Designing liquid-crystalline dendronised hexa-adducts of [60]fullerene via click chemistry

ABSTRACT

Liquid-crystalline [60]fullerodendrimers were constructed via click chemistry based on the reaction between hexa-adducts of [60]fullerene (C₆₀) bearing 12 azide groups and alkyne-terminated cyanobiphenyl dendrons of first- and second-generation. The structure of all the new compounds was confirmed by IR, UV, ¹H and ¹³C NMR spectroscopies and mass spectrometry. The mesomorphic properties were studied by polarised optical microscopy, differential scanning calorimetry and small-angle X-ray scattering. The hexa-adduct of C₆₀ functionalised with the first-generation dendrons gave rise to the formation of a smectic A phase and a rectangular columnar phase (c2mm symmetry) while the hexa-adduct of C₆₀ decorated with the second-generation dendrons displayed only a rectangular columnar phase (c2mm symmetry). Our results show that the hexa-adduct of C₆₀ is a unique synthetic platform for the design of fullerodendrimers and dendronised materials.

GRAPHICAL ABSTRACT

KEYWORDS:

• Hexa-adducts of fullerene
• cyanobiphenyl-based dendrimers
• click chemistry
• liquid crystals
• smectic phases
• columnar rectangular phases

Disclosure statement

No potential conflict of interest was reported by the authors.

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Additional information

Funding

Financial support from the MINECO (project CTQ2015-70174-P) and Diputación General de Aragón-Fondo Social Europeo (DGA-FSE) (project E04) is gratefully acknowledged. RD thanks the Swiss National Science Foundation [Grant Number 200021-165715] for financial support. JFN and UH gratefully acknowledge financial support from the University of Strasbourg, the CNRS, the International Center for Frontier Research in Chemistry (icFRC) and the LabEx Chimie des Systèmes Complexes.