Reduction-sensitive, robust vesicles with a non-covalently modifiable surface as a multifunctional drug-delivery platform.

The design and synthesis of a novel reduction-sensitive, robust, and biocompatible vesicle (SSCB[6]VC) are reported, which is self-assembled from an amphiphilic cucurbit[6]uril (CB[6]) derivative that contains disulfide bonds between hexaethylene glycol units and a CB[6] core. The remarkable features of SSCB[6]VC include: 1) facile, non-destructive, non-covalent, and modular surface modification using exceptionally strong host-guest chemistry; 2) high structural stability; 3) facile internalization into targeted cells by receptor-mediated endocytosis, and 4) efficient triggered release of entrapped drugs in a reducing environment such as cytoplasm. Furthermore, a significantly increased cytotoxicity of the anticancer drug doxorubicin to cancer cells is demonstrated using doxorubicin-loaded SSCB[6]VC, the surface of which is decorated with functional moieties such as a folate-spermidine conjugate and fluorescein isothiocyanate-spermidine conjugate as targeting ligand and fluorescence imaging probe, respectively. SSCB[6]VC with such unique features can be used as a highly versatile multifunctional platform for targeted drug delivery, which may find useful applications in cancer therapy. This novel strategy based on supramolecular chemistry and the unique properties of CB[6] can be extended to design smart multifunctional materials for biomedical applications including gene delivery.

Anion templating from a silver(i) dithiophosphate 1D polymer forming discrete cationic and neutral octa- and decanuclear silver(i) clusters.

We report on a Ag5 coordination polymer and discrete Ag8 and Ag10 dithiophosphate clusters. The cluster formation and structures were affected by the stoichiometric control of the M : L molar ratios used. The cluster [Ag5{S2P(O(i)Pr)2}4]n(PF6)n, , is a monomeric unit within a coordination polymer formed through the reaction between [Ag(CH3CN)4]PF6 and the dithiophosphate ligand, [S2P(O(i)Pr)2](-), used in a M : L molar ratio of 5 : 4. All other clusters formed in the study are discrete units with encapsulated anions within the metal framework. The clusters [Ag8(X){S2P(O(i)Pr)2}6](PF6) (X = F, , Cl, , Br, ) are all cationic and contain monoanionic halogens. The related cluster [Ag8(H/D){S2P(O(i)Pr)2}6](PF6) contains either a hydride or a deuteride ion, and , respectively. The cluster [Ag8(S){S2P(O(i)Pr)2}6], , is neutral due to the di-anionic nature of the encapsulated sulfide anion. Clusters were all formed by reacting [Ag(CH3CN)4]PF6 and [S2P(O(i)Pr)2](-) in a M : L molar ratio of 8 : 6 and stirring for 1 h in THF; thereafter the respective anions (one equiv.) were added in situ. The cluster [Ag10(I)4{S2P(O(i)Pr)2}6], , is also neutral due to the charge balancing of the additional metal and halogen. In this case the M : L : X molar ratio was 10 : 6 : 4. All new clusters were characterized by (1)H and (31)P NMR, and elemental analysis, and , , were characterized by single crystal X-ray diffraction.