In Search of 1,4-Diazabutatrienes, the Elusive Isocyanide Homodimers. The Superchameleonic F-NC.

Isocyanides might dimerize forming 1,4-diazabutatrienes, never isolated but eventually proposed as reaction intermediates. We herein disclose a computational study on the homo- and heterodimerization of isocyanides, in particular on the influence of the substituents onto the structural and energetics parameters of these processes. As a result, we have identified some reaction partners that are predicted to give stable 1,4-diazabutatrienes by surpassing low energy barriers. Of special significance is the homodimerization of F-NC, in which this species is revealed as an excellent acceptor and, quite surprisingly, also as a suitable donor.