Kinetics and mechanism of the highly efficient generation of singlet oxygen in dimethyldioxirane decomposition induced by the chloride ion

Article abstract of DOI:10.1134/S0023158412010077

The decomposition of dimethyldioxirane induced by the chloride anion has been investigated by methods of infrared chemiluminescence and quantum chemistry. The reaction leads to efficient generation of singlet excited molecular oxygen ¹O₂ (the excitation yield in acetone is 61%). A mechanism of peroxide decomposition is proposed in which the key reactions are the addition of the chloride ion to an oxygen atom of dioxirane, resulting in dioxirane ring opening and the formation of the 2-chlorooxy-2-hydroxy propane alcoholate (k₁), and the interaction of the latter with another dimethyldioxirane molecule. This interaction results either in the formation of an adduct, which further decomposes to evolve ¹O₂, and catalyst regeneration (k₂) or in the formation of the 2-chloroxyisopropyl radical, which leads to the irreversible consumption of the chloride ion catalyst (k₃). The decay kinetics of the infrared chemiluminescence of ¹O₂ has been studied in a wide range of reactant concentrations. The temperature dependence of the rate constant of the reaction of dimethyldioxirane with the chloride ion has been determined by a kinetic analysis of the mechanism proposed: log(2k₁) = (11.1 ± 0.7) - (46 ± 4)/Θ, where Θ = 2.3RT kJ/mol. Estimation of the ratio of the rates of the reaction of the 2-chlorooxy-2- hydroxy propane alcoholate with dimethyldioxirane via two pathways (k ₃/k₂) has demonstrated that the fraction of the process involving electron transfer does not exceed 1.5% under the experimental conditions examined. Nevertheless, the latter reaction, which withdraws the chloride ion from the catalytic cycle of dimethyldioxirane decomposition yielding singlet oxygen, has a marked effect on the overall kinetics of the process. Pleiades Publishing, Ltd., 2012.

Full text of DOI:10.1134/S0023158412010077

ISSN 0023ꢀ1584, Kinetics and Catalysis, 2012, Vol. 53, No. 1, pp. 42–53. © Pleiades Publishing, Ltd., 2012.
Original Russian Text © M.Yu. Ovchinnikov, D.V. Kazakov, S.L. Khursan, 2012, published in Kinetika i Kataliz, 2012, Vol. 53, No. 1, pp. 44–55.
Kinetics and Mechanism of the Highly Efficient Generation
of Singlet Oxygen in Dimethyldioxirane Decomposition Induced
by the Chloride Ion
M. Yu. Ovchinnikov*, D. V. Kazakov, and S. L. Khursan
Institute of Organic Chemistry, Ufa Scientific Center, Russian Academy of Sciences, Ufa, 450054 Bashkortostan, Russia
* eꢀmail: chemlum@anrb.ru
Received May 5, 2011
Abstract—The decomposition of dimethyldioxirane induced by the chloride anion has been investigated by
methods of infrared chemiluminescence and quantum chemistry. The reaction leads to efficient generation of
singlet excited molecular oxygen 1O2 (the excitation yield in acetone is 61%). A mechanism of peroxide decomꢀ
position is proposed in which the key reactions are the addition of the chloride ion to an oxygen atom of dioxꢀ
irane, resulting in dioxirane ring opening and the formation of the 2ꢀchlorooxyꢀ2ꢀhydroxy propane alcoholate
(
k
1), and the interaction of the latter with another dimethyldioxirane molecule. This interaction results either
in the formation of an adduct, which further decomposes to evolve 1O2, and catalyst regeneration (
2) or in
the formation of the 2ꢀchloroxyisopropyl radical, which leads to the irreversible consumption of the chloride
k
1
ion catalyst (
range of reactant concentrations. The temperature dependence of the rate constant of the reaction of dimeꢀ
thyldioxirane with the chloride ion has been determined by a kinetic analysis of the mechanism proposed:
log(2 1) = (11.1 0.7) – (46 4)/ , where = 2.3RT kJ/mol. Estimation of the ratio of the rates of the reaction
of the 2ꢀchlorooxyꢀ2ꢀhydroxy propane alcoholate with dimethyldioxirane via two pathways (k3 2) has demonꢀ
k3). The decay kinetics of the infrared chemiluminescence of O2 has been studied in a wide
k
Θ
Θ
/k
strated that the fraction of the process involving electron transfer does not exceed 1.5% under the experimental
conditions examined. Nevertheless, the latter reaction, which withdraws the chloride ion from the catalytic cycle
of dimethyldioxirane decomposition yielding singlet oxygen, has a marked effect on the overall kinetics of the process.
