- Organic Thin-film Solar Cells Using Benzotrithiophene Derivatives Bearing Acceptor Units as Non-Fullerene Acceptors
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New star-shaped non-fullerene acceptors (5Z,5′Z,5′′Z)-5,5′,5′′-((benzo[1,2-b : 3,4-b′ : 5,6-b′′]trithiophene-2,5,8-triyltris(4-octylthiophene-5,2-diyl))tris(methaneylylidene))tris(3-octyl-2-thioxothiazolidin-4-one) (1: BTT-OT-ORD) and 2,2′,2′′-((5Z,5′Z,5′′Z)-((benzo[1,2-b : 3,4-b′ : 5,6-b′′]trithiophene-2,5,8-triyltris(4-octylthiophene-5,2-diyl))tris(methaneylylidene))tris(3-octyl-4-oxothiazolidine-5,2-diylidene))trimalononitrile (2: BTT-OT-OTZDM) with a benzotrithiophene core, alkyl-thiophen units, and acceptor units were designed and synthesized. The HOMO-LUMO levels of 1 and 2 were determined by photoemission spectroscopy and UV-Vis absorption spectroscopy. Binary blend and ternary blend bulk heterojunction (BHJ) organic solar cells with non-fullerene acceptors 1 and 2 were fabricated with the inverted device structures of glass/ITO/ZnO/active_layer/MoO3/Ag. Both binary blend BHJ solar cells with 1 and 2 show lower JSC and larger VOC values than P3HT : PCBM solar cells. On the other hand, ternary blend BHJ organic solar cells, including 10 % of 1, exhibited a larger power conversion efficiency than P3HT : PCBM solar cells because the JSC value was largely improved.
- Matsumoto, Kouichi,Yamashita, Kazuhiro,Sakoda, Yuuki,Ezoe, Hinata,Tanaka, Yuki,Okazaki, Tatsuya,Ohkita, Misaki,Tanaka, Senku,Aoki, Yuki,Kiriya, Daisuke,Kashimura, Shigenori,Maekawa, Masahiko,Kuroda-Sowa, Takayoshi,Okubo, Takashi
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p. 4620 - 4629
(2021/09/10)
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- Disposable cartridge concept for the on-demand synthesis of turbo Grignards, Knochel–Hauser amides, and magnesium alkoxides
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Magnesium organometallic reagents occupy a central position in organic synthesis. The freshness of these compounds is the key for achieving a high conversion and reproducible results. Common methods for the synthesis of Grignard reagents from metallic magnesium present safety issues and exhibit a batch-to-batch variability. Tubular reactors of solid reagents combined with solution-phase reagents enable the continuous-flow preparation of organomagnesium reagents. The use of stratified packed-bed columns of magnesium metal and lithium chloride for the synthesis of highly concentrated turbo Grignards is reported. A low-cost pod-style synthesizer prototype, which incorporates single-use prepacked perfluorinated cartridges and bags of reagents for the automated on-demand lab-scale synthesis of carbon, nitrogen, and oxygen turbo magnesium bases is presented. This concept will provide access to fresh organomagnesium reagents on a discovery scale and will do so independent from the operator’s experience in flow and/or organometallic chemistry.
- Adamo, Andrea,Berton, Mateo,McQuade, D. Tyler,Sheehan, Kevin
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supporting information
p. 1343 - 1356
(2020/07/10)
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- Reversible Formation of Alkyl Radicals at [Fe4S4] Clusters and Its Implications for Selectivity in Radical SAM Enzymes
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All kingdoms of life use the transient 5′-deoxyadenosyl radical (5′-dAdoa ) to initiate a wide range of difficult chemical reactions. Because of its high reactivity, the 5′-dAdo?must be generated in a controlled manner to abstract a specific H atom and avoid unproductive reactions. In radical S-Adenosylmethionine (SAM) enzymes, the 5′-dAdo?is formed upon reduction of SAM by an [Fe4S4] cluster. An organometallic precursor featuring an Fe-C bond between the [Fe4S4] cluster and the 5′-dAdo group was recently characterized and shown to be competent for substrate radical generation, presumably via Fe-C bond homolysis. Such reactivity is without precedent for Fe-S clusters. Here, we show that synthetic [Fe4S4]-Alkyl clusters undergo Fe-C bond homolysis when the alkylated Fe site has a suitable coordination number, thereby providing support for the intermediacy of organometallic species in radical SAM enzymes. Addition of pyridine donors to [(IMes)3Fe4S4-R]+ clusters (R = alkyl or benzyl; IMes = 1,3-dimesitylimidazol-2-ylidene) generates Ra , ultimately forming R-R coupled hydrocarbons. This process is facile at room temperature and allows for the generation of highly reactive radicals including primary carbon radicals. Mechanistic studies, including use of the 5-hexenyl radical clock, demonstrate that Fe-C bond homolysis occurs reversibly. Using these experimental insights and kinetic simulations, we evaluate the circumstances in which an organometallic intermediate can direct the 5′-dAdo?toward productive H-Atom abstraction. Our findings demonstrate that reversible homolysis of even weak M-C bonds is a feasible protective mechanism for the 5′-dAdo?that can allow selective X-H bond activation in both radical SAM and adenosylcobalamin enzymes.
