Vanadium( v ) arylimido alkylidene N-heterocyclic carbene complexes containing fluorinated alkoxide or halogenated phenoxide ligands for the syndiospecific ROMP of cyclic olefins

• Published in: New journal of chemistry Vol. 48; no. 34; pp. 14865 - 14872
• Main Authors: Nomura, Kotohiro, Kuwahara, Shuko, Suthala, Jirapa, Kawamoto, Yuta, Shimoyama, Daisuke, Buchmeiser, Michael R.
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 27.08.2024
• Subjects: Alkenes; Alkylidene; Chemical synthesis; Fluorination; Metathesis; Polymerization; Polymers; Regularity; Ring opening; Structural analysis; Syndiotacticity; Vanadium
• ISSN: 1144-0546; 1369-9261
• DOI: 10.1039/D4NJ02537G

[V(N-2,6-Cl 2 C 6 H 3 )(CHSiMe 3 )(OC 6 X 5 )(NHC)] [X = F (1), Cl (2), NHC = 1,3-bis-(2,6-dimethylphenyl)-imidazol-2-ylidene], exhibited remarkable catalytic activities [TOF = 133–193 s −1 (1), 90.9–126 s −1 (2)] for ring opening metathesis polymerisation (ROMP) of norbornene (NBE) at 25 °C to afford ring-opened polymers not only with high cis -(93–98%) selectivity, but also with exclusive syndiotactic stereo-regularity. These polymerisations proceeded in a living manner under optimised conditions. The activity improved at 50 °C with decreasing in the cis specificity. Synthesis and the structural analysis of the fluorinated alkoxide complexes, [V(N-2,6-X 2 C 6 H 3 )(CHSiMe 3 ){OC(CF 3 ) 3 }(NHC)] [X = F (3), Cl (4)] have been studied, and the difluorophenylimdo complex (3) exhibited comparable catalytic activities for ROMP of NBE. The cis selectivities in the resultant polymers prepared by 3 were low (88%) and the selectivities in the ring-opened poly(tetracyclododecene) (TCD) were low (61–66%) compared to those in poly(NBE)s. The resultant ring opened poly(TCD) possessed syndiotactic stereo-regularity confirmed by DSC thermogram of the hydrogenated polymers.