DOI: 10.1134/S0023158412010077
Singlet oxygen (1O2) has been attracting researꢀ
chers’ attention for many years due to its essential role
in organic synthesis and biological processes [1–11].
The participation of 1О2 in chemiluminescent reacꢀ
tions is also important [11, 12]. A reaction accompaꢀ
nied by the highly efficient generation of 1О2, namely,
the decomposition of dioxiranes [13–16] catalyzed by
An earlier ab initio study [20] suggested a mechaꢀ
nism of 1О2 generation in the reaction of DMD with
the chloride ion (Scheme 1). The key role in this
mechanism is played by the 2ꢀchlorooxyꢀ2ꢀhydroxy
propane alcoholate, and 1О2 results from the exotherꢀ
mic reaction of this intermediate with dioxirane.
O
O
Cl
H3C
H3C
a number of anions (Cl–, Br–, I–,
t
ꢀBuO–, −, and
O2
+ Cl–
,
OH– [17–19], was discovered earlier. The 1О2 yield
measured in this peroxide system by infrared chemiluꢀ
minescence (IRCL) is rather high. For example, the
yield of this species from the reaction of dimethyldioxꢀ
irane (DMD) with the chloride ion in aqueous aceꢀ
tone is almost quantitative [18, 19].
H3C
O
H3C
O–
O
O
Cl
H3C
H3C
H3C
+
Data concerning this reaction would be useful for
gaining a deeper insight into the generation of excited
states in reactions of peroxides and into the factors
affecting the stability of dioxiranes in solution. In
addition, the high yield of 1О2 makes the dioxirane–
nucleophilic ion system promising for use in chemical
lasers and in organic syntheses. Investigation of the
conditions under which the maximum possible yield
of 1О2 is attainable requires a detailed study of the
reaction mechanism.
O
H3C
–O
1O2 + Cl– + 2CH3COCH3.
Scheme 1
.
Later theoretical studies [21] showed that the reguꢀ
larities revealed by the study of the DMD–Cl– system
are valid for the process involving methyl(trifluoromeꢀ
thyl)dioxirane (TFD).
42

KINETICS AND MECHANISM OF THE HIGHLY EFFICIENT GENERATION
43
The present work continues the investigation of the which corresponds to α ≥ 0.98 in the above indicated
mechanism of the reactions of dioxiranes with anions range of salt concentrations.
and is devoted to the kinetics of the reactions that
occur in the DMD–Cl– system. The work is aimed at
revealing possible side processes affecting the 1О2 yield
and at constructing a kinetic scheme consistent with
the accumulated array of experimental data.
Chemiluminescence in the IR spectral range was
recorded using an earlier described setup [28] with a
liquid nitrogen–cooled FEUꢀ83 photomultiplier,
which is sensitive in the IR range. The 1О2 emission
wavelength range was cut out using an IKSꢀ7 cutoff
light filter ( = 1000–13000 nm). When studying the
λ
kinetics of chemiluminescence decay, a solution of
DMD (1 ml) was placed into a temperatureꢀconꢀ
trolled reactor situated above the FEU photocathode.
