Nitrosyl cyanide

In a recent series of papers C. Wittig and his group have reported on the photolysis of NCNO in its first absorption band (540 - 900 nm). These experiments have been done both in a static gas cell (165) and in a pulsed molecular beam (166). 

This molecule is ideal for photodissociation dynamics studies, since it has allowed excited states in the visible region of the spectrum which is more easily accessible with tunable lasers. Both products can in principle be detected using the LIF method, though at the present time only the product distribution of the CN radical has been measured, since NO is often present as an impurity. The spectroscopy is also well studied 

Despite the fact that the NO fragment distribution has not yet been measured, they have made considerable progress in the understanding of the photodissociation dynamics of this molecule. In the first paper, they were able to show that there is a competition between one-photon and two-photon photodissociation. 

The latter process is not competitive with the former above the thermodynamic threshold. Furthermore, as long as the available energy was kept below the thermochemical threshold for the production of vibrationally excited CN radicals, it was possible to fit the observed rotational distributions with phase space theory. The upper electronic state that is involved in the two-photon dissociation was shown to originate below 22,000 cm l and is thought to be repulsive. It could be the same state that has its absorption maximum at 270 nm. 

The same authors were able to measure the high-resolution absorption spectrum of NCNO by detecting the two-photon photodissociation product rotationally hot CN radicals as a function of wavelength. This method allowed them to assign the constants for the ground and excited states. 

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Direct preparation of the gas is potentially hazardous, and explosive decomposition of the impure gas in the condensed state (below -20°C) has occurred. A safe procedure involving isolation of the 1 1 adduct with 9,10-dimethylanthracene is preferred. The impure gas contains nitrogen oxide and it is known that nitrosyl cyanide will react with the latter to form an explosive compound [1], The need to handle this compound of high explosion risk in small quantities, avoiding condensed states, is stressed [2],... 

Nitrosophenol (1,4-Benzoquinone monoxime), 2264 Nitrosyl chloride, 4023 Nitrosyl cyanide, 0541 Nitrosylruthenium trichloride, 4144 Nitrosylsulfuric acid, 4438 Nitrosyl tetralluorochlorate, 3985 Peril uoro-tert-n itrosobutanc, 1370 Potassium nitrosodisulfate, 4661 Sodium 4-nitrosophenoxide, 2181 1,3,5 -Trinitrosohexahydro-1,3,5-triazine, 1217 Trinitrosophloroglucinol, 2117... 

Nitrosyl cyanide, generated from nitrosyl chloride and silver cyanide in chloroform at — 20 °C, affords unstable products with various dienes, e.g. butadiene and 2,3-di-methyl-1,3-butadiene. With methyl sorbate, compound 182 is produced (equation 103), thebaine (183) gives 184 (equation 104)97 and 9,10-dimethylanthracene yields the stable cycloadduct 185, which decomposes into its components on heating and consequently can serve as a source of nitrosyl cyanide. Thus heating 185 with 1,4-diphenylbuta-1,3-diene gives the dihydrooxazine 186 and dimethylanthracene (equation 105)98. 

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