Theoretical Investigations of Para-Methoxystyrene/Styrene Polymerization Catalyzed by Cationic Methyl- and Dibenzobarrelene-Based α-Diimine Palladium Complexes DOI Creative Commons

Ling Zhu,

Yi Luo, Xin Wen

et al.

Inorganics, Journal Year: 2024, Volume and Issue: 12(12), P. 315 - 315

Published: Dec. 5, 2024

The polymerization mechanism of para-methoxystyrene catalyzed by cationic α-diimine palladium complexes with various ancillary ligands was rigorously examined using density functional theory. In the classical methyl-based complex [{(2,6-iPr2C6H3)-N=C(Me)-C(Me)=N-2,6-iPr2C6H3)}PdMe]+ (A+), 2,1-insertion is favored over 1,2-insertion, both thermodynamically and kinetically, during chain initiation step. resulting η3-π-benzyl intermediates face a substantial energy barrier, yielding only trace amounts polymer, as experimentally verified. contrast, dibenzobarrelene-based [{(2,6-iPr2C6H3)-N=C(R)-C(R)=N-2,6-iPr2C6H3)}PdMe]+ (R = dibenzobarrelene, B+) shows similar barriers for 2,1- 1,2-insertions. Continuous 2,1/2,1 or 2,1/1,2 insertions are impeded excessive barriers. However, theoretical calculations reveal that 1,2-insertion product can seamlessly transition into propagation stage, producing polymer high 1,2-regioselectivity. observed activity A+ B+ towards stems from barrier differences between 1,2- 2,1-insertions, influenced steric hindrance ligands. Further investigation effects on stage involved computational modeling analogous increased bulk. These studies established direct correlation difference ∆∆G (1,2–2,1) van der Waals volume ligand. Larger volumes correspond to reduced differences, thus enhancing regioselectivity polymerization. Moreover, experimental inertness styrene attributed formation stable kinetic thermodynamic intermediates, which obstruct further monomer insertion due an extremely reactive barrier. findings contribute deeper understanding mechanistic aspects offer insights designing new metal catalysts para-alkoxystyrenes.

Language: Английский

Mono- and Trinuclear Phosphine-Phenolate Nickel(II) Complexes as Precatalysts in Ethylene/Acrylate Copolymerization DOI

Alfons J. Pineda‐Knauseder,

Toby J. Woods, Damien Guironnet

et al.

Organometallics, Journal Year: 2025, Volume and Issue: unknown

Published: Feb. 3, 2025

Language: Английский

Citations

0
Unraveling the Reactivity of SiO2-Supported Nickel Catalyst in Ethylene Copolymerization with Polar Monomers: A Theoretical Study DOI Open Access
Daniela E. Ortega, Diego Cortés‐Arriagada

Polymers, Journal Year: 2025, Volume and Issue: 17(9), P. 1268 - 1268

Published: May 6, 2025

Understanding the catalytic behavior of heterogeneous systems for copolymerization ethylene with polar monomers is essential developing advanced functional polyolefins. In this study, we conducted a quantum chemical investigation SiO2-supported Ni–allyl–α-imine ketone catalyst (Ni-OH@SiO2) to uncover factors governing monomer insertion, selectivity, and reactivity. Using DFT calculations energy decomposition analysis (ALMO-EDA), evaluated coordination insertion six industrially relevant monomers, comparing their homopolymerization. Our results show that special (SPMs) aliphatic spacers, such as vinyltrimethoxysilane (vTMS) 5-hexenyl acetate (AMA), exhibit favorable profiles due enhanced electrostatic orbital interactions minimal steric hindrance. contrast, fundamental (FPMs), including methyl acrylate (MA) vinyl chloride (vCl), higher activation barriers increased Pauli repulsion strong electron-withdrawing effects conjugation group. AMA displayed lowest barrier (7.4 kcal/mol) highest thermodynamic stability (−17.6 kcal/mol). These findings provide molecular-level insight into mechanisms comonomer selectivity in Ni–allyl catalysts supported on silica, extending experimental understanding. This work establishes key structure–reactivity relationships offers design principles efficient Ni-based copolymerization.

Language: Английский

Citations

0
Groups 3 and 4 single-site catalysts for olefin-polar monomer copolymerization DOI

C. Li,

Guoqiang Fan,

Gang Zheng

et al.

Chinese Chemical Letters, Journal Year: 2025, Volume and Issue: unknown, P. 111297 - 111297

Published: May 1, 2025

Language: Английский

Citations

0
Theoretical Investigations of Para-Methoxystyrene/Styrene Polymerization Catalyzed by Cationic Methyl- and Dibenzobarrelene-Based α-Diimine Palladium Complexes DOI Creative Commons

Ling Zhu,

Yi Luo, Xin Wen

et al.

Inorganics, Journal Year: 2024, Volume and Issue: 12(12), P. 315 - 315

Published: Dec. 5, 2024

The polymerization mechanism of para-methoxystyrene catalyzed by cationic α-diimine palladium complexes with various ancillary ligands was rigorously examined using density functional theory. In the classical methyl-based complex [{(2,6-iPr2C6H3)-N=C(Me)-C(Me)=N-2,6-iPr2C6H3)}PdMe]+ (A+), 2,1-insertion is favored over 1,2-insertion, both thermodynamically and kinetically, during chain initiation step. resulting η3-π-benzyl intermediates face a substantial energy barrier, yielding only trace amounts polymer, as experimentally verified. contrast, dibenzobarrelene-based [{(2,6-iPr2C6H3)-N=C(R)-C(R)=N-2,6-iPr2C6H3)}PdMe]+ (R = dibenzobarrelene, B+) shows similar barriers for 2,1- 1,2-insertions. Continuous 2,1/2,1 or 2,1/1,2 insertions are impeded excessive barriers. However, theoretical calculations reveal that 1,2-insertion product can seamlessly transition into propagation stage, producing polymer high 1,2-regioselectivity. observed activity A+ B+ towards stems from barrier differences between 1,2- 2,1-insertions, influenced steric hindrance ligands. Further investigation effects on stage involved computational modeling analogous increased bulk. These studies established direct correlation difference ∆∆G (1,2–2,1) van der Waals volume ligand. Larger volumes correspond to reduced differences, thus enhancing regioselectivity polymerization. Moreover, experimental inertness styrene attributed formation stable kinetic thermodynamic intermediates, which obstruct further monomer insertion due an extremely reactive barrier. findings contribute deeper understanding mechanistic aspects offer insights designing new metal catalysts para-alkoxystyrenes.

Language: Английский

Citations

0