Thermochemistry of 1,2-dioxetane and its methylated derivatives. Estimate of activation parameters

O’Neal, H. E.; Richardson, William H.

doi:10.1021/ja00725a029

Cited by 102 publications

(31 citation statements)

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“…The initial postulation of a biradical mechanism was supported by activation parameters determined for a series of variously substituted dioxetanes (5) (Richardson et al, 1974(Richardson et al, 1975(Richardson et al, , 1973 and bv thermochemical calculations (O'Neal and Richardson, 1970 ;Richardson et al, 1974 ). The relative insensitivity of the dioxetane decomposition rate to substitution, particularly in comparing the Dhenvl, anisyl, and benzyl substituted dioxetanes (Sc,d,e) supportscleavage of the oxygen-oxygen bond, which is one bond removed from the position of substitution, in the rate-determining step.…”

Section: N Oro Itmentioning

confidence: 92%

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Chemiluminescence of Organic Compounds

Schuster

Schmidt

1982

Advances in Physical Organic Chemistry

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Section: N Oro Itmentioning

confidence: 92%

“…The other mechanistic extreme is the two-step mechanism, first considered bv ',hite andHarding (1964, 1965) an," exanined experimentally first /by Richardson (O'Neal and Richardson, 1970 ;Richardson et al, 1972).…”

Section: N Oro Itmentioning

confidence: 99%

Chemiluminescence of Organic Compounds

Schuster

Schmidt

1982

Advances in Physical Organic Chemistry

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“…The result of this double promotion is to greatly weaken, or break, the 00 bond and also greatly increase the antibonding character of the C C bond thus causing it to weaken or break as well. O'Neal and Richardson (11) demonstrated that the kinetic data for thermal decomposition is consistent with a two-step niechanism. Since the 1,2-dioxetanes have an estimated half-life stability at 60°C that ranges from 10 s (for the unmethylated con~pound) to over 2 h, it is reasonable to assume that 1,2-dioxetane is excited from its ground state during the decomposition proCan.…”

Section: (3al)2(4al)2(2b2)2(la)2(5al)2(3bl)2(2a2)2mentioning

confidence: 85%

Decomposition Mechanism of 1,2-Dioxetane

Barnett¹

1974

Can. J. Chem.

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An orbital correlation diagram was constructed for the thermal decomposition of 1,2-dioxetane into products that allow chemiluminescence. A decomposition mechanism is proposed that gives a temperature dependent rupture of the OO bond, thus allowing ring twisting which is followed by the rupture of the CC bond. This mechanism is consistent with results of the thermochemical analysis for this type of reaction. The equilibrium structure of 1,2-dioxetane was determined from the molecular orbital calculations and gave a planar configuration for the COOC ring.

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“…This is about as exothermic as is the decomposition of tetramethyl-1,2-dioxetane (15). These compounds might thus have enhanced rates of thermolysis (16) and be luminescent.…”

Section: Thermolysis Of 1 Andmentioning

confidence: 99%

Bis(dimethoxymethyl) peroxide and bis(1,1-dimethoxyethyl) peroxide

Kopecky¹,

Molina²

1987

Can. J. Chem.

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The title compounds 1 and 2, the first examples of peroxides polysubstituted at the a and a' positions by alkoxy groups, are formed by benzophenone sensitized photooxygenation of trimethoxymethane and 1 , 1 ,1-trimethoxyethane, respectively. No peroxide was formed from tetramethoxymethane. Allowing 98% hydrogen peroxide and trimethoxymethane to stand results in an 80% yield of 1, so that 1 and 2 are probably formed by such a disproportionation reaction during photooxygenation. Compound 1 is converted quantitatively to methanol, methyl formate, and dimethyl carbonate in pyridine solution at 60°C. In acidic methanol both 1 and 2 undergo solvolysis rapidly with exclusive cleavage of the carbon -peroxy oxygen bond. Signals for the ether and peroxy oxygens of 1 appear at 34 and 263 ppm and those of 2 appear at 40 and 264 ppm in the 170 nuclear magnetic resonance spectrum. Luminescence results when 1 and 2 are heated to 150°C. IntroductionThe present study grew out of a desire to learn about the properties of trimethoxymethyl hydroperoxide and bis(trimethoxymethyl) peroxide in connection with another problem. A possible route to these compounds might be the benzophenone-sensitized photooxygenation of trimethoxymethane. Cyclic acetal derivatives of some aldehydes have been oxidized to hydroperoxides and peroxides with oxygen (1) but trimethoxymethane does not appear to have been converted to such products, although the central C-H bond ought to be relatively reactive with a bond dissociation energy (BDE) of about 89 kcal/mol. This value is estimated as follows. Replacement of an alkyl group by a methoxy group on a hydrocarbon lowers the C-I3 BDE by an amount that decreases with decreasing C-H BDE of the corresponding hydrocarbon (2). The BDE of the central C-H bond in isobutane is 93.3 kcal/mol (3) and substitution of a methyl group by a methoxy group should lower the BDE by about 3 kcal/mol (2). Replacement of the two remaining methyl groups by methoxy groups would lower the BDE more, but by decreasing amounts estimated to be 1 and 0.5 kcal/mol. Although attack on the central C-H hydrogen should be relatively easy, none of the desired peroxide or hydroperoxide was formed in the reaction.

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Thermochemistry of 1,2-dioxetane and its methylated derivatives. Estimate of activation parameters

Cited by 102 publications

References 0 publications

Chemiluminescence of Organic Compounds

Chemiluminescence of Organic Compounds

Decomposition Mechanism of 1,2-Dioxetane

Bis(dimethoxymethyl) peroxide and bis(1,1-dimethoxyethyl) peroxide

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