What is "nitrilimine"

n. (context organic chemistry English) nitrile imide

Nitrilimines or nitrile amides are a class of organic compounds sharing a common functional group with the general structure R-CN-NR corresponding to the conjugate base of an amine bonded to the N-terminus of a nitrile. The dominant structure for the parent compound nitrilimine is that of the propargyl-like in scheme 1 with a C-N triple bond and with a formal positive charge on nitrogen and two lone pairs and a formal negative charge on the terminal nitrogen. Other structures such as hypervalent , allene-like , allylic and carbene are of lesser relevance.

$\ce{H-\!{\equiv}}{\color{Blue}\ce{N+}}\!{-}\!{\color{Red}\ce{N-}}\!{-}\!{\color{Red}\ce H}$

H-\!{\equiv}N=N-H

$\ce H\!{-}\!{\color{Red} \ce{C-}}\!{=}{\color{Blue}\ce{N+}}\!\ce{=N-H}$

$\ce H\!{-}\!{\color{Blue} \ce{C+}}\!\ce{=N}\!{-}\!{\color{Red}\ce{N-}}\!\ce{-H}$

H-C{:}\!-N=N-H

Nitrilimines were first observed in the thermal decomposition of 2- tetrazoles releasing nitrogen:

Nitrilimines are linear 1,3-dipoles represented by structures and . A major use is in heterocyclic synthesis. E.g. with alkynes they generate pyrazoles in a 1,3-dipolar cycloaddition. Due to their high energy, they are usually generated in situ as a reactive intermediate.