Basket-shaped quinacridone cyclophanes: synthesis, solid-state structures, and properties

A series of basket-shaped quinacridone (QA) cyclophanes 1–6 has been synthesized and characterized. Single-crystal X-ray analysis of 5 shows no infinite π–π aggregation between QA cores, reflecting a significant isolated effect of the bridging tethers. Photophysical properties have been carefully investigated. All cyclophanes show much higher quantum yields in concentrated solutions compared to the non-bridged QA analogue 7. Further application of 1 as a green dopant in EL devices exhibits current efficiencies of 11.2 and 7.2 cd A−1 with doping concentrations of 0.5 and 3 wt%, respectively. QA cyclophanes maintain a high luminescent yield in both concentrated solution and high doping concentration EL devices, verifying that the basket-shaped functionalization is an ideal strategy for depressing fluorescence quenching of QA dyes in the condensed phase.