Unravelling the Pathway Complexity in Conformationally Flexible N‐Centered Triarylamine Trisamides. Issue 25 (16th December 2016)

• Record Type: Journal Article
• Authors: Adelizzi, Beatrice; Filot, Ivo A. W.; Palmans, Anja R. A.; Meijer, E. W.
• Is Part Of: Chemistry. Volume 23:Issue 25(2017)
• Page Start: 6103
• Page End: 6110
• Publication Date: 2016-12-16
• Subjects: CD inversion -- handeness inversion -- pathway complexity -- supramolecular polymerization -- triphenylamine; Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.201603938
• Languages: English
• ISSNs: 0947-6539

Abstract

Abstract: Two families of C 3 ‐symmetrical triarylamine‐trisamides comprising a triphenylamine‐ or a tri(pyrid‐2‐yl)amine core are presented. Both families self‐assemble in apolar solvents via cooperative hydrogen‐bonding interactions into helical supramolecular polymers as evidenced by a combination of spectroscopic measurements, and corroborated by DFT calculations. The introduction of a stereocenter in the side chains biases the helical sense of the supramolecular polymers formed. Compared to other C 3 ‐symmetrical compounds, a much richer self‐assembly landscape is observed. Temperature‐dependent spectroscopy measurements highlight the presence of two self‐assembled states of opposite handedness. One state is formed at high temperature from a molecularly dissolved solution via a nucleation–elongation mechanism. The second state is formed below room temperature through a sharp transition from the first assembled state. The change in helicity is proposed to be related to a conformational switch of the triarylamine core due to an equilibrium between a 3:0 and a 2:1 conformation. Thus, within a limited temperature window, a small conformational twist results in an assembled state of opposite helicity. Abstract : Twisting supramolecular helices : A molecular conformational change propagates through the supramolecular assembly to induce a handedness inversion of the helical superstructure.