Stability and Reactivity of Low-Spin Ferric Hydroperoxo and Alkylperoxo Complexes with Bipyridine and Phenantroline Ligands Full article
| Conference |
Physical Methods for Catalytic Research at the Molecular Level: International memorial K.I. Zamaraev conference 28 Jun - 2 Jul 1999 , Novosibirsk |
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| Journal |
Journal of Molecular Catalysis A: Chemical
ISSN: 1381-1169 |
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| Output data | Year: 2000, Volume: 159, Number: 2, Pages: 233-245 Pages count : 13 DOI: 10.1016/S1381-1169(00)00197-7 | ||||
| Tags | EPR, Ferric alkylperoxo complexes, Ferric hydroperoxo complexes, NMR spectroscopy, Reactivity studies | ||||
| Authors |
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| Affiliations |
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Funding (2)
| 1 | Russian Foundation for Basic Research | 97-03-32495 |
| 2 | Haldor Topsoe A/S |
Abstract:
In this work the first-order rate constants of self-decomposition of hydroperoxo and alkylperoxo complexes [Fe(bpy)2(OOH)Py](NO3)2 (2a-Py), [Fe(phen)2(OOH)Py](NO3)2 (2b-Py) and [Fe(bpy)2(OOtBu)CH3CN](NO3)2 (3a-CH3CN) were determined in the presence of various substrates and at various temperatures. It was observed, that the alkylperoxo species are far less stable than corresponding hydroperoxo intermediates, k=1.2×10−2 s−1 (3a-CH3CN in CH3CN at −10°C) and k=2×10−4 s−1 (2a-Py in CH3CN at −10°C). The sixth ligand (Py in 2a-Py and 2b-Py; CH3CN in 3a-CH3CN) can be replaced by other donor molecules B in appropriate solvent systems. Using d9-tBuOOH, 2D NMR signals of tBuOO moieties of complexes 3a-CH3CN, 3a-CH3OH and 3a-H2O were observed. The rate of decomposition of hydroperoxo complexes [Fe(bpy)2(OOH)B](NO3)2 (2a-B), where B are derivatives of Py (3-Br-Py, 3-Me-Py, 4-Me-Py and 4-Me2N-Py) increases with the growth of basisity of B (push effect). Such effect is markedly smaller for alkylperoxo species [Fe(bpy)2(OOtBu)B](NO3)2 (3a-B). The addition of organic substrates (cyclohexane, cyclohexene, methyl phenyl sulfide) in concentrations up to 3 M at −10°C to +20°C does not noticeably change the rate of self-decomposition of 2a-B, [Fe(phen)2(OOH)B](NO3)2 (2b-B) and 3a-B. Thus the intermediates concerned do not directly react with organic substrates. The reactivity patterns of 2a-B, 2b-B and 3a-B were characteristic for free radical oxidation. OH· and HO2· radicals were trapped in solution containing 2a-Py, and tBuOO· free radicals were detected in solution in the presence of 3a-B. The determined rates of self-decomposition of complexes 2a-B, 2b-B and 3a-B can be used for evaluation of the upper limit for their reactivity towards organic substrates.
Cite:
Sobolev A.P.
, Babushkin D.E.
, Talzi E.P.
Stability and Reactivity of Low-Spin Ferric Hydroperoxo and Alkylperoxo Complexes with Bipyridine and Phenantroline Ligands
Journal of Molecular Catalysis A: Chemical. 2000. V.159. N2. P.233-245. DOI: 10.1016/S1381-1169(00)00197-7 WOS Scopus РИНЦ ANCAN OpenAlex
Stability and Reactivity of Low-Spin Ferric Hydroperoxo and Alkylperoxo Complexes with Bipyridine and Phenantroline Ligands
Journal of Molecular Catalysis A: Chemical. 2000. V.159. N2. P.233-245. DOI: 10.1016/S1381-1169(00)00197-7 WOS Scopus РИНЦ ANCAN OpenAlex
Dates:
| Submitted: | May 1, 1999 |
| Accepted: | Feb 28, 2000 |
| Published online: | Jul 27, 2000 |
| Published print: | Oct 2, 2000 |
Identifiers:
| Web of science: | WOS:000089431200009 |
| Scopus: | 2-s2.0-0034597018 |
| Elibrary: | 13335597 |
| Chemical Abstracts: | 2000:728065 |
| Chemical Abstracts (print): | 134:21937 |
| OpenAlex: | W1966028779 |