- Resonance Raman Investigation of the ?* Antibonding Distribution in Excited Triplet Aqueous p-Benzoquinone
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The time-resolved resonance Raman spectra of triplet p-benzoquinone in water have been investigated at 266, 315, 355, and 416 nm.Recent improvements in the apparatus are described.The C=C ring stretch (Wilson's 8a) and the symmetric C=O stretch are tentat
- Rossetti, R.,Beck, S. M.,Brus, L. E.
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- Study of the ESI-mass spectrometry ionization mechanism of Fischer carbene complexes
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By means of deuterium-labeling experiments, we have carried out a systematic ESI-MS study to determine the mechanism of ESI ionization of alkenyl and alkynyl group 6 Fischer carbene complexes. These compounds can be ionized under ESI conditions only in the presence of additives such as hydroquinone (HQ) or tetrathiafulvalene (TTF). Our results demonstrate that in the ESI source an anion-radical is formed after the initial HQ- or TTF-mediated electron transfer to the metallic carbene complex. For alkenyl carbene complexes, this species evolves by extrusion of a hydrogen radical to form an allenylchromium anion that is detected as the [M - H]- ion in the mass spectrum. The preference for this mechanistic pathway could be rationalized by DFT calculations. In the case of alkynyl carbene complexes, experiments combining deuterated substrate, additive, and solvent demonstrate that the previously proposed allene-anion carbene complex is not formed. Instead, the H transfer from the ethoxy group in the anion radical, followed by extrusion of a hydrogen radical, leads to an allenyl anion that is detected in the ESI-MS as [M - H - CO]-.
- Wulff, William D.,Korthals, Keith A.,Martinez-Alvarez, Roberto,Gomez-Gallego, Mar,Fernandez, Israel,Sierra, Miguel A.
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p. 5269 - 5277
(2007/10/03)
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- Structure-property correlations in model compounds of oligomer liquid crystals
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Structure-property correlations of the following model compounds for oligomer liquid crystals (LCs) have been investigated: monomers, C 6H5O(CH2)xCH3 (x = 4 and 5); dimers, C6H5O
- Sasanuma, Yuji,Ono, Tetsushi,Kuroda, Yoshihiko,Miyazaki, Emi,Hikino, Ken,Arou, Jun,Nakata, Kohji,Inaba, Hideaki,Tozaki, Ken-Ichi,Hayashi, Hideko,Yamaguchi, Kentaro
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p. 13163 - 13176
(2007/10/03)
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- Resonance Raman and FTIR spectra of isotope-labeled reduced 1,4-benzoquinone and its protonated forms in solutions
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Resonance Raman (RR) and FTIR spectra are observed for 1,4-benzoquinone and its 18O2 and d4 isotopomers in their reduced states and their protonated forms, including the anion radical, semiquinone radical, dianion, and pro
- Zhao,Imahori,Zhan,Sakata,Iwata,Kitagawa
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p. 622 - 631
(2007/10/03)
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