Molecular pentagonal tiling: self-assemblies of pentagonal-shaped macrocycles at liquid/solid interfaces

Abstract

We present a systematic scanning tunneling microscopy study on the 2D self-assembly of pentagonal shaped macrocycles at the liquid/solid interface to gain insight about 2D pentagonal molecular crystallization. Macrocycles with alkyl ester groups form an anti-parallel type linear pattern mainly via favorable intermolecular interactions between the interdigitated alkyl chains at the 1,2,4trichlorobenzene (TCB)/graphite interface. On the other hand, at the TCB/Au(111) interface, they showed a random pattern and an anti-parallel type linear pattern. The selection between both motifs is ascribed to the balance between the intermolecular and molecule-substrate interactions. Most interestingly, the parent molecule forms dense anti-parallel and parallel linear patterns reflecting the intrinsic pentagonal core shape. Moreover, bright and mobile spots were often observed in the networks to occupy free spaces, including the cavity of the macrocycles, which we attribute to a coadsorbed solvent molecule or Au ion.

Flexibility Coexists with Shape-Persistence in Cyanostar Macrocycles

“…1 Shape persistence is advantageous for many applications: synthesis of macrocycles, 2 preorganization, 3 in silico design, 4 catalysis, 5 configurationally stable stereochemistry, 6 and hierarchical self-assembly 7,8,9 of multi-functional architectures, 3a,8a,10 To design shape-persistent macrocycles, Moore has suggested that they have limited degrees of conformational freedom, i.e., they are rigid. 11 Yet, through the results obtained in the present study, we were confronted with an apparent contradiction involving cyanostar macrocycles (Figure 1a).…”

Stereochemistry of 2D Molecular Crystallization

“…Perfect tilings would require the fivefold-symmetric shapes to be combined with other shapes, [32] as demonstrated by Dürer, Kepler and Penrose. [33] Self-assembly of fivefold-symmetric shape-persistent macro-cycles has been previously studied at the solid-liquid interface, [34] and pentagonal features were discussed for rubrene and para-terphenyldicyanocerium on noble metal surfaces. [35,36] However, systematic studies of closepacking strategies of pentagonal molecules in the plane have only been addressed with penta-substituted derivatives of corannulene so far.…”

Entwicklung struktureller Komplexität durch Selbstorganisation in flüssigkristallinen Systemen

“…[345 ] Der gleiche Typ von Fünfeckketten wurde neben anderen Motiven für Metall‐organische Netze aus 1,3,5‐Trispyridylbenzol und Kupferatomen auf Au(111)‐Oberflächen gefunden (Abbildung 51 a,b);346 eine ähnliche Struktur wurde auch für den fünfeckigen Makrocyclus 97 auf einer Au(111)‐Oberfläche erhalten (Abbildung 51 c). 347…”

“… 2D‐Gitter aus Fünfecken: a,b) Fünfeckketten von 1,3,5‐Trispyridylbenzol 96 mit Cu und346 c) Makrozyklus 97 (R=H) auf einer Au(111)/1‐Octansäure‐Oberfläche,347 d) dichteste Fünfeckpackung in Kristallstrukturen 348. e–i) Muster von 98 auf einer HOPG‐TCB‐Oberfläche (HOPG=highly ordered pyrolytic graphite, TCB=1,2,4‐Trichlorbenzol) 350.…”

“…346 mit Genehmigung der American Chemical Society, 2011. c) Wiedergegeben aus Lit. 347 mit Genehmigung der Royal Society of Chemistry. d) Wiedergegeben aus Lit.…”