Hydrogen Cyanide Oligomers

Hydrogen cyanide, H-C=N , is a colorless, extremely toxic, volatile liquid, mp -13.4°C, bp -1-25.6 °C, with a high dielectric constant (107 at 25 °C). It functions as a weak acid Ka = 4.9 x 10 °). It is made by acidifying aqueous solutions of cyanides or industrially by the exothermic reaction of methane with ammonia in a fast flow/rapid quench system (equation 16). Hydrogen cyanide polymerizes readily nnder a variety of conditions hydrogen cyanide oligomers include the trimer aminomalononitrile and the tetramer diaminomaleonitrile (Figure 8). 

Other properties showing indications of cooperativity in hydrogen cyanide oligomers were also investigated from the theoretical side. The trends in... 

Kofranek, M., Lischka, H., and Karpfen, A., Ah initio studies on hydrogen-bonded clusters. I. Linear and cyclic oligomers of hydrogen cyanide, Chem. Phys. 113, 53-64 (1987). 

There are different fashions how to induce water removal in condensation reactions. By simply heating amino acids with or without potent agents of condensations such as hydrogen cyanide, HC=N, cyan amide, N=C-NH2, and carbon-oxy-sulfide COS, oligomers and polymers, called proteinoids, readily formed. The detection of enzymatic activities in these polymeric proteinoids was unsuccessful except for about ten degrading enzymatic activities. Synthetic activities that build up molecules, for instance, kinase, ligase, and polymerase, were not detectable. The disadvantage of these mixtures of proteinoids is that they do not exhibit a distinct structure or a function. 

M. Kofranek, A. Karpfen, and H. Lischka, Chem. Phys., 113, 53 (1987). Ab Initio Studies on Hydrogen-Bonded Clusters. 1. Linear and Cyclic Oligomers of Hydrogen Cyanide. 

Hydrogen cyanide can also be converted to cyanoacetylene and hydrogen cyanate, both precursors of pyrimidines. These reactions were reproduced in the laboratory. In fact, in 1828, F. Wohler made urea from hydrogen cyanate and ammonia, the first synthesis of an animal substance from inorganic materials. Very likely, all these processes occurred primarily in an aqueous environment where and OH" ions acted as specific-acid or specific-base catalysts. It is particularly impressive that the three major classes of nitrogen containing biomolecules, purines, pyrimidines, and amino acids are formed by the hydrolysis of the oligomers formed directly from... 

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