Carbanion Rearrangements in the Gas Phase: The Unusual Claisen Rearrangement of Deprotonated Allyl Vinyl Ether

1990 ◽  
Vol 43 (9) ◽  
pp. 1479 ◽  
Author(s):  
PCH Eichinger ◽  
JH Bowie
Keyword(s):  
Gas Phase ◽  
Vinyl Ether ◽  
Condensed Phase ◽  
Claisen Rearrangement ◽  
Negative Ions ◽  
Marked Contrast ◽  
Wittig Rearrangement ◽  
Major Reaction

Allyl vinyl ether is reported to undergo a facile Wittig rearrangement to yield penta-1,4-dien-3-ol under base- catalysed conditions in the condensed phase. In marked contrast, the Wittig rearrangement is not a major reaction in the gas phase. Instead, initial rearrangement occurs by a Claisen process and subsequent fragmentations involve some of the most complex interconversions yet proposed for negative ions.

Electron attachment to chloronitrobenzene: Formation of negative ions from gas phase and condensed phase molecules

2008 ◽  
Vol 455 (4-6) ◽  
pp. 139-144 ◽  
Author(s):  
Iwona Dąbkowska ◽  
Mario Orzol ◽  
Ilko Bald ◽  
Judith Langer ◽  
Eugen Illenberger
Keyword(s):  
Gas Phase ◽  
Condensed Phase ◽  
Electron Attachment ◽  
Negative Ions

Ion chemistry of second-row transition metals in hydrocarbon flames: cations and anions of Y, Zr, Nb, and Mo

1995 ◽  
Vol 73 (12) ◽  
pp. 2263-2271 ◽  
Author(s):  
Christine C.Y. Chow ◽  
John M. Goodings
Keyword(s):  
Transition Metals ◽  
Gas Phase ◽  
Atmospheric Pressure ◽  
Chemical Ionization ◽  
Negative Ions ◽  
Ion Concentration ◽  
Oxidation States ◽  
Metallic Ions ◽  
Ion Chemistry ◽  
Hydrocarbon Flames

A pair of laminar, premixed, CH4–O2 flames above 2000 K at atmospheric pressure, one fuel-rich (FR) and the other fuel-lean (FL), were doped with ~10−6 mol fraction of the second-row transition metals Y, Zr, Nb, and Mo. Since these hydrocarbon flames contain natural ionization, metallic ions were produced in the flames by the chemical ionization (CI) of metallic neutral species, primarily by H3O+ and OH− as CI sources. Both positive and negative ions of the metals were observed as profiles of ion concentration versus distance along the flame axis by sampling the flames through a nozzle into a mass spectrometer. For yttrium, the observed ions include the YO+•nH2O (n = 0–3) series, and Y(OH)4−. With zirconium, they include the ZrO(OH)+•nH2O (n = 0–2) series, and ZrO(OH)3−. Those observed with niobium were the cations Nb(OH)3+ and Nb(OH)4+, and the single anion NbO2(OH)2−. For molybdenum, they include the cations MoO(OH)2+ and MoO(OH)3+, and the anions MoO3− and MoO3(OH)−. Not every ion was observed in each flame; the FL flame tended to favour the ions in higher oxidation states. Also, flame ions in higher oxidation states were emphasized for these second-row transition metals compared with their first-row counterparts. Some ions written as members of hydrate series may have structures different from those of simple hydrates; e.g., YO+•H2O = Y(OH)2+ and ZrO(OH)+•H2O = Zr(OH)3+, etc. The ion chemistry for the production of these ions by CI in flames is discussed in detail. Keywords: transition metals, ions, flame, gas phase, negative ions.

Gas-phase chemistry of the negative ions derived from azo- and hydrazobenzene

1991 ◽  
Vol 56 (2) ◽  
pp. 607-612 ◽  
Author(s):  
Steen Ingemann ◽  
Roel H. Fokkens ◽  
Nico M. M. Nibbering
Keyword(s):  
Gas Phase ◽  
Negative Ions ◽  
Gas Phase Chemistry ◽  
Phase Chemistry

Preparation and Pyrolysis of Stereoisomeric Bromobicyclo[n.1.0]alkanes ( n = 6, 8 , 10)

1987 ◽  
Vol 42 (4) ◽  
pp. 489-494 ◽  
Author(s):  
Eckehard V. Dehmlow ◽  
Roland Kramer
Keyword(s):  
Thermal Stability ◽  
Gas Phase ◽  
Condensed Phase ◽  
Secondary Products ◽  
Gas Phase Reactions ◽  
Stereoselective Reduction ◽  
Derivatives Of ◽  
Thermal Stability Of

Abstract The title compounds la-3c were prepared by stereoselective reduction of the respective dibromides. Pyrolysis gave allylic bromides (8, 9, 11) as primary and dienes (10, 12) as secondary products. Product ratios were independent of the stereochemistry of the starting materials. No differences of the rearrangement rates of the stereoisomers were observed in gas phase reactions of the derivatives of bicyclo[6.1.0]- and bicyclo[8.1.0]alkanes. With the larger bicyclo[10.1.0] derivatives, however, distinct differences in the thermal stability of cis-trans-isomers4c/5c or 2c/3c were found in condensed phase.

Formation of gas-phase negative ions in vinylene carbonate

1983 ◽  
Vol 49 (2) ◽  
pp. 113-122 ◽  
Author(s):  
R.N. Compton ◽  
P.W. Reinhardt ◽  
H.C. Schweinler
Keyword(s):  
Gas Phase ◽  
Negative Ions ◽  
Vinylene Carbonate

scholarly journals Surface Reactions in Interstellar Space

2002 ◽  
Vol 12 ◽  
pp. 55-57 ◽  
Author(s):  
Eric Herbst
Keyword(s):  
Surface Chemistry ◽  
Gas Phase ◽  
Condensed Phase ◽  
Current Knowledge ◽  
Surface Reactions ◽  
Future Research ◽  
Interstellar Space ◽  
Interstellar Molecules ◽  
Grain Surface

AbstractIt is impossible to explain the abundances of some gas-phase and most condensed-phase interstellar molecules without the use of grain chemistry. Nevertheless, grain-surface chemistry is relatively poorly understood for a variety of reasons. Our current knowledge of this chemistry and its use in interstellar models is discussed along with specific needs for future research.

Determination of the Force Constants of Non-linear XY2 Molecules in the Gas-Phase by the GF Matrix Method

2004 ◽  
Vol 59 (9) ◽  
pp. 621-622 ◽  
Author(s):  
Fatih Ucun ◽  
Vesile Gūçlü
Keyword(s):  
Gas Phase ◽  
Condensed Phase ◽  
Matrix Method ◽  
Solid Phase ◽  
Force Constants ◽  
Matrix Solution ◽  
The Matrix ◽  
Newton Raphson ◽  
Raphson Method

The force constants of the internal coordinates of nonlinear XY2 molecules in the gas-phase were calculated by using the GF matrix method. The matrix solution was carried out by means a computer program built relative to the Newton-Raphson method and the calculations were listed in a table. The force constants of some molecules in the liquidand solid- phase were also found and compared with these ones, and it was seen that the force constants for more condensed phase are lower as in an agreement with having its lower frequency.

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