Mechanosynthesis of Noels-type NHC-Ruthenium Complexes and Applications in ROMP

The use of ball-mills enabled the efficient mechanosynthesis of a variety of N-aryl,N-alkyl imidazolium salts and of corresponding NHC-silver(I) complexes. Transmetalation with ruthenium via mechanochemistry allowed the rapid access (1.5 min to 1 h) to complexes having a similar structure to Noels-type precatalysts. Evaluation of the complexes in the Ring-Opening Metathesis Polymerization of norbornene in different solvent, including non-toxic ones, showed a high catalytic activity for one of them, comparable to the one of Noels catalyst.