After a specified temperature was reached, a solution
of tetrabutylammonium chloride (1 ml) was quickly
introduced into the dioxirane solution from a temperꢀ
atureꢀcontrolled injector and IRCL was detected. The
EXPERIMENTAL
The solvents (CCl4, CHCl3, CH2Cl2, and acetone)
were purified and dried using a standard procedure
[23]. 1,4ꢀDimethylnaphthalene used in endoperoxide
synthesis was purified by vacuum distillation. Water
was doubly distilled.
maximum CL intensity (
its decay in time was monitored. The digital signal of
I
CL) was reached in ~1 s, and
The synthesis of DMD was carried out according to
a slightly modified standard procedure [24, 25]. Bidisꢀ
tilled water (76 ml), NaHCO3 (52 g), and acetone
(68 ml) were placed in a 1000ꢀml roundꢀbottom flask
connected through an air condenser to a trap cooled
with liquid nitrogen. Next, a weak vacuum (0.5–
0.7 kgf/cm2) was produced with a water jet air pump
and an inert gas was passed through the flask. The mixꢀ
ture was vigorously stirred with a mechanical stirrer,
ICL as a function of
t was processed using nonlinear
regression analysis.
A solution of DMD in CCl4 free of acetone was
prepared by a known procedure [29].
Molecular chlorine was identified in a CCl4
medium. For this purpose, the optical absorption
spectrum of the products of the reaction of DMD with
the chloride ion in the presence of CF3COOH was
compared to the known absorption spectrum of Cl2
and oxone (ternary salt 2KHSO5
⋅
KHSO4 K2SO4)
⋅
(35 g) was added. The peroxide started accumulating
in the receiver immediately after the beginning of the
synthesis. Approximately 20 min after, an additional
amount of oxone (35 g) and acetone (15–20 ml) were
introduced into the flask. A new portion of oxone
(30 g) and acetone (15–20 ml) were added in 20–
25 min. The reaction was performed until the complete
cessation of the evolution of gas bubbles. The total duraꢀ
tion of the procedure was 1–1.5 h. After the end of the
synthesis, the trap was warmed and the remaining
amount of DMD was let to flow down into the receiver.
A yellowish DMD solution (0.09–0.11 mol/l) in aceꢀ
tone was thus obtained. Water was removed from the
product by decantation (some amount of H2O passed
from the reaction flask into the DMD solution during
the synthesis). A test tube with DMD was placed in an
(λmax = 335 nm) [30].
The G3MP2B3 composite method [31] was used to
calculate the energy characteristics of the process,
namely, the heats of particular reaction steps and the
electron affinities of the reactants and intermediates.
Solvation by acetone was taken into account in the
framework of the polarized continuum model [32–34]
using the B3LYP hybrid functional [35], which
includes the Becke (B3) threeꢀparameter potential
[36] and the Lee–Yang–Parr (LYP) correlation
potential [37] in combination with the triple splitꢀ
valence basis set augmented with
dꢀ and pꢀtype
polarization functions and the set of diffuse functions
[6ꢀ311+G(d,p)] [38]. Calculations were performed
using the Gaussian 03 RevisionꢀD02 program [39].
The visualization and primary processing of the quanꢀ
tum chemical calculation results were carried out
using the ChemCraft program [40].
acetone bath cooled to –70 С, and water that was
°
crystallizing on the bottom of the tube was frozen out
for 4–6 h. Thereafter, the DMD solution in acetone
was decanted in to a clean test tube. The solution of
dioxirane in acetone was stored over a molecular sieve
RESULTS AND DISCUSSION
at –25 С.
°
1,4ꢀDimethylnaphthalene endoperoxide was synꢀ
thesized according to a known procedure [26, 27].
Dimethyldioxirane is a strong oxidant widely used
in organic synthesis [13–16, 41]. The high reactivity of
The reaction of DMD with the chloride ion was DMD implies its chemical instability; however, under
studied in wide ranges of DMD concentrations (from our experimental conditions, DMD in acetone solution
4
×
10–4 to
(from
10–5 to
range 278–316 K. The source of chloride ions was the tion in acetone, log
salt ꢀBu4NCl, which undergoes almost complete disꢀ where = 2.3RT kJ/mol [42], which corresponds to
sociation in acetone [22], which was used in our the lifetime (1/ app) of DMD from 70 days at 278 K to
experiments as the solvent: the degree of dissociation 16 h at 316 K under the given conditions. Dioxirane
measured at a tetrabutylammonium chloride conꢀ disappears rapidly upon the addition of tetrabutylamꢀ
centration of = 293 K is 0.58, monium chloride to the DMD solution, and the reacꢀ
10–2 mol/l and
4
×
10–2 mol/l) and Cl– concentrations is fairly stable. Indeed, the logarithm of the apparent
5
×
8
×
10–4 mol/l) in the temperature rate constant of the decrease in the peroxide concentraꢀ
app, is (10.2 0.6) – (90 4)/ ,
k
θ
n
θ
k
α
4
×
T
KINETICS AND CATALYSIS Vol. 53
No. 1
2012

44
OVCHINNIKOV et al.
