Double Deprotonation of CH3CN by an Iron‐Aluminium Complex

• Published in: Angewandte Chemie International Edition 2023-04, Vol.62 (16), p.n/a
• Main Authors: Stadler, Benedek, Gorgas, Nikolaus, White, Andrew J. P., Crimmin, Mark R.
• Format: Article
• Language: English
• Subjects: Acetonitrile; Aluminium; Aluminum; Anions; Bimetals; Communication; Communications; C−H Activation; Dianions; Iron; Nitriles
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.202219212

Herein we present the first double deprotonation of acetonitrile (CH3CN) using two equivalents of a bimetallic iron‐aluminium complex. The products of this reaction contain an exceeding simple yet rare [CHCN]2− dianion moiety that bridges two metal fragments. DFT calculations suggest that the bonding to the metal centres occurs through heavily polarised covalent interactions. Mechanistic studies reveal the intermediacy of a monomeric [CH2CN]− complex, which has been characterised in situ. Our findings provide an important example in which a bimetallic metal complex achieves a new type of reactivity not previously encountered with monometallic counterparts.[1, 2] The isolation of a [CHCN]2− dianion through simple deprotonation of CH3CN also offers the possibility of establishing a broader chemistry of this motif. The double deprotonation of CH3CN was achieved using an iron‐aluminium complex, yielding products containing a simple yet rare [HC=C=N]2− dianion, characterised by X‐ray crystallography. DFT calculations suggest that the mechanism proceeds via a stepwise double deprotonation of the substrate by two equivalents of the bimetallic complex, with the intermediacy of a [NCCH2]− anion, which was observed spectroscopically in situ.