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New types of polyurethanes (PUs) were prepared from condensation polymerization of isophorone diisocyanate (IPDI) with various combination of 9-butyl-3,6-bis(4-hydroxyphenyl)carbazole (Cz) and 2,5-bis(4-hydroxyphenyl)-1,3,4-oxadiazole (OXD), and end-capped with 4- tert- butyl phenol. The Cz-OXD PUs can also be used as host for phosphorescent dye. Red EL emission was obtained when Ir(btp) 2 (acac) or Ir(2-phq) 2 (acac) was used as the phosphorescent dyes in Cz-OXD (3:1) PU. Maximum brightness of 394 cd/m 2 and EL efficiency of 1 cd/A were achieved for the Ir(2-phq) 2 (acac) base device. In addition, white light PLED was demonstrated when co-dopant of Ir(btp) 2 (acac) and Firpic were used.

[reaction: see text] A diverse array of oxometallic species were examined as catalysts in nucleophilic acyl substitution (NAS) reactions of methyl (or ethyl) esters with protic nucleophiles. Among them, oxotitanium acetylacetonate (TiO(acac)(2)) and vanadyl chloride (VOCl(2)-(THF)(x)()) served as the most efficient and water-tolerant catalysts. Transesterifications of methyl and/or ethyl esters with functionalized (including acid- or base-sensitive) 1 degrees and 2 degrees alcohols can be carried out chemoselectively in refluxed toluene or xylene in a 1:1 substrate stoichiometry using 1 mol % catalyst loading. The resultant products were furnished in 85-100% yields by simple aqueous workup to remove water-soluble catalysts. The new NAS protocol is also amenable to amines and thiols in 74-91% yields, albeit with higher loading (2.5 equiv) of protic nucleophiles. Representative examples of commercial interests such as Padimate O and antioxidant additives for plastics were also examined to demonstrate their practical applications. A 1:1 adduct between TiO(acac)(2) and a given 1-octadecanol was identified as (C(18)H(37)O)(2)Ti(acac)(2) and was responsible for its subsequent NAS of methyl esters.

The innovative polyurethane-type polymers from a triphenylamine derivative, [N,N′-bis(4-hydroxyphenyl)-N,N′-diphenylbenzidine] (TPA) and a carbazole derivative, [9-butyl-3,6-bis(4-hydroxyphenyl)carbazole] (Cz) can be linked through isophorone diisocyanate (IPDI) bridges and incorporated as hole-transporting layers in high-performance PLED devices. The TPA–IPDI–Cz type of polyurethane (PU) materials (P1–P5) showed superb hole injection and transport properties based on the results of the hole-only-device study. We prepared the devices in two kinds of configuration: system (1) Indium Tin Oxide (ITO)/PU (20 nm)/{Iridium(III) bis(2-phenylpyridine), [Ir(ppy)3] + 2-(4-biphenyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (t-PBD) + polyvinylcarbazole (PVK)] (50 nm)/Mg (10 nm)/Ag (100 nm), for the device with P1 (DP1), the brightness increased to 14 000 cd m−2, the current efficiency rose to 13.4 cd A−1, and the turn-on voltage was reduced to 21 V (at 100 cd m−2). In system (2) ITO/PEDOT–PSS (30 nm)/PU (20 nm)/[Ir(ppy)3 + t-PBD + PVK] (50 nm)/Mg (10 nm)/Ag (100 nm), with PEDOT–PSS as the hole-injection layer, was compared to the standard device (S2) having the configuration ITO/PEDOT–PSS (50 nm)/[Ir(ppy)3 + t-PBD + PVK] (50 nm)/Mg (10 nm)/Ag (100 nm); the brightness of the double layer device with P5 (DDP5) increased to 12 500 cd m−2 and the current efficiency dramatically rose to 34.7 cd A−1, compared with values of 6250 cd m−2 and 21.8 cd A−1, respectively, for S2.