achiral molecules into twisted nanostructures in the absence of chiral substances.Here we show that two achiral centrosymmetric quinacridone(QA)derivatives,N,N’-di(n-hexyl)-1,3,8,10-tetramethylquinacridone(C6TMQA)and N,N’-di(n-decyl)-1,3,8,10-tetramethylquinac ridone(C10TMQA),can be employed as building blocks to fabricate well-defi ned twisted nanostructures by controlling the solvent composition and concentration.Bowknot-like bundles with twisted fiber arms were prepared from C6TMQA,whilst uniform twisted fibers were generated from C10TMQA in ethanol/THF solution.Spectroscopic characterization and molecular simulation calculations revealed that the introduction of ethanol into the solution could induce a staggered aggregation of C6TMQA(or C10TMQA)molecules and the formation of twisted nanostructures.Such twisted materials generated from achiral organic functional molecules may be valuable in the design and fabrication of new materials for optoelectronic applications.展开更多
基金supported by the National Natural Science Foundation of China (50773027 and 50733002)the National Basic Research Development Program (2009CB939700)111 Project (B06009)
文摘A series of cholesterol-appended quinacridone (QA) derivatives 1a-1d have been synthesized,in which 1b and 1c could form stable organogels in a wide range of organic solvents upon ultrasound irradiation.Field emission scanning electronic microscope (FESEM) and transmission electron microscopy (TEM) of xerogels or precipitates indicated that 1b and 1c formed 1D fibrous nanostructure,while 1a assembled into 3D flower-like microstructures.The ultrasound-induced organogel process was characterized by kinetic UV-vis and photoluminescence spectroscopic methods suggesting the formation of ?-? aggregates in the gel state.Experimental results demonstrated that the ultrasound could promote molecules to contact frequently in the solution and induce semistable initial aggregates,which propagate to form nano/micro superstructures.The aggregation model was optimized by semiempirical AM1 calculation suggesting the hierarchical self-assembly process.In addition,the formed xerogel film exhibited mechanochromic property,and the phase transition process was accompanied by the fluorescence changes between yellowish green and orange.
基金supported by the National Natural Science Foundation of China (50773027 & 50903037)
文摘Two novel quinacridone (QA) cyclophanes with intrinsic intramolecular dye-dye interactions have been designed and synthesized.X-ray crystal structures as well as detailed photophysical properties have been well demonstrated.These two dyes have a major advantage that efficient fluorescence quenching can be observed even in their dilute solutions.A comparison of photophysical properties between the dimeric QA cyclophane and its reference monomeric counterpart indicates that the dimerization is predominant for the fluorescence quenching of QA dyes in solution.This study provided some model QA derivatives with dimeric structures for understanding the fluorescence quenching of QA dyes in solutions.
基金by the National Natural Science Foundation of China(50733002 and 50773027)the Major State Basic Research Development Program(2009CB939700)and 111 Project(B06009).
文摘It is a great challenge to spontaneously assemble achiral molecules into twisted nanostructures in the absence of chiral substances.Here we show that two achiral centrosymmetric quinacridone(QA)derivatives,N,N’-di(n-hexyl)-1,3,8,10-tetramethylquinacridone(C6TMQA)and N,N’-di(n-decyl)-1,3,8,10-tetramethylquinac ridone(C10TMQA),can be employed as building blocks to fabricate well-defi ned twisted nanostructures by controlling the solvent composition and concentration.Bowknot-like bundles with twisted fiber arms were prepared from C6TMQA,whilst uniform twisted fibers were generated from C10TMQA in ethanol/THF solution.Spectroscopic characterization and molecular simulation calculations revealed that the introduction of ethanol into the solution could induce a staggered aggregation of C6TMQA(or C10TMQA)molecules and the formation of twisted nanostructures.Such twisted materials generated from achiral organic functional molecules may be valuable in the design and fabrication of new materials for optoelectronic applications.
