Dissymmetrical Chiral Peropyrenes: Synthesis via Iridium-Catalyzed C-H Activation/Alkyne Benzannulation and Study of Their Properties.

Dissymmetrical chiral peropyrenes with electron-rich and electron-deficient aryl substituents in the bay regions were synthesized via iridium-catalyzed C-H activation and alkyne benzannulation. The electronic properties were studied using cyclic and differential pulse voltammetry. The enantiomers were separated and exhibited high glum and gabs values in circularly polarized luminescence (CPL) and circular dichroism (CD), respectively. Variable-temperature NMR experiments were conducted on symmetrical and dissymmetrical chiral peropyrenes to compare the barrier to rotation of the aryl groups in the bay region.

Synthesis and Properties of Achiral and Chiral Dipyrenoheteroles and Related Compounds.

Achiral and chiral isomers of dipyrenoheteroles were synthesized via alkyne benzannulation. The electronic properties of these compounds were examined using cyclic voltammetry and differential pulse voltammetry. The enantiomers of the chiral isomers were separated, and their optical properties were examined in circular dichroism and circularly polarized luminescence studies. The chiral isomers exhibited a large bathochromic shift, relative to the achiral isomer, in both absorbance and fluorescence, resulting from decreased symmetry, rather than a change in the size of the backbone.