Polymerization of phenylacetylene catalyzed by rhodium(<scp>i</scp>) complexes with <i>N</i>-functionalized N-heterocyclic carbene ligands

Angoy, Marta ; Jiménez, M. Victoria ; Lahoz, Fernando J. ; Vispe, Eugenio ; Pérez-Torrente, Jesús J. (Universidad de Zaragoza)

Resumen: A series of neutral [RhX(nbd)(κC-MeIm∩Z)] and cationic [Rh(nbd)(κ2C,N-MeIm∩Z)]+ (X = Cl, Br; MeIm = 3-methylimidazol-2-yliden-1-yl; ∩Z = N-functionalized wingtip; nbd = 2,5-norbornadiene) complexes featuring NHC ligands functionalized with a 1-aminopropyl, 3-dimethylaminopropyl, pyridin-2-ylmethyl, or quinolin-8-ylmethyl substituent have been prepared. These complexes efficiently catalyze the polymerization of phenylacetylene without base as a co-catalyst affording stereoregular polyphenylacetylenes of very high molar mass. Polymers of Mw up to 2 × 106 g mol−1 and moderate dispersity have been prepared with neutral chloro-complexes having aminopropyl wingtips. Catalyst precursors bearing functionalized NHC ligands with a flexible amino-alkyl wingtip are significantly more active than those having a heterocyclic substituent. These complexes are in general much more active than related compounds having N-functionalized phosphine ligands. Polymer characterization by SEC/MALS/DRI analysis has revealed the presence of a fraction of branched polymer of high molar mass in most samples obtained with catalysts having N-heterocyclic substituents at the NHC ligand. The N-donor function at the NHC ligand likely behaves as an internal base for the deprotonation of phenylacetylene to give the initiating alkynyl cationic [Rh(nbd)(C[triple bond, length as m-dash]C-Ph)(κC-MeIm∩ZH)]+ species. However, the participation of neutral alkynyl species [Rh(nbd)(C[triple bond, length as m-dash]C-Ph)(κC-MeIm∩Z)] should be considered in order to rationalize the notable catalytic activity of some neutral chloro-complexes.

Idioma: Inglés

DOI: 10.1039/d1py01650d

Año: 2022

Publicado en: POLYMER CHEMISTRY 13, 10 (2022), 1411-1421
ISSN: 1759-9954

Factor impacto JCR: 4.6 (2022)

Categ. JCR: POLYMER SCIENCE rank: 18 / 85 = 0.212 (2022) - Q1 - T1

Factor impacto CITESCORE: 8.6 - Materials Science (Q1) - Chemistry (Q1) - Chemical Engineering (Q1) - Biochemistry, Genetics and Molecular Biology (Q1)

Factor impacto SCIMAGO: 1.014 - Biomedical Engineering (Q1) - Bioengineering (Q1) - Polymers and Plastics (Q1) - Organic Chemistry (Q1) - Biochemistry (Q2)

Financiación: info:eu-repo/grantAgreement/ES/DGA-FSE/E42-20R
Financiación: info:eu-repo/grantAgreement/ES/MICINN/PID2019-103965GB-I00/AEI/10.13039/501100011033

Tipo y forma: Artículo (Versión definitiva)

Área (Departamento): Área Química Inorgánica (Dpto. Química Inorgánica)