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Reversible J- to H-aggregate transformation in thin films of a perylenebisimide organogelator†
Alexandru Sarbu,Laure Biniek,Jean-Michel Guenet,Philippe J. Mésini,Martin Brinkmann
Journal of Materials Chemistry C Pub Date : 12/08/2014 00:00:00 , DOI:10.1039/C4TC02444C
Abstract

A perylene bisimide organogelator is shown to behave as a reversible stimuli responsive material: thermal annealing and contact with organic non solvents allow to switch back and forth between a green J-type (Form I) and a red H-type (Form II) aggregate in thin films and powders of a N,N′-substituted H-bonding perylenebisimide (PBI-C10). Both, Form I and II were characterized by transmission electron (low dose high-resolution and electron diffraction) and atomic force microscopies, UV-vis and FTIR spectroscopies. The Form I → Form II transformation implies a redistribution of inter-molecular H-bonds between PBI molecules that form columnar stacks in Form I and supramolecular helices with enhanced long-range stacking in Form II. The reverse transformation is triggered by a contact of Form II films with H-bonding organic non solvents e.g. linear alcohols. It is proposed that solvent molecules diffusing in the Form II films can disrupt long-range H-bonding within helical stacks of Form II. Accordingly, PBI-C10 is shown to behave as a functional material responding successively to thermal and molecular stimuli.

Graphical abstract: Reversible J- to H-aggregate transformation in thin films of a perylenebisimide organogelator
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