10–4 mol/l, 298 K) determined using the decomposiꢀ
tion of 1,4ꢀdimethylnaphthalene endoperoxide as the
standard was 61 10%.
Searching for conditions favorable for 1О2 generaꢀ
tion in the DMD–Cl– system in acetone, we discovꢀ
ered that the 1О2 yield depends on the proportions of
the reactants. Indeed, as can be seen from Fig. 1, the
[Cl–]0
×
104, mol/l
6
0
2
4
8
10
7
6
5
4
3
2
1
20
15
10
5
1
1
'
ratio of the light sum (S) to the DMD concentration,
i.e., the value proportional to the yield of singlet oxyꢀ
gen, remains unchanged at concentration ratios of
[DMD]0 : [Cl–]0 = 10–30 and decreases with an
increasing peroxide concentration in the reaction
solution when the initial DMD concentration exceeds
the chloride ion concentration by a factor greater than
50–100. A similar regularity is observed as the chloride
ion concentration is varied (Fig. 1): the yield of singlet
oxygen remains unchanged at comparatively low
[DMD]0 : [Cl–]0 ratios, and a decrease in the catalyst
concentration to 1–2 mol % results in a considerable
2
0
0
2
4
×
6
8
[DMD]0
103, mol/l
Fig. 1. Relative yield of molecular singlet oxygen versus
the dimethyldioxirane concentration at [Cl ] = (1)
–
0
–4
–5
decrease in the ratio of S to the peroxide concentration
in the solution, i.e., in a decrease in the singlet oxygen
generation efficiency.
2.5
and (
6.0
×
2
10 and (
1
') 5.0
× 10 mol/l in acetone at 278 K
) versus the chloride ion concentration at [DMD]
10 mol/l in acetone at 288 K.
=
0
–3
×
The regularities of chemiluminescence revealed in
the DMD–Cl– system suggest the existence of a side
reaction pathway yielding no 1О2. The larger the excess
of dioxirane in the reaction mixture, the stronger the
influence of the “dark” reaction on the chlorideꢀ
induced decomposition of peroxide.
ICL
8
,
rel. units
–ln(ICL/I0)
5
4
3
2
1
0
6
4
2
Kinetics of the Reaction
Evidently, the chemiluminescence intensity is proꢀ
portional to the rate of DMD decomposition (w)
induced by the chloride anion. Based on the results of
experimental [18, 19] and theoretical [20] studies, we
assumed that the reaction proceeds via a catalytic
mechanism according to which the variation of the CL
intensity during the reaction is described by the reacꢀ
tion
5
10
, s
15
20
0
t
[Cl–][DMD],
(1)
1
ICL
=
ϕCL
w
=
ϕCL
k
Fig. 2. Typical decay kinetics of IRCL from
О forming in
2
the reaction between DMD and the chloride ion and its semiꢀ
where ϕCL is the quantum yield of CL and
k
is the rate
–3
logarithmic anamorphosis ([DMD] = 6.0
× 10 mol/l,
0
constant of the catalytic process. Since the concentraꢀ
tion of the catalyst is assumed to be constant, the CL
intensity should be directly proportional to the current
concentration of DMD and Eq. (1) is formally a
pseudoꢀfirstꢀorder kinetic equation. Therefore, the
linearization of the kinetic curves in semilogarithmic
–
–4
[Cl ] = 6.5 × 10 mol/l, acetone, 283 K).
0
tion time varies between a few seconds and ~10 min,
depending on the initial concentrations of the reacꢀ
tants. The chloride ion induces efficient catalytic
decomposition of DMD accompanied by singlet oxyꢀ
gen generation and IR light emission [17–19]. Note
that it is the chloride ion that is responsible for the
rapid decomposition of DMD, because the replaceꢀ
coordinates (lnICL–t) will make it possible to deterꢀ
mine the apparent rate constant from the slope ratio of
the anamorphosis of a kinetic curve. The apparent rate
constant kapp is equal to the product of the rate conꢀ
stant of the catalytic process and the initial (current)
chloride ion concentration.
