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Visible‐Light‐Induced Heptacene Generation under Ambient Conditions: Utilization of Single‐crystal Interior as an Isolated Reaction Site
Author(s) -
Hayashi Hironobu,
Hieda Nao,
Yamauchi Mitsuaki,
Chan Yee Seng,
Aratani Naoki,
Masuo Sadahiro,
Yamada Hiroko
Publication year - 2020
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.202002155
Subject(s) - single crystal , decomposition , photochemistry , molecule , reactivity (psychology) , absorption (acoustics) , chemistry , crystal (programming language) , materials science , crystallography , organic chemistry , medicine , alternative medicine , pathology , computer science , programming language , composite material
The photo‐induced generation of unstable molecules generally requires stringent conditions to prevent oxidation and the concomitant decomposition of the products. The visible‐light‐induced conversion of two heptacene precursors to heptacene was studied. Single crystals of bis‐ and mono‐α‐diketone‐type heptacene precursors ( 7‐DK2 and 7‐DK1 , respectively), were prepared to investigate the effect of precursor structure on reactivity. The photoirradiation of a 7‐DK2 single crystal cleaved only one α‐diketone group, forming an intermediate bearing a pentacene subunit, while that of a 7‐DK1 single crystal gave rise to characteristic absorption peaks of heptacene and their increase in intensity with photoirradiation time, indicating the generation of heptacene without decomposition. Heptacene production was not observed when the precursors were photoirradiated in solution, implying that the single crystal interior provided isolation from the external environment, thus preventing heptacene oxidation.