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Columnar Self‐Assembly in Electron‐Deficient Heterotriangulenes
Author(s) -
Kivala Milan,
Pisula Wojciech,
Wang Suhao,
Mavrinskiy Alexey,
Gisselbrecht JeanPaul,
Feng Xinliang,
Müllen Klaus
Publication year - 2013
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201300253
Subject(s) - thermotropic crystal , steric effects , phenylene , crystallography , conjugated system , self assembly , crystallinity , chemistry , electron acceptor , supramolecular chemistry , materials science , polymer chemistry , polymer , crystal structure , stereochemistry , photochemistry , liquid crystalline , organic chemistry
A series of soluble carbonyl‐bridged heterotriangulenes, in which flexible n ‐dodecyl chains are attached through different spacers to the planar nitrogen‐centered polycyclic core, have been synthesized. The introduction of triisopropylsilylethynyl moieties enabled, for the first time, the characterization of single‐crystal columnar packing of a substituted heterotriangulene by X‐ray crystallography. Electrochemical studies disclosed the carbonyl‐bridged heterotriangulene core as a reasonably strong acceptor for a reversible two‐electron transfer. The tendency of substituted heterotriangulenes to self‐assemble in solution, on surfaces, and in the bulk appeared to sensitively depend on the nature of the lateral substituents, their steric demand, and the applied solution processing conditions. It can be concluded that 1) additional phenylene moieties between the heterotriangulene core and the n ‐dodecyl chains facilitate self‐assembly by extending the π‐conjugated polycyclic disc, 2) the rod‐like ethynylene spacers introduce some additional flexibility and hence lower the overall aggregation tendency, and 3) the combination of both features in the phenylene–ethynylene moieties induces thermotropic liquid crystallinity.