Hydrogen peroxide oxygenation of alkanes including methane and ethane catalyzed by iron complexes in acetonitrile

Article abstract of DOI:10.1002/adsc.200303147

This paper describes an investigation of the alkane oxidation with hydrogen peroxide in acetonitrile catalyzed by iron(III) perchlorate (1), iron(III) chloride (2), iron(III) acetate (3) and a binuclear iron(III) complex with 1,4,7-triazacyclononane (4). The corresponding alkyl hydroperoxides are the main products. Nevertheless in the kinetic study of cyclohexane oxidation, the concentrations of oxygenates (cyclohexanone and cyclohexanol) were measured after reduction of the reaction solution with triphenylphosphine (which converts the cyclohexyl hydroperoxide to the cyclohexanol). Methane and ethane can be also oxidized with TONs up to 30 and 70, respectively. Chloride anions added to the oxidation solution with 1 activate the perchlorate iron derivative in acetonitrile, whereas the water as additive inactivates 2 in the H ₂O₂ decomposition process. Pyrazine-2-carboxylic acid (PCA) added to the reaction mixture decreases the oxidation rate if 1 or 2 are used as catalysts, whereas compounds 3 and 4 are active as catalysts only in the presence of small amount of PCA. The investigation of kinetics and selectivities of the oxidations demonstrated that the mechanisms of the reactions are different. Thus, in the oxidations catalyzed by the 1, 3+PCA and 4+ PCA systems the main oxidizing species is hydroxyl radical, and the oxidation in the presence of 2 as a catalyst has been assumed to proceed (partially) with the formation of ferryl ion, (Fe^IV=O)²⁺. In the oxidation catalyzed by the 4+PCA system (TONs attain 240) hydroxyl radicals were generated in the rate-determining step of monomolecular decomposition of the iron diperoxo adduct containing one PCA molecule. A kinetic model of the process which satisfactorily describes the whole set of experimental data was suggested. The constants of supposed equilibriums and the rate constant for the decomposition of the iron diperoxo adduct with PCA were estimated.

Full text of DOI:10.1002/adsc.200303147

FULL PAPERS
Hydrogen Peroxide Oxygenation of Alkanes Including Methane
and Ethane Catalyzed by Iron Complexes in Acetonitrile
Georgiy B. Shul×pin,a,* Galina V. Nizova,a Yuriy N. Kozlov,a Laura Gonzalez
Cuervo,b Georg S¸ss-Finkb
a
Semenov Institute of Chemical Physics, Russian Academy of Sciences, Moscow 119991, ulitsa Kosygina, dom 4, Russia
Fax: (‡ 7095)-1376130, e-mail: Shulpin@chph.ras.ru
b
¬
√
√
Institut de Chimie, Universite de Neuchatel, Avenue de Bellevaux 51, Case postale 2, 2007 Neuchatel, Switzerland
Received: September 9, 2003; Accepted: January 17, 2004
Abstract: This paper describes an investigation of the amount of PCA. The investigation of kinetics and
alkane oxidation with hydrogen peroxide in acetoni- selectivities of the oxidations demonstrated that the
trile catalyzed by iron(III) perchlorate (1), iron(III) mechanisms of the reactions are different. Thus, in
chloride (2), iron(III) acetate (3) and a binuclear the oxidations catalyzed by the 1, 3 ‡ PCA and 4 ‡
iron(III) complex with 1,4,7-triazacyclononane (4). PCA systems the main oxidizing species is hydroxyl
The corresponding alkyl hydroperoxides are the main radical, and the oxidation in the presence of 2 as a
products. Nevertheless in the kinetic study of cyclo- catalyst has been assumed to proceed (partially) with
2‡
hexane oxidation, the concentrations of oxygenates the formation of ferryl ion, (FeIV O) . In the
ˆ
(cyclohexanone and cyclohexanol) were measured oxidation catalyzed by the 4 ‡ PCA system (TONs
after reduction of the reaction solution with triphe- attain 240) hydroxyl radicals were generated in the
nylphosphine (which converts the cyclohexyl hydro- rate-determining step of monomolecular decomposi-
peroxide to the cyclohexanol). Methane and ethane tion of the iron diperoxo adduct containing one PCA
can be also oxidized with TONs up to 30 and 70, molecule. A kinetic model of the process which
respectively. Chloride anions added to the oxidation satisfactorily describes the whole set of experimental
solution with 1 activate the perchlorate iron deriva- data was suggested. The constants of supposed
tive in acetonitrile, whereas the water as additive equilibriums and the rate constant for the decom-
inactivates 2 in the H2O2 decomposition process. position of the iron diperoxo adduct with PCA were
Pyrazine-2-carboxylic acid (PCA) added to the reac- estimated.
tion mixture decreases the oxidation rate if 1 or 2 are
used as catalysts, whereas compounds 3 and 4 are Keywords: alkanes; alkyl hydroperoxides; hydrogen
active as catalysts only in the presence of small peroxide; iron complexes; methane; oxidation
Introduction
oxidations catalyzed by iron ions.[22] In a recent pub-
[20d]
¬
lication, Paczesniak and Sobkowiak
demonstrated
Iron compounds are used as initiators and catalysts in that ™in acetonitrile, in contrast to water, iron(III) is
oxidation of various organic compounds with hydrogen reduced by hydrogen peroxide, according to 2:1 stoi-
peroxide.[1,2] Iron complexes containing various ligands chiometry∫. The authors concluded that ™the system is
(usually chelating cyclic N-bases) play a very important very sensitive towards almost any experimental varia-
role in living cells as well as in biomimetic oxidations.[3,4] bles, i.e., solvent, ligand, water content in organic
In addition to the well-known Fenton reagent (which solvent, and the oxidation state of metal ion, which
uses FeII in stoichiometric amounts), synthetically useful can be rapidly changed at the beginning of the exper-
so-called Gif systems,[5] and ™oxygenated Fenton re- iment∫.[20d]
agents∫[6] have been described by Barton and Sawyer
In the present study we have investigated alkane
groups. Interesting studies on iron-catalyzed alkane oxidation with hydrogen peroxide in acetonitrile cata-
oxidations have been carried out in recent decades by lyzed by simple iron(III) complexes such as the per-
the groups of Feringa,[7] Fish,[8] Fontecave,[9] Groves,[10] chlorate (containing ™naked∫ iron cation) (1; see
[14]
Lippard,[11] Mansuy,[12] Mascharak,[13] Menage,
Scheme 1) and those bearing more strongly bound
¬
Nam,[15] Newcomb,[16] Nishida,[17] Que,[18] Shilov and ligands, i.e., chloride (2) and acetate (3). Finally, we
Shteinman,[19] Sobkowiak,[20] and Stavropoulos.[21] Many employed as a catalyst a binuclear iron(III) complex
papers are devoted to mechanisms of hydrocarbon with 1,4,7-triazacyclononane (4) which can be consid-
Adv. Synth. Catal. 2004, 346, 317 332
DOI: 10.1002/adsc.200303147
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Georgiy B. Shul×pin et al.
FULL PAPERS
ered as a structural model of some iron-containing predominant product), cyclohexanone, and cyclohexa-
biologically active compounds, and especially enzymes. nol.
Some fragments of this work have been published
previously as preliminary communications.[23]
Oxidation Catalyzed by Iron(III) Perchlorate
Results and Discussion
First of all we investigated the cyclohexane oxidation
with hydrogen peroxide under catalysis by the most
We have found that iron(III) salts catalyze the hydrogen ™simple∫ iron salt, i.e., iron(III) perchlorate (1) which
peroxide decomposition in acetonitrile. In the presence does not contain any ligands strongly bound to iron. The
of alkane, RH, for example, cyclohexane, CyH, in oxygenation leads to the formation of cyclohexyl hydro-
addition to the decomposition of H2O2 to afford O2 and peroxide, cyclohexanol and cyclohexanone. The reac-
H2O (catalase activity of the catalyst) one can observe tion efficiency is not high and turnover numbers (i.e.,
alkane oxygenation with formation of the correspond- number of mols of products per one mol of the catalyst,
ing alkyl hydroperoxide, ROOH (cyclohexyl hydroper- TON) attain only 10 after approximately 3 min. The rate
oxide, CyOOH) as the main primary product (oxygen- dependencyof the oxygenation is first order with respect
ase activity) which further gradually decomposes yield- to the initial hydrogen peroxide (Figure 1). The initial
ing more stable products, the ketone (aldehyde) and rate of molecular oxygen evolution is also proportional
alcohol. Concentrations of the three products were to the initial concentration of H2O2.
determined by GC using a method proposed by us
First order has been found for catalyst1, and the initial
previously.[1d,24] The reactions were quenched by the reaction rate decreases when PCA is added to the
addition of solid triphenylphosphine to the reaction reaction solution (Figure 2). The dependence of the
solution, and GC analysis gave the concentrations of initial cyclohexane oxidation rate on the initial cyclo-
cyclohexanol and cyclohexanone. A comparison of the hexane concentration (a plateau at [cyclohexane]0 >
alcohol and ketone concentrations (measured by GC) 0.4 mol dmÀ3; Figure 3) is in accordance with the
before and after the addition of PPh3 testified that assumption concerning competition between cyclohex-
cyclohexyl hydroperoxide was formed as main product ane and the solvent (acetonitrile) for the interaction
in the initial period. Indeed, the solution untreated with with an active oxidizing species (see below).
