- Contrasting photodynamics between C60-dithiapyrene and C 60-pyrene dyads
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The photodynamics of a C60-dithiapyrene donor-acceptor conjugate were compared with the corresponding Cftirpyrene conjugate. The photoinduced charge separation and subsequent charge recombination processes were examined by time-resolved fluorescence measurements on the picosecond timescale and transient absorption measurements on the picosecond and microsecond timescales with detection in the visible and near-infrared regions. We have observed quite long lifetimes (i.e., up to 1.01 ns) for the photogenerated charge-separated state in a C60-dithiapyrene dyad without the need for i) a long spacer between the two moieties, or ii) a gain in aromaticity in the radical ion pair.
- Guldi, Dirk M.,Spaenig, Fabian,Kreher, David,Perepichka, Igor F.,Van Der Pol, Cornelia,Bryce, Martin R.,Ohkubo, Kei,Fukuzumi, Shunichi
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- Dependence of single-molecule conductance on molecule junction symmetry
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The symmetry of a molecule junction has been shown to play a significant role in determining the conductance of the molecule, but the details of how conductance changes with symmetry have heretofore been unknown. Herein, we investigate a naphthalenedithiol single-molecule system in which sulfur atoms from the molecule are anchored to two facing gold electrodes. In the studied system, the highest single-molecule conductance, for a molecule junction of 1,4-symmetry, is 110 times larger than the lowest single-molecule conductance, for a molecule junction of 2,7-symmetry. We demonstrate clearly that the measured dependence of molecule junction symmetry for single-molecule junctions agrees with theoretical predictions.
- Taniguchi, Masateru,Tsutsui, Makusu,Mogi, Ryoji,Sugawara, Tadashi,Tsuji, Yuta,Yoshizawa, Kazunari,Kawai, Tomoji
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p. 11426 - 11429
(2011/10/04)
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- Ethylenic silicon compounds and thermoplastic elastomers obtained therefrom
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The invention provides organosilicon compounds of the formula: STR1 in which: N IS 1, 2 OR 3; Each R, which may be identical or different, is a monovalent organic group which contains a carbon-carbon double bond and from 2 to 10 carbon atoms; Each R1, which may be identical or different, is a straight or branched alkyl radical optionally substituted by one or more halogen atoms or cyano groups; an aryl radical or an alkylaryl radical optionally substituted by one or more halogen atoms; R2 is a straight or branched divalent alkylene or alkylidene radical possessing up to 4 carbon atoms; X is a divalent radical consisting of, or containing, at least one hetero-atom selected from oxygen, sulphur and nitrogen atoms, the radical being attached to the radical R2 via a said hetero-atom; G is an organic radical of valency (m+ l) possess from 1 to 30 carbon atoms; m is 1, 2 or 3; And each Y, which may be identical or different, is a functional group selected from: --NO2, STR2 --COOM (where M represents a sodium, potassium or lithium atom); --COOR4 ; STR3 --COCl; --OH; --OR4 ; STR4 --SH; --SR4 ; STR5 --CONH2 ; --CSNH2 ; --CN; --CH2 --NH2 ; --CHO; STR6 --NCO; STR7 wherein R3 represents a hydrogen atom or a straight or branched alkyl radical possessing up to 6 carbon atoms and R4 represents an alkyl radical possessing up to 4 carbon atoms, with the proviso that two Y groups can together constitute an imide group STR8 wherein R5 represents a hydrogen atom or a straight or branched alkyl radical possessing up to 4 carbon atoms. These are useful intermediates in the preparation of disilanes and silicon polymers, in particular of polyethylenic silicon compounds which can be polymerized with an α, ω-dihydrogenopolysiloxane to give thermoplastic elastomers.
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