Multiple Efficient Fluorescence Emission from Cucurbit[10]uril-[Cd₄Cl₁₆]^8–-Based Pillared Diamond Porous Supramolecular Frameworks

Abstract

Cucurbit[10]uril (Q[10] or CB[10]), with the largest rigid cavity (ca. 1.0 nm) yet characterized in the cucurbiturils family, and indeed among all artificial macrocyclic receptors to date, has been successfully exploited to construct a novel Q[10]-[CdCl]-based pillared diamond porous supramolecular framework. Single-crystal X-ray diffraction analysis revealed that the three-dimensional open-nanotube-type porous framework is constructed from free Q[10] molecules and [CdCl] cluster anions through the outer surface interactions of Q[10]. Notably, the Q[10]-based porous framework host can accommodate guest dyes, such as rhodamine B (G1), pyrenemethanamine hydrochloride (G2), and bathocuproine hydrochloride (G3), to form solid materials with efficient red-green-blue (RGB) fluorescence. This work not only exemplifies a facile approach for the construction of macrocycle-based porous frameworks but also offers a simple, lower cost, yet still highly efficient means of preparing multi-emitting, including white-light-emitting, solid luminescent materials.

Synthesis, Adsorption, and Recognition Properties of a Solid Symmetric Tetramethylcucurbit[6]uril-Based Porous Supramolecular Framework

“…[6]-Based Porous Supramolecular Framework. Quite a few experimental results have proven that Q[n]-based porous supramolecular frameworks can take up various dyes and fused ring compounds and form solid fluorescent assemblies [29,30]. In the present case, different pores, gaps, spaces, and channels can be observed in the TMeQ immersing A in an acetonitrile solution containing FG6 yielded luminescent material FG6@A that exhibited a ∼2.5fold increase in fluorescence enhancement compared with the free FG6 (Figure 3(a)).…”

“…In general, loading porous framework A with a fluorescent guest could change conformation or aggregation state of the fluorescent guest and result in its fluorescence enhancement or quenching. Recent studies have shown that Q[n]-based supramolecular assemblies or frameworks can adsorb a variety of VOCs, whereas the adsorbed VOC could influence the florescence properties of the resulting FG@A luminescent materials [29,30]. us, the adsorption of 12 common VOCs was tested: dichloromethane, trichloromethane, tetrachloromethane, methanol, ethanol, acetone, acetonitrile, ethyl ether, benzene, toluene, formaldehyde, and tetrahydrofuran.…”

“…Nowadays, we know that the outer surface interaction of cucurbit[n]urils (Q[n]s), which is attributed to the positive electropotential outer surface of Q[n]s results in the formation of these novel Q[n]-based porous supramolecular frameworks [17]. Our group and others also demonstrated a series of Q[n]-based porous supramolecular frameworks in the absence and presence of different structure directing agents in different mediums [14,[22][23][24][25][26][27][28][29][30][31]. For example, allapally and Tian demonstrated a crystalline form of Q [6] via the outer surface interaction of cucurbit[n]uril, which exhibited high thermal stability, permanent porosity, and the highest specific surface area of any known solid-state forms of Q [6] [22].…”

“…Cao and coworkers demonstrated a series of supramolecular compounds constructed from decamethylcucurbit [5]uril (Me 10 Q [5]) and different HPAs or POMs; they found that the Me 10 Q[5]-HPA or POMs-based supramolecular framework exhibited reversible photochromic properties as well as excellent photocatalytic activity toward the degradation of methyl orange and rhodamine B under visible light irradiation [14,25,26]. Recently, we demonstrated a series of simple Q [10]-based supramolecular frameworks in the absence and presence of structure directing agents in aqueous HCl or HNO 3 solutions [27][28][29][30], which not only exhibited sequence selectivity isolation of specific metal cations, thus leading to these architectures being used as metal-selective materials [28], but also exhibited novel adsorption capacities for certain dyes and became novel luminescent materials [29], which could have special selective response to certain volatile compounds [30]. More recently, Fedin and coworkers demonstrated a series of novel supramolecular frameworks based on Q [6] and mono-/polynuclear bismuth(III)-and mercury(II)-ions.…”

Recent Advances in the Use of Metal-Organic Frameworks for Dye Adsorption

“…Interestingly, RhB@MOF could also be used to differentiate molecules with very similar structures such as o -, m - and p -xylenes, as well as fluoro-, chloro-, and bromobenzenes, rendering it a useful luminescent probe for the sensing of VOCs. A supramolecular cadmium framework was also prepared using cucurbit[10]uril (CB[10]) as the organic linker (Yao et al, 2017 ). Upon the encapsulation of rhodamine B, pyrenemethanamine hydrochloride and bathocuproine hydrochloride, the framework was observed to exhibit red-green-blue fluorescence, respectively.…”