Title

Exohedral functionalization of fullerene by substituents controlling of molecular organization for spontaneous c60 dimerization in liquid crystal solutions and in a bulk controlled by a potential

Publication Name

Polymers

Abstract

A study was carried out on the possibility of orderly and spontaneous dimerization at room temperature of C60 cages in fullerene liquid crystal fullerene dyads (R-C60). For this purpose, dyads with a structural elements feature supporting π-stacking and Van der Waals interactions were tested, due to the presence of terthiophene donors linked through an α-position or dodecyloxy chains. In addition, this possibility was also tested and compared to dyads with shorter substituents and the pristine C60. Research has shown that only in dyads with the features of liquid crystals, π-dimerization of C60 units occurs, which was verified by electrochemical and spectroelectrochemical (ESR) measurements. Cyclic voltammetry and differential voltammetry studies reveal π-dimeriza-tion in liquid crystal dyad solution even without the possibility of previous polymerization (ca-thodic or anodic) under conditions in the absence of irradiation and without the availability of reaction initiators, and even with the use of preliminary homogenization. These dyads undergo six sequential, one-electron reductions of π-dimer (R-C60···C60-R), where two electrons are added suc-cessively to each of the two fullerene cages and first form two radical anion system (R-C60)•−(R-C60)•− without pairing with the characteristics of two doublets. Similarly, the second reductions of π-dimer occur at potentials that are close to the reduction potential for the conversion to a system of two triplet dianions (R-C60)2−(R-C60)2−. Electron paramagnetic resonance spectra indicate a significant interaction between C60 cages. Interestingly, the strength of intermolecular bonds is so significant that it can overcome Coulombic repulsion, even with such highly charged particles as dianions and tri-anions. Such behavior has been revealed and studied so far only in covalently bonded C60 dimers.

Open Access Status

This publication may be available as open access

Volume

13

Issue

16

Article Number

2816

Funding Number

EETK97115

Funding Sponsor

Ministry of Science and Technology, Taiwan

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Link to publisher version (DOI)

http://dx.doi.org/10.3390/polym13162816