My watch list  

Design and Sensing Properties of a Self‐Assembled Supramolecular Oligomer


Supramolecular polymers are a class of macromolecules stabilized by weak non‐covalent interactions. These self‐assembled aggregates typically undergo stimuli‐induced reversible assembly and disassembly. They thus hold great promise as so‐called functional materials. In this work, we present the design, synthesis, and responsive behavior of a short supramolecular oligomeric system based on two hetero‐complementary subunits. These “monomers” consist of a tetrathiafulvalene‐functionalized calix[4]pyrrole (TTF‐C[4]P) and a glycol diester‐linked bis‐2,5,7‐trinitrodicyanomethylenefluorene‐4‐carboxylate (TNDCF), respectively. We show that when mixed in organic solvents, such as CHCl3, CH2ClCH2Cl, and methylcyclohexane, supramolecular aggregation takes place to produce short oligomers stabilized by hydrogen bonding and donor–acceptor charge‐transfer (CT) interactions. The self‐associated materials were characterized by 1H NMR and UV/Vis/NIR absorption spectroscopy, as well as by concentration‐ and temperature‐dependent absorption spectroscopy and dynamic light scattering (DLS) analyses of both the monomeric and oligomerized species. The self‐associated system produced from TTF‐C[4]P and TNDCF exhibits a concentration‐dependent aggregation behavior typical of supramolecular polymers. Further support for the proposed self‐assembly came from theoretical calculations. The fluorescence emitting properties of TNDCF are quenched under conditions that promote the formation of supramolecular aggregates containing TTF‐C[4]P and TNDCF. This quenching effect has been utilized as a probe for the detection of substrates in the form of anions (i.e., chloride) and nitroaromatic explosives (i.e., 1,3,5‐trinitrobenzene). Specifically, the addition of these substrates to mixtures of TTF‐C[4]P and TNDCF produced a fluorescence “turn‐on” response.

Explosive fluorescence: The hetero‐complementary monomeric subunits, tetrathiafulvalene–calix[4]pyrrole (TTF‐C[4]P) and bis‐2,5,7‐trinitrodicyanomethylenefluorene‐4‐carboxylate (TNDCF), assemble to form oligomeric structures at higher concentrations. Dual‐analyte‐responsive behavior is seen, with de‐aggregation of the supramolecular oligomers and a corresponding increase in the fluorescence intensity being seen in the presence of 1,3,5‐trinitrobenzene (TNB) or Cl anions.

Authors:   Steffen Bähring, Luis Martín‐Gomis, Gunnar Olsen, Kent A. Nielsen, Dong Sub Kim, Troels Duedal, Ángela Sastre‐Santos, Jan O. Jeppesen, Jonathan L. Sessler
Journal:   Chemistry - A European Journal
Year:   2015
Pages:   n/a
DOI:   10.1002/chem.201503701
Publication date:   02-Dec-2015
More about Wiley
Your browser is not current. Microsoft Internet Explorer 6.0 does not support some functions on Chemie.DE