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Kang LJ, Xing L, Luscombe CK. Exploration and development of gold- and silver-catalyzed cross dehydrogenative coupling toward donor–acceptor π-conjugated polymer synthesis. Polym Chem 2019. [DOI: 10.1039/c8py01162a] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The synthesis of donor–acceptor conjugated polymers using Au- and Ag-catalyzed cross dehydrogenative coupling was achieved for the first time.
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Affiliation(s)
- Lauren J. Kang
- Department of Chemistry
- University of Washington
- Seattle
- USA
| | - Liwen Xing
- Molecular Engineering and Sciences Institute
- University of Washington
- Seattle
- USA
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Zhang J, Kang LJ, Parker TC, Blakey SB, Luscombe CK, Marder SR. Recent Developments in C-H Activation for Materials Science in the Center for Selective C-H Activation. Molecules 2018; 23:E922. [PMID: 29659537 PMCID: PMC6017541 DOI: 10.3390/molecules23040922] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Revised: 04/10/2018] [Accepted: 04/11/2018] [Indexed: 12/18/2022] Open
Abstract
Abstract: Organic electronics is a rapidly growing field driven in large part by the synthesis of ∏-conjugated molecules and polymers. Traditional aryl cross-coupling reactions such as the Stille and Suzuki have been used extensively in the synthesis of ∏-conjugated molecules and polymers, but the synthesis of intermediates necessary for traditional cross-couplings can include multiple steps with toxic and hazardous reagents. Direct arylation through C-H bond activation has the potential to reduce the number of steps and hazards while being more atom-economical. Within the Center for Selective C-H Functionalization (CCHF), we have been developing C-H activation methodology for the synthesis of ∏-conjugated materials of interest, including direct arylation of difficult-to-functionalize electron acceptor intermediates and living polymerization of ∏-conjugated polymers through C-H activation.
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Affiliation(s)
- Junxiang Zhang
- School of Chemistry & Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332, USA.
| | - Lauren J Kang
- Department of Chemistry, University of Washington, Seattle, WA 98195, USA.
| | - Timothy C Parker
- School of Chemistry & Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332, USA.
| | - Simon B Blakey
- Department of Chemistry, Emory University, Atlanta, GA 30322, USA.
| | - Christine K Luscombe
- Department of Material Science and Engineering, University of Washington, Seattle, WA 98195, USA.
| | - Seth R Marder
- School of Chemistry & Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332, USA.
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Kozyrskyj AL, Letourneau NL, Kang LJ, Salmani M. Associations between postpartum depressive symptoms and childhood asthma diminish with child age. Clin Exp Allergy 2016; 47:324-330. [PMID: 27770463 DOI: 10.1111/cea.12837] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Revised: 08/16/2016] [Accepted: 09/15/2016] [Indexed: 12/22/2022]
Abstract
BACKGROUND Affecting 19% of women, postpartum depression is a major concern to the immediate health of mothers and infants. In the long-term, it has been linked to the development of early-onset asthma at school entry, but only if the depression persists beyond the postnatal period. No studies have tested whether associations with postpartum depressive symptoms and early-onset asthma phenotypes persist into later school age. OBJECTIVE To determine associations between maternal postpartum depressive symptoms and childhood asthma between the ages of 5-10 by using a nested longitudinal design. METHODS Data were drawn from the 1994-2004 administrations of the Canadian National Longitudinal Survey of Children and Youth, which tracks the health of a nationally representative sample of children in Canada. Child asthma was diagnosed by a health professional, and maternal depressive symptoms were assessed by the Centre for Epidemiological Studies Depression scale. Analyses were conducted by using a multilevel modelling approach, in which longitudinal assessments of asthma in 1696 children were nested within the exposure of postpartum depression. RESULTS Postpartum depressive symptoms had a 1.5-fold significant association with childhood asthma between the ages 6-8. This was independent of male sex, maternal asthma, non-immigrant status, low household socioeconomic status, being firstborn, low birthweight, low family functioning and urban-rural residence, of which the first 4 covariates elevated the risk of asthma. Statistical significance was lost at age 8 when maternal prenatal smoking replaced urban-rural residence as a covariate. At ages 9-10, an association was no longer evident. CONCLUSIONS AND CLINICAL RELEVANCE Women affected by postpartum depressive symptoms are concerned about long-term health effects of their illness on their infants. Although postpartum depressive symptoms were associated with school-age asthma at ages 6 and 7, this association diminished later. Both home and school life stress should be considered in future studies on asthma development later in childhood.
