Synthesis and Characterization of 1-Hydroxy-4,5-arene-Fused Tropylium Derivatives
Takuya Kodama, Y. Kawashima, K. Uchida, Zhirong Deng, Mamoru Tobisu
Abstract
The properties of 1-hydroxy-4,5-arene-fused tropyliums were assessed based on experimental and theoretical investigations. An X-ray crystallographic analysis revealed a decrease of bond alternation in the seven-membered ring of 1-hydroxy-4,5-benzotropylium derivatives compared with that of the parent 4,5-benzotropones, which is indicative of an increase in aromaticity upon protonation. NICS and AICD calculations also supported the increased aromaticity of 1-hydroxy-4,5-arene-fused tropylium. The pKa values for a series of 1-hydroxy-4,5-arene-fused tropylium derivatives were also determined.
Topics & Concepts
AromaticityProtonationChemistryRing (chemistry)Alternation (linguistics)Characterization (materials science)StereochemistryMedicinal chemistryComputational chemistryCrystallographyMoleculeOrganic chemistryMaterials scienceNanotechnologyLinguisticsPhilosophyIonSynthesis and Properties of Aromatic CompoundsSynthesis of Organic CompoundsSynthesis of Indole Derivatives