Chemical resolution of spiroindanones and synthesis of chiroptical polymers with circularly polarized luminescence.

Herein, the synthesis and chemical resolution of 1,1'-spirobisindane-3,3'-dione have been accomplished utilizing inexpensive and readily available benzaldehyde and acetone as starting materials, and (1R,2R)- or (1S,2S)-1,2-diphenylethane-1,2-diol as a recyclable chiral resolution reagent. The further transformation of R- and S-1,1'-spirobisindane-3,3'-dione into chiral monomers and polymers has been achieved by the reasonable design of the synthetic route and the optimization of the polymerization conditions. The resulting chiroptical polymers exhibit blue emission with thermally activated delayed fluorescence (TADF), excellent optical activities with circular dichroism intensities per molar absorption coefficient (gabs) of up to 6.4 × 10-3, and intense circularly polarized luminescence (CPL) with luminescence dissymmetry factor (glum) values of up to 2.4 × 10-3.

Dibenzo[b,d]furan/thiophene-fused double boron-based multiresonance emitters with narrowband ultrapure green electroluminescence.

Herein, double boron (DB)-based narrowband pure-green multiresonance (MR) emitters DBF-DBN and DBT-DBN have been designed and synthesized. Dibenzo[b,d]furan and dibenzo[b,d]thiophene as linkages between two B-N skeletons endow target DB-MR-emitters with a rigid and symmetric molecular structure, which efficiently extends the π-conjugation length and suppresses vibrational relaxation, resulting in a narrowband pure-green emission. DBT-DBN exhibits a remarkably higher reverse intersystem crossing (RISC) rate (kRISC = 7.4 × 105 s-1) than DBF-DBN (kRISC = 1.1 × 105 s-1) due to the heavy-atom effect of sulfur. The organic light-emitting diode (OLEDs) based on DBT-DBN shows an ultrapure green emission with maximum external quantum efficiencies (EQEs) up to 31.3%, an emission peak at 520 nm, and a narrow full-width at half-maximum (FWHM) of 24 nm, meeting the BT.2020 green standard.