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The formation of dihydrogen trioxide (HOOOH) is reported as indeed the characteristic feature of the decomposition of various silyl as well as germyl hydrotrioxides, generated by the low-temperature ozonation of the corresponding silanes and germanes. Results of the detailed experimental and theoretical studies of the NMR and IR spectral characterization of the polyoxides under investigation as well as of the mechanism of their formation and decomposition are presented.

A thorough evaluation of the estimated power indicates that the gas-phase mechanism of the reaction is governed by radical or biradical mediators, whilst the solution-phase mechanism is distinguished by hydride transfer and the creation of a transitional ion pair which comprises of HOOO- anion. Finally, the amount of ozonation of alcohols and toxicity of ozone consumed in the blood can be determined.

The functioning of the sulfonic acid comprising of SBA-15 silica materials are evaluated as catalysts for the effect of compressing phenol and acetone to bisphenol A. It seems that a coordinated effort between the two close performing groups could be working in this reaction.

The ozonation of cumene in acetone, methyl acetate, and tert-butyl methyl ether at -70degree centigrade at low temperature produced the corresponding hydrotrioxide along with hydrogen trioxide, HOOOH. Ozonation of triphenylmethane produced only triphenylmethyl hydrotrioxide, (C6H5)3COOOH, which further supports the radical mechanism for the first step of ozonation of the C- H bonds in hydrocarbons.

Research has been conducted on the thianthrene 5-oxide. The oxidation of this oxide with peroxybenzoic acids has been investigated in different oxygen bases as solvents and the results are discussed.

Nuclear magnetic resonance spectrometry was done to study the kinetics of deiodination of o-iodocumyl alcohols by cyclohexyl radicals. The results revealed that the homolytic cleavage of the I-O bond in (tert-butylperoxy)iodanes with the formation of iodanyl (9-I-2) and tert-butylperoxyl radicals is the primary decomposition step. It was also indicated that the deiodination of o-iodocumyl alcohols by cyclohexyl radicals occurs via the SH2 type mechanism.

The role of water in the decomposition of hydrogen trioxide (HOOOH) on a singlet potential energy surface was investigated. Specifically, the quantum mechanics underpinning intramolecular 1,3-proton transfer in HOOOH was analyzed via ab initio self-consistent field calculations. The computations showed that the inclusion of water as a bifunctional catalyst lowered the energy barrier for the decomposition reaction.

The various mechanisms involved in the low temperature, methyltrioxohenium(VII)-catalyzed transformation of the hydrotrioxides (ROOOH) into dihydrogen trioxide (HOOOH) are discussed. The approach is shown to be extremely efficient and effective for a quantitative preparation of HOOH.

Various density functional methods were employed to study the hydrogen-bonded gas-phase molecular clusters of dihydrogen trioxide (HOOOH). The results obtained demonstrated that HOOOH could form relatively strong hydrogen-bonded cyclic dimers, trimers and tetramer with organic bases such as acetone and dimethyl ether and retard the decomposition in these bases as solvents by preventing a proton transfer.

The effect of ortho substituents in iodobenzenes on the rate of the abstraction of iodine by cyclohexyl radicals is examined. The stabilization of the transition state, resembling a 9-I-2 iodanyl radical, by electron-withdrawing groups describes a positive sign of the Hammett rho value in the radical abstraction of halogen atoms.

Ozonation of norcarane (1) yielded endo and exo norcarane hydrotrioxides(2a, 2b), which is characterized by 1H and 13C NMR spectroscopy. The main focus of intense investigations is on Hydrogen trioxide (HOOOH) and its organic derivatives, that is, alkyl hydrotrioxides (ROOOH).

The ozonation of 1,2-diphenylhydrazine and 1,2-dimethylhydrazine is examined. The abstraction of a methyl H atom of the Ch3NNHCh3 radical by HOOO in the solvent cage results in the formation of formic acid and nitromethane in the ozonolysis of 1,2-dimethylhydrazine.

