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Controlling Chain Coupling and Single‐Chain Ligation by Two Colours of Visible Light
Author(s) -
Frisch Hendrik,
Bloesser Fabian R.,
BarnerKowollik Christopher
Publication year - 2019
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201811541
Subject(s) - photochemistry , cycloaddition , visible spectrum , chain reaction , irradiation , chemistry , chain (unit) , sequence (biology) , absorption (acoustics) , single chain , macromolecule , reactivity (psychology) , combinatorial chemistry , materials science , optoelectronics , catalysis , organic chemistry , physics , medicine , biochemistry , astronomy , antibody , immunology , biology , alternative medicine , pathology , nuclear physics , composite material
While photochemical synthesis offers access to spatiotemporal reaction control, its potential to selectively address specific reactions by the colour of light is usually limited by ubiquitous spectral absorption overlaps of the reactive groups. Herein, a new concept is introduced that actively suppresses one ligation reaction by triggering the cycloreversion of the [2+2] cycloaddition of styrylpyrene. Combination of the photoreversible styrylpyrene chemistry with the [4+4] cycloaddition of 9‐triazolylanthracene makes it possible to initially induce chain coupling using UV light and to subsequently ligate the formed single‐chain nanoparticle (SCNP) with a second polymer chain using blue light. Seizing upon the first sequence‐independent λ‐orthogonal reactivity established here, the same macromolecular architecture was obtained in reverse irradiation sequence, by blue and subsequent violet light irradiation—completely foregoing high‐energy UV light.