Latent ruthenium carbene complexes with six-membered N- and S-chelate rings

Tuning the Latent Behavior of Molybdenum Imido Alkylidene N-Heterocyclic Carbene Complexes in Dicyclopentadiene Polymerization

“…This is in line with the previously reported associative mechanism, which entails first coordination of the monomer, concomitant rearrangement of the ligand sphere, and finally, dissociation of the triflate, which then generates the metathesis-active complex (vide infra). 46 For this reason, we were not surprised to find that both Mo triflate bonds in LC-3 (217.4(2) and 219.10(19) pm) are longer than in Mo-1 (216.7 (8) and 218(7) pm 29 ), which facilitates triflate dissociation.…”

“…Latent catalysts should be tolerant toward all components of the polymerization mixture as well as toward decomposition or thermal degradation and, ideally, toward air. Generally, latent catalysts or precatalysts for ROMP can be activated by light, heat, acids, or mechanical force. ,− So far, most precatalysts for the ROMP of DCPD are based on ruthenium, due to their tolerance toward moisture and protic groups. , Generally, latency in the well-defined ruthenium alkylidene catalysts is achieved with chelating alkylidenes such as N -chelating (pyridyl, Schiff base, quinoline, quinoxalines), − ,− O -chelating (ether, carboxylate), ,− and S -chelating (thioether) , structural motifs.…”

“…3,7−11 So far, most precatalysts for the ROMP of DCPD are based on ruthenium, due to their tolerance toward moisture and protic groups. 3,12 Generally, latency in the well-defined ruthenium alkylidene catalysts is achieved with chelating alkylidenes 13 such as N-chelating (pyridyl, Schiff base, quinoline, quinoxalines), 7−9,14−19 Ochelating (ether, carboxylate), 12,20−23 and S-chelating (thioether) 8,13 structural motifs.…”

Hoveyda–Grubbs catalysts with an N→Ru coordinate bond in a six-membered ring. Synthesis of stable, industrially scalable, highly efficient ruthenium metathesis catalysts and 2-vinylbenzylamine ligands as their precursors

“…It should be mentioned that some of catalysts 11 have been synthesized recently in a more complex way in lower yields [32].…”

“…Among all these applications, the use of the catalysts for the polymerization of dicyclopentadiene has the greatest industrial importance [3,9,29–31]. Noteworthy, there are only rare and sporadic publications describing the synthesis and properties of the Grubbs catalysts with an N→Ru coordinate bond in a six-membered ring [32–38].…”