Interaction of mono- and diisocyanoazulenes with gold surfaces: first examples of self-assembled monolayer films involving azulenic scaffolds.

The formation and properties of a new class of self-assembled monolayers (SAM) of aryl isocyanides and diisocyanides based on the nonbenzenoid azulenic framework have been investigated using FTIR spectroscopy and ellipsometry. Syntheses of several new members of the isocyanoazulene family, a recently established type of aryl isocyanides, are reported as well. The FTIR spectra for the isocyanoazulene derivatives absorbed on the gold surface indicate the terminal upright coordination of every isocyanoazulene molecule studied. In addition, the ellipsometric thicknesses have been measured and are consistent with those calculated for single monolayers of the isocyanides oriented along the surface normal. Unlike SAMs of some benzenoid aryl isocyanides, the nonbenzenoid isocyanoazule-based SAMs proved resistant to oxidation, oligomerization, and isomerization into the corresponding nitriles under ambient conditions, which is an important prerequisite to their future applications.