Cationic Ru^II Complexes with N‐Heterocyclic Carbene Ligands for UV‐Induced Ring‐Opening Metathesis Polymerization

Open sesame: Novel cationic RuII complexes with N-heterocyclic carbene ligands (see structure) have been prepared and used as UV-triggerable photoinitiators for ring-opening metathesis polymerization. They may be used for the high-yield synthesis of bulk polymers as well as for surface functionalization. Laser pulse radiolysis and NMR spectroscopy experiments supported by quantum chemical calculations give insight into the initiation mechanism.