Journal
ACS CATALYSIS
Volume 2, Issue 12, Pages 2547-2556Publisher
AMER CHEMICAL SOC
DOI: 10.1021/cs300549u
Keywords
ROMP; DFT calculations; N-heterocyclic carbene; regioselectivity; stereoselectivity; solvent effect; reaction mechanism; metathesis
Categories
Funding
- UMN Initiative for Renewable Energy and the Environment [RL-0015-11]
- U.S. National Science Foundation [CHE-0952054]
- Dow Chemical Company
- Division Of Chemistry
- Direct For Mathematical & Physical Scien [0952054] Funding Source: National Science Foundation
Ask authors/readers for more resources
Mechanistic details of the ring-opening metathesis polymerization of 3-substituted-Z-cyclooctenes (3RCOEs) catalyzed by the second-generation Grubbs' catalyst were systematically studied at the M06-2X/SDDI6-311+G(2df,p)//M06-L/SDDI6-31G(d) level of theory to elucidate factors contributing to observed regioselectivities. All possible conformational isomers for Z-cyclooctene (4 total) and 3-methyl-Z-cyclooctene (16 total) were taken into account. The potential energy surfaces for both the initiation and the propagation steps were calculated including all stereochemically distinct approaches of the cycloalkene to the active catalyst. In contrast to the situation with smaller cycloalkenes, the rate-limiting step for the polymerization of Z-c-yclooctenes was determined to be the breakdown of the metallacyclobutane intermediate. This change is attributed to increased repulsive interactions between the growing polymer chain and the mesityl groups of the N-heterocyclic carbene ligand when the effective cone angle increases upon ring-opening. Most of the observed regioselectivity for 3RCOEs derives from differential steric interactions, but solvation also plays a role.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available