Indeed, at a 10ꢀ to 30ꢀfold excess of peroxide over
the catalyst, the decomposition of DMD in acetone
solution induced by chloride anions is a firstꢀorder
reaction with respect to the DMD concentration
throughout the temperature range examined (Fig. 2).
ment of the quaternary ammonium cation n
ꢀBu4N+
with Na+ (in the decomposition of dioxirane in aqueꢀ
ous acetone in the presence of sodium chloride) leads
to similar results.
The 1О2 yield in the reaction of DMD with Cl– in
acetone ([DMD]0 = 2
×
10–3 mol/l,
[n
ꢀBu4NCl]0 = 2
×
KINETICS AND CATALYSIS Vol. 53
No. 1
2012

KINETICS AND MECHANISM OF THE HIGHLY EFFICIENT GENERATION
45
kapp
10, s–1
×
7
2
6
5
4
3
2
1
1
0
2
4
6
8
10
[Cl–] 104, mol/l
×
Fig. 3. Typical plots of the apparent rate constant versus The chloride ion concentration at (1) 287.5 and (2) 292 K ([DMD] =
0
–3
6.0
× 10 mol/l, acetone).
ICL
2.5
,
rel. units
–ln(ICL/I0)
4
3
2
1
0
2.0
1.5
1.0
0.5
0
100 200 300 400 500 600 700
, s
t
1
Fig. 4. Decay kinetics of IRCL from
О forming in the reaction between DMD and the chloride ion and its semilogarithmic
2
–2
–
–4
anamorphosis ([DMD] = 3.0 × 10 mol/l, [Cl ] = 2.2 × 10 mol/l, acetone, 278 K).
0
0
In addition, under these conditions, kapp depends linꢀ the variation of the initial DMD concentration: an
early on the chloride ion concentration (Fig. 3). At the
same time, there is experimental evidence that the
process examined is more complicated than was iniꢀ
tially assumed. Firstly, the straight line representing
the dependence of the apparent rate constant on the
chloride ion concentration intercepts a short segment
on the abscissa axis. This segment is reproduced from
one run to another and depends on temperature in a
systematic way. The abscissa intercept corresponding
to a certain concentration of the chloride ion was
interpreted as a measure of the irreversible loss of part
of the catalyst in some noncatalytic side process. Secꢀ
increase in the reactant concentration resulted in a
noticeable increase in the reaction time (from a few
seconds to several minutes), i.e., in a decrease in the
apparent rate constant of DMD consumption. Howꢀ
ever, this experimental observation will not be in conꢀ
flict with the expected kinetics (Eq. (1)) if the catalyst
concentration [Cl–] decreases during the process and.
Therefore, it can serve as further indirect evidence of
the occurrence of a parallel side reaction leading to the
irreversible consumption of chloride ions. Moreover, it
turned out that, when the reaction is carried out with
ondly, a seemingly paradoxical result was observed for a >50ꢀfold excess of dioxirane over the chloride ion
KINETICS AND CATALYSIS Vol. 53
No. 1
2012

46
OVCHINNIKOV et al.
A
0.8
0.6
0.4
0.2
0
300
320
340
360
, nm
380
400
λ
Fig. 5. Optical absorption spectrum of the products of the reaction between DMD and the chloride ion (solid line) recorded immeꢀ
–2 –2
4 0 3 0 0 4
diately after mixing the reactants (
295 K) and (for comparison) the spectrum of Cl in CCl [30] (dashed line).
[nꢀBu NCl] = 2.0 × 10 mol/l, [CF COOH] = 0.3 mol/l, [DMD] = 4.5 × 10 mol/l, CCl ,
2
4
concentration, the IRCL decay does not obey Eq. (2) to the peroxide concentration (Fig. 1), according to
but follows a different kinetic law (cf. Figs. 2 and 4).
which the contribution from the noncatalytic process
is pronounced at reactant concentration ratios of
[DMD]0 : [Cl–]0 > 50. The contribution from the nonꢀ
catalytic process decreases the yield of singlet molecuꢀ
lar oxygen and changes the kinetic order of the overall
process.