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Affiliation(s)
- A L Kozyrskyj
- Department of Pediatrics, University of Alberta, Edmonton, AB, Canada.,School of Public Health, University of Alberta, Edmonton, AB, Canada.,Department of Obstetrics and Gynecology, University of Alberta, Edmonton, AB, Canada
| | - N L Letourneau
- Faculty of Nursing & Cumming School of Medicine (Pediatrics & Psychiatry), University of Calgary, Calgary, AB, Canada
| | - L J Kang
- Department of Pediatrics, University of Alberta, Edmonton, AB, Canada
| | - M Salmani
- Department of Mathematics & Statistics, University of New Brunswick, Fredericton, NB, Canada
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Abstract
End-functionalized poly(3-hexylthiophene) (P3HT) has contributed to continued advancements in conjugated polymer applications, especially within organic electronics. P3HT synthesized using Kumada catalyst-transfer polymerization (KCTP) has many favourable attributes such as controlled molecular weight, high regioregularity, and narrow dispersity. With the addition of reactive end-groups, P3HT plays an important role in advancing the development of hybrid materials and preparation of block copolymers. Exploring methods of end-functionalization that result in heteroatom-bond formation, giving a non-carbon atom bonded to the terminal thiophene, could help control and understand the p–n junction of hybrid materials. This research highlight focuses on the development of a novel and facile way of end-functionalizing P3HT with chalcogens.
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Zeigler DF, Candelaria SL, Mazzio KA, Martin TR, Uchaker E, Suraru SL, Kang LJ, Cao G, Luscombe CK. N-Type Hyperbranched Polymers for Supercapacitor Cathodes with Variable Porosity and Excellent Electrochemical Stability. Macromolecules 2015. [DOI: 10.1021/acs.macromol.5b01070] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- David F. Zeigler
- Department of Chemistry and ‡Department of
Materials Science and Engineering, University of Washington, Seattle, Washington 98195, United States
| | - Stephanie L. Candelaria
- Department of Chemistry and ‡Department of
Materials Science and Engineering, University of Washington, Seattle, Washington 98195, United States
| | - Katherine A. Mazzio
- Department of Chemistry and ‡Department of
Materials Science and Engineering, University of Washington, Seattle, Washington 98195, United States
| | - Trevor R. Martin
- Department of Chemistry and ‡Department of
Materials Science and Engineering, University of Washington, Seattle, Washington 98195, United States
| | - Evan Uchaker
- Department of Chemistry and ‡Department of
Materials Science and Engineering, University of Washington, Seattle, Washington 98195, United States
| | - Sabin-Lucian Suraru
- Department of Chemistry and ‡Department of
Materials Science and Engineering, University of Washington, Seattle, Washington 98195, United States
| | - Lauren J. Kang
- Department of Chemistry and ‡Department of
Materials Science and Engineering, University of Washington, Seattle, Washington 98195, United States
| | - Guozhong Cao
- Department of Chemistry and ‡Department of
Materials Science and Engineering, University of Washington, Seattle, Washington 98195, United States
| | - Christine K. Luscombe
- Department of Chemistry and ‡Department of
Materials Science and Engineering, University of Washington, Seattle, Washington 98195, United States
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O'Brien CJ, Nixon ZS, Holohan AJ, Kunkel SR, Tellez JL, Doonan BJ, Coyle EE, Lavigne F, Kang LJ, Przeworski KC. Part I: the development of the catalytic Wittig reaction. Chemistry 2013; 19:15281-9. [PMID: 24115040 DOI: 10.1002/chem.201301444] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2013] [Indexed: 11/12/2022]
Abstract
We have developed the first catalytic (in phosphane) Wittig reaction (CWR). The utilization of an organosilane was pivotal for success as it allowed for the chemoselective reduction of a phosphane oxide. Protocol optimization evaluated the phosphane oxide precatalyst structure, loading, organosilane, temperature, solvent, and base. These studies demonstrated that to maintain viable catalytic performance it was necessary to employ cyclic phosphane oxide precatalysts of type 1. Initial substrate studies utilized sodium carbonate as a base, and further experimentation identified N,N-diisopropylethylamine (DIPEA) as a soluble alternative. The use of DIPEA improved the ease of use, broadened the substrate scope, and decreased the precatalyst loading. The optimized protocols were compatible with alkyl, aryl, and heterocyclic (furyl, indolyl, pyridyl, pyrrolyl, and thienyl) aldehydes to produce both di- and trisubstituted olefins in moderate-to-high yields (60-96%) by using a precatalyst loading of 4-10 mol%. Kinetic E/Z selectivity was generally 66:34; complete E selectivity for disubstituted α,β-unsaturated products was achieved through a phosphane-mediated isomerization event. The CWR was applied to the synthesis of 54, a known precursor to the anti-Alzheimer drug donepezil hydrochloride, on a multigram scale (12.2 g, 74% yield). In addition, to our knowledge, the described CWR is the only transition-/heavy-metal-free catalytic olefination process, excluding proton-catalyzed elimination reactions.
