Ligand Coordination Driven by Monomer and Polymer Chain: The Intriguing Case of Salalen–Ti Catalyst for Propene Polymerization

2017 ◽  
Vol 50 (14) ◽  
pp. 5332-5336 ◽  
Author(s):  
Giovanni Talarico ◽  
Peter H. M. Budzelaar
Keyword(s):  
Polymer Chain ◽  
Propene Polymerization ◽  
Ligand Coordination

Lifetime of growing polymer chain in stopped-flow propene polymerization using pre-treated Ziegler catalysts

2000 ◽  
Vol 201 (3) ◽  
pp. 289-295 ◽  
Author(s):  
Hideharu Mori ◽  
Mikio Yamahiro ◽  
Minoru Terano ◽  
Masato Takahashi ◽  
Tetsuya Matsukawa
Keyword(s):  
Polymer Chain ◽  
Stopped Flow ◽  
Propene Polymerization

Conformation of Polymer Chain in the Bulk

1976 ◽  
Vol 1 ◽  
pp. 112-121
Author(s):  
J. P. Cotton ◽  
D. Decker ◽  
H. Benoit ◽  
B. Farnoux ◽  
J. Higgins ◽  
...  
Keyword(s):  
Polymer Chain

Undulations of a Straight Polymer Chain Embedded in a Membrane

1996 ◽  
Vol 6 (12) ◽  
pp. 1743-1757
Author(s):  
M. Singh-Zocchi ◽  
M. M. Kozlov ◽  
W. Helfrich
Keyword(s):  
Polymer Chain

Mechanistic Insights into Fe Catalyzed α-C-H Oxidations of Tertiary Amines

2019 ◽  
Author(s):  
Christopher J. Legacy ◽  
Frederick T. Greenaway ◽  
Marion Emmert
Keyword(s):  
Free Radical ◽  
Catalytic Mechanism ◽  
Catalyst System ◽  
Oxidation Products ◽  
Tertiary Amines ◽  
Catalyst Activation ◽  
Rate Determining Step ◽  
Fe Catalyst ◽  
Ligand Coordination ◽  
Rate Kinetics

We report detailed mechanistic investigations of an iron-based catalyst system, which allows the α-C-H oxidation of a wide variety of amines, including acyclic tertiary aliphatic amines, to afford dealkylated or amide products. In contrast to other catalysts that affect α-C-H oxidations of tertiary amines, the system under investigation employs exclusively peroxy esters as oxidants. More common oxidants (e.g. tBuOOH) previously reported to affect amine oxidations via free radical pathways do not provide amine α-C-H oxidation products in combination with the herein described catalyst system. Motivated by this difference in reactivity to more common free radical systems, the investigations described herein employ initial rate kinetics, kinetic profiling, Eyring studies, kinetic isotope effect studies, Hammett studies, ligand coordination studies, and EPR studies to shed light on the Fe catalyst system. The obtained data suggest that the catalytic mechanism proceeds through C-H abstraction at a coordinated substrate molecule. This rate-determining step occurs either at an Fe(IV) oxo pathway or a 2-electron pathway at a Fe(II) intermediate with bound oxidant. We further show via kinetic profiling and EPR studies that catalyst activation follows a radical pathway, which is initiated by hydrolysis of PhCO3 tBu to tBuOOH in the reaction mixture. Overall, the obtained mechanistic data support a non-classical, Fe catalyzed pathway that requires substrate binding, thus inducing selectivity for α-C-H functionalization.<br>

Sign in / Sign up

Export Citation Format

Share Document