Selenocyanates and Isoselenocyanates

Functional Groups cm Region im Intensity IR Raman Comments 

Acid azides and nitro-aromatic azides 2240-2170 4.46-4.61 s m-s asym N=N=N str 

Diazoketones and diazoesters, 2075-2050 4.82-4.88 s m-s (Ketones C=0 str, 1650-1600cm and strong band. 

Aryl carbodi-imines Ar-N=C=N-Ar 2145-2135 4.66-4.68 vs m-s, p j C=N str doublet due to Fermi resonance band at 

Mantica and G. Zerbi, Gazz. Chim. Ital., I960, 90, 53. 

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Two new syntheses of selenocyanates and isoselenocyanates are closely related to the synthesis of the corresponding thiocyanates and isothiocyanates. Thus, the easily prepared Ph3P(SeCN)2 reacts with primary alcohols below -60 °C to produce directly the corresponding alkyl selenocyanates in good yields, and the photochemical isomerization of benzylselenocyanates offers a new route to the corresponding isoselenocyanates. ... 

Alkyl selenocyanates diselenldes. Primary alcohols are converted by the reagent into alkyl selenocyanates in about 80% yield. If the reaction mixture is treated with 5% KOH in CH3OH for 2 hours the alkyl selenocyanates are transformed to dialkyl diselenides (about 70% yield). The reagent converts secondary alcohols into selenocyanates and to a lesser extent into isoselenocyanates. It does not react with tertiary alcohols. 

An equilibrium of prop-2-yl selenocyanates (84) and allenes (85) was obtained on gas-phase thermolysis (0.1-0.01 Torr 350-400°C) of 84. This isomerization by [3,3]sigmatropic rearrangements provided access to the highly reactive allenyl isoselenocyanates (85). The isoselenocyanates (85) can only be handled in solution due to their pronounced tendency to polymerize. Although these are less reactive with nucleophiles than allenyl isothiocyanates, treatment with nucleophiles afforded selenazoles in moderate yield. [95AG(E)1627]... 

All tellurium derivatives with exception of the diorgano tellurium diselenocyanates have infrared absorption bands in the regions that would indicate N-Te bonding. The frequencies for v(C-Se) in the diorgano tellurium selenocyanates (598 cm ) fall between the frequencies for organic isoselenocyanates (630 20 cm and those for normal selenocyanates (550-520 cm" ). 

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