Oxanorbornene-Fused Phenazine-Pyrene Scaffolds with Different Configurations.

New molecular scaffolds of C-, Z- and box-shaped configurations are constructed by fusing phenazine and pyrene units with oxanorbornene. As revealed by X-ray crystallography, the C-shaped molecules exhibit two interesting π-π stacking modes of phenazine depending on the substituting groups, and the box-shaped molecule accommodates two chloroform molecules in the cavity and forms H-bonds with another four molecules of chloroform. The C- and Z-shaped molecules as a pair of diastereomers exhibit almost the same charge transfer absorption and emission including positive solvatochromism, indicating that the intramolecular charge transfer between pyrene (π-donor) and phenazine (π-acceptor) is not dependent on the overall molecular geometry.