Izvorni znanstveni članak
Photoresponsive Cellulose Nanocrystals
Ilari Filpponen
; Department of Forest Products Technology, School of Chemical Technology, Aalto University, Finland
Hasan Sadeghifar
; Organic Chemistry of Wood Components Laboratory, Department of Forest Biomaterials, North Carolina State University, United States
Dimitris S Argyropoulo
; Laboratory of Organic Chemistry, Department of Chemistry, Faculty of Science, University of Helsinki, Finland
Sažetak
In this communication a method for the creation
of fluorescent cellulose nanoparticles using click chemistry
and subsequent photodimerization of the installed side‐
chains is demonstrated. In the first step, the primary
hydroxyl groups on the surface of the CNCs were
converted to carboxylic acids by using TEMPO‐mediated
hypohalite oxidation. The alkyne groups, essential for the
click reaction, were introduced into the surface of TEMPO‐
oxidized CNCs via carbodiimide‐mediated formation of an
amide linkage between monomers carrying an amine
functionality and carboxylic acid groups on the surface of
the TEMPO‐oxidized CNCs. Finally, the reaction of
surface‐modified TEMPO‐oxidized cellulose nanocrystals
and azido‐bearing coumarin and anthracene monomers
were carried out by means of a click chemistry, i.e.,
Copper(I)‐catalyzed Azide‐Alkyne Cycloaddition
(CuAAC) to produce highly photo‐responsive and
fluorescent cellulose nanoparticles. Most significantly, the
installed coumarin and/or anthracene side‐chains were
shown to undergo UV‐induced [2+2] and [4+4]
cycloaddition reactions, bringing and locking the cellulose
nanocrystals together. This effort paves the way towards
creating, cellulosic photo responsive nano‐arrays with the
potential of photo reversibility since these reactions are
known to be reversible at varying wavelengths.
Ključne riječi
cellulose; click chemistry; fluorescence; photodimerization
Hrčak ID:
71559
URI
Datum izdavanja:
15.6.2011.
Posjeta: 1.804 *