Synthesis of Highly Twisted, Nonplanar Aromatic Macrocycles Enabled by an Axially Chiral 4,5-Diphenylphenanthrene Building Block
作者:Yuanming Li、Akiko Yagi、Kenichiro Itami
DOI:10.1021/jacs.9b13549
日期:2020.2.12
The synthesis, structures, and properties of highly twisted, nonplanar aromatic macrocycles are described. These macrocycles with an approximately 90° twist angle were synthesized by an effective synthetic approach through a quadruple Suzuki-Miyaura coupling of 4,5-bisarylphenanthrene as a novel axially chiral nonplanar buildingblock. By varying the cross-coupling partner as the spacer, a family of
synthesized by incorporating the propeller-shaped tetraphenylethylene (TPE) moieties into the framework. The macrocycle M1 displayed unique toluene-dependent fluorescence emissionbehavior, an emission peaking at 508 nm was observed in the absence of toluene, while first decreasing and then increasing fluorescence intensity along with blue-shift emission was witnessed with increasingly addition of toluene
Dications of Fluorenylidenes. The Relationship between Redox Potentials and Antiaromaticity for Meta- and Para-Substituted Diphenylmethylidenefluorenes
作者:Nancy S. Mills、Cornelia Tirla、Michele A. Benish、Amber J. Rakowitz、Lisa M. Bebell、Caroline M. M. Hurd、Anna L. M. Bria
DOI:10.1021/jo051599u
日期:2005.12.1
donation in these systems. A strong correlation between NICS and σ constants suggests that factors that affect the magnitude of the charge on the benzylic (α) carbon of the diphenylmethylcation affect the antiaromaticity of the fluorenyl cation. Calculated atomic charges on carbons 1−8 and 10−13 show an increase in positivecharge, and therefore greater delocalization of charge in the fluorenyl system