Thus, although 1О2 formation is the dominant proꢀ
cess in the reaction of dioxirane with the chloride ion,
it is apparently not the only pathway. Note that the
kinetic measurements confirm and supplement the
results of the studies of the ratio of the IRCL light sum
Nature of the “Dark” Reaction Pathway
Table 1. Ionization potentials of the anions serving as
When analyzing the possibility of a noncatalytic
reaction occurring in the system, we based on the fact
that, firstly, DMD is a very strong oxidizer and, secꢀ
ondly, the anions involved in the formation of 1О2
(Scheme 1), which oxidized species, are often prone
to reduction reactions accompanied by electron transꢀ
fer. For this reason, we assumed that the side pathway
that does not lead to the formation of 1О2 (“dark”
reaction) is the oxidation of chlorineꢀcontaining
anions with dioxirane into catalytically inactive speꢀ
potent catalysts for dioxirane decomposition
IP, eV
Compound
calculation
by the G3MP2B3
method
experiment
[43, 44]
DMD*
–
1.87
2.74
3.69
2.32
cies, such as Cl2
.
TFD*
Cl–
–
Actually, the reactions forming the basis of the
known methods of analysis of organic peroxides,
namely, iodometry and bromometry, are similar to the
hypothesized “dark” reaction of DMD. Chlorine is a
stronger oxidizer and is less prone to redox reactions of
this type, and this accounts for the minor role of the
side pathway of the reaction. Therefore, to prove our
assumption, it is necessary to establish conditions
favorable for the electronꢀtransfer process and molecꢀ
ular chlorine formation. That is why the reaction of
DMD with the chloride ion was carried out in carbon
tetrachloride (to prevent possible reactions of radical
species with the C–H bonds of the solvent) in the
presence of trifluoroacetic acid (to increase the redox
potential of dioxirane). We found earlier [18, 19] for
3.62
2.28
ClO–
Cl–2
2.4 0.1**
2.45
ClO(CH3)2CO–
–
–
2.77
3.60
ClO(CH3)(CF3)CO–
Notes: * The values of electron affinity (EA) are given for the dioxꢀ
iranes.
** Average of 8 measurements.
KINETICS AND CATALYSIS Vol. 53
No. 1
2012

KINETICS AND MECHANISM OF THE HIGHLY EFFICIENT GENERATION
47
DMD decomposition under the action of the bromine pleting the redox process and leading to the experiꢀ
ion that addition of an acid markedly suppresses the
catalytic pathway of the reaction. The reaction of
DMD with nꢀBu4NCl in an acidic medium is indeed
mentally observed evolution of molecular chlorine. We
cannot exclude the formation, under our experimental
conditions, of catalytically inactive compounds with a
covalently bonded chlorine atom.
accompanied by the appearance of the characteristic
odor of chlorine and by the formation of Cl2 molecules
(identified by spectrophotometry) in less than 10 s
(Fig. 5).
According to Scheme 1, DMD decomposition is
catalyzed by the chloride ion and by its oxidized speꢀ
cies, namely, the 2ꢀchlorooxyꢀ2ꢀhydroxy propane
alcoholate. To see which of these anionic species is
responsible for the electron transfer process, we calcuꢀ
lated the electron affinities (EA) of DMD and TFD
and the ionization potentials (IP) of the correspondꢀ
ing anions in the gas phase (Table 1).
It was assumed previously that the hypochlorite ion
can be the oxidized form of the catalyst continuing the
catalytic chain of DMD decomposition [18, 19].
However, this is unlikely because of the low ionization
potential of ClO– (2.32 eV, see Table 1), since otherꢀ
wise the oneꢀelectron transfer would be efficient at
least in the reaction with TFD (2.77 eV, see Table 1).
