Host–Guest Recognition and Fluorescence of a Tetraphenylethene‐Based Octacationic Cage

Abstract

We report the synthesis and characterization of a three‐dimensional tetraphenylethene‐based octacationic cage that shows host–guest recognition of polycyclic aromatic hydrocarbons (e.g. coronene) in organic media and water‐soluble dyes (e.g. sulforhodamine 101) in aqueous media through CH⋅⋅⋅π, π–π, and/or electrostatic interactions. The cage⊃coronene exhibits a cuboid internal cavity with a size of approximately 17.2×11.0×6.96 Å3 and a “hamburger”‐type host–guest complex, which is hierarchically stacked into 1D nanotubes and a 3D supramolecular framework. The free cage possesses a similar cavity in the crystalline state. Furthermore, a host–guest complex formed between the octacationic cage and sulforhodamine 101 had a higher absolute quantum yield (ΦF=28.5 %), larger excitation–emission gap (Δλex‐em=211 nm), and longer emission lifetime (τ=7.0 ns) as compared to the guest (ΦF=10.5 %; Δλex‐em=11 nm; τ=4.9 ns), and purer emission (ΔλFWHM=38 nm) as compared to the host (ΔλFWHM=111 nm).

Adaptive Chirality of an Achiral Cucurbit[8]uril‐Based Supramolecular Organic Framework for Chirality Induction in Water

“…When compared with 1, SOF-1 has much better fluorescence properties (F F = 55.3 % and t = 4.91 ns) due to the efficient restriction of the intramolecular motion (RIM) of the TPE units in the interlocked framework structure of SOF-1 in the excited state (Figures 2 b and S21, Table S3). [23] Meanwhile, the emission wavelength was blue-shifted to 552 nm (Dl = À34 nm) because of the decrease in the degree of conjugation of the TPE core, as a result of the restriction of rotation (RIR) of the TPEs in SOF-1. [21b] Based on the fluorescence titration experiment of 2 with CB [8], coumarin dimerization in the cavity of CB [8] can induce an increase and red-shift of the emission at 420 nm with low intensity (F F < 0.1 %) (Figure S22).…”

Unveiling the Uncommon Fluorescent Recognition Mechanism towards Pertechnetate Using a Cationic Metal–Organic Framework Bearing N‐Heterocyclic AIE Molecules

“…As a well‐known functional group, the TPE backbone with AIE effect endows ZJU‐X8 with fluorescence properties [15] . We speculated that the fluorescence color might be affected when the nitrates were replaced by TcO 4 − /ReO 4 − [16] . Unexpectedly, ZJU‐X8 underwent a spectroscopic change from brilliant blue to flavovirens under UV light irradiation, implying its recognition capability.…”

“…[15] We speculated that the fluorescencec olor might be affected when the nitrates were replaced by Tc O 4 À /ReO 4 À . [16] Unexpectedly,Z JU-X8u nderwent as pectroscopic change from brilliant blue to flavovirensu nder UV light irradiation, implyingi ts recognition capability.T ov erify the recognition capability of ZJU-X8 toward TcO 4 À ,t he fluorescence spectra wererecorded by changing the concentration of surrogate ReO 4 À .U pon excitation at 365 nm, ZJU-X8 showed brilliant blue emission at 479 nm (Figure 2a)whilethe bare ReO 4 À hadn ofluorescence emission. In at ypical experiment,8mg of ZJU-X8 was added into 8mLo fa queous solution of ReO 4 À in different concentrationsa nd the mixture was stirred for 12 ht oe nsure anion-exchange equilibrium.…”

Chiral proline-substituted porous organic cages in asymmetric organocatalysis

“…Porous organic cages (POC), [16][17][18][19][20][21][22][23][24][25] which are assembled by individual organic molecules with guest-accessible intrinsic cavities, have shown vigorous development trends in many elds, such as gas storage and separation, [26][27][28][29][30][31][32] sensing, [33][34][35][36] hostguest chemistry, [37][38][39][40][41] and catalyst supports. [42][43][44][45][46][47] Compared with extended porous frameworks, POCs have clear advantages in solution processing, regeneration and functionalization.…”