The Triply Deprotonated Acetonitrile Anion CCN 3- Stabilized in a Solid.

The unprecedented, fully deprotonated form of acetonitrile, the acetonitriletriide anion CCN3-, is experimentally realized for the first time in the stabilizing bulk host framework of the Ba-5[TaN4][C2N] nitridometalate via a one-pot synthesis from the elements under moderate conditions (920 K). The molecular structure of this long-sought acetonitrile derivative is confirmed by X-ray diffraction, as well as NMR, IR, and Raman spectroscopy. The anion is isoelectronic to the CO2 molecule, and, in contrast to acetonitrile (H3C-C N), the electron pairs are shifted towards two double bonds, that is, [C=C=N](3-).