Polyaromatic molecular tubes with a subnanometer pore and the guest-induced emission enhancement behavior

Abstract

New polyaromatic molecular tubes with a subnanometer pore (0.8 nm) were prepared. The tube bearing six sulfonate groups on the periphery and twelve methoxy groups at the openings provides a cylindrical hydrophobic cavity with a length of ∼1.3 nm. The aqueous tube can quantitatively bind one molecule of hydrocarbon guests in water with accompanying guest-induced emission enhancement (up to ∼3 times) of the host framework.

Alkylation‐, Heating‐, and Doping‐Induced Emission Enhancement of a Polyaromatic Tube in the Solid State

“…[13] In the 1 and % 1nm, respectively (Figure 3a). [11] Fluorescence spectrumo f1 in CH 2 Cl 2 exhibited an anthracene-based emission band around 380-570nm( l ex = 375 nm, F F = 55 %), which is similar to that of 2a in CH 2 Cl 2 (Figure 3c). The solution-state emission property of 1 was also comparable to that of 2a-c and meta-substituted tube 3.…”

“…The solid-statef luorescenceo f the tube is greatly enhanced (up to 2.1-fold) by exteriora lkylation due to the suppression of intermolecular aggregation of the polyaromatic frameworks (Figure 1a,r ight). [11] However, DPAd erivative 3' possesses two phenyl-anthryl bonds, which freely rotate at room temperature, so that the main coupling products were am ixture of undesired acyclic oligomers. Prototypical tube 3 composed of three DPAf rameworks formed by the homocoupling reactiono fmeta-substituted 3' (Figure1c).…”

“…a) Schematic representation of the solid-state morphology of polyaromatic tubes without/with alkyl side chains and b) anthracene-based molecular tubes 1 and 2a-c (synthesized in this work) and tube 3 [11]. Stereochemical charactersofc )meta-substituted 3' and d) ortho-substituted 1' and their optimized structures (R =-OCH 3 ;DFT,B 3LYP/6-31G* level).…”

A Pentacene‐based Nanotube Displaying Enriched Electrochemical and Photochemical Activities

“…[*] K. Kuroda have recently established that ap olyaromatic tube,c omprising three anthracene rings alternately connected by three biphenyl derivatives,c an be prepared in only four steps starting from simple 9,10-anthraquinone. [15] Thea nthracenebased tube possesses ac ylindrical subnanometer pore with alength of approximately 1nm. Theanthracene panels are all in close proximity (within 1nm) without intramolecular pstacks due to the biphenyl linkers.T hus,w ed esigned new pentacene-based nanotube 1 (Figure 1c)a nd applied our synthetic method to the target molecule using commercially available pentacenequinone as as tarting material.…”

A Switchable Open/closed Polyaromatic Macrocycle that Shows Reversible Binding of Long Hydrophilic Molecules

“…Unlike common polyaromatic hydrocarbons (e.g., anthracene,p yrene,a nd perylene), nucleophilic addition of alcohols or water to the acridinium panel under basic conditions gives rise to flexible acridane panels (Figure 1c, right). Ther esultant neutral frameworks can revert to the originals under acidic conditions.W ee xpected that the incorporation of multiple acridinium panels into as hapepersistent polyaromatic tubular structure [7] could generate new pH-responsive macrocyclic molecule 1 (Figure 1b). [8] Thet etracationic framework provides hydrophilic exterior surfaces so that the polyaromatic macrocycle is usable in water without the attachment of typical hydrophilic substituents.I mportantly,t he open macrocycle,w hich is prepared in only three steps,can be reversibly transformed into the closed macrocycle (2)b ysimple addition of base ( Figure 1a).…”