Ligand and Structural Variation in Ruthenium-Based Initiators

3 Ligand and Structural Variation in Ruthenium-Based Initiators Variations in and Substitution of Phosphine-Ligands 

Wifh fhese systems, initiation of various substituted NBEs and 7-oxanorborn-5-enes occurs rapidly and quantitatively, yet polymerizations do not proceed in a living manner. In order to obtain truly living systems, investigations in terms of stability versus Bronsted acids such as DCl and bases were carried out [198]. Interestingly, and in contrast to the behavior of classical water-soluble systems such as 

In this context it is worth mentioning that (Tp(PPh3)( / -O2CCHPh2)Ru (=CHPh) is a (poor) catalyst for the ROMP of NBE without a co-catalyst, while molybdenum alkylidenes prepared from the Tp-ligand of the formula Mo(Tp)(CHCMe2Ph)(N-2,6-i-Pr2-C6H3)(OTf) require a co-catalyst (AlCl,) in order to be ROMP active [214]. 

Variation in the Alkylidene Moiety Ru-Allenylidene, Vinylidene, Cumulenylidene, and Other Complexes 

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