Hyponitrite esters

The hyponitrites (16), esters of hyponitrous acid (HO N=N OH), are low temperature sources of alkoxy or acyloxy radicals. A detailed study of the effect of substituents on k4 for the hyponitrite esters has been reported by Quinga and Mendenhall,114... 

A review of chemiluminescent and bioluminescent methods in analytical chemistry has been given by Kricka and Thorpe. A two-phase flow cell for chemiluminescence and bioluminescencc has been designed by Mullin and Seitz. The chemiluminescence mechanisms of cyclic hydrazides, such as luminol, have been extensively analysed. " Fluorescence quantum yields of some phenyl and phenylethynyl aromatic compounds in peroxylate systems have been determined in benzene. Excited triplet states from dismutation of geminate alkoxyl radical pairs are involved in chemiluminescence from hyponitrite esters. Ruorophor-labelled compounds can be determined by a method based on peroxyoxalate-induced chemiluminescence. Fluorescence and phosphorescence spectra of firefly have been used to identify the multiplicity of the emitting species. " The chemiluminescence and e.s.r. of plasma-irradiated saccharides and the relationship between lyoluminescence and radical reaction rate constants have also been investigated. Electroluminescence from poly(vinylcarbazole) films has been reported in a series of four... 

One of the most certain ways in which an excited state may be expected is by the operation of the conservation of spin [43]. If for example these rules require that triplet products are most probable, then excitation is likely since almost all organic molecules have singlet ground states. Although this concept commonly applies only to oxygen and nitroso-compounds (there are no chemiluminescent reactions known of the latter sort) among stable molecules, it seems to be important for the reaction of fragments and unstable intermediates (e. g. from dioxetans and hyponitrite esters). 

Another example, discussed with the dioxetans later, which involves cage reaction of triplet radicals is that of the decomposition of hyponitrite esters [48]. Hydrogen abstraction from one radical R2CH-0 by another leads to triplet carbonyl products in high yield. 

In the presence of metal catalysts such as rhodium compounds, aldehydes can add directly to alkenes to form ketones. The reaction of co-alkenyl aldehydes with rhodium catalyst leads to cyclic ketones, with high enantioselectivity if chiral ligands are employed. Aldehydes also add to vinyl esters in the presence of hyponitrites and thioglycolates. ° ... 

The violence of the explosion when the ethyl ester was heated at 80°C was not so great as reported previously. The propyl and butyl esters explode if heated rapidly, but decompose smoothly if heated gradually [1], Dialkyl hyponitrites with alkyl groups below C(, are shock-sensitive [2], The shock-sensitivity decreases with increasing MW, and it was not possible to detonate esters above C6. The aryl esters were insensitive and the alkyl esters became so on dilution with solvent [3], Individually indexed compounds are ... 

Hyponitrous acid. In contrast to nitrous and nitric acids, hyponitrous acid crystallizes from ether as colourless crystals which easily decompose, explosively if heated. The detailed molecular structure of this acid has not been determined, but it is known that the molecular weights of the free acid and its esters correspond to the double formula, H2N2O2, that it is decomposed by sulphuric acid to N2O, and that it can be reduced to hydrazine, H2N-NH2. Infrared and Raman studies show conclusively that the hyponitrite ion has the trans configuration (a), but the N-N frequency suggests that the central bond has an order of rather less than two. ... 

Figure 4, (Fe) vs. for ether from 2-butyl-tert-butoxy radical pairs generated from per ester (-%-) and hyponitrite (-0-) (13,22)...

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