PPh3 contained alkyl hydroperoxide, CyOOH, which
It is noteworthy that lithium chloride added to the
completely or partially decomposed in GC to produce reaction solution dramatically accelerates the dioxygen
ˆ
CyOH, Cy O and other compounds. Added triphenyl- evolution process (Figure 4). Another remarkable fea-
phosphine quantitatively reduced CyOOH to CyOH. ture of this effect is a bell-shaped dependence on
For the precise determination of oxygenate concentra- [LiCl]added. It is reasonableto assume that in the presence
tions only data obtained after reduction of the reaction
sample with PPh3 were usually used, taking into account,
however, that the original reaction mixture contained
the three products, cyclohexyl hydroperoxide (as a
Figure 1. Cyclohexane (0.46 mol dmÀ3) oxidation with H2O2
catalyzed by Fe(ClO4)3 (5 Â 10À4 mol dmÀ3) in MeCN at
25 8C. Plots of initial rates of oxygenate accumulation (curve
1) and O2 evolution (curve 2) versus initial concentration of
Scheme 1.
H2O2 are shown.
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Hydrogen Peroxide Oxygenation of Alkanes
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Figure 4. Hydrogen peroxide (0.05 mol dmÀ3) decomposition
catalyzed by Fe(ClO4)3 (5 Â 10À4 mol dmÀ3) in MeCN at
25 8C: H2O2 consumption (curve 1) and O2 evolution (curve
2) versus initial concentration of added LiCl.
Figure 2. Cyclohexane (0.46 mol dmÀ3) oxidation with H2O2
(0.25 mol dmÀ3) catalyzed by Fe(ClO4)3 in MeCN at 25 8C:
initial oxygenate formation rate versus concentration of
Fe(ClO4)3 (curve 1) and versus concentration of added
PCA ([Fe(ClO4)3] ˆ 5  10À4 mol dmÀ3) (curve 2).
The data on methane and ethane oxidation with
hydrogen peroxide catalyzed by iron perchlorate are
summarized in Tables 2 and 3. It can be seen that in the
case of ethane the TONs attain 68.
Iron(III) Chloride as a Catalyst
It has been demonstrated by spectrophotometry that no
aggregation of FeCl3 species takes place in the acetoni-
trile solution. Indeed, absorbance with iron ions is
proportional to iron concentration in the 2 Â 10À5 to
10À3 mol dmÀ3 range and thus Beer×s law is valid. The
rate dependency of the oxygenation is first order with
respect to compound 2 as a catalyst at [FeCl3] < 2 Â
10À3 mol dmÀ3 (Figure 5). In contrast to the situation
found for the catalysis by compound 1, in the case of the
FeCl3-catalyzed oxidation the reaction is first order for
cyclohexane and no plateau was observed (Figure 6).
The initial rate dependence is depicted with bell-shape
curves for oxygenate accumulation, hydrogen peroxide
consumption and O2 evolution (Figure 7).
Figure 3. Plot of the cyclohexane oxygenate accumulation
initial rate versus initial concentration of cyclohexane (in
MeCN at 25 8C; [H2O2]0 ˆ 0.25 mol dmÀ3; [Fe(ClO4)3] ˆ 5 Â
10À4 mol dmÀ3).
of LiCl iron(III) cations can coordinate chloride anions
The efficient activation energy of the FeCl3-catalyzed
to afford the same species that are present in the solution oxidation of cyclohexane was estimated to be equal to
of FeCl3 (the oxidation catalyzed by iron chloride will be 14 kcal molÀ1 (Figure 8). As could be predicted, LiClO4
discussed in the next Section).
We also determined regioselectivity parameters for reaction rate only insignificantly (Figure 9).
the oxidations of certain higher branched alkanes. In The oxidation of methane gave methyl hydroperoxide
added to the reaction solution decreased the initial
Table 1 the parameters are summarized for the oxida- as the main product and a lesser amount of form-
tions catalyzed by the iron complexes studied in the aldehyde (Figure 10). Benzene is oxidized mainly to
present work as well as, for comparison, by certain other phenol. The dependence of the initial oxidation rate on
systems for which the mechanism is clear. It can be benzene concentration is shown in Figure 11. Propane
concluded that the selectivity parameters are similar to and isobutane can also be oxidized by the same system to
those found previously for the systems operating with afford mainly the corresponding alkyl hydroperoxides
À
generation of free hydroxyl radicals (the ™H2O2-VO3 - (Table 4). It is noteworthy that, like in the case of
PCA∫ reagent, ™H2O2-hn∫, ™H2O2-FeSO4∫).
compound 1, oxidation catalyzed by 2 is also depressed
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Georgiy B. Shul×pin et al.
Selectivity
FULL PAPERS
Table 1. Selectivity parameters in the iron-catalyzed oxidations of higher alkanes by H2O2.
Entry
Substrate
Catalyst
2,2,4-Trimethylpentane
18:28:38[a]
1: 5: 1e3(ClO
1: 7: 5e7Cl
1: 5: 1e3(OAc)
1: 2.5: 18
1: 4: 9
1: 2: 6
1: 3: 6eSO
1: 5: 50
18:28:38[a]
1: 7: 4e3(ClO
1: 8.5: 34
1: 6: 18
1: 26: 200
18:28:38[a]
1: 4: 30
1: 8: 61
1: 6: 22
1: 4: 12
1: 22: 200
trans/cis[d]
1
1
2
3
4
5
6
7
8
F
F
F
)
3
4
3 ¥ 6 H2O
2(OH) ‡ PCA
4 ‡ PCA
n-u4NVO3-PCA[b]
hn
F
4
[LMnIV(O)3MnIVL](PF6)2-MeCO2H[c]
Methylcyclohexane
3-Methylhexane
9
10
11
12
F
)
4 3
4 ‡ PCA
n-Bu4NVO3-PCA[b]
[LMnIV(O)3MnIVL](PF6)2-MeCO2H[c]
13
14
15
16
17
Fe(ClO4)3
4 ‡ PCA
n-Bu4NVO3-PCA[b]
hn
[LMnIV(O)3MnIVL](PF6)2-MeCO2H[c]
cis-Decalin
18
19
20
21
22
23
24
FeCl3 ¥ 6 H2O
Fe(OAc)2(OH) ‡ PCA
3
9
2
1.3
3.5
0.12
4 ‡ PCA
n-Bu4NVO3-PCA[b]
hn
FeSO4
[LMnIV(O)3MnIVL](PF6)2-MeCO2H[c]
trans-Decalin
trans/cis[d]
1
4.5
3
2.4
1.3
25
26
27
28
29
30
31
FeCl3 ¥ 6 H2O
Fe(OAc)2(OH) ‡ PCA
4 ‡ PCA
n-Bu4NVO3-PCA[b]
hn
FeSO4
9
33
[LMnIV(O)3MnIVL](PF6)2-MeCO2H[c]
[a]
Parameter 18:28:38 are normalized (i.e., calculated taking into account the number of hydrogen atoms at each position)
relative reactivities of hydrogen atoms at primary, secondary and tertiary carbons, respectively. The parameters were
calculated based on concentrations of isomeric alcohols formed in the reaction and were measured after the reduction of the
reaction solution with PPh3.
[b]
[c]
[d]
PCA is pyrazine-2-carboxylic acid; for this system, which oxidizes with the formation of hydroxyl radicals, see
Refs.[1b, d,24b, c,f, g,25]
L is 1,4,7-trimethyl-1,4,7-triazacyclononane; for this system, which operates without involvement of free radicals, see
Refs.[1d,24f, g,26]
This parameter is the trans/cis ratio of isomers of tert-alcohols formed in the oxidation of cis- or trans-decalins.
by the addition of PCA and for 2 this effect is even more On the other hand saturated hydrocarbons are not
strongly pronounced (Figure 12).
known to form strong complexes with iron ions. There-
fore the observed alkane oxidation induced by iron-
catalyzed hydrogen peroxide decomposition is due to an
oxidizing action of an intermediate species generated in
Comparison of Fe(ClO4)3 and FeCl3 as Generators of
Oxidizing Species. On the Mechanism of the Oxidation the course of H2O2 decomposition.
