Self-assembly of alkylated and perfluoroalkylated scissor-shaped azobenzene dyads into distinct structures

Abstract

Scissor-shaped azobenzene dyads possessing alkyl side chains can hierarchically self-assemble through the folded conformation into toroidal and tubular nanostructures. We now found that the introduction of perfluoroalkyl side chains transforms...

Photoswitchable Binary Nanopore Conductance and Selective Electronic Detection of Single Biomolecules under Wavelength and Voltage Polarity Control

“…The voltage polarity to detect DNA in these experiments is consistent with net transport in the direction of electrophoretic motion, as is generally the case for nanopore DNA sensing . A reduced and unsteady baseline current is common in DNA sensing using unfunctionalized SiN x nanopores. , It is generally ascribed to “sticking” of the DNA to the nanopore surface, and a plethora of surface chemical approaches have been developed to prevent such sticking. ,, While the 4-(propargyloxy)­azobenzene coating does not prevent occasional sticking, further modification of azobenzene moiety with various functional groups, for example, fluorous groups, could chemically tune this behavior without sacrificing the photoswitchability. − In an electrokinetic sense, maltodextrin is the antithesis of DNA: It is neutral and therefore nonresponsive to electrophoresis. Instead, transportand thus sensingof maltodextrin occurs via electroosmosis that requires a charged nanopore surface. ,, The voltage polarity for sensing maltodextrinopposite to that of electrophoresis for anionic DNAindicates a negative surface charge.…”

Multiple Azoarenes Based Systems – Photoswitching, Supramolecular Chemistry and Application Prospects

“…Scissor shaped azobenzene dyads such as A‐57 a – c and A‐58 a – c have been synthesized, which self‐assemble in discrete nanotoroid structures, and further organize into 2D porous nanotubes (Figure 10). [44a–c] The UV irradiation in these systems causes photoisomerization and disassembly into monomers, whereas the reverse isomerization with visible light reconstructs the nanostructure assembly. Such hierarchical self‐assembly and UV‐induced disassembly change with slight modification in substituents [44a] .…”

Photo-modulation of supramolecular polymorphism in the self-assembly of a scissor-shaped azobenzene dyad into nanotoroids and fibers

“…1a-iii). 8 Based on the above monomer structure/self-assembly relationships, we envisaged that the introduction of bulky but strongly aggregating substituents might realize supramolecular polymorphism 9 via a monomer that could provide both discrete toroidal and extended brous nanoaggregates. As one such substituent, we herein introduced cholesterol units 10 and investigated the self-assembly of the resulting dyad 1 (Fig.…”