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Affiliation(s)
- Christopher J O'Brien
- School of Chemical Sciences, Dublin City University, Glasnevin, Dublin 9 (Ireland) http://webpages.dcu.ie/∼obrienc/OBrien_Group/Home.html.
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Abstract
Using a homemade electrogastrography (EGG) system, we studied the characteristics of the myoelectrical rhythm in Chinese patients with nonulcer dyspepsia (NUD). Based on short-term Fourier transformation, recorded slow waves could be automatically analyzed to obtain the following parameters: dominant frequency/power, percent of normal frequency (2-4 cpm), power ratio, etc. EGG parameters, Helicobacter pylori status, histological examination of gastric mucosa, and dyspeptic symptoms were recorded in 27 NUD patients. Compared to 32 healthy controls, the Chinese NUD patients had abnormal postprandial EGG parameters including a lower percentage of regular 2-4 cpm slow waves (70.10 +/- 2.97% vs 79.08 +/- 2.95%, P < 0.05), a lower level of increment of dominant power (0.62, +/- 0.91 vs 3.76 +/- 0.58 dB, P < 0.05), lower power ratio (1.42 +/- 0.28 vs 2.79 +/- 0.39, P < 0.05) and a higher instability coefficient (0.36 +/- 0.03 vs 0.26 +/- 0.03, P < 0.05). However, Helicobacter pylori infection and its associated gastritis did not influence any EGG parameters in NUD patients. Six main dyspeptic symptoms and total symptom score had no correlation with any EGG parameters. In conclusion, Chinese NUD patients may have abnormal postprandial stomach myoelectrical activity, but these EGG abnormalities are not a direct result of Helicobacter pylori infection and its related gastritis and do not contribution to the dyspeptic symptoms.
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Affiliation(s)
- C L Lu
- Department of Medicine and Surgery, Taipei Veterans General Hospital and School of Medicine, National Yang-Ming University, Taiwan
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Lu CL, Chen CY, Chang FY, Chang SS, Kang LJ, Lu RH, Lee SD. Effect of a calcium channel blocker and antispasmodic in diarrhoea-predominant irritable bowel syndrome. J Gastroenterol Hepatol 2000; 15:925-30. [PMID: 11022835 DOI: 10.1046/j.1440-1746.2000.02230.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
BACKGROUND Irritable bowel syndrome (IBS) is a colonic function disorder. Both pinaverlum bromide (a selective calcium channel blocker) and mebeverine (an antispasmodic) are reported to be effective in the long-term (12-16 weeks) treatment of IBS patients. Their efficacy in the short-term treatment of IBS patients and colonic transit time is unclear. Furthermore, substance P and neuropeptide Y have either excitatory or inhibitory effects on colonic motility. Whether the efficacy of both drugs is mediated through these neuropeptides remains unknown. METHODS AND RESULTS A clinical trial was conducted with 91 patients with diarrhoea-predominant IBS. After basal measurement of the total colonic transit time, IBS patients were randomized to receive either pinaverlum bromide (50 mg, t.i.d.) or mebeverine (100 mg, t.i.d.) for 2 weeks. The symptomatic scores regarding defaecation, total colonic transit time and serum levels of substance P and neuropeptide Y were measured before and after treatments. The daily defaecation frequency was markedly decreased after treatment (pinaverlum bromide, 2.9+/-1.2 vs 2.0+/-1.0, P< 0.05; mebeverine, 2.7+/-1.1 vs 2.1+/-1.0, P< 0.05). The stool consistency became well formed after both treatments (P< 0.05). Both drugs similarly improved the global well-being in these IBS patients (pinaverlum bromide vs mebeverine 73.4 vs 71.8%, P> 0.05). The total colonic transit time was significantly prolonged only after pinaverlum bromide treatment (21.4+/-15.5 vs 30.8+/-14.8 h, P< 0.01). Neither substance P nor neuropeptide Y serum level was significantly changed after either treatments. CONCLUSION Pinaverlum bromide and mebeverine have similar therapeutic efficacies on diarrhoea-predominant IBS patients. Prolonged colonic transit time may be one of the factors responsible for the efficacy of pinaverlum bromide on the IBS patients. Substance P and neuropeptideY appear less important in the pathogenesis of diarrhoea-predominant IBS.
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Affiliation(s)
- C L Lu
- Department of Medicine and Surgery, Taipei Veterans General Hospital and National Yang-Ming University, Taiwan
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