Novel thermo- and oxidation-responsive supramolecular polymeric vesicles in water were constructed from amphiphilic supramolecular diblock copolymers at 37 °C via pillar[6]arene-ferrocene based host–guest interaction, in which the host polymer was pillar[6]arene-terminal-modified poly(N-isopropylacrylamide) (PNIPAM-P[6]) synthesized by reversible addition–fragmentation chain transfer (RAFT) polymerization and the guest polymer was ferrocene-terminal-modified methoxy-poly(ethylene glycol) (mPEG-Fc). The host polymer formed micelles in water at 25 °C, and upon addition of guest mPEG-Fc, a hydrophilic supramolecular diblock copolymer PNIPAM-P[6] ⊃ mPEG-Fc was formed, which could become amphiphilic when heated to 37 °C and further self-assembled into supramolecular polymeric vesicles. The resulting vesicles exhibited good thermo- and oxidation-responsiveness, due to the solubility of the host polymer at different temperatures and the oxidation of the ferrocene moiety of the guest polymer, respectively. More importantly, the supramolecular polymeric vesicles could be further applied in the encapsulation of an anticancer drug (doxorubicin hydrochloride) and its controlled release in response to temperature and oxidizing agents.

•A pillar[6]arene-functionalized cholesterol derivative 1 was synthesized as a LMWG.•LMWG 1 could form an organogel in cyclohexane/n-hexanol.•The organogel was reversibly responsive to the temperature and shear stress.•The sol-gel phase transition behaviors could be tuned by the host-gust interaction.A pillar[6]arene-functionalized cholesterol derivative 1 was synthesized as a low molecular weight gelator (LMWG), which could form an organogel in the cyclohexane/n-hexanol (10:1, v/v) at 10 °C. The resulting organogel was reversibly responsive to the temperature and shear stress, respectively, and more importantly, it also could be tuned into the solution by the addition of ferrocenyl aminium derivative 2 and tuned back into the organogel followed by the addition of per-butylated pillar[6]arene (P[6]), due to the host-guest interactions.Download high-res image (205KB)Download full-size image

The swelling–shrinking transition of hydrogels is crucial for their wide applications such as actuators and drug delivery. We hereby fabricated a smart hydrogel with ferrocene groups on pendant of polymer networks. While it was immersed in the water-soluble pillar[6]arene (WP6) aqueous solution, the hydrogel was dramatically swollen, which was an approximately 11-fold promotion in weight compared with that in pure water, due to the formation of the inclusion complexes between WP6 and ferrocene groups in the hydrogel. In particular, the well-swollen hydrogel exhibited good responsiveness to multistimuli including temperature, pH, redox, and competitive guests by tuning the dissociation/formation of WP6–ferrocene inclusion complexes or the strength of their charges. Meanwhile, potential application of such a smart hydrogel in pH-responsive drug release was demonstrated as well.

Novel neutral guest molecules, G1–G7, are studied for their host–guest complexation with per-ethylated pillar[5]arene (EtP[5]A). Among them, G1 and G7, dibenzyl tetramethylene bis-carbamate derivatives, are found to afford a novel stable pseudo[2]rotaxane with EtP[5]A, respectively, and G7⊂EtP[5]A shows photoresponsive properties.

Two new triazole-based macrocyclic molecules, triazolophanes 1 and 2, have been synthesized by the copper(I)-catalyzed cycloaddition of bis-triazole azides and bis-alkynes. The X-ray crystal structures of triazolophanes 1 and 2 revealed that both of them had an oblique-pillar cavity with the chair-like conformation in the solid state, and in their crystal structures both of them could self-assemble through intermolecular nonconventional CH⋯N hydrogen-bonding interactions. 1H NMR titration studies indicated that triazolophane 2 could selectively and strongly bind HSO4−, H2PO4−, and HP2O73− to form 1:2 host–guest complexes in CDCl3 among the tested anions.

Squaramide-based tripodal anion receptors 1–3 have been prepared and their anion binding properties with various inorganic anions were investigated. Receptor 1 formed a dimeric complex in solid state and a 1:1 complex in solution with SO42−. All receptors 1–3 could selectively encapsulate SO42−via hydrogen bonds over other examined anions.

A novel and highly stable inclusion complex was formed between per-butylated pillar[6]arene and a ferrocenium cation, while the reduced form ferrocene only showed extremely weak binding affinity with per-butylated pillar[6]arene in organic solvents.

Novel linear supramolecular polymers were constructed by the orthogonal self-assembly of a heteroditopic monomer and a homoditopic monomer. The polymerization is driven by a combination of quadruple hydrogen bonding and benzo-21-crown-7 based host–guest complexation. The disassembly–assembly of these novel polymers could be reversibly switched by addition/removal of K+.

With 9,10-bis(3,3,3-triphenylprop-1-ynyl)anthracene (BTPYA) doped TPBi as an emissive layer, tunable OLED devices exhibited different emission colors (blue, near-white, green-yellow) controlled by the dopant ratio and driving voltage. The emissions were composed of the electrofluorescence of BTPYA, TPBi, and the electromer of BTPYA, an electroplex formed between BTPYA and TPBi.

A series of new P-bridgehead tripodal urea-based anion receptors 1–3 bearing phosphine oxide (PO) were synthesized and characterized. Their anion-binding ability was examined by UV–vis, 1H NMR, 31P NMR, and ESI-MS. The results revealed that receptors 1–3 showed good sensitivity, selectivity, and binding affinity for H2PO4− over NO3− and Br−, and among them receptor 2 showed the best binding affinity for H2PO4− over F−, Br−, CH3COO−, HSO4−, and NO3−. The Job plot experiments indicated that receptors 1–3 formed 1:1 stoichiometric complex with H2PO4−.

A novel pillar[5]arene-based heteroditopic receptor for ion pair recognition of alkylammonium salts with different alkyl chain lengths and different counterions was prepared, which showed the best association constant enhancement (71 times) to n-BuNH3+Cl− compared with monotopic receptor 1,4-dimethoxypillar[5]arene over corresponding Br− and CF3COO− salts in chloroform.

Novel neutral guest molecules, G1–G7, are studied for their host–guest complexation with per-ethylated pillar[5]arene (EtP[5]A). Among them, G1 and G7, dibenzyl tetramethylene bis-carbamate derivatives, are found to afford a novel stable pseudo[2]rotaxane with EtP[5]A, respectively, and G7⊂EtP[5]A shows photoresponsive properties.

Novel linear supramolecular polymers were constructed by the orthogonal self-assembly of a heteroditopic monomer and a homoditopic monomer. The polymerization is driven by a combination of quadruple hydrogen bonding and benzo-21-crown-7 based host–guest complexation. The disassembly–assembly of these novel polymers could be reversibly switched by addition/removal of K+.

Squaramide-based tripodal anion receptors 1–3 have been prepared and their anion binding properties with various inorganic anions were investigated. Receptor 1 formed a dimeric complex in solid state and a 1:1 complex in solution with SO42−. All receptors 1–3 could selectively encapsulate SO42−via hydrogen bonds over other examined anions.

A novel and highly stable inclusion complex was formed between per-butylated pillar[6]arene and a ferrocenium cation, while the reduced form ferrocene only showed extremely weak binding affinity with per-butylated pillar[6]arene in organic solvents.