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Tunable Energy Landscapes to Control Pathway Complexity in Self‐Assembled N ‐Heterotriangulenes: Living and Seeded Supramolecular Polymerization
Author(s) -
Valera Jorge S.,
Gómez Rafael,
Sánchez Luis
Publication year - 2018
Publication title -
small
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.785
H-Index - 236
eISSN - 1613-6829
pISSN - 1613-6810
DOI - 10.1002/smll.201702437
Subject(s) - supramolecular chemistry , supramolecular polymers , polymerization , monomer , chemistry , self assembly , materials science , combinatorial chemistry , polymer , molecule , organic chemistry
Herein, the synthesis and self‐assembling features of N ‐heterotriangulenes 1 – 3 decorated in their periphery with 3,4,5‐trialkoxy‐ N ‐(alkoxy)benzamide moieties that enable kinetic control of the supramolecular polymerization process are described. The selection of an appropriate solvent results in a tunable energy landscape in which the relative energy of the different monomeric or aggregated species can be regulated. Thus, in a methylcyclohexane/toluene (MCH/Tol) mixture, intramolecular hydrogen‐bonding interactions in the peripheral side units favor the formation of metastable inactivated monomers that evolve with time at precise conditions of concentration and temperature. A pathway complexity in the supramolecular polymerization of 1 – 3 cannot be determined in MCH/Tol mixtures but, importantly, this situation changes by using CCl 4 . In this solvent, the off‐pathway product is a face‐to‐face H‐type aggregate and the on‐pathway product is the slipped face‐to‐face J‐type aggregate. The autocatalytic transformation of the metastable monomeric units, as well as the two competing off‐ and on‐pathway aggregates allow the realization of seeded and living supramolecular polymerizations. Interestingly, the presence of chiral, branched side chains in chiral ( S )‐ 2 noticeably retards the kinetics of the investigated transformations. This work brings to light the relevance of controlling the pathway complexity in self‐assembling units and opens new avenues for the investigation of complex and functional supramolecular structures.