title: Tuning the nature and stability of self-assemblies formed by ester benzene 1,3,5-tricarboxamides: the crucial role played by the substituents.
abstract: As the benzene 1,3,5-tricarboxamide (BTA) moiety is commonly used as the central assembling unit for the construction of functionalized supramolecular architectures, strategies to tailor the nature and stability of BTA assemblies are needed. The assembly properties of a library of structurally simple BTAs derived from amino dodecyl esters (ester BTAs, 13 members) have been studied, either in the bulk or in cyclohexane solutions, by means of a series of analytical methods (NMR, DSC, POM, FT-IR, UV-Vis, CD, ITC, high-sensitivity DSC, SANS). Two types of hydrogen-bonded species have been identified and characterized: the expected amide-bonded helical rods (or stacks) that are structurally similar to those formed by BTAs with simple alkyl side chains (alkyl BTAs), and ester-bonded dimers in which the BTAs are connected by means of hydrogen bonds linking the amide N-H and the ester C[double bond, length as m-dash]O. MM/MD calculations coupled with simulations of CD spectra allow for the precise determination of the molecular arrangement and of the hydrogen bond pattern of these dimers. Our study points out the crucial influence of the substituent attached on the amino-ester α-carbon on the relative stability of the rod-like versus dimeric assemblies. By varying this substituent, one can precisely tune the nature of the dominant hydrogen-bonded species (stacks or dimers) in the neat compounds and in cyclohexane over a wide range of temperatures and concentrations. In the neat BTAs, stacks are stable up to 213 °C and dimers above 180 °C whilst in cyclohexane stacks form at c* > 3 × 10-5M at 20 °C and dimers are stable up to 80 °C at 7 × 10-6M. Ester BTAs that assemble into stacks form a liquid-crystalline phase and yield gels or viscous solutions in cyclohexane, demonstrating the importance of controlling the structure of these assemblies. Our systematic study of these structurally similar ester BTAs also allows for a better understanding of how a single atom or moiety can impact the nature and stability of BTA aggregates, which is of importance for the future development of functionalized BTA supramolecular polymers.
authors.affiliation: Sorbonne Universités, UPMC Univ Paris 06, CNRS, Institut Parisien de Chimie Moléculaire, Equipe Chimie des Polymeres, 4 Place Jussieu, F-75005 Paris, France. matthieu.raynal@upmc.fr.
authors.forename: Alaric
authors.initials: A
authors.lastname: Desmarchelier
authors.affiliation: Sorbonne Universités, UPMC Univ Paris 06, CNRS, Institut Parisien de Chimie Moléculaire, Equipe Chimie des Polymeres, 4 Place Jussieu, F-75005 Paris, France. matthieu.raynal@upmc.fr and Department of Physical-Chemistry, Institute of Chemistry, University of Campinas, Brazil.
authors.forename: Bruno Giordano
authors.initials: BG
authors.lastname: Alvarenga
authors.affiliation: Sorbonne Universités, UPMC Univ Paris 06, CNRS, Institut Parisien de Chimie Moléculaire, Equipe Chimie des Polymeres, 4 Place Jussieu, F-75005 Paris, France. matthieu.raynal@upmc.fr.
authors.forename: Xavier
authors.initials: X
authors.lastname: Caumes
authors.affiliation: Sorbonne Universités, UPMC Univ Paris 06, CNRS, Institut Parisien de Chimie Moléculaire, Equipe Chimie des Polymeres, 4 Place Jussieu, F-75005 Paris, France. matthieu.raynal@upmc.fr.
authors.forename: Ludovic
authors.initials: L
authors.lastname: Dubreucq
authors.affiliation: Sorbonne Universités, UPMC Univ Paris 06, CNRS, Institut Parisien de Chimie Moléculaire, Equipe Chimie des Polymeres, 4 Place Jussieu, F-75005 Paris, France. matthieu.raynal@upmc.fr.
authors.forename: Claire
authors.initials: C
authors.lastname: Troufflard
authors.affiliation: Sorbonne Universités, UPMC Univ Paris 06, CNRS, Institut Parisien de Chimie Moléculaire, Equipe Chimie des Polymeres, 4 Place Jussieu, F-75005 Paris, France. matthieu.raynal@upmc.fr.
authors.forename: Martine
authors.initials: M
authors.lastname: Tessier
authors.affiliation: Aix Marseille Université, Centrale Marseille, CNRS, iSm2, UMR 7313, 13397 Marseille Cedex 20, France.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Vanthuyne
authors.affiliation: Service de Chimie des Matériaux Nouveaux, Université de Mons/Materia Nova, Place du Parc, 20, B-7000 Mons, Belgium.
authors.forename: Julien
authors.initials: J
authors.lastname: Idé
authors.affiliation: Service de Chimie des Matériaux Nouveaux, Université de Mons/Materia Nova, Place du Parc, 20, B-7000 Mons, Belgium.
authors.forename: Thomas
authors.initials: T
authors.lastname: Maistriaux
authors.affiliation: Service de Chimie des Matériaux Nouveaux, Université de Mons/Materia Nova, Place du Parc, 20, B-7000 Mons, Belgium.
authors.forename: David
authors.initials: D
authors.lastname: Beljonne
authors.affiliation: Service de Chimie des Matériaux Nouveaux, Université de Mons/Materia Nova, Place du Parc, 20, B-7000 Mons, Belgium.
authors.forename: Patrick
authors.initials: P
authors.lastname: Brocorens
authors.affiliation: Service de Chimie des Matériaux Nouveaux, Université de Mons/Materia Nova, Place du Parc, 20, B-7000 Mons, Belgium.
authors.forename: Roberto
authors.initials: R
authors.lastname: Lazzaroni
authors.affiliation: Sorbonne Universités, UPMC Univ Paris 06, CNRS, Institut Parisien de Chimie Moléculaire, Equipe Chimie des Polymeres, 4 Place Jussieu, F-75005 Paris, France. matthieu.raynal@upmc.fr.
authors.forename: Matthieu
authors.identifier: http://orcid.org/0000-0001-6830-1668
authors.initials: M
authors.lastname: Raynal
authors.affiliation: Sorbonne Universités, UPMC Univ Paris 06, CNRS, Institut Parisien de Chimie Moléculaire, Equipe Chimie des Polymeres, 4 Place Jussieu, F-75005 Paris, France. matthieu.raynal@upmc.fr.
authors.forename: Laurent
authors.initials: L
authors.lastname: Bouteiller