2-Azidoimidazolium Ions Captured by N-Heterocyclic Carbenes: Azole-Substituted Triazatrimethine Cyanines
2016; Multidisciplinary Digital Publishing Institute; Volume: 6; Issue: 4 Linguagem: Inglês
10.3390/cryst6040040
ISSN2073-4352
AutoresSimone Haslinger, Gerhard Laus, Volker Kahlenberg, Klaus Wurst, Thomas Bechtold, Stefan Vergeiner, Herwig Schottenberger,
Tópico(s)Synthesis and Catalytic Reactions
Resumo1,3-Disubstituted 2-azidoimidazolium salts (substituents = methyl, methoxy; anion = PF6) reacted with N-heterocyclic carbenes to yield yellow 2-(1-(azolinylidene)triazen-3-yl)-1,3-R2-imidazolium salts (azole = 1,3-dimethylimidazole, 1,3-dimethoxyimidazole, 4-dimethylamino-1-methyl-1,2,4-triazole; R = methyl, methoxy; anion = PF6). Crystal structures of three cationic triazenes were determined. Numerous interionic C–H···F contacts were observed. Solvatochromism of the triazenes in polar solvents was investigated by UV-Vis spectroscopy, involving the dipolarity π* and hydrogen-bond donor acidity α of the solvent. Cyclovoltammetry showed irreversible reduction of the cations to uncharged radicals. Thermoanalysis showed exothermal decomposition.
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