Three-dimensional periodic supramolecular organic framework ion sponge in water and microcrystals

Abstract

Self-assembly has emerged as a powerful approach to generating complex supramolecular architectures. Despite there being many crystalline frameworks reported in the solid state, the construction of highly soluble periodic supramolecular networks in a three-dimensional space is still a challenge. Here we demonstrate that the encapsulation motif, which involves the dimerization of two aromatic units within cucurbit[8]uril, can be used to direct the co-assembly of a tetratopic molecular block and cucurbit[8]uril into a periodic three-dimensional supramolecular organic framework in water. The periodicity of the supramolecular organic framework is supported by solution-phase small-angle X-ray-scattering and diffraction experiments. Upon evaporating the solvent, the periodicity of the framework is maintained in porous microcrystals. As a supramolecular ‘ion sponge’, the framework can absorb different kinds of anionic guests, including drugs, in both water and microcrystals, and drugs absorbed in microcrystals can be released to water with selectivity.

In Situ Loading and Delivery of Short Single- and Double-Stranded DNA by Supramolecular Organic Frameworks

“…Diamondoid SOFs are regular porous supramolecular polyelectrolytes co-assembled by tetracationic monomers and CB [8]. 32 With (4-phenyl)pyridinium as the binding subunit through the CB [8] encapsulation-enhanced dimerization binding motif, which has found wide applications in supramolecular self-assembly, [39][40][41][42][43][44][45][46][47][48][49][50] the water-soluble, polycationic frameworks form ordered pores that have a size of approximately 2.2 nm. 32 Previously, we demonstrated their robustness as molecular drug carriers to attain intracellular transport and low cytotoxicity.…”

“…32 With (4-phenyl)pyridinium as the binding subunit through the CB [8] encapsulation-enhanced dimerization binding motif, which has found wide applications in supramolecular self-assembly, [39][40][41][42][43][44][45][46][47][48][49][50] the water-soluble, polycationic frameworks form ordered pores that have a size of approximately 2.2 nm. 32 Previously, we demonstrated their robustness as molecular drug carriers to attain intracellular transport and low cytotoxicity. 38,51 Given the polyanionic feature of DNA and the approximately 2.0 nm diameter of dsDNA, 52,53 we hypothesized that diamondoid SOFs would be suitable carriers for the inclusion of both short ssDNA, with smaller diameter as compared to dsDNA, and dsDNA through multivalent electrostatic interactions, 54,55 which is the basis for all reported polycationic DNA carriers.…”

“…SOF-a-g, constructed from 1a-g and CB [8] (1∶2), were thus used to exploit this potential ( Figure 1). The first six frameworks have been reported for the inclusion of discrete organic guests and for SOF postmodification, 32,56 while SOF-g was designed to test the generality of this new delivery strategy.…”

“…Recently, we developed a general strategy for the generation of water-soluble, three-dimensional supramolecular organic frameworks (SOFs) from the coassembly of pre-organized multi-cationic monomers with cucurbit [8]uril (CB [8]). [32][33][34][35][36][37] As a family of selfassembled, water-soluble, porous polyelectrolytes, diamondoid SOFs were demonstrated to adsorb anionic guests and deliver adsorbed chemotherapeutic reagents, such as pemetrexed, into tumor cells. 38 Herein, we describe seven SOFs, with a pore size of approximately 2.0-2.2 nm, that can incorporate short single -or doublestranded (ss-or ds-) DNA (21,23, and 58 nt) in a facile manner by simply mixing the two species together and deliver the DNA strands into noncancerous and cancerous cells.…”

A polyrotaxanated covalent organic network based on viologen and cucurbit[7]uril

“…Owing to their rich redox chemistry 18 and their ability to form inclusion complexes with a number of macrocyclic receptors such as crown ethers 21 , calixarenes 22 , cyclodextrins 23 , cucurbiturils 24,25 , viologens, i.e., 4,4′-bipyridinium ions, are among the most studied ionic moieties in supramolecular chemistry [26][27][28] . To date, several viologen-based ICOFs have been synthesized by conventional methods 15,18,29,30 ; however, the products of these usually high-temperature reactions tend to be insoluble, microcrystalline powders with morphologies that are difficult to control and that have a limited range of practical application.…”