3,1?-Bridged 2-[2?-(4?-dialkylaminophenyl)ethenyl] pyrylium and 1-Benzopyrylium Dyes - Synthesis and Vis/NIR Absorption/Emission Behaviour

Autor:	U.‐W. Grummt, Wolfgang Günther, Peter Czerney
Rok vydání:	1998
Předmět:	Turn (biochemistry) Crystallography Stereochemistry Chemistry Proton NMR General Medicine Chromophore Absorption (chemistry) Ring (chemistry) Molecular electronic transition Planarity testing Spectral line
Zdroj:	Journal f�r Praktische Chemie/Chemiker-Zeitung. 340:214-222
ISSN:	1521-3897 0941-1216
DOI:	10.1002/prac.19983400304
Popis:	A series of new 3,1′-bridged 2-[2′-(4″-dialkylaminophenyl)ethenyl]-4,6-diarylpyrylium perchlorates (3), 2-[2′-(4″-dialkylaminophenyl)ethenyl]-7-diethylamino-1-benzopyrylium perchlorates 5–8, 2-[4′-(4″-dialkylaminophenyl)butadien-1′,3″-yl]-, and 2-[2′-(7″-diethylaminocoumar-3″-yl)ethenyl]-7-diethylamino-1-benzopyrylium perchlorates 10–12 were synthesized and characterized by means of elemental analysis, m.p., Vis/NIR, and 1H NMR spectra. Semiempirical MO calculations were performed to elucidate the essential features of the chromophores. The size of the bridging ring strongly affects the geometry of the chromophores which, in turn, determines the extent of charge transfer of the longest wavelength electronic transition. Increasing deviation from planarity causes the polymethine-like chromophore to become more polyene-like.
Databáze:	OpenAIRE
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