Tetracyanoethylene as a Building Block in the π-Expansion of 1,4-Dihydropyrrolo[3,2-b]pyrroles

四氰基乙烯作为1,4-二氢吡咯并[3,2-b]吡咯的π扩展构建块

Guler Yagiz Erdemir, Iryna Knysh, Kamil Skonieczny, Denis Jacquemin, Daniel T. Gryko

DOI: 10.1021/acs.joc.4c01555

期刊: The Journal of Organic Chemistry

摘要

The outcome of the reaction of tetracyanoethylene with 1,4-dihydropyrrolo[3,2-b]pyrroles (DHPPs) strongly depends on the character of the substituents present at positions 2 and 5. With electron-withdrawing substituents, the reaction does not occur at all, while, in contrast, the presence of electron-donating substituents yields addition–elimination products. When thiazol-2-yl substituents are located at positions 2 and 5, addition occurs at the thiazole ring, rather than of the DHPP core. In cases where very electron-rich heterocycles are present at positions 2 and 5, a second addition occurs followed by aromatization, leading to the formation of an additional benzene ring bridging two heterocyclic scaffolds. The reaction occurs only at one site since the presence of the strongly electron-withdrawing tricyanoethylene group has a profound impact on electron density at the remaining free position 6. The DHPPs possessing a tricyanoethylene group are strongly polarized and thus enable a push–pull system showing red-shifted absorption and negligible fluorescence. In contrast, dyes possessing a 1,2-dicyanobenzene moiety exhibit strong emission bathochromically shifted by over 100 nm compared to parent 1,4-dihydrotetraarylpyrroles[3,2-b]pyrroles (TAPPs). Computational studies shed light on the evolution of the photophysical properties as a function of the substitution pattern of the final systems.

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期刊信息

期刊:

ISSN: 0022-3263

国际分区

类目分区
CHEMISTRY, ORGANIC1

国内分区

类目分区
化学2
化学, 有机化学2
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