Synthesis of Bottlebrush Polymers by Z-/E-Specific Living Ring-Opening Metathesis Polymerization, Exhibiting Different Thermal Properties

[Image: see text] Synthesis of bottlebrush polymers (BBPs) and block copolymers by Z-/E-specific living ring-opening metathesis polymerization (ROMP) of N-substituted-norbornene-2,3-dicarboximides containing long alkyl chains (n-octadecyl, n-tetradecyl, etc.) has been attained by the vanadium(V)–alkylidene catalysts V(CHSiMe(3))(ArN)[OC(CF(3))(3)](PMe(3))(2) [Ar = 2,6-Cl(2)C(6)H(3) (1), C(6)F(5) (2)] and V(CHSiMe(3))(2,6-F(2)C(6)H(3)N)(OC(6)Cl(5))(PMe(3))(2) (3). The ROMPs using 1 afforded the BBPs with exclusive Z selectivity (98 to >99% cis) even at high temperature (up to 80 °C) in the presence of PMe(3), whereas the ROMPs using 3 gave the BBPs with high E selectivity (90% trans). These ROMPs proceeded in a living manner (even at 80 °C using 1), affording various (amphiphilic) block copolymers while maintaining high E/Z selectivity. The resultant Z- and E-selective BBPs especially prepared from N-(n-octadecyl)norbornene-2,3-dicarboximide possessed different melting temperatures due to different degrees of interpolymer alkyl side chain interaction (side chain crystallization).