We investigated the structure-morphology-performance relationship of diketopyrrolopyrrole (DPP)-based low band gap polymers with different donor cores in organic field effect transistors (OFETs) and organic photovoltaics (OPVs). The change in the chemical structure led to strong physical property differences, such as crystalline behavior, blend morphology, and device performance. In addition, the choice of solvents and additives enabled one to fine tune the properties of these materials in the condensed state. For instance, when thin films were processed from solvent mixtures, both in the pure polymer and in a blend, we observed an enhanced edge-on orientation and the formation of thinner and longer polymer fibrils. In the BHJ blends, processing from a solvent mixture reduced the size scale of the phase separation and promoted the formation of a fibrillar network morphology, having a polymer-PCBM mixture filling the interfibrillar regions. The characteristic length scale of the fibrillar network dictated the specific inner surface area, which directly correlated to the performance in the OPV devices. When the BHJ mixture was processed from a single solvent, a large-scale phase separated morphology was observed that was stratified, normal to the film surface. A strong scattering anisotropy was observed in the resonant soft X-ray scattering of the blends that provided insight into the packing of the polymer chains within the fibrils. The morphology and performance trend in OPVs paralleled the performance in an OFET, suggesting that similar processing conditions should be considered in OFET fabrication.

The enzymatic β-C–H hydroxylation of the feedstock chemical isobutytic acid has enabled the asymmetric synthesis of a wide variety of polyketides. The analogous transitionmetal catalyzed enantioselective β-C–H functionalization of isobutyric acid-derived substrates should provide a versatile method for constructing useful building blocks with enantioenriched α-chiral centers from this abundant C-4 skeleton. However, the desymmetrization of ubiquitous isopropyl moieties by organometallic catalysts has remained an unanswered challenge. Herein, we report the design of chiral mono-protected aminomethyl oxazoline (MPAO) ligands that enable desymmetrization of isopropyl groups via palladium insertion into the C(sp3)-H bonds of one of the prochiral methyl groups. We detail the enantioselective β-arylation, -alkenylation and -alkynylation of isobutyric acid/2-amino-isobutyric acid derivatives, which may serve as a platform for the construction of α-chiral centers.

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cDNAs encoding KEPI, a novel protein kinase C (PKC)-potentiated inhibitory protein for type 1 Ser/Thr protein phosphatase (PP1), were identified. They were found among morphine-regulated brain mRNAs identified using subtracted differential display techniques. Full-length rat, mouse, and human cDNA and genomic sequences were elucidated with library screening and data base searching. Rat kb KEPI mRNAs were detected in brain, especially in the cerebral cortex and hippocampus, and in heart and skeletal muscle. Brain KEPI mRNA was up-regulated by both acute and chronic morphine treatments. The human KEPI gene contains four exons extending over more than 100 kb of genomic sequence on 6q24-q25, near the opiate receptor gene. These sequences displayed sufficient homology with the porcine PP1 inhibitor CPI-17 that we asked whether KEPI could share the ability of CPI-17 to modulate PP1 activity in a PKC-dependent fashion. Recombinant mouse KEPI is phosphorylated by PKC with a K m of 2.6 M and a t 1/2 of 20 min. Phospho-KEPI inhibits PP1␣ with an IC 50 of 2.7 nM, a potency more than 600-fold greater than that displayed by unphosphorylated KEPI. Neither phosphonor dephospho-KEPI inhibits protein phosphatase 2A. Up-regulation of KEPI expression by morphine, an agonist at PKC-regulating G-protein-coupled receptors, provides a novel signaling paradigm in which the halflives of serine/threonine phosphorylation events can be influenced by activities at G i /G o -coupled receptors that modulate KEPI expression, KEPI phosphorylation, and KEPI regulation of PP1 activity.Agonists at many G protein-coupled receptors activate G i and G o proteins, which in turn inhibit adenylate cyclase, alter fluxes through calcium and potassium channels, and enhance phospholipase activities that release activators of calcium/ phospholipid-dependent protein kinase (PKC) 1 (1-7). Second messenger changes caused by activation of G i /G o -coupled receptors can also change levels of gene expression.Morphine activation of G i /G o -coupled receptors alters second messengers, ion fluxes, and gene expression patterns in ways that could contribute to long term consequences of receptor occupancy such as tolerance, dependence, and addiction (8 -10). We have developed and used modifications of subtractive hybridization and differential display (SDD)-PCR approaches to seek morphine-regulated genes. These approaches thus provide a number of short cDNAs that correspond to morphine-regulated mRNAs.To define interesting novel genes that might correspond to these apparently morphine-regulated cDNAs, we have screened mouse and rat brain cDNA libraries with probes derived from pools of short cDNAs that were morphine-regulated in initial SDD experiments. One of these cDNAs hybridized to a novel 2.6-kb mRNA species that was expressed specifically in brain, heart, and muscle and was up-regulated by acute and chronic morphine treatments in brain. The sequence of this cDNA displayed homologies with the previously elucidated CPI-17 and PHI/PNG genes (11, 12), which are PKC-...