Functionalizing nanodiamond particles with N-heterocyclic iminium bromides and dicyano methanides

- Prato reaction as efficient method to generate multifunctional nanodiamond surfaces.
- Reactivity of ylides can be related to the stability and electron deficiency.
- Competing reaction of surface carbonyls to oxazolidines reported.

A versatile and efficient method for the covalent functionalization of nanodiamond has been developed. Isolable or in situ generated pyridinium methanides are applied as azomethine ylide components in Prato reactions with surface annealed diamond. Hereby, pyrrolidine rings are formed in a 1,3-dipolar cycloaddition between the π-bonds on the partially graphitized diamond surface and the ylide leading to covalent modification of the diamond surface with a multifunctional moiety. Furthermore, the underlying principles and concurrent reaction pathways such as the reaction of surface carbonyl groups in a [3 + 2] cycloaddition with the ylide have been investigated using differently treated diamond nanoparticles as starting materials and pyridinium salts and methanides.

π-Bonds generated on nanodiamond by thermal annealing enable the functionalization with pyridinium based azomethine ylides in a Prato reaction.130