The design, synthesis, and characterization of solution-processable polymers for organic light emitting diode (OLED) applications are presented. Theoretical calculations were employed to identify a carbazole-pyrimidine based building block as an optimized host material for the emissive layer of an idealized OLED stack. Efficient, free radical homopolymerization and copolymerization with a novel methacrylate-based heteroleptic iridium(III) complex leads to a library of nonconjugated polymers with pendant semiconductors. Optoelectronic characterization reveals impressive photoluminescence quantum yield (PLQY) values exceeding 80% and single-layer OLEDs show optimal performance for copolymers containing 6 mol % of iridium comonomer dopant.

Despite the number of methods available for dehalogenation and carbon-carbon bond formation using aryl halides, strategies that provide chemoselectivity for systems bearing multiple carbon-halogen bonds are still needed. Herein, we report the ability to tune the reduction potential of metal-free phenothiazine-based photoredox catalysts and demonstrate the application of these catalysts for chemoselective carbon-halogen bond activation to achieve C-C cross-coupling reactions as well as reductive dehalogenations. This procedure works both for conjugated polyhalides as well as unconjugated substrates. We further illustrate the usefulness of this protocol by intramolecular cyclization of a pyrrole substrate, an advanced building block for a family of natural products known to exhibit biological activity.

Abstract This review summarizes the field of metal‐catalyzed ring‐expanding carbonylation of epoxides. Specifically, epoxide carbonylation to ‐, ‐, and ‐lactones is reviewed, in addition to epoxide carbonylation to succinic anhydrides, 1,3‐oxazinane‐2,4‐diones and 1,3‐oxathiolan‐2‐ones. For each reaction, the mechanism of catalysis and control of stereochemistry are discussed and the scope and limitations of the catalysts are considered. Experimental conditions and procedures are also presented. In addition, non‐carbonylative routes preparing similar products are compared.

We have fabricated highly efficient green phosphorescent organic light-emitting diodes by solution process. Very interestingly, we found that the device efficiency is affected by interface between hole transport layer (HTL) and emission layer (EML). It was proved through spin cleaning process of cross-linkable HTL after curing which may affect the interface mixing. In addition, we tried to add complement layer to manipulate such effects. As a result, we significantly improved device efficiency (up to 72.7 cd/A) after spin cleaning process of the cross-linkable HTL material.

Triazine-based unimolecular initiators are shown to mediate the controlled radical polymerization of several monomer classes, yielding polymers with low dispersities, targeted molecular weights, and active chain ends. We report the modular synthesis of structurally and electronically diverse triazine-based unimolecular initiators and demonstrate their ability to efficiently control the radical polymerization of modified styrene monomers. Copolymerizations of styrene with butyl acrylate or methyl methacrylate were conducted to highlight the monomer family tolerance of this system. Notably, in the case of methyl methacrylate and styrene, up to 90 mol% methyl methacrylate comonomer loadings could be achieved while maintaining a controlled polymerization, allowing the synthesis of a range of block copolymers. This class of triazine-based mediators has the potential to complement current methods of controlled radical polymerization and marks an important milestone in ongoing efforts to develop initiators and mediators with high monomer tolerance that are both metal and sulfur-free.

A novel strategy for the synthesis and characterization of branched polymer brushes by sequential light-mediated controlled radical polymerizations is described. Initially, linear brushes are prepared by surface-initiated copolymerization of methyl methacrylate and 2-hydroxyethyl methacrylate (HEMA). In a subsequent step, the HEMA side chains are functionalized with initiating groups for secondary graft polymerization, leading to hierarchical, branched architectures. The increased steric bulk due to the polymer side chains results in a dramatic increase in film thickness when compared to the starting linear brushes. This strategy also allows chemical gradient and complex three-dimensional structures to be obtained by employing grayscale photomasks in combination with controlled radical polymerization. (C) 2016 Wiley Periodicals, Inc.

The controlled radical polymerization of a variety of acrylate monomers is reported using an Ir-catalyzed visible light mediated process leading to well-defined homo-, random, and block copolymers. The polymerizations could be efficiently activated and deactivated using light while maintaining a linear increase in molecular weight with conversion and first order kinetics. The robust nature of the fac-[Ir(ppy)3] catalyst allows carboxylic acids to be directly introduced at the chain ends through functional initiators or along the backbone of random copolymers (controlled process up to 50 mol % acrylic acid incorporation). In contrast to traditional ATRP procedures, low polydispersity block copolymers, poly(acrylate)-b-(acrylate), poly(methacrylate)-b-(acrylate), and poly(acrylate)-b-(methacrylate), could be prepared with no monomer sequence requirements. These results illustrate the increasing generality and utility of light mediated Ir-catalyzed polymerization as a platform for polymer synthesis.