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Efficient Self‐Contained Photoacid Generator System Based on Photochromic Terarylenes
Author(s) -
Li Ruiji,
Nakashima Takuya,
Kanazawa Rui,
Galangau Olivier,
Kawai Tsuyoshi
Publication year - 2016
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201603768
Subject(s) - photochromism , moiety , aromatization , chemistry , quantum yield , generator (circuit theory) , photochemistry , yield (engineering) , organic chemistry , materials science , catalysis , fluorescence , optics , physics , quantum mechanics , metallurgy , power (physics)
Abstract A series of highly sensitive neutral photoacid generators (PAGs) based on photochromic terarylenes was prepared. Like the example presented herein, these compounds show a subsequent thermal elimination of a Brønsted acid after a light‐triggered 6π‐electrocyclization, concomitant with the hexatriene aromatization. A novel type of molecular systems was developed, in which one thiazolyl moiety was replaced by a thienyl group. Depending on the solvents and on the nature of the acid source, the quantum yield (QY) for acid generation could reach up to 0.6. Comparative studies on the acid source clearly showed that aromatic leaving groups tend to extinguish the molecular system photoefficiency. A second type was also prepared, in which the nature of the hetero‐aromatic rings were identical to our previous example, but their sequence was modified. Therefore, a second level of improvement was achieved in nonpolar solvents, pushing the QY value up to 0.7. Finally, we demonstrated the mesylic acid‐releasing PAG as a photocatalyst in a chemically amplified positive resist system.