Gold and Silver Chains from Tetrahydrothiophenocucurbit[6]uril as Au or Ag-Nanoparticles

Tetrahydrothiophenocucurbit[5 and 6]uril has been synthesized from tetrathiophenoglycoluril diether, providing thioether functionality at the exterior equatorial position of the cucurbituril cage. This functionality has been investigated for chemical modification through sulfoxide formation and subsequent Pummerer rearrangement to the acetoxy derivative of the tetrahydrothiophenocucurbit[5]uril. Nanoparticles of Au and Ag were prepared in the presence of tetrahydrothiophenocucurbit[6]uril, which curiously led to the formation of nanoparticle chains, growing in length over days to weeks.

Potential Applications of Cucurbit[n]urils and Their Derivatives in the Capture of Hazardous Chemicals

Cucurbit[n]urils (Q[n]s) are a relatively young family of macrocycles, consisting of glycoluril units bridged by methylene groups, and their unique structures have attracted extensive attention from chemists in recent decades. Due to the presence of a rigid hydrophobic inner cavity and two polar outer portals lined with carbonyl groups, Q[n]s not only encapsulate guest species into the cavity, but also coordinate with metal ions/clusters. Considerable achievements have been obtained in the fields of Q[n]s-based host-guest chemistry, coordination chemistry, as well as the combination of host-guest and coordination chemistry. Furthermore, the outer surface of Q[n]s has been demonstrated to be capable of interacting with definite species to generate supramolecular architectures in recent years. With more in-depth research into Q[n]s, their application studies have also emerged as a hot topic. This Minireview focuses on recent advances in the potential applications of solid-state materials based on Q[n]s and their derivatives for the capture and adsorption of hazardous chemicals from a solution or a gas mixture.

Preparation of polyethylene glycol-polyacrylic acid block copolymer micelles with pH/hypoxic dual-responsive for tumor chemoradiotherapy

Block copolymers of poly(ethylene glycol)-poly(acrylic acid) linked with metronidazole (MN-PAA-PEG) were prepared via carbodiimide and esterification methods, and self-assembled into core-shell micelles as nano radiosensitizers and carriers of doxorubicin (DOX) delivery. These DOX/MN-PAA-PEG micelles exhibited good pH value and hypoxia dual-responsive properties via analyzing the change of micelle size and drug‒release behavior under hypoxia humor condition. The results of the cell test indicated that DOX was efficiently delivered by DOX/MN-PAA-PEG micelles into the cell nuclei. Compared to 22.4 % of their DOX release under pH 7.4, the rate of DOX release from DOX/MN-PAA-PEG micelles under reducing condition (pH 5.0) was up to 55.9 %. DOX-loaded micelles under 600 MU electron radiation and hypoxia induced the rapidest apoptosis of the tumor-cells, indicating the synergistic effect of their radiotherapy and chemotherapy from the prepared micelles. In vivo investigation and fluorescence imaging revealed that MN-PAA-PEG possessed no toxicity on main organs, and DOX/MN-PAA-PEG micelles were mainly accumulated in the tumor site at 10 h of post-injection, suggesting their good passive tumor-targeted effect. These results suggested that DOX/MN-PAA-PEG micelles were promising candidates for chemoradiotherapy on tumor.

Cucurbit[7]uril-anchored polymer vesicles enhance photosensitization in the nucleus

Effective photosensitizers (PSs) are highly desirable in many applications, such as photodynamic therapy and catalytic chemistry. Here, we demonstrated that vesicles of cucurbit[7]uril (Q[7] or CB[7])-anchored polymers enhanced photosensitization in the nucleus. The polyacrylic acid chain spacer triggered Q[7] polymers on the surfaces of the vesicles at a regular distance, thus not only leading to efficient inhibition of the aggregation induced self-quenching of the porphyrin based cationic PS in aqueous solution but also maintaining the PS at high concentration on the nanoscale via stable host-guest interactions. Further experiments indicated that Q[7] polymer based vesicles as a PS loading vehicle had a high penetration depth, entering the nuclei of cancer cells. Therefore, highly enhanced photosensitization and efficient anticancer effects were achieved.

Synthesis and separation of cucurbit[n]urils and their derivatives

Cucurbit[n]uril chemistry has become an important part of contemporary supramolecular chemistry since cucurbit[n]urils (Q[n]s) are not only able to encapsulate various guests, but are also capable of coordinating to a wide range of metal ions, leading to the establishment of Q[n]-based host-guest chemistry and coordination chemistry. Each of these impressive developments can be attributed to the growth of protocols for obtaining Q[n]s. In this review, we survey synthetic procedures for obtaining cucurbit[n]urils and their substituted derivatives together with the separation and purification of these remarkable compounds. The coverage is aimed at both existing workers in the field as well as at those requiring an "entry" into Q[n]-based research.

Direct syntheses of cucurbit[7]uril-anchored polyacrylic acid microspheres and adsorption of basic dyes by the derivative

A series of cucurbit[7]uril-anchored polyacrylic acids were synthesized using (NH₄)₂S₂O₈ as both an initiator and oxidant. The polymers were further esterified with 2-naphthol to yield derivatives, which could be used as a stationary phase for the absorption of basic dyes.