Tetramethyl-dioxetane

As to the nature of the electronically excited state, the investigation of the thermolysis of tetramethyl-1.2-dioxetane revealed a high yield (about 50%) of excited triplet acetone 34> ... 

Bartlett, P.D., Baumstark, A.L. and Landis, M.E. (1977) Rearrangement of tetramethyl-1,2- dioxetane by boron trifluoride in aprotic solvents. Journal of the American Chemical Society, 99 (6), 1890-1892. 

Baumstark, A.L. and Vasquez, P.C. (1984) Reaction of tetramethyl-1,2- dioxetane with phosphines deuterium isotope effects. Journal of Organic Chemistry, 49 (5), 793-798. 

The interaction of equal molar amounts of triphenylantimony and tetramethyl-1,2-dioxetane in CDCI3 at ambient temperatures has been found to give 77% yield of stable insertion product306. ... 

Additionally, [Ir(X)(CO)(PPh3)2] (X = Cl, Br) catalyzes the cleavage of tetramethyl-1,2-dioxetane (tmd), presumably via reactions depicted in Scheme 24. 

In Table 3 the activation energies of tetramethyl-1,2-dioxetane by a variety of isothermal and nonisothermal kinetic methods are compared. The values range... 

TABLES. ACTIVATION ENERGIES OF TETRAMETHYL-1,2-DIOXETANE BY A VARIETY OF KINETIC METHODS... 

The behaviour of 1,2-dioxetanes with easily oxidized substituents, for example, jV-methyldihydroacridinylidenyl (Entry 2 in Table 4), indolyl, or N,N-dimethylaminophenyF (Entry 5 in Table 4), is quite distinct from the simple derivatives, for example, tetramethyl-1,2-dioxetane (Entry 19 in Table 4). First of... 

Oxidation of luminol (see Example 7.22) and thermolysis of endoperox-ides or 1,2-dioxetanes provide important examples of chemiluminescent reactions. Tetramethyl-1,2-dioxetane (181) has been studied in great detail the thermolysis is clearly first order and the activation enthalpy in butyl phthal-ate is A// 27 kcal/mol. The enthalpy difference between the reactants and ground-state products is A// = -63 kcal/mol. 

Figure 7.57. State correlation diagram for the chemiluminescence reaction of tetramethyl-1,2-dioxetane (by permission from Turro, 1978).

Tetrakis(bromomethyl)-9,9-dimethyl-l,2,4,5,7,8-hexoxonane, 3173 Tetramethyl-1,2-dioxetane, 2508... 

Lechtken P, Hoehne G. Thermolysis of tetramethyl-1,2-dioxetane. Angew Chem Inti Ed. 1973 12 772-3. 

Dioxetanes such as tetramethyl-1,2-dioxetane (525) are known to undergo thermal decomposition to form two carbonyl compounds via a concerted or stepwise (radical) mechanism, accompanied by chemiluminescence (Section 5.6) (Scheme 6.254).135,511,1440 The degradation of 525 results principally in acetone phosphorescence (2max = 430 nm) and the reaction is very sensitive to quenching by oxygen. 

Treatment of 0-halo hydroperoxides of tetrasubstituted olefins with base results exclusively in formation of allylic hydroperoxides. In this case treatment of the 0-halo hydroperoxide with silver acetate in CH2CI2 proved effective. For example, tetramethyl-1,2-dioxetane (2) was obtained in this way in an optimum yield of 35% ... 

The typical reaction of 1,2-dioxetanes is thermal decomposition. On warming tetramethyl-1,2-dioxetane in benzene or other solvents, blue light is emitted. Such a phenomenon is known as chemiluminescence [11]. It has been demonstrated that, according to the principle of conservation of orbital symmetry, one mole of acetone in an electronically excited state is formed. In this way, an electronically excited molecule (symbolized by ) is created by a thermal process. With emission of light, the ground state is restored ... 

Luminescence due to the decomposition of tetramethyl-1,2-dioxetane in benzene yielded a maximum value for wavelength of 430-440 mvi. This is similar to the spectrum of luminescence obtained by Kopecky (1969) for the thermal decomposition of 3,3,4-trimethyl-l,2-dioxetane with a maximum emission of 430-440 mji. Decomposition of these transient 1,2-dioxetanes form the electronically excited carbonyl compounds acetone and acetone/acetaldehyde, respectively. By excitation of acetone and acetaldehyde either singly, or as a 50% mixture of each with O2 generated from KO2, we obtained identical photon interference data placing the maximum emission around 435 my. 

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