Forbidden Chemistry: Two-Photon Pathway in [2+2] Cycloaddition of Maleimides

Research output: Contribution to journalResearch articleContributedpeer-review

Contributors

Abstract

Two-photon excitation provides high spatial resolution in three dimensions of the corresponding chemical or physical processes, allowing submicrometer structuring in stereolithography and three-dimensional (3D) microfabrication. While studying two-photon structuring applications, we observed an undescribed phenomenon in photochemistry that dictates reactivity of maleimide groups in two-photon mode. A low-absorbance transition formerly ignored in classical photochemistry has been found for maleimides. This transition was assigned to symmetry-breaking donor-acceptor complex formation, which revealed a formally forbidden pathway in [2+2] cycloaddition reactions of maleimide moieties. This synthetic pathway allowed for the creation of hydrogel materials under physiological conditions at low laser excitation energy (0.1 J/cm2 at 800 nm) without the use of photoinitiators, which makes it truly two-photon click chemistry.

Details

Original languageEnglish
Pages (from-to)10184-10187
Number of pages4
JournalJournal of the American Chemical Society
Volume139
Issue number30
Publication statusPublished - 6 Jul 2017
Peer-reviewedYes

External IDs

PubMed 28682611
ORCID /0000-0002-6209-2364/work/142237672
ORCID /0000-0003-0189-3448/work/159607179