It is known[27] that catalytic decomposition of hydro-
On the one hand neither hydrogen peroxide nor iron gen peroxide with iron ions in aqueous solution occurs as
salts induce the alkane oxidation under mild conditions. an ion-radical-chain process, and the oxidation state of
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Table 2. Methane oxidation with H2O2 catalyzed by iron complexes.[a]
Entry
Catalyst [mol dmÀ3]
Time [h]
Product concentration, Â 103 (mol dmÀ3)
TON
Yield [%]
CH3OOH
CH3OH
HCHO
Fe(ClO4)3 (1 Â 10À3)
1
2
1
5.6
3.5
2.3
2.4
2.2
2.4
3[b]
7
1.4
Fe(OAc)2(OH) (1 Â 10À3)
‡ PCA (5  10À3)
3
4
5
6
2
4
6
7
0.0
0.0
0.0
0.0
9.6
19.3
24.0
25.0
1.0
1.1
4.2
5.6
31
10
5.1
1.8
Fe(OAc)2(OH) (1 Â 10À4)
‡ PCA (3.5  10À4)
7
6[c]
8.0
0.0
2.5
[a]
Conditions: methane, 90 bar; H2O2, 0.6 mol dmÀ3; 25 8C; solvent acetonitrile. Turnover number (TON) equals the number
of moles of all products per mole of a catalyst. Yields of all products are based on H2O2 introduced into the reaction.
In the analogous reaction in the absence of methane, formaldehyde (formed from acetonitrile) was detected (1.3 Â
10À3 mol dmÀ3).
[b]
[c]
In the absence of methane formaldehyde (0.8 Â 10À3 mol dmÀ3) was detected.
Table 3. Ethane oxidation with H2O2 catalyzed by iron complexes.[a]
Entry
Catalyst [mol dmÀ3]
Time [h]
Product concentration, Â 103 (mol dmÀ3)
TON
Yield [%]
CH3CH2OOH
CH3CH2OH
CH3CHO
1
2
Fe(ClO4)3 (5 Â 10À4)
3[b]
2[c]
30.0
0.4
1.0
7.8
3.2
3.3
68
12
5.7
1.9
F
2e((OOHA)c()1 Â 10À3)
‡ PCA (5  10À3)
3
F
2e((OOHA)c()1 Â 10À4)
4
2.5
4.0
1.8
8
1.4
‡ PCA (3.5  10À4)
[a]
Conditions: ethane, 27 bar; H2O2, 0.6 mol dmÀ3; 25 8C; solvent acetonitrile. Turnover number (TON) equals the number of
moles of all products per mole of a catalyst. Yields of all products are based on H2O2 introduced into the reaction.
Acetic acid was not detected.
[b]
[c]
In the absence of ethane acetaldehyde and ethanol were not detected after 3 h.
Table 4. Oxidation of light alkanes with H2O2 catalyzed by FeCl3.[a]
Entry
1
Alkane
Products (concentration  103, mol dmÀ3)
CH3CH(OOH)CH3 (5.5),
CH3CH2CHO (1.0),
CH3CH2CH2OOH (1.4),
CH3COCH3 (1.1),
TON
17
Yield [%]
1.6
Propane[a]
CH3CH2CO2H (0.3)
(CH3)3COOH (0.24),
(CH3)3COH (5.0),
2
Isobutane[b]
21
1.7
(CH3)2CCHO (5.0),
(CH3)2CCO2H (0.25)
[a]
Conditions: propane, 7 bar; H2O2, 0.05 mol dmÀ3; FeCl3, 5 Â 10À4 mol dmÀ3; solvent acetonitrile; 25 8C; 1 h. Turnover
number (TON) equals the number of moles of all products per mole of a catalyst. Yield of all products is based on H2O2
introduced into the reaction.
[b]
Conditions: isobutane, 5 bar; H2O2, 0.05 mol dmÀ3; FeCl3, 5 Â 10À4 mol dmÀ3; solvent acetonitrile; 25 8C; 1 h.
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Georgiy B. Shul×pin et al.
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Figure 7. Decomposition of H2O2 catalyzed by FeCl3 ¥ 6 H2O
(5 Â 10À4 mol dmÀ3) in MeCN at 25 8C. Plots of initial rates of
the cyclohexane oxygenates accumulation (curve 1) as well as
(in the absence of cyclohexane) of H2O2 consumption (curve
2), and O2 evolution (curve 3) versus initial H2O2 concen-
tration are shown.
Figure 5. Cyclohexane oxidation with H2O2 catalyzed by
FeCl3: plot of dependence of the oxygenate accumulation
initial rate (curve 1) and the H2O2 consumption initial rate
(curve 2) on initial FeCl3 ¥ 6 H2O concentration (at [cyclo-
hexane]0 ˆ 0.46 mol dmÀ3 and [H2O2]0 ˆ 0.05 mol dmÀ3) at
25 8C.
Figure 8. The Arrhenius plot for the cyclohexane
(0.23 mol dmÀ3) oxygenation by H2O2 (0.02 mol dmÀ3) in
MeCN catalyzed by FeCl3 (5 Â 10À4 mol dmÀ3) which corre-
sponds the activation energy Ea ˆ 14 kcal molÀ1.
Figure 6. Plot of the cyclohexane oxygenate accumulation
([FeCl3] ˆ 5  10À4 mol dmÀ3) initial rate versus initial con-
centration of cyclohexane at 25 8C (curve 1: at [H2O2]0 ˆ
0.02 mol dmÀ3; curve 2: at [H2O2]0 ˆ 0.05 mol dmÀ3).
iron ions alternates (Fe3‡ > Fe2‡). The oxidation of
Fe2‡ ion with H2O2 leads to the formation of hydroxyl
radical. The present study demonstrates that an oxidiz-
ing species generated in the H2O2-Fe(ClO4)3-CH3CN
system is the hydroxyl radical and we propose that the
.
mechanism of HO formation includes the same stages
as in aqueous solution:
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Hydrogen Peroxide Oxygenation of Alkanes
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Figure 9. Hydrogen peroxide decomposition catalyzed by
FeCl3 (5 Â 10À4 mol dmÀ3): plot of O2 evolution initial rate
versus concentration of added LiClO4 (in acetonitrile, 25 8C,
[H2O2]0 ˆ 0.05 mol dmÀ3).
Figure 11. Reaction of benzene with H2O2 (0.04 mol dmÀ3)
catalyzed by FeCl3 (5 Â 10À4 mol dmÀ3) in MeCN at 25 8C.
Graph A: accumulation of phenol with time at various initial
concentrations of benzene (mol dmÀ3). Graph B: plot of
phenol accumulation initial rate measured from data of graph
A versus initial concentration of benzene.
CH3CN system. In accordance with this proposal the
CyOOH formation rate should be proportional to the
concentrations of both H2O2 and Fe(ClO4)3. Our
experimental data (see Figures 1 and 2) support this
Figure 10. Oxidation of methane (55 bar) by H2O2 (initial
concentration 0.06 mol dmÀ3) in MeCN in the presence of proposal. The effective bimolecular rate constant of the
artificial air (1 bar) catalyzed by FeCl3 (5 Â 10À4 mol dmÀ3) at
initiation reaction with iron(III) perchlorate in acetoni-
40 8C. Curves for H2O2 consumption (1), accumulation of
trile was calculated using the rate of ROOH formation
at 25 8C and it equals to 0.24 dm3 molÀ1 sÀ1.
methyl hydroperoxide (2) and formaldehyde (3) are shown.
Concentrations of methanol were measured by GC before
and after the reduction of the reaction mixture with PPh3.
.
Radical HO can react both with alkane, RH, and
solvent, CH3CN, via routes (1) and (2):
In the presence of a substantial concentration of
cyclohexane when all hydroxyl radicals are accepted by
the alkane ([CyH] > 0.46 mol dmÀ3) the cyclohexyl
hydroperoxide formation rate corresponds to the rate
of active species initiation by the H2O2-Fe(ClO4)3-
ꢀ1†
ꢀ2†
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Georgiy B. Shul×pin et al.
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catalysts. The rate constant ratio found for Fe(ClO4)3 is
close to those calculated on the basis of radiation-
chemical measurements[25] (in more detail such a
discussion will be given below in the Section devoted
to the catalysis by complex 4). The same ratio is
noticeably higher for FeCl3.
When chloride ions (LiCl) were added to the iron(III)
perchlorate solution the complex dependence of the
reaction rate was noticed (see Figure 4). At the [LiCl]0/
[Fe(ClO4)3]0 ˆ 3 the rates of oxidations and oxygen
evolution are practically equal to the rates of processes
catalyzed by FeCl3. This influence of the LiCl additive is
due to different reactivities in the initiation of ™naked∫
Fe3‡ ion and its chloride complexes (formed in equili-
brium Fe3‡ ‡ n ClÀ > FeCln
). Data presented in
(3Àn)‡
Figure 4 show that complexes containing one and two
ClÀ ions in the iron coordination sphere exhibit the
highest activity. When the number of iron-bound
chloride ions grows (to 3 and 4) the catalyst activity
decreases. Consequently, adding ClÀ ions to the reaction
solution not only changes the process selectivity (re-
Figure 12. Accumulation of oxygenates in cyclohexane
(0.23 mol dmÀ3) oxidation with H2O2 (0.05 mol dmÀ3) cata-
lyzed by FeCl3 (5 Â 10À4 mol dmÀ3) in MeCN at 25 8C in the
absence (curve 1) and in the presence of PCA (5 Â
10À4 mol dmÀ3; curve 2).
