Nucleophilic addition polymerisation

Whereas pyrroles are resistant to nucleophilic addition and substitution, they are very susceptible to attack by electrophilic reagents and react almost exclusively by substitution. Pyrrole itself, N- and C-monoalkyl and to a lesser extent C, C -dialkylpyrroles, are polymerised by strong acids so that many of the electrophilic... 

Nucleophilic metal alkylidene complexes are more useful for promoting the metathesis polymerisation of cycloolefins than electrophilic metal carbenes. For instance, Br2(Me3CCH20)2W=CHCMe3 is a moderately active catalyst [75,89] that can be further activated by the addition of Lewis acids such as GaBr3 to... 

The previously accepted pathway consisted of P-H oxidative addition to Pt(0) to form 19 followed by coordination and insertion of the alkene in the Pt-P bond to form 20 and a final reductive elimination to furnish the product and regenerate the catalyst. Another possibility is the nucleophilic attack of phosphido complex 19 to the alkene ( Michael addition mechanism, as in anionic polymerisation) to generate the zwitterionic intermediate 21. This complex can yield the hydrophosphination product 11 via one of two complementary pathways. Carbanion attack at the cationic platinum hydride i.e. intramolecular hydrogen transfer) would yield the final phosphine complexed to Pt(0) that would be displaced by an equivalent of PHR R to furnish, after oxidative addition, starting complex 19. Alternatively, the anionic carbon atom in 21 could attack the platinum centre directly, forming the cyclic intermediate 22. From here Pt-P bond dissociation would generate 20, which would furnish the product after reductive elimination. 

Authors stated that 2.5 mol% of azobisisobutyronitrile (AIBN) was used as an initiator to obtain complete conversion of the monomer after 2 h, at 80 °C. Low temperatures are favourable for thiol-ene additions. However, for polymerisations, the reaction temperature should be increased to avoid crystallisation of the polymer during polymerisation [33]. Gel permeation chromatography (GPC) analyses showed that fatty acid-based polyesters with Mn = 12 kDa (reactions 2 and 3, Scheme 6.11) could be synthesised via thiol-ene polymerisation. However, this approach was less suitable for the polymerisation of reactions 1 and 3, Scheme 6.11, which led to a Mn value of only 5 kDa. The high reactivity of the anhydride functionalities towards nucleophiles (in this case the thiol groups) caused the scission of the monomer or polymer backbone via thioester formation, leading to a decrease in molecular weight [33]. 

The reactivity of acrylic compounds can provide extensive opportunities to access to various original ILs. As shown on Fig. 1, on an acrylic type compound, it is possible to introduce an Ionic Part (IP) on two different sites via a nucleophilic substitution at the end of the esteiifying chain (Way 1) or via a Michael type addition on the activated double bond (Way 2). As a consequence it s possible to obtain cationic or anionic polymerisable monomers using Way 1, depending on the type of ionic part. 

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