Authors
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Tsurkan, M. ; Jungnickel, C. ; Schlierf, M. ; Werner, C.
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Title
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Forbidden chemistry: Two-photon pathway in [2+2] cycloaddition of maleimides
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Date
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06.07.2017
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Number
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53705
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Abstract
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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.
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Publisher
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Journal of the American Chemical Society
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Wikidata
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Citation
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Journal of the American Chemical Society 139 (2017) 10184-10187
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DOI
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https://doi.org/10.1021/jacs.7b04484
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Tags
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