.
placing HO by FeIV ˆ O as oxidizing species, see below)
but also increases the oxidation rate.
The observed alkane oxidation rate should depend on
the RH concentration as depicted by Eq. (3):
In the case of FeCl3 a complex mode for the rate
dependence on hydrogen peroxide concentration can be
due to the addition of water (present in 30% aqueous
H2O2) to the reaction solution. The water additive does
not practically affect the catalytic activity of iron
perchlorate, however it does decrease the correspond-
ing activity of iron chloride.
ꢀ3†
Selectivity parameters obtained in the oxidation of
branched alkanes (see Table 1) also support the con-
where Wi is the rate of the hydroxyl radical generation in clusion about different active species operating in the
this system. The alkane (cyclohexane) oxidation rate studied systems. The selectivity obtained in Fe(ClO4)3-
approaches Wi when [RH]0 grows. It follows from catalyzed oxidation is close to that determined in
Eq. (3) that a two-fold decrease of the oxidation rate hydroxyl radical-induced oxidations. The corresponding
in comparison with the maximum possible rate can be parameters for FeCl3-catalyzed oxidations are higher.
realized at the alkane (cyclohexane) concentration
determined from the condition
We have also found striking differences in selectivity
of the dec-1-ene (compound 5) oxidation according to
Scheme 2 by the two systems. The data obtained are
summarized in Table 5. It can be clearly seen that if
Fe(ClO4)3 is used as a catalyst the main product of the
dec-1-ene oxidation is (after reduction of the reaction
mixture with PPh3) the corresponding allyl alcohol 6,
À
ꢀ4†
independently of the rate and mechanism of hydroxyl which is formed by the hydroperoxidation of allylic C H
radical formation.
bonds. On the contrary, catalysis with FeCl3 gave
We have demonstrated in our kinetic experiments that predominantly the corresponding epoxide 7.
the dependence modes of the ROOH formation rate on
the cyclohexane concentration are different for cases of
Fe(ClO4)3 and FeCl3 as catalysts (compare Figure 3 and
Figure 6). We found a curve with a plateau in the first
case whereas only linear dependency can be noted for
the second catalyst in the same concentration interval.
This difference means that the ratios between rate
constants for the CH3CN and RH oxidations are differ-
ent for the cases of Fe(ClO4)3 and FeCl3, and conse-
quently that oxidizing species are different for the two Scheme 2.
324
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Hydrogen Peroxide Oxygenation of Alkanes
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Table 5. Dec-1-ene (5) oxidation by hydrogen peroxide catalyzed by iron(III) salts.[a]
Entry
Reaction time
[min]
1,2-Epoxydecane (6)
concentration
3-Hydroxydec-1-ene (7)
concentration
Product 6/7 ratio
[Â103 mol dmÀ3]
[Â103 mol dmÀ3]
Catalyst Fe(ClO4)3
1
2
0.5
1.0
0.13
0.20
0.33
0.70
0.39
0.29
Catalyst FeCl3
3
4
0.5
1.0
1.04
2.10
0.22
0.40
4.72
5.25
[a]
Product concentrations were measured after reduction of the reaction solution with triphenylphosphine. Reaction
conditions: dec-1-ene, 0.4 mol dmÀ3; catalyst, 5 Â 10À4 mol dmÀ3; hydrogen peroxide, 0.25 mol dmÀ3 (entries 1 and 2),
0.05 mol dmÀ3 (entries 3 and 4); 25 8C.
For the two systems based on Fe(ClO4)3 and FeCl3 the number of these ligands in the iron ion coordination
modes of dependency of the initial rate on the initial sphere) in accordance with Eqs. (5) and (6) depends on
hydrogen peroxide concentration are distinct (compare the composition of this coordination sphere. If so, the
Figure 1, curve 1 and Figure 7, curve 1). We assume that less water there is in the coordination sphere of the
this situation is a result of a competition between chloride complex the higher is the yield of species
chloride anion, hydrogen peroxide and water for the site Fe(Li)O2‡, which is confirmed by our experimental data.
at coordination sphere of iron ion. The composition of In the reaction with a perchlorate complex containing
this sphere affects the reactivity of a formed species. water, the one-electron channel, Eq. (5), is a predom-
Changes of the hydrogen peroxide concentration in the inant route.
system lead simultaneously to the corresponding
changes of water content because we use 30% or 35%
aqueous solutions of H2O2. In the case of FeCl3 a
complex mode for the rate dependence on hydrogen
peroxide concentration can be due to the addition of
water to the reaction solution. The water additive does
ꢀ5†
ꢀ6†
not practically affect the catalytic activity of iron An alternative route of the formation of various
perchlorate, however it does decrease the correspond- oxidizing species can be the following. The first stage
ing activity of iron chloride. Complexes containing in the of the oxidation of Fe2‡(Li)j species proceeds as the
coordination sphere both H2O and ClÀ exhibit less transfer of two electrons. However, in the absence of the
reactivity in comparison with complexes which do not chloride ion and a substantial amount of water the
contain water molecule. It can be thus concluded that following transformation occurs:
ClÀ additive activates the perchlorate iron derivative in
acetonitrile whereas the water additive inactivates
chloride complexes in the H2O2 decomposition process.
ꢀ7†
As was mentioned above all the data obtained testify
that in the case of Fe(ClO4)3 as a catalyst the properties The rate constant of reaction (7) governs the life time of
of the oxidizing species are close to those of hydroxyl Fe(Li)jO2‡ species and consequently the probability of
radical. In these experiments the chloride anion was alkane oxidation either by this species or by hydroxyl
absent and concentrations of hydrogen peroxide and radical. In this process the increase of water content will
water were 0.25 and 1.0 mol dmÀ3, respectively. When lead to a decrease in the selectivity.
FeCl3 was used as a catalyst ([H2O2]0 ˆ 0.05 mol dmÀ3
and [H2O] ˆ 0.2 mol dmÀ3) the experimental data
showed that the oxidation was induced by a more Iron(III) Acetate as a Catalyst
selective and less reactive species. One can assume that
this species is the ion of iron(IV), for example, in the We obtained some preliminary results on the catalysis
form of ferryl ion, FeIV ˆ O.
by iron(III) acetate existing in the form of Fe(OAc)2
Different oxidizing species can be generated via (OH) (3). Surprisingly, it turned out that compound 3
several routes. It is probable that the ratio of one- catalyzes the alkane oxidation only if PCA is added as a
electron, Eq. (5), and two-electron, Eq. (6), channels of co-catalyst (Figure 13). The initial reaction rate and the
the H2O2 oxidation of complex Fe2‡(Li)j (where Li are final yield of products grow with increases of the PCA
various ligands, for example, ClÀ, H2O2, H2O, and j is concentration. Selectivity parameters of branched al-
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Georgiy B. Shul×pin et al.
FULL PAPERS
kane oxidations under catalysis by Fe(OAc)2(OH)-PCA
system are low (see Table 1) and we can conclude that
the reaction proceeds with participation of hydroxyl
radicals. This system oxidizes also methane (TONs were
up to 31; see Table 2, entry 6) and ethane (see Table 3,
entries 2 and 3).
Oxidation Catalyzed by a Binuclear Iron(III) Complex
Containing 1,4,7-Triazacyclononane
Finally, we studied the catalytic action of the binuclear
iron(III) complex 4 containing the 1,4,7-triazacyclono-
nane ligand.[28] Complex 4 turned out to be almost
inactive as a catalyst in the cyclohexane oxidation with
H2O2 at room temperature. However, the addition of a
comparatively small amount of PCA to the reaction
solution caused intense alkane oxidation (Figure 14).
The primary reaction product was cyclohexyl hydro-
peroxide, which decomposed during the reaction to
produce the corresponding cyclohexanone and cyclo-
hexanol. Total TON attained was 240 after 24 h. In
kinetic measurements we determined only the concen-
trations of the ketone and the alcohol after the reduction
with triphenylphosphine.
Figure 14. Cyclohexane (0.46 mol dmÀ3) oxidation by H2O2
(0.59 mol dmÀ3) catalyzed by 4 (2.5 Â 10À4 mol dm3) in the
absence (curves a) and in the presence of PCA (25 Â
10À4 mol dmÀ3; curves b) in MeCN at 25 8C. Accumulation
of cyclohexanol (curves 1) and cyclohexanone (curves 2)
(concentrations were measured after the reduction with
PPh3) are shown.
