Nonbenzenoid aromatic isocyanides: New coordination building blocks for organometallic and surface chemistry

This review is focused on the emerging chemistry of nonbenzenoid aromatic isocyanides, a relatively new family of aryl isocyanide molecules. Two types of systems are discussed: (1) isocyanoazulenes, for which five archetypal isomeric structures may be envisioned, and (2) η5-stabilized isocyanocyclopentadienides. So far, the latter are represented by isocyanoferrocene, 1,1′-diisocyanoferrocene, and isocyanocymantrene. In addition, the synthesis and chemistry of the linear 2,6-diisocyanoazulene motif, including regioselective installation and complexation of its –NC termini with controlled orientation of the azulenic dipole, are described. Self-assembly of nonbenzenoid aryl isocyanides and diisocyanides on gold(1 1 1) surfaces is reviewed as well.