EPR Spectroscopic Detection of the Elusive Fe V ═O Intermediates in Selective Catalytic Oxofunctionalizations of Hydrocarbons Mediated by Biomimetic Ferric Complexes
Full article
| Common |
Language:
Английский,
Genre:
Full article,
Status:
Published,
Source type:
Original
|
| Journal |
ACS Catalysis
ISSN: 2155-5435
|
| Output data |
Year: 2015,
Volume: 5,
Number: 5,
Pages: 2702-2707
Pages count
: 6
DOI:
10.1021/acscatal.5b00169
|
| Tags |
bioinspired catalysis, enantioselective epoxidation, EPR, iron, mechanism |
| Authors |
Lyakin Oleg Y.
1,2
,
Zima Alexandra M.
1,2
,
Samsonenko Denis G.
1,3
,
Bryliakov Konstantin P.
1,2
,
Talzi Evgenii P.
1,2
|
| Affiliations |
| 1 |
Novosibirsk State University, Pirogova 2, Novosibirsk 630090, Russian Federation
|
| 2 |
Boreskov Institute of Catalysis, Pr. Lavrentieva 5, Novosibirsk 630090, Russian Federation
|
| 3 |
Nikolaev Institute of Inorganic Chemistry, Pr. Lavrentieva 3, Novosibirsk 630090, Russian Federation
|
|
Funding (1)
|
1
|
Russian Science Foundation
|
14-13-00158
|
Herein, we report the EPR spectroscopic study of the bioinspired catalyst systems for selective hydrocarbon oxofunctionalizations based on dinuclear ferric complexes with TPA* and PDP* aminopyridine ligands , hydrogen peroxide and acetic acid (TPA* = tris(3,5-dimethyl-4-methoxypyridyl-2-methyl)amine, PDP* = bis(3,5-dimethyl-4-methoxypyridylmethyl)-(S,S)-2,2'-bipyrrolidine). Using very low temperatures −75 to −85 °C, the extremely unstable and reactive iron-oxygen intermediates, directly reacting with olefins even at −85 °C have been detected for the first time. Their EPR parameters (g1 = 2.070-2.071, g2 = 2.005-2.008, g3 = 1.956-1.960) were very similar to those of the known oxoiron(V) complex [(TMC)FeV=O(NC(O)CH3)]+ (g1 = 2.053, g2 = 2.010, g3 = 1.971, TMC = 1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane). On the basis of EPR and reactivity data, the detected intermediates were assigned to the FeV=O active oxidizing species of the catalyst systems studied.