Etude quantitative des réactions d'ozonolyse. XIII. Sur la structure du zwitterion de Criegee

Electronic structure of the Criegee intermediate. Ramifications for the mechanism of ozonolysis

“…The OO and CO bond strengths are calculated to be 43.5 and 55.9 kcal/mol, respectively, so that the planar lA/(4tr) state is stable with respect to dissociation.36 The planar 3A '(4t) state is only 19.4 kcal/mol above the state and so it is also bound with respect to dissociation. Even the planar Wadt, Goddard / Electronic Structure of the Criegee Intermediate 3 " (5 ) and " (57 ) states are bound states as they are 33.0 and 34.6 kcal/mol above the 1 ,(4 ) state.37 Breaking the CO bond in the 5 states leads to CH2(3Bi) + 2 (' 8) for the triplet state and CFhC'Bi) + 02(* 8) for the singlet 4) COO plan H2CO(3A") + 0(3P) -43.5 1 3 '( 4) COO plan H2CO(3A") + 0(3P) -24.1 1 3 "( 5) COO plan H2CO(3A") + 0(3P) -10.5…”

Ozonides form the photooxidation of diazo compounds in the presence of oxygen-18 labeled aldehydes and molecular oxygen-18

“…In all of this earlier work, the assumption was made that the structure of the zwitterion has no contribution from forms such as o+ cr 1 Fliszár and coworkers have now been able to rule out any contribution from structure 1 to ozonide formation based on a very elegant experiment involving the ozonolysis of an unsymmetrical olefin in alcohol solvent and analysis of the alkoxy hydroperoxides produced. 20 The possibility that incorporation of 180 in the peroxide bridge need not indicate a nonzwitterion path to ozonide, as we had earlier concluded,10-16 has been raised by Fliszár and coworkers.14 According to this view, finding of 180 in the peroxide bridge is consistent with an exclusive zwitterion mechanism if the following additional path to ozonide is available.…”

High-performance liquid chromatography of selected organic peroxides with oxidative amperometric detection

“…In seeking to obtain information with regard to understanding the mechanisms associated with the ozonation process and formation of organic peroxides, and to develop sensitive and selective methods for this purpose, the approach has been to investigate the utility of electrochemical based techniques, as detection procedures, in conjunction with chromatographic methods of analysis. The literature contains little information with regard to determining organic peroxides using electrochemical based techniques except for polarographic (dc), [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22] biamperometric (or dead stop end-point), 23,24 coulometric (controlled-potential), 25 etc., techniques employed more than a quarter century earlier. The high-performance liquid chromatographic (HPLC) determination of organic peroxides and hydroperoxides has been performed with various spectroscopic modes of detection such as UV, [26][27][28][29][30][31][32] IR, 30 NMR, 30 mass spectrometric 30 and chemiluminescence.…”