The Structural Diversity of Benzofuran Resorcinarene Leads to Enhanced Fluorescence

Abstract

An unexpected and previously unknown resorcinarene mono‐crown with a fused benzofuran moiety in its macrocyclic core was obtained as a byproduct from a bridging reaction of tetramethoxy resorcinarene with tetraethylene glycol ditosylate. The formation of the fused benzofuran moiety in the resorcinarene macrocycle resulted in a unique rigid and puckered boat conformation, as shown by XRD studies in the solid state. Modification of the macrocycle was also observed to affect the photophysical properties in solution by enhancing the fluorescence brightness compared with a conventional resorcinarene macrocycle. The fluorescent properties enabled unique detection of structural features, that is, the rigid boat conformation with the conjugated benzofuran system and the more flexible crown bridge part, in solution.

Sensitive Assays by Nucleophile-Induced Rearrangement of Photoactivated Diarylethenes

“…For this reason, alternative structures were considered. Unsubstituted benzothiophene shows slight emission (Φ f = 0.019) compared to a barely higher intensity of dibenzothiophene (Φ f = 0.08). , The more promising related example is benzofuran with negligible fluorescence and dibenzofuran with a much higher fluorescence quantum yield (Φ f = 0.53) of its unsubstituted form. , Thus, DAE probe 15 bearing a benzofuran moiety was synthesized and, as expected, the colorless acetonitrile solution of the 15o does not show fluorescence at any excitation wavelength. Upon UV-induced ring-closure, only very weak emission signals appear at around 300 nm when exciting the sample between 200 and 250 nm.…”

A perspective to resorcinarene crowns

“…19 Uniqueness of the reaction comes from the modification of the parent aromatic core, which previously has been considered to be virtually intact for changes during the resorcinarene functionalization synthesis. In compound 6b a benzofuran ring is formed as a part of the macrocycle core.…”

Interdisciplinary Nature of Nanoscience: Implications for Education

“…The ideas of other researchers, who had a deep understanding of spectroscopic methods, helped her group members overcome methodological obstacles as they learned to use and interpret fluorescence spectrometers. The collaboration that existed most deeply at the level of instrumentation resulted in joint publications with spectroscopy specialists, and a more comprehensive understanding of, e.g., the fluorescence mechanisms and structural changes in supramolecular assemblies of resorcinarenes [58].…”