Metathesis Polymerization of 5-n-Butyl-2-Norbornene in the Presence of Dimethyl Maleate

The interaction of the second-generation Grubbs catalyst and dimethyl maleate is investigated. It is shown that this interaction affords a new ruthenium-carbene complex capable of participating in the metathesis reaction. The metathesis homopolymerization of cyclooctene and 5-n-butyl-2-norbornene mediated by the first- or second-generation Grubbs catalyst in the presence of dimethyl maleate acting as a chain transfer agent is studied in detail. Conditions for the synthesis of previously unknown telechelic poly(5-n-butyl-2-norbornene) are optimized. The formation of heterodyads between the polyene block and dimethyl maleate fragments is revealed. Effect of the concentration of initial reactants, their ratio, accessibility of the main-chain double bond of polyene, catalyst type, temperature, and reaction time on the molecular weight and depth of the cross-metathesis reaction is explored. The efficiency of using dimethyl maleate as a chain transfer agent is demonstrated.