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Abstract We report on a dendronized bis‐urea macrocycle1self‐assembling via a cooperative mechanism into two‐dimensional (2D) nanosheets formed solely by alternated urea‐urea hydrogen bonding interactions. The pure macrocycle self‐assembles in bulk into one‐dimensional liquid‐crystalline columnar phases. In contrast, its self‐assembly mode drastically changes in CHCl3or tetrachloroethane, leading to 2D hydrogen‐bonded networks. Theoretical calculations, complemented by previously reported crystalline structures, indicate that the 2D assembly is formed by a brick‐like hydrogen bonding pattern between bis‐urea macrocycles. This assembly is promoted by the swelling of the trisdodecyloxyphenyl groups upon solvation, which frustrates, due to steric effects, the formation of the thermodynamically more stable columnar macrocycle stacks. This work proposes a new design strategy to access 2D supramolecular polymers by means of a single non‐covalent interaction motif, which is of great interest for materials development.
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Influence of Amide Connectivity on the Hydrogen‐Bond‐Directed Self‐Assembly of [n.n]Paracyclophanes
Abstract Reported here is the synthesis and self‐assembly characterization of [n.n]paracyclophanes ([n.n]pCps,n=2, 3) equipped with anilide hydrogen bonding units. These molecules differ from previous self‐assembling [n.n]paracyclophanes ([n.n]pCps) in the connectivity of their amide hydrogen bonding units (C‐centered/carboxamide vs.N‐centered/anilide). This subtle change results in a ≈30‐fold increase in the elongation constant for the[2.2]pCp‐4,7,12,15‐tetraanilide ([2.2]pCpNTA) compared to previously reported[2.2]pCp‐4,7,12,15‐tetracarboxamide ([2.2]pCpTA), and a ≈300‐fold increase in the elongation constant for the[3.3]pCp‐5,8,14,17‐tetraanilide ([3.3]pCpNTA) compared to previously reported[3.3]pCp‐5,8,14,17‐tetracarboxamide ([3.3]pCpTA). The[n.n]pCpNTAmonomers also represent the reversal of a previously reported trend in solution‐phase assembly strength when comparing[2.2]pCpTAand[3.3]pCpTAmonomers. The origins of the assembly differences are geometric changes in the association between[n.n]pCpNTAmonomers—revealed by computations and X‐ray crystallography—resulting in a more favorable slipped stacking of the intermolecular π‐surfaces ([n.n]pCpNTAvs.[n.n]pCpTA), and a more complementary H‐bonding geometry ([3.3]pCpNTAvs.[2.2]pCpNTA).
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- PAR ID:
- 10237018
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Chemistry – A European Journal
- Volume:
- 26
- Issue:
- 72
- ISSN:
- 0947-6539
- Format(s):
- Medium: X Size: p. 17588-17597
- Size(s):
- p. 17588-17597
- Sponsoring Org:
- National Science Foundation
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