Epoxidation of Alkenes with H2O2 Catalyzed by Dititanium-Containing 19-Tungstodiarsenate(III): Experimental and Theoretical Studies
Full article
| Общее |
Language:
Английский,
Genre:
Full article,
Status:
Published,
Source type:
Original
|
| Journal |
European Journal of Inorganic Chemistry
ISSN: 1434-1948
, E-ISSN: 1099-0682
|
| Output data |
Year: 2010,
Volume: 2010,
Number: 33,
Pages: 5312-5317
Pages count
: 6
DOI:
10.1002/ejic.201000615
|
| Tags |
Density functional calculations, Epoxidation, Hydrogen peroxide, Polyoxometalates, Titanium |
| Authors |
Donoeva Baira G.
1
,
Trubitsina Tatiana A.
1
,
Antonova Nadya S.
2
,
Carbo Jorge J.
2
,
Poblet Josep M.
2
,
Al-Kadamany Ghada
3
,
Kortz Ulrich
3
,
Kholdeeva Oxana A.
1
|
| Affiliations |
| 1 |
Boreskov Institute of Catalysis SB RAS
|
| 2 |
Rovira i Virgili University
|
| 3 |
International University Bremen
|
|
Funding (5)
|
1
|
Government of Catalonia
|
2009SGR462
|
|
2
|
Government of Catalonia
|
XRQTC
|
|
3
|
Russian Foundation for Basic Research
|
09-03-91333
|
|
4
|
Ministry of Economy and Business
|
CTQ2008-06549-C02-01/BQU
|
|
5
|
Ministry of Economy and Business
|
|
Epoxidation of a range of alkenes with aqueous H2O2 easily proceeds in the presence of the dititanium-containing 19-tungstodiarsenate(III) [Ti2(OH)2As2W19O67(H2O)]8– (1), which contains five-coordinate Ti atoms. The results of product and kinetics studies support a mechanism that involves a reversible interaction between H2O2 and the Ti–OH group of 1 to produce a titanium hydroperoxo complex followed by electrophilic oxygen atom transfer from the hydroperoxo ligand to the alkene substrate in the rate-limiting step. The effect of the alkene substrate nature has been investigated at the DFT level. A clear correlation between the energy of πC=C orbitals in the alkene and the turnover frequency values has been found, thereby indicating that the higher nucleophilicity of the alkene, the higher the reactivity. ONIOM (ONIOM = our own n-layered integrated molecular orbital and molecular mechanics) calculations have been employed to evaluate the role of steric effects of alkene substituents. The calculations show that the steric bulk can play a secondary role and tunes the activity in specific cases such as trans-stilbene.