The binuclear complex 4 induced catalytic decom-
position of hydrogen peroxide dissolved in acetonitrile.
The reaction was accompanied by molecular oxygen with the formation of the corresponding alkyl hydro-
evolution (catalase activity) and the oxidation of alkane peroxide (oxidase activity). The data on the selectivity
of the oxidation of several branched hydrocarbons are
summarized in Table 1, which also contains the selec-
tivity parameters of other systems capable of oxidizing
alkanes via various mechanisms. The values presented in
Table 1 show that the principle species that induces the
alkane oxidation under catalysis by the ™4 ‡ PCA∫
system is the hydroxyl radical possessing low selectivity.
It is necessary to note, however, that the selectivity
parameters for the ™4 ‡ PCA∫ system are somewhat
higher than for other systems, whose oxidation action
doubtless involves hydroxyl radicals. This leads us to
suggest that the ™4 ‡ PCA∫ system generates not only
low-selective hydroxyl radicals but also, in another
channel, other species that more selectively interact
with alkanes, for instance, ferryl species. Nevertheless,
the reaction involving hydroxyl radicals predominates.
This conclusion is also substantiated by our estimates of
the oxidizing species reactivity in the ™4 ‡ PCA∫ system.
These estimates were obtained in two series of
experiments. In the first one, we studied the dependence
of the initial rate of cyclohexane oxidation determined
as rate W0 of the cyclohexyl hydroperoxide, CyOOH,
formation on the initial cyclohexane concentration
under UV (l ꢁ 253 nm) irradiation of its solution in
acetonitrile in the presence of hydrogen peroxide
(Figure 15A, curve 1). It is known that the photolysis
of H2O2 is accompanied by its decomposition to
generate hydroxyl radicals:
Figure 13. Cyclohexane (0.46 mol dmÀ3) oxidation by H2O2
(0.1 mol dmÀ3) catalyzed by Fe(OAc)2(OH) (5 Â 10À4 mol
dmÀ3) in MeCN at 25 8C. Kinetic curves for accumulation of
the oxygenates at various concentrations of added PCA (in
mol dmÀ3) are shown.
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Hydrogen Peroxide Oxygenation of Alkanes
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ꢀ8†
ꢀ10†
Taking these transformations into account, the conclu-
sion can be drawn that an increase in the CyH concen-
tration should cause an increase in the rate of its
oxidation whose limiting value corresponds to rate W8 of
hydroxyl radical formation in reaction (8). An analysis
of kinetic scheme (8) to (10) leads to Eq. (11) for the
initial stationary rate of CyOOH formation:
As neither acetonitrile nor cyclohexane absorb in the
specified spectral region, it is reasonable to assume that
the cyclohexane oxidation observed in the photochem-
ical experiments is induced by hydroxyl radicals and
occurs in accordance with Eqs. (9) and (10):
ꢀ9†
ꢀ11†
where k9 and k10 are the rate constants for reactions (9)
and (10), respectively. An analysis of the experimental
dependence of W0 on [CyH]0 taking into account
Eq. (11) (Figure 15A, straight line 2) gives the ratio
k10/k9 ˆ 0.013.
The second series of experiments were carried out to
study the dependence of CyOOH initial rate formation
W0 on [CyH]0 when hydrogen peroxide decomposition
was catalyzed by complex 4 (Figure 15B, curve 1). We
assume that hydroxyl radicals are formed in the rate-
determining step of this reaction at a rate equal to the
rate of cyclohexane oxidation. This assumption leads us
to an equation identical to (11). The ratio between the
rate constants obtained in these experiments, k10/k9 ˆ
0.011 (Figure 15B, straight line 2), is very close to that
measured in the photochemical experiments (0.013) and
to the value determined from radiation-chemical meas-
urements (k10/k9 ˆ 0.012). It follows that the cyclohex-
ane oxidation during the hydrogen peroxide decompo-
sition catalyzed by complex 4 is doubtless induced by
hydroxyl radicals. Note that the classic chain mechanism
of induced cyclohexane oxidation at rates equal to those
observed experimentally is impossible at room temper-
ature because of the low reactivity of cyclohexyl peroxyl
radicals and, therefore, a low parameter of hydrocarbon
oxidizability by the chain mechanism (see the Electronic
Supplement to Ref.[25]).
It is important to note that molecular oxygen evolu-
tion is observed even at a high cyclohexane concen-
tration, when all hydroxyl radicals are certainly accept-
ed by the hydrocarbon. This is evidence that hydroxyl
radicals do not participate in the hydrogen peroxide
decomposition to afford molecular oxygen and water.
We must therefore consider two parallel hydroperoxide
decomposition processes: those with and without the
participation of hydroxyl radicals.
We studied the kinetics of cyclohexyl hydroperoxide
formation and molecular oxygen evolution to elucidate
the details of the reaction mechanism. First, it was
established that both the rate of CyOOH formation and
the rate of O2 evolution were directly proportional to the
complex 4×s initial concentration if PCAwas present in a
Figure 15. Cyclohexane oxidation by H2O2 (0.59 mol dmÀ3)
induced by UV irradiation (graph A) and catalyzed by the ™4
(2.5  10À4 mol dmÀ3) ‡ PCA (25  10À4 mol dmÀ3)∫ system
(graph B) in MeCN at 25 8C. Dependence of the initial
oxidation rate, WROOH, on the initial cyclohexane concen-
tration (curve 1) as well as its linear anamorphosis (curve 2)
are shown for both cases.
Adv. Synth. Catal. 2004, 346, 317 332
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Georgiy B. Shul×pin et al.
FULL PAPERS
more than five-fold excess with respect to [4]. This led us
to suggest that the rate-limiting steps of these processes
occurred with the participation of non-aggregated initial
catalyst molecules.
The dependence of the CyOOH formation initial rate
on [4] is shown in Figure 16. Its mode indicates the
catalytic activity of adducts containing only one PCA
molecule. Adducts containing more than one or no PCA
molecules do not exhibit catalytic activity. Accordingly,
the following transformations should be taken into
account in considering the reaction mechanism:
ꢀ12†
ꢀ13†
The catalytic activity of the whole system should be
attributed to the formation of the 4 ¥ PCA adduct. The
CyOOH formation initial rate depended on the initial
concentration of hydrogen peroxide in a complex way
(Figure 17). Initially, the process was close to second
order in hydrogen peroxide, and, at [H2O2]0 >
1 mol dmÀ3, the reaction rate ceased to depend on
hydrogen peroxide concentration. Such a character of
the dependence was evidence of an iron diperoxo
complex×s participation at the stage of hydroxyl radical
generation.
Taking into account the formation of mono- and
diperoxo complexes and assuming that the rate-deter-
mining step of hydroxyl radical formation is monomo-
lecular decomposition of the diperoxo complex con-
taining one PCA molecule as a ligand, reactions (12)
and (13) should be augmented by the following steps:
Figure 16. Cyclohexane (0.46 mol dmÀ3) oxidation by H2O2
(0.59 mol dmÀ3) catalyzed by the ™4 (2.5  10À4 mol dmÀ3) ‡
PCA∫ system in MeCN at 25 8C. Graph A: accumulation of
cyclohexanol (curves 1) and cyclohexanone (curves 2) (con-
centrations were measured after the reduction with PPh3) at
different concentrations (in mol dmÀ3) of added PCA: 25 Â
10À4 (curves a) and 75 Â 10À4 (curves b). Graph B: depend-
ence of the initial cyclohexane oxidation rate, WROOH, (curve
1) and of simultaneous O2 evolution (curve 2) on the
concentration of added PCA. The simulated curve for WROOH
ꢀ14†
ꢀ15†
Eq. (17) satisfactorily describes the experimental data
shown in Figures 16 and 17 at the following constant
parameters: k16 ˆ 0.13 sÀ1, K12 ˆ 16 dm3 molÀ1, K13 ˆ
6250 dm3 molÀ1, K14 ˆ 12.5 dm3 molÀ1 and K15 ˆ
ꢀ16†
If we assume that the concentrations of the 4 ¥ PCA, 4 ¥ 2 10 dm3 molÀ1 (compare the experimental and simulated
PCA, 4 ¥ PCA ¥ H2O2 and 4 ¥ PCA ¥ 2 H2O2 intermediate curves in Figures 16 and 17). The mode of the depend-
complexes are quasi-equilibrium, then, at a high CyH ence of the molecular oxygen evolution rate on [PCA] is
concentration when all hydroxyl radicals formed in identical to that of the dependence of d[CyOOH]/dt on
reaction (16) interact with cyclohexane and at [PCA]0/ [PCA]. It follows that the same intermediate complex
[4]0 ꢁ 5, the suggested kinetic scheme can be used to participates in the rate-limiting steps of both processes,
obtain the equation for the stationary rate of CyOOH namely, the diperoxo derivative of compound 4 con-
formation:
taining one PCA molecule, 4 ¥ PCA ¥ 2 H2O2. The dioxy-
ꢀ17†
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Hydrogen Peroxide Oxygenation of Alkanes
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peroxide (Fluka) was added to the solution of the catalyst, co-
catalyst and substrate in acetonitrile (Fluka, distilled over P2O5
before the reaction).
