- Electrical conductivity and glass formation in nitrile-functionalized pyrrolidinium bis(trifluoromethylsulfonyl)imide ionic liquids: Chain length and odd-even effects of the alkyl spacer between the pyrrolidinium ring and the nitrile group
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The electrical conductivity of a series of pyrrolidinium bis(trifluoromethylsulfonyl)imide ionic liquids, functionalized with a nitrile (cyano) group at the end of an alkyl chain attached to the cation, was studied in the temperature range between 173 K and 393 K. The glass formation of the ionic liquids is influenced by the length of the alkyl spacer separating the nitrile function from the pyrrolidinium ring. The electrical conductivity and the viscosity do not show a monotonic dependence on the alkyl spacer length, but rather an odd-even effect. An explanation for this behavior is given, including the potential energy landscape picture for the glass transition. This journal is the Partner Organisations 2014.
- Leys, Jan,Tripathi, Chandra Shekhar Pati,Glorieux, Christ,Zahn, Stefan,Kirchner, Barbara,Longuemart, Stephane,Lethesh, Kallidanthiyil Chellappan,Nockemann, Peter,Dehaen, Wim,Binnemans, Koen
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p. 10548 - 10557
(2014/06/09)
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- Replacing -CH2CH2- with -CONH- does not significantly change rates of charge transport through AgTS-SAM//Ga 2O3/EGaIn junctions
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This paper describes physical-organic studies of charge transport by tunneling through self-assembled monolayers (SAMs), based on systematic variations of the structure of the molecules constituting the SAM. Replacing a -CH2CH2- group with a -CONH- group changes the dipole moment and polarizability of a portion of the molecule and has, in principle, the potential to change the rate of charge transport through the SAM. In practice, this substitution produces no significant change in the rate of charge transport across junctions of the structure AgTS-S(CH 2)mX(CH2)nH//Ga2O 3/EGaIn (TS = template stripped, X = -CH2CH2- or -CONH-, and EGaIn = eutectic alloy of gallium and indium). Incorporation of the amide group does, however, increase the yields of working (non-shorting) junctions (when compared to n-alkanethiolates of the same length). These results suggest that synthetic schemes that combine a thiol group on one end of a molecule with a group, R, to be tested, on the other (e.g., HS~CONH~R) using an amide-based coupling provide practical routes to molecules useful in studies of molecular electronics.
- Thuo, Martin M.,Reus, William F.,Simeone, Felice C.,Kim, Choongik,Schulz, Michael D.,Yoon, Hyo Jae,Whitesides, George M.
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supporting information; experimental part
p. 10876 - 10884
(2012/08/28)
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- A dehydrohalogenation methodology for synthesizing terminal olefins under mild conditions
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A new methodology for preparing terminal olefins in good yield by dehydrohalogenation of primary alkyl iodide with tetrabutylammonium fluoride in dimethyl sulfoxide at room temperature is presented. Optimization of the mild reaction conditions and assays on various alkyl iodides are described. Georg Thieme Verlag Stuttgart.
- Berube, Marie,Kamal, Fatima,Roy, Jenny,Poirier, Donald
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p. 3085 - 3091
(2008/02/08)
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- Orthocarbonsaeure-ester mit 2,4,10-Trioxaadamantanstruktur als Carboxylschutzgruppe; Verwendung zur Synthese von substituierten Carbonsaeuren mit Hilfe von Grignard-Reagenzien
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The surprising stability of 2,4,10-trioxa-3-adamantyl derivatives 1 against nucleophilic substitution by organomagnesium compounds is discussed and shown to be caused by unfavourable stereoelectronic and steric factors governing the substitution of these cage compounds (Scheme 2).As a consequence, a number of Grignard reagents 2 containing the carboxyl group masked as 2,4,10-trioxa-3-adamantyl group could be prepared and have been reacted in a second step with various electrophiles (cf.Scheme 4).In the products 7-13 and 15b the carboxyl masking group is removed by mild ac id hydrolysis and saponification (cf.Scheme 3) to yield the corresponding acids 16a-21a, 22, and 23a.Acids 21a and 23a have been further transformed to give the macrocyclic lactones 24 and 26, isolated from Galbanum oleo-gum-resin, and acid 22 to give 12-methyl-13-tridecanolide (25), isolated from Angelica root oil.In addition 1-bromo-ω-(2,4,10-trioxa-3-adamantyl)alkanes 1c and 1b have been used to synthesize (+/-)-methyl recifeiolate (29b) and pure cis-ambrettolic acid ((Z)-32a).
- Voss, Gundula,Gerlach, Hans
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p. 2294 - 2307
(2007/10/02)
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