Methyl isocyanide orisocyanomethane is anorganic compound and a member of theisocyanide family. This colorless liquid is isomeric and isoelectronic to methyl cyanide (acetonitrile), but its reactivity is very different. In contrast to the faintly sweet, ethereal odor of acetonitrile, the smell of methyl isocyanide, like that of other simple volatile isocyanides, is distinctly penetrating and vile.[1] Methyl isocyanide is mainly used for making 5-memberedheterocyclic rings. The C-N distance in methyl isocyanide is very short, 1.158 Å as is characteristic of isocyanides.[2]
Methyl isocyanide was first prepared byA. Gautier by reaction ofsilver cyanide withmethyl iodide.[3][4] The common method for preparing methyl isocyanides is the dehydration ofN-methylformamide.[5] Many metal cyanides react with methylating agents to give complexes of methyl isocyanide.[6] This kind of reactivity has been invoked as being relevant to the origin of life.[7]
Methyl isocyanide is very endothermic (ΔfH⦵(g) = +150.2 kJ/mol, 3.66 kJ/g) and can thus isomerize explosively to acetonitrile.[10] A sample exploded when heated in a sealed ampoule, and during redistillation at 59 °C and 1 bar, a drop of liquid fell back into the dry boiler flask and exploded violently. The explosive properties of methyl isocyanide have been studied in detail.[11]
^Fehlhammer, Wolf P.; Fritz, Marcus. (1993). "Emergence of a CNH and Cyano Complex Based Organometallic Chemistry".Chemical Reviews.93 (3):1243–1280.doi:10.1021/cr00019a016.
^Clothier, P. Q. E.; Glionna, M. T. J.; Pritchard, H. O. (July 1985). "Thermal explosions of methyl isocyanide in spherical vessels".The Journal of Physical Chemistry.89 (14):2992–2996.Bibcode:1985JPhCh..89.2992C.doi:10.1021/j100260a008.
