C-H-activated Csp2-Csp3 diastereoselective gridization enables ultraviolet-emitting stereo-molecular nanohydrocarbons with mulitple H•••H interactions

we reported an achiral Pd-PPh3-cataylized diastereoselective (> 99:1 d.r.) gridization based on the C-H-activation at the fluorene the 9-position to give dimeric and trimeric windmill-type nanogrids (DWGs and TWGs). The cis-cis-TWGs exhibit unique intramolecular and multiple H…H interactions with a low field shift to 8.51 ppm, which is rare for hydrocarbon aromatics. These non-conjugated stereo-nanogrids show ultraviolet (UV) emission behaviors with peaks at 361-393 nm in film and 356-373 nm in crystal state, and circularly polarized luminescence with high luminescent dissymmetry factors (|gPL| =0.012). Significantly, the nondoped organic light-emitting diodes (OLEDs) based on cis-trans-TWG1 emitter exhibits an UV EL peak of ~386 nm (CIE: 0.17, 0.04) with a maximum external quantum efficiency (EQE) of 4.17%, which represents the record-high result among nondoped UV OLEDs based on hydrocarbon compounds, which is also the first efficient UV OLEDs based on macrocycles. These nanohydrocarbon offer potential nanoscafflolds for UV light-emitting optoelectronic applications.