Issue 42, 2019

Original polymorphism in a naphthalene bisimide π-conjugated organogelator: a complex interplay between hydrogen bonding and heterocycle π-stacking

Abstract

This study focuses on the structure of different supramolecular assemblies formed in the gel phase and in the solid state by a naphthalene-bisimide organogelator: N,N′-di(2-(3,4,5-trioctyloxybenzamido))eth-1-yl naphthalene-1,4,5,8 tetracarboxylic acid bisimide (NDI2). This molecule is formed by a naphthalene bisimide core with symmetric dendrons composed of a flexible alkyl linker, an amide group and a trialkoxyphenyl group. The structure, especially the original polymorphism of this molecule, was correlated with optical and electronic properties in the solid state. Four polymorphs have been prepared in pure form: a dried gel phase, a quenched metastable liquid crystalline phase, a crystalline phase and its sister phase with molten alkyl side chains. The molecular packing of those phases was determined by X-ray diffraction, electron diffraction and high resolution TEM. UV-vis and infrared spectroscopy of the polymorphs uncover the nature of intermolecular π-stacking and H-bonding interactions. In the fibrils of the gel phase, NDI2 molecules form columnar stacks and the fiber axes correspond to the direction of H-bonds between amide groups. The crystalline phase shows an unusual packing where each NDI is π-stacked between two phenyl groups of the adjacent NDI2 molecules. In the metastable LC phase NDI2 molecules assemble into 6/1 supramolecular helices grouped in a frustrated trigonal unit cell. Temperature-dependent TEM, UV-vis and FTIR helped to unveil the molecular reorganization upon transformation between these different polymorphs. Finally, a global phase diagram has been obtained.

Graphical abstract: Original polymorphism in a naphthalene bisimide π-conjugated organogelator: a complex interplay between hydrogen bonding and heterocycle π-stacking

Supplementary files

Article information

Article type
Paper
Submitted
09 Aug 2019
Accepted
29 Sep 2019
First published
09 Okt 2019

J. Mater. Chem. C, 2019,7, 13120-13129

Original polymorphism in a naphthalene bisimide π-conjugated organogelator: a complex interplay between hydrogen bonding and heterocycle π-stacking

M. Diebold, E. Christ, L. Biniek, L. Karmazin, B. Heinrich, C. Contal, S. Ghosh, P. J. Mesini and M. Brinkmann, J. Mater. Chem. C, 2019, 7, 13120 DOI: 10.1039/C9TC04402G

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements