Photoresponsive materials (PRMs) have long been a hot topic and photo-modulated smart surface is very appealing. Particularly, liquid crystalline PRMs are able to amplify and stabilize photoinduced orientation thanks to their self-assembling and ordering characteristics. Herein, the first pillararene-based azobenzene liquid crystalline PRM with well-defined structure is presented, which can avoid the usually ill-defined composition drawback of polymer PRMs and prevent the severe H-aggregation from suppressing or even completely blocking photoresponse in simple azobenzene derivatives. The pillar[5]arene-based macrocyclic azobenzenes with variant length spacers show wide temperature range smectic liquid crystalline mesophases and excellent film-formation property. The tubular pillar[5]arene macrocyclic framework provides sufficient free volume for azobenzene moieties to achieve reversible photoisomerization and photoalignment; thus, their thin films demonstrate excellent light-triggered modulation of surface free energy, wettability, and even photoalignment-mediated orientation of an upper layer discotic liquid crystal columnar mesophase. Such pillararene-based azobenzene liquid crystals represent novel and promising PRMs with extensive fascinating applications.

Two novel types of supramolecular nanocarriers fabricated by the amphiphilic host–guest inclusion complex formed from water-soluble pillar[6]arene (WP6) and azobenzene derivatives G1 or G2 have been developed, in which G1 is structurally similar to G2 but has an extra phenoxy group in its hydrophobic region. Supramolecular micelles can be initially formed by WP6 with G1, which gradually transform into layered structures with liquid-crystalline properties, whereas stable supramolecular vesicles are obtained from WP6 and G2, which exhibit dual photo- and pH-responsiveness. Notably, the resulting WP6⊃G2 vesicles can efficiently encapsulate anticancer drug mitoxantrone (MTZ) to achieve MTZ-loaded vesicles, which maintain good stability in a simulated normal physiological environment, whereas in an acid environment similar to that of tumor cells or with external UV irradiation, the encapsulated drug is promptly released. More importantly, cytotoxicity assay indicates that such vesicles have good biocompatibility and the MTZ-loaded vesicles exhibit comparable anticancer activity to free MTZ, especially with additional UV stimulus, whereas its cytotoxicity for normal cells was remarkably reduced. Flow cytometric analysis further confirms that the cancer cell death caused by MTZ-loaded vesicles is associated with apoptosis. Therefore, the dual pH- and UV-responsive supramolecular vesicles are a potential platform for controlled release and targeted anticancer drug delivery.

Two novel photochromic macrocycles 1 and 2 bearing dithienylethene units and urea building blocks have been synthesized, and their photochromic properties are described. Macrocycle 2 shows good photochromic properties, while the relatively smaller size of macrocycle 8b exhibits photochemically inactive properties due to the unfavourable ring conformational constraint. Moreover, the crystal structures of the urea-protected precursor macrocyles 3a, 3b, and 8b are presented.

A novel, bifunctional, quadruple hydrogen-bonding ureido-pyrimidinone (UPy) unit bridged by photochromic dithienylethene (1) has been synthesized, which affords linear assemblies in solution and undergoes concentration-dependent ring-opening polymerization. The two UPy functional groups of 1 can dimerize intramolecularly to form a cyclic monomer with the two thienyl rings fixed in a parallel conformation, which prohibits its photocyclization. We exploited the photochemical reactivity and resonance difference of the linker of the bis-UPy derivative as well as using the more typical ¹H NMR, DOSY, and Ubbelohde viscometry methods to investigate for the first time the ring–chain polymerization mechanism. Moreover, we fabricated a mixed polymer film with a fluorescent dye noncovalently endcapping the linear photochromic assemblies through quadruple hydrogen bonds, which showed nondestructive fluorescent read-out ability for data storage by fluorescence resonance energy transfer (FRET) from the fluorescent dye to the closed form of the diarylethene.

A selective nitration of calix[4]arene at the upper rim in one pot process was described by monitoring the time dependence of the distribution of products by high-performance liquid chromatography (HPLC). The discrimination of five nitrated products was accomplished by molecular symmetry considerations and ¹H NMR analysis. As a result, unusual 5,11,17-trinitrocalix[4]arene (2d) was obtained in 57% isolated yield. 5,11-Dinitro-calix[4]arene (2b) and 5,11,17-trinitrocalix[4]arene (2d) with tetranitrocalix[4]arene 2e were further characterized by crystal X-ray diffraction analysis. Furthermore, as an example of potential application, trinitrocalix[4]arene 2d could be converted to triaminocalix[4]arene 3d conveniently.