- Brown, Alexandra C.,Suess, Daniel L. M.
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supporting information
p. 14240 - 14248
(2020/09/15)
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- Chromium(II)-Catalyzed Diastereoselective and Chemoselective Csp2-Csp3 Cross-Couplings Using Organomagnesium Reagents
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A simple protocol for performing chromium-catalyzed highly diastereoselective alkylations of arylmagnesium halides with cyclohexyl iodides at ambient temperature has been developed. Furthermore, this ligand-free CrCl2 enables efficient electrophilic alkenylations of primary, secondary, and tetiary alkylmagnesium halides with readily available alkenyl acetates. Moreover, this chemoselective C-C coupling reaction with stereodefined alkenyl acetates proceeds in a stereoretentive fashion. A wide range of functional groups on alkyl iodides and alkenyl acetates are well tolerated, thus furnishing functionalized Csp2-Csp3 coupling products in good yields and high diastereoselectivity. Detailed mechanistic studies suggest that the in situ generated low-valent chromium(I) species might be the active catalyst for these Csp2-Csp3 cross-couplings.
- Li, Jie,Ren, Qianyi,Cheng, Xinyi,Karaghiosoff, Konstantin,Knochel, Paul
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supporting information
p. 18127 - 18135
(2019/11/19)
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- Configurational Assignment of ‘Cryptochiral’ 10-Hydroxystearic Acid Through an Asymmetric Catalytic Synthesis
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An asymmetric catalytic total synthesis of (S)-10-hydroxystearic acid (1) for comparison of its absolute configuration to that of samples obtained by fermentative hydration of oleic acid is reported. The synthesis involves two catalytic key-steps, namely Ru-catalyzed anti-Markovnikov hydration of 9-decynoic acid (7) to 10-oxodecanoic acid (5), followed by titanium-mediated asymmetric catalytic addition of dioctylzinc (25) to 5 in presence of the chiral ligand N,N’-((1R,2R)-cyclohexane-1,2-diyl)bis(1,1,1-trifluoromethanesulfonamide) (6). The synthesis is short and efficient and avoids use of protecting groups. Ozonolysis of 10-undecynoic acid (9) to 5 provides an alternative entry point into the synthetic route. The double dehydrobromination of (ω,ω-1)-dibromoalkanoic acids to ω-alkynoic acids under a variety of conditions was investigated with 10,11-dibromoundecanoic acid (11) as model substrate and using qNMR to quantify all reaction products. The synthetic approaches presented here have the potential to be generalized to the asymmetric catalytic synthesis of a variety of n-hydroxy-fatty acids.
- Brunner, Andreas,Hintermann, Lukas
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p. 928 - 943
(2016/12/09)
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- Preparation of 2-magnesiated 1,3,5-triazines via an iodine-magnesium exchange
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Functionalized iodo- and diiodo-1,3,5-triazine derivatives readily undergo an I/Mg exchange with BuMgCl, sBuMgCl, or OctMgBr at low temperatures furnishing 2-magnesiated and 2-zincated 1,3,5-triazines (after transmetalation with ZnCl2). This me
- Peng, Zhihua,Haag, Benjamin A.,Knochel, Paul
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supporting information; experimental part
p. 5398 - 5401
(2011/02/26)
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- PROCESS FOR THE PREPARATION OF DELMOPINOL AND DERIVATIVES THEREOF
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A process for the preparation of delmopinol (3-(4-propylheptyl)-4-morpholinethanol) or a derivative or a pharmaceutically acceptable salt, or a solvate thereof, including an hydrate, comprises reacting oxazolidin [2, 3-c] morpholine and a grignard reagent, and optionally converting the delmopinol (or derivative) free base into a pharmaceutically acceptable salt. The oxazolidin [2, 3-c] morpholine and the grignard reagent are useful as intermediates in the production process.
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Page/Page column 12
(2008/06/13)
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- Method for producing alkyl-bridged ligand systems and transition metal compounds
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The invention relates to a method for producing highly substituted alkyl-bridged ligand systems on the basis of indene derivatives and transition metal compounds. Said alkyl-bridged ligand systems can be obtained in high yields using this method.
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- Thermochemical Bond Dissociation Energies of Carbon-Magnesium Bonds
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The heats of formation of 29 alkylmagnesium bromides, isobutyl bromide, and neopentyl bromide have been determined, and bond dissociation energies have been derived for the Grignard reagents.For saturated alkyl derivatives the C-Mg bond strength decreases with an increasing number of β-hydrogens in the series methyl, neopentyl, isobutyl, butyl, ethyl, 1-ethylpropyl, 1-methylpropyl, isopropyl, and t-butyl.Bonding in alkyl bromides and alkylmagnesium bromides is discussed.
- Holm, Torkil
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p. 464 - 467
(2007/10/02)
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- Method for repelling ticks and insects
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Process for repelling ticks and other biting insects comprising topically administering to humans or to domesticated animals a composition comprising at least one active compound selected from the group made up of alkylated pyrrolidones and alkylated pyrrolidenones.
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