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A novel luminescent macrocycle has been conveniently synthesized, which displays flexible conformations and interesting solid-state host – guest properties. Besides, the macrocycle exhibits excellent thermally activated delayed fluorescence (TADF) emission with a photoluminescence quantum yield of 80%, which represents the highest value among reported TADF macrocycles. [ABSTRACT FROM AUTHOR]

The exploration of macrocycle-based nonporous adaptive crystals (NACs) for adsorption and separation has been one of the hotspots in supramolecular chemistry and crystal engineering. Herein, we developed calix[3]acridan-based NACs to separate industrially important 4-picoline from its isomer mixtures with over 93.8% purity. [ABSTRACT FROM AUTHOR]

A supramolecular strategy to construct thermally activated delayed fluorescence (TADF) materials through host–guest charge transfer interactions was proposed. Consequently, a new class of macrocycle namely calix[3]acridan was conveniently synthesized in 90 % yield. The host–guest cocrystal formed by calix[3]acridan and 1,2‐dicyanobenzene exhibited efficient TADF properties due to intense intermolecular charge transfer interactions. Moreover, the spatially separated highest occupied molecular orbital and lowest unoccupied molecular orbital resulted in a very small singlet–triplet energy gap of 0.014 eV and hence guaranteed an efficient reverse intersystem crossing for TADF. Especially, a high photoluminescence quantum yield of 70 % was achieved, and it represents the highest value among the reported intermolecular donor–acceptor TADF materials. [ABSTRACT FROM AUTHOR]

Recently, circularly polarized organic light‐emitting diodes (CP‐OLEDs) fabricated with thermally activated delayed fluorescence (TADF) emitters are developed rapidly. However, most devices are fabricated by vacuum deposition technology, and developing efficient solution‐processed CP‐OLEDs, especially nondoped devices, is still a challenge. Herein, a pair of triptycene‐based enantiomers, (S,S)‐/(R,R)‐TpAc‐TRZ, are synthesized. The novel chiral triptycene scaffold of enantiomers avoids their intermolecular π–π stacking, which is conducive to their aggregation‐induced emission characteristics and high photoluminescence quantum yield of 85% in the solid state. Moreover, the triptycene‐based enantiomers exhibit efficient TADF activities with a small singlet‐triplet energy gap (ΔEST) of 0.03 eV and delayed fluorescence lifetime of 1.1 µs, as well as intense circularly polarized luminescence with dissymmetry factors (|gPL|) of about 1.9 × 10−3. The solution‐processed nondoped CP‐OLEDs based on (S,S)‐/(R,R)‐TpAc‐TRZ not only display obvious circularly polarized electroluminescence signals with gEL values of +1.5 × 10−3 and −2.0 × 10−3, respectively, but also achieve high efficiencies with external quantum, current, and power efficiency up to 25.5%, 88.6 cd A−1, and 95.9 lm W−1, respectively. [ABSTRACT FROM AUTHOR]

A strategy of chiral donor–acceptor copolymerization is proposed to develop chiral nonconjugated polymers with thermally activated delayed fluorescence (TADF). Based on this strategy, two pairs of chiral polymers (R,R)‐/(S,S)‐pTpAcDPS and (R,R)‐/(S,S)‐pTpAcBP were synthesized. The alternating copolymerization of the chiral donors and acceptors could effectively separate the frontier molecular orbitals, which made the polymers show small ΔEST of 0.01–0.03 eV and efficient TADF properties. Moreover, the polymers also showed the quantum yield of up to 92 % and the circularly polarized luminescence. The solution‐processed circularly polarized organic light‐emitting diodes showed circularly polarized electroluminescence signals with high external quantum efficiencies of up to 22.1 % and maximum luminance of up to 34350 cd m−2. This is the first report of CP‐OLEDs based on chiral TADF polymer, which provides a useful and valuable guidance for the development of high‐efficiency CPEL polymers. [ABSTRACT FROM AUTHOR]

Macrocycles denoted as saucer[n]arenes (n=4,5) were easily synthesized by the one‐pot condensation of 2,7‐dimethoxynaphthalene (2,7‐DMN) and paraformaldehyde in the presence of TFA or catalytic BF3⋅OEt2. With 1,1‐dimethylpiperidin‐1‐ium as the template, saucer[4]arene was selectively obtained. Crystal structures show that saucer[n]arenes are all composed of 2,7‐DMN moiety bridged by the methylene groups at 1,6‐positions: all of the 7‐methoxy groups lie on one face, and all of the 2‐methoxy groups lie on the other. Saucer[n]arenes exhibit strong fluorescence properties with the quantum yields of 19.6 % and 23.4 %. They form 1:1 complexes with ammonium salts in both solution and solid state (association constant up to 105 M−1 in CDCl3). Chiral quaternary ammonium salts can induce the chirality of the dynamically racemic inherently chiral saucer[n]arenes in solution, and thus show mirror‐imaged circular dichroism signals and circularly polarized luminescence (CPL) properties. [ABSTRACT FROM AUTHOR]

Despite dramatic advances in the template-directed synthesis of archetypal [2]rotaxanes, higher order rotaxanes with multiple molecular components (rings or dumbbells) are relatively daunting subjects owing to their synthetic challenges. With unique interlocked architectures, higher order rotaxanes have found applications in artificial molecular machines. In this feature article, we will focus on the recent advances in higher order rotaxanes with well-defined structures. Different types of rotaxane architectures will be described, and their synthetic approaches will be highlighted. Moreover, the stimuli-responsive molecular motion with increasing complexity in these diverse architectures will also be discussed. [ABSTRACT FROM AUTHOR]

A 2,6‐helic[6]arene‐based bistable [2]rotaxane has been designed and synthesized, which incorporates protonated tertiary ammonium salt as a reversible control unit and hexamethylene chain as a second binding site. In particular, it was found that [2]rotaxane could perform as a triply operable molecular switch through addition and removal of fluoride ions (TBAF/NaBArF), protonation and deprotonation of tertiary amine (HBArF/DBU), and altering the solvent polarity. It represents the first triply operable molecular switch based on helic[6]arenes. [ABSTRACT FROM AUTHOR]

Herein, we report the synthesis of a novel carbaporphyrin incorporating perylene diimide (PDI) and dipyrromethane units. The twisted plane of the PDI subunits imbues carbaporphyrin with intriguing conformational chirality and stable chiroptical properties. Both experimental and theoretical studies reveal that the unique properties arise from the rigidly conjugated macrocyclic architecture and the reduced interchromophoric distance. This work successfully integrates PDIs into carbaporphyrins, thereby expanding their structural diversity and functional potential.