New luminescent compounds consisting of 10H-phenoxaboryl group as an electron-accepting unit and carbazole (9), 9,9dimethylacridane (10), or phenoxazine (11) as an electron-donating unit have been synthesized. Compounds 10 and 11 showed thermally activated delayed fluorescence (TADF) with light blue and green emissions, respectively, with very high PL quantum yields (PLQYs), however, compound 9 exhibited only a prompt emission and no delayed component. Photoluminescence studies and quantum chemical calculation based on density functional theory (DFT) and timedependent density functional theory (TD-DFT) revealed that in comparison with compound 9, HOMO and LUMO for compounds 10 and 11 are well separated, resulting in lowering ∆EST and effective reverse intersystem crossing (RISC) between a lowest triplet excited state (T1) and a lowest singlet excited state (S1). Organic light-emitting diodes (OLEDs) using compounds 10 and 11 exhibited light blue and green emissions with very good maximum ηext of 15.1% and 22.1%, respectively.

the coefficients (a = 0.0102 MPa -1 and b = 2.16) and the HSP of NPB ( D  = 22.6 MPa 1/2 , P  = 6.8 MPa 1/2 , and H  = 5.8 MPa 1/2 for the dispersion, polarity, and hydrogen bonding interactions, respectively). The correlation enabled us to describe the solvent dependence of the solubility of NPB within the root-mean-square deviation of 0.47 in 2 log x from the experimental data. ) Reichardt, C.; Welton, T., Solvents and Solvent Effects in Organic Chemistry. 4th. ed.; Wiley-VCH: Weinheim, 2010.

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heterocyclic 4-membered rings heterocyclic 4-membered rings R 0055 -104Preparation of 2-(3-Hydroxyalkylthio)benzoxazoles and Their Conversion into Thietanes.-Secondary diols react with disulfide (II) in the presence of tributyl-or triphenylphosphine (optimized conditions) to give selectively the title compounds. These can be cleaved to thiethanes on treatment with KH with concomitant formation of benzoxazol-2-one. The oxide (V), derived from the dibenzyl thiethane (IVc), reacts with silylated bases to form thiethane nucleosides.- (IKEMIZU, D.; MATSUYAMA, A.; TAKEMURA, K.; MITSUNOBU, O.; Synlett (1997 Synlett ( ) 11, 1247 Synlett ( -1248 Dep. Chem., Coll. Sci. Eng., Aoyama Gakuin Univ., Setagaya, Tokyo 157, Japan; EN)