Stability of Second Generation Grubbs’ Alkylidenes to Primary Amines: Formation of Novel Ruthenium‐Amine Complexes

Abstract

The stability of second generation Grubbs alkylidenes to primary amines relative to the first generation derivatives is investigated. For both Grubbs alkylidene derivatives, the tricyclohexylphosphine (PCy 3 ) ligand is displaced by n-butyl-A C H T U N G T R E N N U N G amine and diethylenetriamine. However, while displacement of PCy 3 in first generation Grubbs alkylidene derivatives results in decomposition of the catalyst, the N-heterocyclic carbene (NHC) ligand in second generation derivatives is not displaced by primary amines present in up to 100 equivalents. The result is the formation of new stable rutheniumamine complexes. These complexes are characterized and their catalytic activity is evaluated in ring-closing metathesis (RCM) and ring-opening metathesis (ROMP) reactions. While the amine complexes evaluated were minimally active in RCM reactions, the ruthenium-butylamine complex was significantly active in ROMP and exhibited an initiation rate constant that was at least an order of magnitude greater than that of the second generation Grubbs alkylidene from which it was synthesized.

Optimized reaction conditions for the cross-metathesis of methyl oleate and oleylamine with ethyl acrylate

“…To the best of our knowledge this is the first attempt to perform crossmetathesis reactions with this substrate. Although having in mind that the presence of amines often causes problems, for example the need for high catalyst loadings in olefin metathesis reactions [15,16], reaction of 9 using the reaction conditions set up for 4 was investigated. Even with 1 mol% catalyst loading, irrespective which catalyst was used no cross-metathesis reaction was observed.…”

Self-healing polymeric materials based on microencapsulated healing agents: From design to preparation

“…To expand the scope of this particular healing chemistry to more challenging application conditions, comparison studies of three types of Grubbs' catalysts (first-generation (benzylidene-bis(tricyclohexylphosphine)dichlororuthenium), second-generation M a n u s c r i p t ! 49 (benzylidene[1,3-bis(2,4,6-trimethylphenyl)-2-imidazolidinylidene]dichloro(tricyclohexylphosphin e)ruthenium), and Hoveyda-Grubbs' second-generation (1,3-bis(2,4,6-trimethylphenyl)-2-imidazolidinylidene)dichloro(o-isopropoxyphenylmethylene)rut henium)) were investigated for use in self-healing polymers [224,225]. Owing to its thermal stability and functional groups, the second-generation Grubbs' catalyst emerged as the most versatile catalyst, especially for high-temperature processes and applications involving healing chemistries aimed at improving the self-healing performance via noncovalent interactions.…”

Silica‐Protected Micron and Sub‐Micron Capsules and Particles for Self‐Healing at the Microscale

“…[12,13] First, CTAB (0.4 g) and dilute TBAF (18 mL) were dissolved in water (120 mL) at room temperature and stirred with a stir bar at medium speed. Next, PS (0.8 g), PMMA (0.4 g), and Grubbs' catalyst (0.08 g) were dissolved in methylene chloride (16 mL).…”

“…[8] In these encapsulation methods, wax particles protected the catalyst from deactivating species such as amines and alcohols. [12,13] However, smaller wax particles tend to aggregate during synthesis and have poor thermal stability. Second, the DCPD-filled capsules reported by Blaiszik et al are highly aggregated when dry and are not easily dispersed in an epoxy matrix by mechanical stirring.…”