The oxidations of light alkanes (ethane and methane) were
carried out in a Pyrex inlet tube placed in an stainless steel
autoclave with intensive stirring (volume of the reaction
solution was 1 mL and total volume of autoclave was
100 mL). The autoclave was charged with air (under atmos-
pheric pressure) and then, consecutively, with the reaction
solution containing the catalyst and co-catalyst in acetonitrile
and the alkane to the appropriate pressure. The reaction
solutions were analyzed by GC (instruments: LKhM-80-6,
columns 2 m with 5% Carbowax 1500 on 0.25 0.315 mm
Inerton AW-HMDS; carrier gas was argon and DANI-86.10,
capillary column 50 m  0.25 mm  0.25 mm, Carbowax 20M;
integrator SP-4400; the carrier gas was helium). Usually
samples were analyzed twice, i.e., before and after the addition
of the excess of solid PPh3. This method was proposed by us
earlier.[1d,24] Since alkyl hydroperoxides, which are transformed
in the GC injector into a mixture of the corresponding ketone
and alcohol, are quantitatively reduced with PPh3 to give the
corresponding alcohol, this method allows us to calculate the
real concentrations not only of the hydroperoxide but of the
alcohols and ketones present in the solution at a given moment.
Authentic samples of all oxygenated products were used to
attribute the peaks in chromatograms (comparison of reten-
tion times was carriedout for different regimes of GC analysis).
In experiments involving molecular oxygen evolution, the
volume of dioxygen evolved was measured using a thermo-
statted burette. The reaction system was connected to a
manometric burette with water which was saturated with
oxygen prior to use. After certain time intervals, the pressure
was equilibrated using a separation funnel by adjusting the
water level to the same heights.
Figure 17. Cyclohexane (0.46 mol dmÀ3) oxidation by H2O2
catalyzed by the ™4 (2.5  10À4 mol dmÀ3) ‡ PCA (25 Â
10À4 mol dmÀ3)∫ system in MeCN at 25 0C. Dependence of
the initial cyclohexane oxidation rate, WROOH, on the initial
concentration of hydrogen peroxide is shown. The simulated
curve for WROOH is dashed.
gen evolution can occur in the decomposition of this
derivative:
ꢀ18†
This process is similar to the decomposition of hydrogen
peroxide by enzyme catalase. The competition of
reactions (16) and (18) is likely to be caused by the
binuclear structure of compound 4.
Acknowledgements
We thank the Russian Basic Research Foundation (grant No. 98-
03-32015a) and the Swiss National Science Foundation (grant
No. 20 64832.01) for support. The authors are indebted to Prof.
Karl Wieghardt for useful discussions.
Conclusion
Our study shows that ligand environment of iron ions
plays a very important role from the point of view of the
reaction mechanism. For example, addition of chloride
anions to the ™naked∫ iron(III) cation switches the
reaction mechanism from that occurring with formation
of hydroxyl radicals to another mechanism which
operates predominantly with participation of ferryl
species. It is interesting that, in contrast to iron chloride
case, the oxidation catalyzed by a dinuclear complex
containing chelating N3-ligands proceeds via hydroxyl
radicals.
References and Notes
[1] Reviews and books on Fe-induced oxidations: a) A. Ya.
Sychev, V. G. Isak, Uspekhi Khimii 1995, 64, 1183 1208;
b) A. E. Shilov, G. B. Shul×pin, Chem. Rev. 1997, 97,
2879 2932; c) E. K. van den Beuken, B. L. Feringa,
Tetrahedron 1998, 54, 12985 13011; d) A. E. Shilov,
G. B. Shul×pin, Activation and Catalytic Reactions of
Saturated Hydrocarbons in the Presence of Metal Com-
plexes, Kluwer Academic Publishers, Dordrecht, Boston,
Experimental Section
London, 2000, Chapter
X (Homogeneous catalytic
oxidation of hydrocarbons by peroxides and other oxy-
gen atom donors), pp. 430 465; e) G. Tachiev, J. A.
Roth, A. R. Bowers, Int. J. Chem. Kinet. 2000, 32, 24 35;
f) Y. Ishii, S. Sakaguchi, T. Iwahama, Adv. Synth. Catal.
2001, 343, 393 427; g) F. Gozzo, J. Mol. Catal. A: Chem.
2001, 171, 1 22; h) K. Otsuka, Y. Wang, Appl. Catal. A:
Synthesis and properties of compound 4 were published
previously in the literature.[28a]
The oxidations of higher hydrocarbons were carried out in
air in thermostatted Pyrex cylindrical vessels with vigorous
stirring. The total volume of the reaction solution was 0.5
5 mL. Initially, a portion of 35% aqueous solution of hydrogen
Adv. Synth. Catal. 2004, 346, 317 332
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Georgiy B. Shul×pin et al.
FULL PAPERS
General 2001, 222, 145 161; i) H. Fujii, Coord. Chem.
Rev. 2002, 226, 51 60; j) H. B. Dunford, Coord. Chem.
Rev. 2002, 233 234, 311 318.
2003, 34, 531 545; g) M. D. Engelmann, R. T. Bobier, T.
Hiatt, I. F. Cheng, Biometals 2003, 16, 519 527; h) P. C.
Cirino, F. H. Arnold, Angew. Chem. Int. Ed. 2003, 42,
3299 3301; i) A. Bassan, M. R. A. Blomberg, P. E. M.
Siegbahn, Chem. Eur. J. 2003, 9, 4055 4067; j) T.
Kamachi, K. Yoshizawa, J. Am. Chem. Soc. 2003, 125,
4652 4661; k) T. L. Foster, J. P. Caradonna, J. Am.
Chem. Soc. 2003, 125, 3678 3679; l) S. Jin, T. M. Makris,
T. A. Bryson, S. G. Sligar, J. H. Dawson, J. Am. Chem.
Soc. 2003, 125, 3406 3407; m) P. K. Sharma, S. P. de -
Visser, F. Ogliaro, S. Shaik, J. Am. Chem. Soc. 2003, 125,
2291 2300; n) M. Newcomb, D. Aebisher, R. Shen,
R. E. P. Chandrasena, P. F. Hollenberg, M. J. Coon, J.
Am. Chem. Soc. 2003, 125, 6064 6065.
[2] Recent original publications on Fe-induced oxidations:
a) S. Yamaki, S. Kobayashi, E. Kotani, S. Tobinaga,
Chem. Pharm. Bull. 1990, 38, 1501 1503; b) T. Briffaud,
C. Larpent, H. Patin, J. Chem. Soc. Chem. Commun.
1990, 1193 1194; c) N. Mizuno, Y. Seki, Y. Nishiyama, I.
Kiyoto, M. Misono, J. Catal. 1999, 184, 550 552;
d) W. A. Carvalho, M. Wallau, U. Schuchardt, J. Mol.
Catal. A: Chem. 1999, 144, 91 99; e) A. Ventura, G.
Jacquet, V. Camel, A. Bermond, J. Adv. Oxid. Tech. 2002,
5, 113 120; f) G. V. Nizova, B. Krebs, G. S¸ss-Fink, S.
Schindler, L. Westerheide, L. Gonzalez Cuervo, G. B.
Shul×pin, Tetrahedron 2002, 58, 9231 9237; g) M. D.
Gurol , S. S. Lin, J. Adv. Oxid. Tech. 2002, 5, 147 154;
h) K. Barbusinski, J. Majewski, Pol. J. Environ. Stud.
2003, 12, 151 155; i) M. E. Lindsey, G. X. Xu, J. Lu,
M. A. Tarr, Sci. Total Environ. 2003, 307, 215 229; j) J.
Bergendahl, S. Hubbard, D. Grasso, J. Hazard. Materials
[5] a) D. H. R. Barton, D. K. Taylor, Izvest. Akad. Nauk, Ser.
Khim. 1995, 595 604; b) D. H. R. Barton, Tetrahedron
1998, 54, 5805 5817; c) D. H. R. Barton, F. Launay,
Tetrahedron 1998, 54, 12699 12706.
[6] a) D. T. Sawyer, L. Spencer, H. Sugimoto, Isr. J. Chem.
1987/88, 28, 3 12; b) A. Sobkowiak, H.-C. Tung, D. T.
Sawyer, Progr. Inorg. Chem. 1992, 31, 291 352; c) H.-C.
Tung, C. Kang, D. T. Sawyer, J. Am. Chem. Soc. 1992,
114, 3445 3455; d) C. Kang, A. Sobkowiak, D. T.
