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Near‐Infrared Photoinduced Coupling Reactions Assisted by Upconversion Nanoparticles
Author(s) -
Lederhose Paul,
Chen Zhijun,
Müller Rouven,
Blinco James P.,
Wu Si,
BarnerKowollik Christopher
Publication year - 2016
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.201606425
Subject(s) - tetrazole , chemistry , photochemistry , imine , nitrile , covalent bond , cycloaddition , pyrazoline , photon upconversion , nanoparticle , combinatorial chemistry , organic chemistry , materials science , nanotechnology , ion , catalysis
We introduce nitrile imine‐mediated tetrazole–ene cycloadditions (NITEC) in the presence of upconversion nanoparticles (UCNPs) as a powerful covalent coupling tool. When a pyrene aryl tetrazole derivative ( λ abs, max =346 nm) and UCNPs are irradiated with near‐infrared light at 974 nm, rapid conversion of the tetrazole into a reactive nitrile imine occurs. In the presence of an electron‐deficient double bond, quantitative conversion into a pyrazoline cycloadduct is observed under ambient conditions. The combination of NITEC and UCNP technology is used for small‐molecule cycloadditions, polymer end‐group modification, and the formation of block copolymers from functional macromolecular precursors, constituting the first example of a NIR‐induced cycloaddition. To show the potential for in vivo applications, through‐tissue experiments with a biologically relevant biotin species were carried out. Quantitative cycloadditions and retention of the biological activity of the biotin units are possible at 974 nm irradiation.