Ziyong Li

Amide- and urea-functionalized dithienylethene: synthesis, photochromism, and binding with halide anions.

A versatile amide- and urea-functionalized dithienylethene has been successfully synthesized. Upon irradiation with UV or visible light, the compound showed excellent fatigue resistance. As a synthetic receptor, the dithienylethene displayed switchable affinities for Cl(-) and Br(-) anions when the UV/vis light was introduced. The switchable binding ability also had good reversibility.

Dendritic [2]Rotaxanes: Synthesis, Characterization, and Properties

A series of dendritic ammonium salts have been designed and synthesized. Subsequently, they were used to construct the corresponding [2]rotaxanes by a template-directed clipping approach. Unusually, two unsymmetrical dendritic [2]rotaxanes containing fluorophore (pyrene units) were also obtained; their optical properties, such as UV/vis absorption and fluorescence, were measured. The results indicate that these two rotaxanes possess stronger intermolecular interaction in the solid state than in solution. As a result, solutions of high concentration readily formed the excimer. These special rotaxanes might be applied in dynamic fluorescence-reponsive materials, and the rotaxane structure will also be used as a strategy to adjust the aggregated behaviors of fluorescent molecules.

Synthesis of [2]catenanes by template-directed clipping approach.

A series of [2]catenanes were efficiently synthesized in high yields by a template-directed clipping approach with the formation of one macrocycle around another macrocycle containing a dialkylammonium recognition site. Their structures were identified by the NMR spectra and ESI mass spectrometry, and their geometries were investigated by the theoretical calculation.

Switchable azo-macrocycles: from molecules to functionalisation

Azo-based compounds are a class of switchable systems that have been widely investigated. Furthermore, they are also important for the construction of macrocycles with photoresponsive characteristics. In recent years, there have been many reports describing versatile photoswitchable azo-macrocycles. In addition, the process of photoisomerisation has also been applied to the construction of many types of functionalised molecular machines, such as those required for host–guest chemistry, molecular machines and self-assembly systems. In this review, we summarise the recent progress of azo-macrocycles in molecular structure and functionalisation.

Synthesis, Photochromism, and Effects of Metal Ions on Fluorescence of Dithienylethenes Containing Imidazo[2,1-a]isoquinoline

Abstract Dithienylethene derivatives containing imidazo[2,1-a]isoquinolines were directly synthesized by treatment of the diketone with 2-ethynylbenzaldehyde in one pot. Their photochromism indicated that they can easily isomerize between the ring-open and ring-closed isomers upon irradiation with ultraviolet or visible light in CH2Cl2. At the same time, they display high selectivity toward Fe3+ by the fluorescence titration, such that the addition of Fe3+ can obviously suppress their fluorescence intensity. Supplemental materials are available for this article. Go to the publishers online edition of Synthetic Communications® to view the free supplemental file. GRAPHICAL ABSTRACT

Synthesis and Properties of Photochromic Diarylethene Containing N-Salicylideneaniline Units

A symmetrical diarylethene containing N-salicylideneaniline (Schiff base) units was synthesized. The structure was well confirmed by NMR spectroscopy, mass spectrometry, and elemental analysis. Its photochromism was investigated by UV/Vis absorption spectra and NMR. The result displayed that diarylethene can well perform photoisomerization, but no obvious intramolecular proton transfer was observed. Furthermore, we checked the effects of metal cations for the properties of N-salicylideneaniline-based diarylethene, which indicated that Cu2+ and Fe3+ cations can significantly affect the UV/Vis absorption spectra of diarylethene ring-open and ring-closed isomers.

Synthesis and biological evaluation of estrone 3-O-ether derivatives containing the piperazine moiety

Graphical abstract Figure. No caption available. HighlightsEstrone derivatives were synthesized.Biological activities of derivatives were investigated against prostate cancer cells and a1‐ARs.SAR of estrone derivatives was discussed. &NA; A series of new estrone derivatives were designed and synthesized, and their structures were confirmed by spectroscopic methods. All new estrone derivatives were investigated for their in vitro cytotoxic efficacies against a panel of three human prostate cancer cell lines (PC‐3, LNCaP, and DU145). The derivatives 6, 7, 10, 15, 16, 20, 21, 22, 24 and 26 showed important cytotoxic actions against individual carcinoma cell line collections. Moreover, antagonistic activities of compounds (7, 15, 16 and 21) towards a1‐ARs (&agr;1A, &agr;1B, and &agr;1D) were further evaluated using dual‐luciferase reporter assays, and the compounds 16 and 21 exhibited better a1‐ARs subtype selectivity. The structure–activity relationship (SAR) suggested that the substitutes type and position on the phenyl group leads to the interesting variations within pharmacological effects of resultant molecular systems.