Sawyer, Inorg. Chem. 1994, 33, 79 82; e) D. T. Sawyer,
A. Sobkowiak, T. Matsushita, Acc. Chem. Res. 1996, 29,
409 416; f) D. T. Sawyer, Coord. Chem. Rev. 1997, 165,
297 313; g) C. Walling, Acc. Chem. Res. 1998, 31, 155
157; h) P. A. MacFaul, D. D. M. Wayner, K. U. Ingold,
Acc. Chem. Res. 1998, 31, 159 162; i) D. T. Sawyer, J.
Porphyrins Phthalocyanins. 2001, 5, 889 894.
[7] a) G. Roelfes, M. Lubben, S. W. Leppard, E. P. Schudde,
R. M. Hermant, R. Hage, E. C. Wilkinson, L. Que Jr.,
B. L. Feringa, J. Mol. Catal. A: Chem. 1997, 117, 223
227; b) G. Roelfes, M. Lubben, R. Hage, L. Que, Jr., B. L.
Feringa, Chem. Eur. J. 2000, 6, 2152 2159; c) G. Roelfes,
V. Vrajmasu, K. Chen, R. Y. N. Ho, J.-U. Rohde, C.
Zondervan, R. M. la Crois, E. P. Schudde, M. Lutz, A. L.
Spek, R. Hage, B. L. Feringa, E. M¸nck, L. Que Jr.,
Inorg. Chem. 2003, 42, 2639 2653.
¬
2003, 99, 43 56; k) E. Balogh-Hergovich, G. Speier, M.
¬
¬
Reglier, M. Giorgi, E. Kuzmann, A. Vertes, Eur. J. Inorg.
Chem. 2003, 1735 1740; l) V. Balland, F. Banse, E.
¬ ¡
Anxolabehere-Mallart, M. Nierlich, J.-J. Girerd, Eur. J.
Inorg. Chem. 2003, 2529 2535; m) D. Bianchi, M.
Bertoli, R. Tassinari, M. Ricci, R. Vignola, J. Mol. Catal.
A: Chem. 2003, 200, 111 116, 204 205, 419 424; n) F.
Buda, B. Ensing, M. C. M. Gribnau, E. J. Baerends,
Chem. Eur. J. 2003, 9, 3436 3444; o) S. Mukhopadhyay,
A. T. Bell, Angew. Chem. Int. Ed. 2003, 42, 2990 2993;
p) M. N. Kopylovich, A. M. Kirillov, A. K. Baev, A. J. L.
Pombeiro, J. Mol. Catal. A: Chem. 2003, 206, 163 178.
[3] Reviews and books on Fe-catalyzed oxidations in living
cells and biomimetic systems: a) M. Fontecave, S.
¬
Menage, C. Duboc-Toia, Coord. Chem. Rev. 1998,
178 180, 1555 1572; b) A. E. Shilov, G. B. Shul×pin,
Activation and Catalytic Reactions of Saturated Hydro-
carbons in the Presence of Metal Complexes, Kluwer
Academic Publishers, Dordrecht, Boston, London, 2000,
Chapter XI (Oxidation in living cells and its chemical
models), pp. 466 522; c) M. Newcomb, P. H. Toy, Acc.
Chem. Res. 2000, 33, 449 455; d) L. Que, Jr., W. B.
Tolman, Angew. Chem. Int. Ed. 2002, 41, 1114 1137;
e) A. A. Shteinman, Russ. Chem. Bull. 2001, 50, 1795
1810; f) M. J. Burkitt, Progr. React. Kinet. Mech. 2003, 28,
75 103; g) M.-H. Baik, M. Newcomb, R. A. Friesner,
S. J. Lippard, Chem. Rev. 2003, 103, 2385 2419.
[8] a) R. M. Buchanan, S. Chen, J. F. Richardson, M. Bres-
san, L. Forti, A. Morvillo, R. H. Fish, Inorg. Chem. 1994,
33, 3208 3209; b) K. Neimann, R. Neumann, A. Rabion,
R. M. Buchanan, R. H. Fish, Inorg. Chem. 1999, 38,
3575 3580.
¬
[9] a) S. Menage, J. M. Vincent, C. Lambeaux, M. Fontecave,
J. Chem. Soc. Dalton Trans. 1994, 2081 2084; b) J. M.
¬
Vincent, S. Menage, C. Lambeaux, M. Fontecave,
[4] Recent original publications on Fe-catalyzed oxidations
in living cells and chemical models: a) N. Zhang, F. Li,
Q. J. Fu, S. C. Tsang, React. Kinet. Catal. Lett. 2000, 71,
393 404; b) E. T. Farinas, U. Schwaneberg, A. Glieder,
F. H. Arnold,Adv. Synth. Catal. 2001, 343, 601 606; c) T.
Miura, S. Muraoka, Y. Fujimoto, Biochem. Pharmacol.
2002, 63, 2069 2074; d) A. Wada, S. Ogo, S. Nagatomo,
T. Kitagawa, Y. Watanabe, K. Jitsukawa, H. Masuda,
Inorg. Chem. 2002, 41, 616 618; e) M. J. J. Hooiveld, G.
Roosendaal, H. M. van den Berg, J. W. J. Bijlsma,
F. P. J. G. Lafeber, Rheumatology 2003, 42, 784 790;
f) S. Herold, F. J. K. Rehmann, Free Rad. Biol. Med.
¬
Tetrahedron Lett. 1994, 35, 6287 6290; c) S. Menage,
J. M. Vincent, C. Lambeaux, M. Fontecave, J. Mol. Catal.
A: Chem. 1996, 113, 61 75.
[10] a) J. T. Groves, J. Porphyrins Phthalocyanins. 2000, 4,
350 352; b) R. N. Austin, H.-K. Chang, G. J. Zylstra,
J. T. Groves, J. Am. Chem. Soc. 2000, 122, 11747 11748.
[11] a) D. Lee, S. J. Lippard, Inorg. Chem. 2002, 41, 827 837;
b) V. Guallar, B. F. Gherman, W. H. Miller, S. J. Lippard,
R. A. Frieser, J. Am. Chem. Soc. 2002, 124, 3377 3384;
c) M.-H. Baik, B. F. Gherman, R. A. Friesner, S. J.
Lippard, J. Am. Chem. Soc. 2002, 124, 14608 14615;
330
¹ 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
asc.wiley-vch.de
Adv. Synth. Catal. 2004, 346, 317 332

Hydrogen Peroxide Oxygenation of Alkanes
FULL PAPERS
d) M. Wirstam, S. J. Lippard, R. A. Friesner, J. Am.
Chem. Soc. 2003, 125, 3980 3987.
f) G. B. Shul×pin, G. V. Nizova, Mendeleev Commun.
1995, 143 145; g) G. B. Shul×pin, G. V. Nizova, Yu. N.
Kozlov, New J. Chem. 1996, 20, 1243 1256; h) J.
Bernadou, B. Meunier, Chem. Commun. 1998, 2167
2173; i) S. Goldstein, D. Meyerstein, Acc. Chem. Res.
1999, 32, 547 550; j) R. Weiss, V. Bulach, A. Gold, J.
Terner, A. X. Trautwein, J. Biol. Inorg. Chem. 2001, 6,
831 845; k) R. A. Ghiladi, R. M. Kretzer, I. Guzei, A. L.
Rheingold, Y.-M. Neuhold, K. R. Hatwell, A. D. Zuber-
b¸hler, K. D. Karlin, Inorg. Chem. 2001, 40, 5754 5767;
l) U. Schuchardt, M. J. D. M. Jannini, D. T. Richens,
[12] a) J.-F. Bartoli, K. Le Barch, M. Palacio, P. Battioni, D.
Mansuy, Chem. Commun. 2001, 1718 1719; b) J.-F.
Bartoli, F. Lambert, I. Morgenstern-Badarau, P. Battioni,
D. Mansuy, Comptes Rendus Chimie 2002, 5, 263 266.
[13] a) R. J. Guajardo, P. K. Mascharak, Inorg. Chem. 1995,
34, 802 808; b) C. Nguen, R. J. Guajardo, P. K. Ma-
scharak, Inorg. Chem. 1996, 35, 6273 6281.
¬
[14] a) Y. Mekmouche, C. Duboc-Toia, S. Menage, C. Lam-
beaux, M. Fontecave, J. Mol. Catal. A: Chem. 2000, 156,
¬
¬
M. C. Guerreiro, E. V. Spinace, Tetrahedron 2001, 57,
85 89; b) Y. Mekmouche, S. Menage, C. Duboc-Toia, M.
¬
Fontecave, J.-B. Galey, C. Lebrun, J. Pecaut, Angew.
¬ ¬
2685 2688; m) A. Hazell, C. J. McKenzie, L. P. Nielsen,
S. Schindler, M. Weitzer, J. Chem. Soc. Dalton Trans.
2002, 310 317; n) B. Ensing, F. Buda, P. E. Blochl, E. J.
Baerends, Phys. Chem. Chem. Phys. 2002, 4, 3619 3627;
o) D. G. Musaev, H. Basch, K. Morokuma, J. Am. Chem.
