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Although the chemistry of macrocyclic arenes has seen rapid development in recent years, the synthesis of new macrocyclic arenes from aromatic rings with no directing groups remains a challenge. In this work, a new macrocyclic arene, naphth[4]arene (NA[4]A), composed of four naphthalene rings bridged by methylene groups, was synthesized using macrocycle‐to‐macrocycle conversion. NA[4]A shows 1,3‐alternate and 1,2‐alternate conformations in the solid state, which can be selectively obtained. By supramolecular co‐assembly of NA[4]A and 1,2,4,5‐tetracyanobenzene (TCNB) in different concentrations and temperatures, two conformation‐dependent crystalline luminescent co‐assemblies 1,2‐NTC and 1,3‐NTC can be selectively prepared. Interestingly, the two charge‐transfer crystalline assemblies containing NA[4]A with different conformations show bright yellow and green fluorescence, and also display high photoluminescence quantum yields (PLQYs) of 45 % and 43 %. Furthermore, they exhibit color‐tunable two‐photon excited upconversion emission. [ABSTRACT FROM AUTHOR]

Study of enantioselective recognition in water by synthetic chiral macrocyclic receptors is undoubtedly of theoretical and practical significance, but it is a big challenge to achieve the enantioselective recognition with both high enantioselectivity and high affinity in water probably due to the deficiency of such water‐soluble macrocyclic receptors with stable chiral cavities. Herein, we report a new class of chiral macrocyclic arenes named octopus[3]arenes. The enantiomeric macrocycles are composed of three homochiral ethenoanthracene subunits, and they can be synthesized by two pathways and then easily converted into water‐soluble octopus[3]arenes P‐1 and M‐1. Notably, P‐1 and M‐1 with the rigid hexagonal structures and stable chiral hydrophobic cavities exhibit highly enantioselective recognition towards three pairs of chiral ammonium salts in water with the association constant up to 106 M−1 and the S/R selectivity up to 12.89. [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]

An approach to the highly efficient synthesis of C(sp3)‐bridged [6]cycloparaphenylenes (C[6]CPPs) from fluoren[3]arenes (F[3]As) was developed. Consequently, F[3]As as a new kind of macrocyclic arenes were synthesized. Followed by the demethylation, triflation and intramolecular aryl–aryl coupling reactions, C[6]CPPs were then conveniently obtained. Interestingly, C[6]CPPs could be selectively methylated to produce their fully outer‐methyl‐substituted derivatives. The crystal structures showed the hydroxyl‐substituted F[3]As had bowl‐shaped conformations, and the C[6]CPPs exhibited rigid belt‐shaped structures with deep cavities. Moreover, C[6]CPPs exhibited high HOMO energies and narrow energy gaps. An unclosed belt was further obtained, and it not only showed a similar narrow energy gap to those of the aromatic belts, but also displayed strong fluorescence property, which can play a vital role in the design and synthesis of new aromatic belts. [ABSTRACT FROM AUTHOR]