“…22 Recently, we replaced the PAG with a NHC photogenerator and used a stable, commercially available dimeric Ru(II) complex as metathesis inactive catalyst (Scheme 1). 28,29 Our tandem system made up of 1,3-bis(mesityl)imidazolium tetraphenylborate IMesH + BPh 4 À (1) as NHC progenitor and [RuCl 2 (p-cymene)] 2 precatalyst (Ru-1) proved to be very efficient at ROMP of NB. In comparison with the examples discussed above, a safer UVA radiation (320-400 nm) was employed, and no ligand displacement occurred.…”