Naphthocage: A Flexible yet Extremely Strong Binder for Singly Charged Organic Cations

Abstract

We report a quite flexible naphthol-based cage (so-called “naphthocage”) which adopts a self-inclusion conformation in its free state and is able to bind singly charged organic cations extremely strongly (K a > 107 M–1). Ion-selective electrodes prepared with this naphthocage show a super-Nernstian response to acetylcholine. In addition, the highly stable complex (1010 M–1) between ferrocenium and the naphthocage can be switched electrochemically, which lays a basis for its application in stimuli-responsive materials.

Prismarene: An Emerging Naphthol‐Based Macrocyclic Arene

“…This is presumably caused by the low symmetry of the naphthols used for calixnaphthalanes. In contrast, 2,6‐dihydroxynaphthalene‐based macrocyclic hosts, such as oxatub[ n ]arenes, naphthocages, and naphthotubes, possess well‐defined cavities and generally show excellent host–guest chemistry. In 2013, we already proposed that the condensation of 2,6‐dialkoxynaphthalene with paraformaldehyde may give new macrocyclic arenes.…”

“…Instead of phenols and their derivatives,naphthols may be reacted with paraformaldehyde to afford amacrocyclic arene, presumably with an electron-rich and sizable cavity.However, earlier explorations of calixnaphthalenes [7,8] were not very successful. These macrocycles often suffer from difficulties in isolating the multiple isomers formed and show poor or limited guest-binding ability.This is presumably caused by the low symmetry of the naphthols used for calixnaphthalanes.In contrast, 2,6-dihydroxynaphthalene-based macrocyclic hosts, such as oxatub[n]arenes, [9] naphthocages, [10] and naphthotubes, [11] possess well-defined cavities and generally show excellent host-guest chemistry.In2013, we already proposed that the condensation of 2,6-dialkoxynaphthalene with paraformaldehyde may give new macrocyclic arenes.H owever, in our hands,reacting 2,6-dibutoxynaphthalene (80 mm)with paraformaldehyde under optimized conditions (catalyst: p-TsOH, solvent:C H 2 Cl 2 ,2 5 8 8C, 2h)o nly gave as eries of methylene-bridged naphthalene oligomers. [12] To our surprise and delight, Gaeta and co-workers [13] recently reported the successful synthesis of such macrocyclic arenes (named prism[n]arenes) by reacting 2,6-dimethoxynaphthalene with paraformaldehyde under appropriate conditions.…”

Teaching old indicators even more tricks: binding affinity measurements with the guest-displacement assay (GDA)

“…binding affinities (K a ) in an effort to develop binding models and to derive predictive structure-property correlations. [1][2][3][4][5][6][7][8][9][10][11] K a values of guest-inclusion complexes have been reported for many different classes of synthetic hosts. 12,13 Also, protein-ligand binding can be described through a host-guest binding formalism.…”

Transforming a Fluorochrome to an Efficient Photocatalyst for Oxidative Hydroxylation: A Supramolecular Dimerization Strategy Based on Host‐Enhanced Charge Transfer

“…On the other hand, the host-guest complex benefits from the well-defined structure, considerable solubility and adequate dynamicity to ensure the contact of the triplet state guest with other reactants, thus facilitating energy transfer and electron transfer. [41][42][43][44][45][46][47][48][49][50][51][52][53][54] To this end, N,Ndimethyl 2,5-bis(4-pyridinium)thiazolo [5,4-d]thiazole diiodide (MPT), an efficient fluorochrome with acceptor-donoracceptor structure, was designed. [55] As shown in Scheme 1, it self-assembled into supramolecular dimer in the cavity of cucurbit [8]uril (CB [8]) in a parallel and staggered conformation.…”