H atom (HO(sub 3)(super -)) formation by using dioxolanes as suitable model systems that support hydride abstraction by ozone due to the fact that generation of a dioxolyl cation is electronically supported, is studied. The low-temperature ozonation of 2-methyl-1,3-dioxolane in an acetone-d(sub 6), methyl acetate, and tert-butyl methyl ether produced both the corresponding acetal hydrotrioxide ROOOH and the hemiortho ester in molar ratio 1:5 (-78 degree C) is reported.

The HOOO(super -) anion, which can adopt a triplet state (T-1) or a singlet state (S-1), where the former was 9.8 kcal/mol (delta H(298) = 10.3 kcal/mol), which was more stable than the later is reported. The modes of generating S-1 in aqueous solution was discussed, which shows that S-1 represents an important intermediate in ozonation reactions.

The hydrotioxide of isopropyl alcohol and hydrogen trioxide (HOOOH) were observed to form in the low-temperature ozonation of the alcohol. Both polyoxides were characterized for the first time by 17O nuclear magnetic resonance spectroscopy. Results elucidated on the transition structure for the ozonation of isopropyl alcohol. Also, it showed the role of radical intermediates in the reaction.

Ozonation of 2-ethylanthrahydroquinone with an ozone-nitrogen or ozone-oxygen mixture in acetone-d6 and methyl acetate at -78 degrees Celsius generated an oxygen-rich intermediate with a characteristic OOOH absorption. This was used to find new ways to synthesize and characterize hydrogen trioxide (HOOOH). The oxidation of anthrahydroquinone by using ozone rather than oxygen provides HOOOH and the associated quinone as the primary products.

Protonated dihydrogen trioxide (HOOOH) has been postulated in various forms for many years. Protonation can occur at either the terminal (HOOO(H)H(+)) or central (HOOH(OH)(+)) oxygen atom. However, to date there has been no definitive evidence provided for either of these species. In the current work we have employed ab initio methods, CCSD(T) and MP2, with a large basis set (6-311++G(3df,3pd)) to determine the relative stabilities of these species. It is shown that the terminally protonated species is strongly favored relative to the centrally protonated species (DeltaE = 15.8 kcal/mol, CCSD(T)//MP2). The mechanism of formation of HOOO(H)H(+) was determined to occur with a low barrier with the H(3)O(+) occurring in a thermoneutral reaction (DeltaE = -0.3 kcal/mol, CCSD(T)//MP2). Although HOOO(H)H(+) exists as a stable intermediate, it is extremely short-lived and rapidly decomposes (DeltaE* = 8.6 kcal/mol, MP2) to H(3)O(+) and O(2)((1)Delta(g)). The decomposition reaction is stabilized by solvent water molecules. The short-lived nature of the intermediate implies that the intermediate species can not be observed in (17)O NMR spectra, which has been demonstrated experimentally.

We demonstrate in this work by theory and experiment that benzaldehyde hydrotrioxide (PhC(O)OOOH), the intermediate most likely formed in the low-temperature ozonation of benzaldehyde, is too unstable to be detected by NMR (1H, 13C, and 17O) spectroscopy in various organic solvents at temperatures > or = -80 degrees C and that its previous detection must have been erroneous. Several plausible mechanisms for the formation of this polyoxide were explored by using density functional theory. We found that the formation of the hydrotrioxide involves the facile 1,3-dipolar insertion of ozone into the C-H bond (deltaH(double dagger) = 11.1 kcal/mol) in a strongly exothermic process (deltaH(R) = -57.0 kcal/mol). The hydrotrioxide then quickly decomposes in a second concerted, exothermic reaction involving an intramolecular H transfer to form benzoic acid and singlet oxygen (O2(1delta(g))) (deltaH(double dagger) = 5.6 kcal/mol), deltaH(R) = -14.0 kcal/mol). The equilibrium is thus expected to be shifted toward the products; therefore, this intermediate cannot be observed experimentally. Peroxybenzoic acid, still another major reaction product formed in the ozonation reaction, is formed as a result of the surprising instability of the RC(O)O-OOH bond (deltaH(R) = 23.5 kcal/mol), generating HOO* and benzoyloxyl radicals. Both of these radicals can then initiate the chain autoxidation reaction sequence--the abstraction of a H atom from benzaldehyde to form either a benzoyl radical and HOOH or a benzoyl radical and benzoic acid. Because only very small amounts of HOOH were detected in the decomposition mixtures, the recombination of the benzoyl radical with the HOO* radical (deltaH(R) = -80.7 kcal/mol) appears to be the major source of peroxybenzoic acid. A theoretical investigation of the mechanistic possibility of the involvement of still another intermediate, a cyclic tetraoxide (tetraoxolane) formed as a primary product in the 1,3-dipolar cycloaddition of ozone to the carbonyl group of the aldehyde, revealed that the tetraoxide is a "real" molecular entity with the five-membered ring adopting an envelope conformation. The tetraoxide is destabilized by 7.0 kcal/mol relative to the reactant complex, and the transition state for its formation is 17.4 kcal/mol above the reactant complex, which, although accessible under the reaction conditions, is not expected to be competitive with the reaction generating the hydrotrioxide.