Soc. 2002, 124, 4135 4148; p) S. P. de Visser, F. Ogliaro,
P. K. Sharma, S. Shaik, J. Am. Chem. Soc. 2002, 124,
11809 1126; q) N. Suzuki, T. Higuchi, T. Nagano, J. Am.
Chem. Soc. 2002, 124, 9622 9628; r) C. Veeger, J. Inorg.
Biochem. 2002, 91, 35 45; s) J. C. Price, E. W. Barr, B.
Tirupati, J. M. Bollinger, C. Krebs, Biochemistry 2003,
42, 7497 7508; t) T. K. Saha, S. Karmaker, K. Tamagake,
Luminiscence 2003, 18, 162 172.
Chem. Int. Ed. 2001, 40, 949 952; c) A. Breheret, C.
¬
¬
Lambeaux, S. Menage, M. Fontecave, F. Dallemer, E.
Fache, J.-L. Pierre, P. Chautemps, M.-T. Averbusch-
Pouchot, Comptes Rendus Chimie 2001, 4, 27 34.
[15] a) W. Nam, H. J. Han, S.-Y. Oh, Y. J. Lee, M.-H. Choi, S.-
Y. Han, C. Kim, S. K. Woo, W. Shin, J. Am. Chem. Soc.
2000, 122, 8677 8684; b) W. Nam, M. H. Lim, S. K.
Moon, C. Kim, J. Am. Chem. Soc. 2000, 122, 10805
10809.
[16] M. Newcomb, R. Shen, S.-Y. Choi, P. H. Toy, P. F.
Hollenberg, A. D. N. Vaz, M. J. Coon, J. Am. Chem.
Soc. 2000, 122, 2677 2688.
[23] a) Yu. N. Kozlov, L. Gonzalez Cuervo, G. S¸ss-Fink,
G. B. Shul×pin, Russ. J. Phys. Chem. 2003, 77, 575 579;
b) Yu. N. Kozlov, G. V. Nizova, G. B. Shul×pin, Russ. J.
Phys. Chem. 2004, 78, in press.
[17] a) S. Ito, T. Okuno, H. Matsushima, T. Tokii, Y. Nishida,
J. Chem. Soc. Dalton Trans. 1996, 4037 4039, 4479
4484; b) T. Okuno, S. Ito, S. Ohba, Y. Nishida, J. Chem.
Soc. Dalton Trans. 1997, 3547 3551; c) S. Nishino, H.
Hosomi, S. Ohba, H. Matsushima, T. Tokii, Y. Nishida, J.
Chem. Soc. Dalton Trans. 1999, 1509 1413.
[18] a) K. Chen, L. Que, Jr., J. Am. Chem. Soc. 2001, 123,
6327 6337; b) M. Costas, L. Que, Jr. Angew. Chem. Int.
Ed. 2002, 41, 2179 2181; c) J. Kaizer, M. Costas, L. Que,
Jr., Angew. Chem. Int. Ed. 2003, 42, 3671 3673; d) M. P.
Jensen, S. J. Lange, M. P. Mehn, E. L. Que, L. Que, Jr., J.
Am. Chem. Soc. 2003, 125, 2113 2128; e) M. P. Mehn, K.
Fujisawa, E. L. Hegg, L. Que, Jr., J. Am. Chem. Soc.
2003, 125, 7828 7842; f) M. Fujita, M. Costas, L. Que,
Jr., J. Am. Chem. Soc. 2003, 125, 9912 9913.
[19] a) V. S. Belova, A. M. Khenkin, A. E. Shilov, Kinet.
Katal. 1988, 29, 1279; b) A. A. Shteinman, Mendeleev
Commun. 1992, 155 157; c) A. E. Shilov, A. A. Shtein-
man, Acc. Chem. Res. 1999, 32, 763 771.
[20] a) J. Ploszynska, J. Kowalski, A. Sobkowiak, Pol. J.
Chem. 1998, 72, 2514 2516; b) A. Sobkowiak, D. Narog,
D. T. Sawyer, J. Mol. Catal. A: Chem. 2000, 159, 247
256; c) J. Kowalski, J. Ploszynska, A. Sobkowiak, Catal.
[24] a) G. B. Shul×pin, A. N. Druzhinina, React. Kinet. Catal.
Lett. 1992, 48, 333 338; b) G. B. Shul×pin, G. V. Nizova,
React. Kinet. Catal. Lett. 1992, 47, 207 211; c) G. B.
Shul×pin, D. Attanasio, L. Suber, J. Catal. 1993, 142,
147 152; d) G. B. Shul×pin, M. M. Bochkova, G. V.
Nizova, J. Chem. Soc. Perkin Trans. 2 1995, 1465 1469;
e) G. B. Shul×pin, ™Alkane oxidation: estimation of alkyl
hydroperoxide content by GC analysis of the reaction
solution samples before and after reduction with triphe-
nylphosphine∫, The Chemistry Preprint Server, http://
preprint.chemweb.com/orgchem/0106001, 2001, pp. 1 6;
f) G. B. Shul×pin, J. Mol. Catal. A: Chem. 2002, 189, 39
66; g) G. B. Shul×pin, Comptes Rendus Chimie 2003, 6,
163 178.
[25] G. B. Shul×pin, Yu. N. Kozlov, G. V. Nizova, G. S¸ss-Fink,
S. Stanislas, A. Kitaygorodskiy, V. S. Kulikova, J. Chem.
Soc. Perkin Trans. 2 2001, 1351 1371.
[26] a) J. R. Lindsay Smith, G. B. Shul×pin, Tetrahedron Lett.
1998, 39, 4909 4912; b) G. B. Shul×pin, J. R. Lindsay
Smith, Russ. Chem. Bull. 1998, 47, 2379 2386; c) G. B.
Shul×pin, G. S¸ss-Fink, J. R. Lindsay Smith, Tetrahedron
1999, 55, 5345 5358; d) G. B. Shul×pin, G. S¸ss-Fink,
L. S. Shul×pina, J. Mol. Catal. A. 2001, 170, 17 34;
e) G. B. Shul×pin, Petrol. Chem. 2001, 41, 405 413; f)
G. B. Shul×pin, G. V. Nizova, Yu. N. Kozlov, I. G. Pe-
chenkina, New J. Chem. 2002, 26, 1238 1245; G. V.
Nizova, C. Bolm, S. Ceccarelli, C. Pavan, G. B. Shul×pin,
Adv. Synth. Catal. 2002, 344, 899 905.
¬
Commun. 2003, 4, 603 608; d) T. Paczesniak, A. Sobko-
wiak, J. Mol. Catal. A: Chem. 2003, 194, 1 11.
[21] P. Stavropoulos, R. fielenligil-fietin, A. E. Tapper, Acc.
Chem. Res. 2001, 34, 745 752.
[22] a) G. B. Shul×pin, M. M. Kats, Petrol. Chem. 1991, 31,
647 656; b) G. B. Shul×pin, A. N. Druzhinina, Mendeleev
Commun. 1992, 36 37; c) G. B. Shul×pin, G. V. Nizova,
Petrol. Chem. 1993, 33, 107 112; d) G. B. Shul×pin, A. N.
Druzhinina, L. S. Shul×pina, Petrol. Chem. 1993, 33, 321
325; e) F. Minisci, F. Fontana, S. Araneo, F. Recupero, S. [27] Yu. N. Kozlov, A. D. Nadezhdin, A. P. Purmal, Int. J.
Banfi, S. Quici, J. Am. Chem. Soc. 1995, 117, 226 232;
Chem. Kinet. 1974, 6, 383.
Adv. Synth. Catal. 2004, 346, 317 332
asc.wiley-vch.de
¹ 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
331

Georgiy B. Shul×pin et al.
FULL PAPERS
[28] Synthesis and properties of TACN-Fe complexes: a) K.
Wieghardt, K. Pohl, W. Gebert, Angew. Chem. Int. Ed.
1983, 22, 727; b) K. Wieghardt, K. Pohl, D. Ventur,
Angew. Chem. Int. Ed. 1985, 24, 392 393; c) A. Spool,
I. D. Williams, S. J. Lippard, Inorg. Chem. 1985, 24,
2156 2162, d) J. R. Hartman, R. L. Rardin, P. Chaud-
huri, K. Pohl, K. Wieghardt, B. Nuber, J. Weiss, G. C.
Papaefthymiou, R. B. Frankel, S. J. Lippard, J. Am.
Chem. Soc. 1987, 109, 7387 7392; e) E. Y. Tshuva, D.
Lee, W. Bu, S. J. Lippard, J. Am. Chem. Soc. 2002, 124,
2416 2417; f) M. Enomoto, T. Aida, J. Am. Chem. Soc.
2002, 124, 6099 6108.
332
¹ 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
asc.wiley-vch.de
Adv. Synth. Catal. 2004, 346, 317 332