Highly efficient vinylic addition polymerization of 5-vinyl-2-norbornene using benzylic palladium complexes as precatalysts

Abstract

In contrast with the parent norbornene, the vinylic addition polymerization of substituted norbornene derivatives is difficult to achieve. We have found that benzylic palladium complexes are suitable precatalysts in the...

Single‐Component Catalysts for the Vinyl‐Addition Polymerization of Norbornene and its Derivatives

“…Mechanistic studies of such catalysts revealed that an end group of the polymer chain contains the functional groups from the catalysts used. [53,78] For example, Wu et al confirmed the incorporation of Me group from the PdÀ Me moiety of Pd69b into growing polymer chains using in-situ NMR monitoring of norbornene oligomerization (Figure 22a). [80] The catalyst was not eliminated or decomposed, and the slow initiation of polymerization was attributed to the competitive coordination between NB and acetonitrile.…”

“…developed cationic Pd complexes with η 3 ‐benzyl‐ligand ( Pd63−Pd68 , Figure 17). [14a,78] This ligand can be readily converted to σ‐benzyl‐ligand to recover the benzene ring aromaticity and create an available coordination site on the Pd center. These complexes proved to be effective catalysts for the polymerization of NB , 1.4 , and alkenyl norbornenes ( 1.5 , Figure 4).…”

“…This issue has been clarified for catalysts containing a pre‐formed metal−C or metal−H bond. Mechanistic studies of such catalysts revealed that an end group of the polymer chain contains the functional groups from the catalysts used [53,78] . For example, Wu et al.…”

“…The nature of metal−C bonds is also essential. For instance, the nature of the allyl group on Pd dramatically affected initiation efficiency and polymer molecular weights [14a,78,81] . Therefore, although no clear guidelines exist for creating a single‐component catalyst with fast initiation and low propagation, systematic tuning of ligands in the metal coordination sphere results in optimal catalyst structural design.…”

Gas-Transport and the Dielectric Properties of Metathesis Polymer from the Ester of exo-5-Norbornenecarboxylic Acid and 1,1′-Bi-2-naphthol

“…This feature allows involvement in polymerization monomers, bearing two, three, or four substituents, which is often impossible for a polymerization of most olefins. Second, there are at least two ways for polymerization of cycloalkenes (ring-opening metathesis polymerization and vinyl (addition) polymerization [1][2][3][4][5]), which give polymers with different structure and properties. Third, owing to well-developed organic tools, such as cycloaddition reactions [6,7], a huge number of cycloalkenes can be prepared, and this provides an opportunity to perform systematic structure-property investigations.…”