Low-temperature ozonation (-78 degrees C) of 1,3-dioxolanes 1a-1f and 1,3-dioxanes 1g and h in acetone-d6, methyl acetate, and tert-butyl methyl ether produced both the corresponding hemiortho esters (2a-h, ROH) and acetal hydrotrioxides (3a-h, ROOOH) in molar ratios ROH/ROOOH ranging from 0.5 to 23. Both types of intermediates were fully characterized by 1H, 13C, and 17O NMR spectroscopy. DFT calculations suggest that ozone abstracts a hydride ion from 1 to form an ion pair, R+ -OOOH, which subsequently collapses to either the corresponding hemiortho ester (ROH) or the acetal hydrotrioxide (ROOOH). Hemiortho esters decomposed quantitatively into the corresponding hydroxy esters. Experimentally obtained activation parameters for the decomposition of 2a (E(a) = 13.5 +/- 1.0 kcal/mol, log A = 8.3 +/- 1.0) are in accord with a highly oriented transition state involving, according to B3LYP calculations (deltaH(a)(298) = 13.2 kcal/mol), two molecules of water as a bifunctional catalyst. This mechanism is also supported by the magnitude of the solvent isotope effect for the decomposition of 2e, i.e., k(H2O)/k(D2O) = 4.6 +/- 1.2. Besides the hydroxy esters and oxygen (3O2/1O2), dihydrogen trioxide (HOOOH) was formed in the decomposition of most of the acetal hydrotrioxides (ROOOH) investigated. The activation parameters for the decomposition of the hydrotrioxides 3a-e in various solvents were E(a) = 20 +/- 2 kcal/mol, log A = 13.5 +/- 1.5. Several mechanistic possibilities for the decomposition of ROOOH were tested by experiment and theory. The formation of the hydroxy esters and oxygen could be explained by the intramolecular transfer of the proton to form the hydroxy ester. The assistance of water in the decomposition of ROOOH to form the hydroxy esters, either directly or via hemiortho esters, was also investigated. According to DFT calculations, the formation of a hydroxy ester via hemiortho ester is energetically more favorable (deltaH(a)(298) = 14.5 kcal/mol), again due to the catalytic effect of two water molecules. HOOOH generation requires the involvement of water in the decomposition of ROOOH where the direct formation out of ROOOH is energetically preferred. The energy for a reaction between two molecules of water and singlet oxygen (delta1O2) is too high to occur in solution.

The mechanism of the ozonation of isopropyl alcohol was investigated for the gas and the solution phase using second-order many body perturbation theory and density functional theory (DFT) with the hybrid functional B3LYP and a 6-311++G(3df,3pd) basis set. A careful analysis of calculated energies (considering thermochemical corrections, solvation energies, BSSE corrections, the self-interaction error of DFT, etc.) reveals that the gas-phase mechanism of the reaction is dominated by radical or biradical intermediates while the solution-phase mechanism is characterized by hydride transfer and the formation of an intermediate ion pair that includes the HOOO(-) anion. The product distribution observed for the ozonation in acetone solution can be explained on the basis of the properties of the HOOO(-) anion. General conclusions for the ozonation of alcohols and the toxicity of ozone (inhaled or administered into the blood) can be drawn.