Glucose Oxidase
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Carbon Diperoxide
I was wandering this molecule might exist ?
Thanx in advance.
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Hexavalent
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Diperoxides are known to exist, and are often used as free radical-type polymerization initiators. However, I'm not totally sure about carbon
diperoxide...
BTW, you might want to read the Forum Guidelines before posting. This kind of question belongs in 'Beginnings', or even the short questions thread.
[Edited on 1-1-2013 by Hexavalent]
"Success is going from failure to failure without loss of enthusiasm." Winston Churchill
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kavu
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It exists and was observed alongside with other isomers of CO4 by an Italian research group in 2003 using mass spectrometry techniques. The
article describes the findings as follows: "We report herein the experimental discovery of CO4, a metastable molecule sufficiently
long-lived to allow its positive detection as an isolated species in the gas state." (Angew. Chem. Int. Ed. 2003, 42, 2985 – 2990)
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Hexavalent
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I've requested the full paper in References
Until then, do you know how it was prepared, kavu?
"Success is going from failure to failure without loss of enthusiasm." Winston Churchill
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kavu
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Mass specs can be used to synthesize stuff in small amounts by clever usage of chamber feeds. The experimental in the article is way over my head as I
haven't played around with mass specs all that much, but:
"The experiments were performed by using a modified ZABSpec oa-
TOF instrument (VG Micromass) of EBE-TOF configuration, where
E, B stand for electric and magnetic sectors and TOF for orthogonal
time-of-flight mass spectrometer. The instrument was fitted with EI
and CI ion sources, a gas cell located in the first field free region and
two pairs of gas cells located after the magnet along the beam path.
Typical operating conditions of the CI source were as follows: source
temperature: 373 K, repeller voltage: 0 V, emission current 1 mA,
nominal electron energy: 50 eV. Typical EI source conditions were:
source temperature: 373 K, trap current: 200 mA, electron energy:
50 eV. The ions from the source were accelerated to 6–8 kV and their
CAD and NR spectra recorded, by using the first of the collision cells
pair, located between the magnet and the second E sector. The target
gas used in the CAD experiments was He, which was admitted into
the first cell at a pressure adjusted to obtain a 80 % transmittance. In
the NR experiments CH4, used as the neutralizing gas, was also
admitted into the first of the cells pair at such a pressure to obtain a
beam transmittance of 80 %. All ions were then removed by a pair of
high voltage (Æ 0.8 kV) deflecting electrodes, and the beam of fast
neutral species entered the second cell, in which reionization was
achieved by using O2 as the stationary collider. The NR spectra were
averaged over 100 acquisitions to improve the signal-to-noise ratio.
The following MS3 (multi-stage mass spectrometry) experiments were
performed: 1) The selected precursor ion underwent decomposition
by collision with He in one of the cells located in the second field free
region, and the energy-selected daughter ions were structurally
analyzed by CAD-TOF in the cell located in the TOF mass
spectrometer; 2) The same experiment was performed by selecting
the charged fragments formed by collisions occurring in the cell
located in the first field free region. An Apex 47e spectrometer,
(Bruker Spectrospin AG), equipped with an external CI/EI ion source
and a cylindrical infinity cell[33] was used in FTICR experiments. The
ions generated in the source and driven into the resonance cell, were
mass-selected by soft ejection techniques and allowed to react with
the neutral species at pressures ranging from 10-8 to 10-7 Torr.
Accurate mass analyses were performed to unambiguously identify
the charged products."
[Edited on 1-1-2013 by kavu]
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arsphenamine
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Since it was only detected by mass spec, that strongly suggests that it is unstable and very short lived, as confirmed in the abstract:
CO4, the proof: Although theoretically predicted to be detectable, CO4 has proved so far experimentally elusive. We report its
discovery as a result of a mass spectrometric and theoretical study showing that CO4 does exist as a metastable molecule in the gas phase, with a
lifetime=1 μs (see picture showing the neutralization–reionization MS of CO4+ with arrows indicating the recovery peaks).
DOI: 10.1002/anie.200350936
Searching on carbon diperoxide is unproductive, carbon tetraoxide less so.
CO4 has several forms: D2d symmetry (the one of interest), and clusters of the OCO3 and O2CO2 types. So, you need to
read more cautiously than usual.
The Italian group modeled 8 of these at a lazy basis set level, only sophisticated enough for a qualitative feel of relative energies. This is
understandable since they had a good clue as to actual experimental production.
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