This would be inconsistent with experimental facts:
the catalytic decomposition of TFD induced by small
amounts of chloride ions occurs at a high rate and with
a high yield of singlet oxygen [19]. Thus, the results of
the study of the structure carrying the catalytic chain
indirectly confirm the validity of the catalytic dioxꢀ
irane decomposition mechanism in which the
ClO(CH3)(R)CO– anion continues the catalytic chain
[20, 21].
It can be seen from Table 1 that the method used in
the calculation (G3MP2B3) reproduces the experiꢀ
mental values of IP of the anions Cl–, −, and ClO–
Cl2
with a high accuracy, indicating the reliability of the
estimates of the electron affinity of the dioxiranes
DMD and TFD and the ionization potentials of the
anionic intermediates ClO(CH3)(R)CO–, where R =
CH3 or CF3. It is most likely that, in the process studꢀ
ied, the reducing agent is the oxidized form of the catꢀ
alyst, namely, the 2ꢀchlorooxyꢀ2ꢀhydroxy propane
alcoholate. To take into account the solvating effect of
acetone, the solvation energies of the participants of the
oneꢀelectron transfer were calculated by the polarizaꢀ
tion continuum method [32–34]. The solvation correcꢀ
tion was determined in the B3LYP/6ꢀ311+G(d,p)
approximation. Indeed, the interaction of 2ꢀchloroxꢀ
yisopropoxide with DMD is the most favorable proꢀ
cess in acetone:
Thus, the interaction of the 2ꢀchlorooxyꢀ2ꢀ
hydroxy propane alcoholate with DMD proceeds via
two competing pathways (Scheme 2). The first of them
(a) generates 1О2, whereas the second one (b) yields an
inactive chlorine species (for example, Cl2) and is a
combination of reactions initiated by electron transfer
from the catalyst to the dioxirane.
1O2
O
Cl
O
(а)
H3C
H3C
H3C
+
ClO(CH3)2CO– + DMD
→
electron transfer,
H3C
O–
(b)
O
Cl2
ΔG
= 62.5 kJ/mol
;
Scheme 2.
Cl– + DMD
→
electron transfer,
ΔG = 214 kJ/mol.
Thus, the transfer of one electron from the 2ꢀchloꢀ
rooxyꢀ2ꢀhydroxy propane alcoholate to the dioxirane
requires much less energy than the oxidation of the
free Cl– anion. At the same time, electron transfer
from 2ꢀchlorooxyꢀ2ꢀhydroxy propane alcoholate to
the dioxirane is characterized by a positive Gibbs
energy; i.e., the efficiency of the “dark” process should
be low as compared to that of the catalytic process. This
is in agreement with the experimentally observed reguꢀ
larities of the process examined. We did not study the
subsequent fate of the reduced, inactive form of the catꢀ
alyst (presumably, atomic chlorine). It can be assumed
that Cl– abstracts an H atom from the solvent molecule
or recombines with a chloride anion. The latter reaction
is exothermic ( 125 kJ/mol) and occurs in aqueous soluꢀ
As the DMD concentration is raised, an increasing
amount of the chloride anion is oxidized into inactive
species. Since the catalytic process is not stoichiometꢀ
ric (i.e., several DMD molecules decompose on one
Cl– anion), even a slight decrease in the chloride ion
concentration should decrease the rate of catalytic
dioxirane decomposition yielding 1О2 and, accordꢀ
ingly, the IRCL decay rate.
Kinetic Analysis of the Reaction between DMD
and the Chloride Ion
Based on the results of the study of catalytic 1О2
generation [20] and the aboveꢀdescribed “dark” chloꢀ
ride ion oxidation leading to catalyst the withdrawal
from the system, we proposed the following scheme of
tion with a diffusion rate constant of
k
d = (7.8 0.8)
×
109 L mol–1 s–1 [45]. The resulting radical anion has a
comparatively low IP (Table 1) and can transfer the
excess electron to the dioxirane molecule, thus comꢀ the reaction between DMD and the chloride ion:
KINETICS AND CATALYSIS Vol. 53
No. 1
2012

48
OVCHINNIKOV et al.
O
O
Cl
H3C
H3C
k
1
+ Cl–
(I)
H3C
H3C
O
O
H3C
O
O–
1O2 + Cl– + 2CH3COCH3
(II)
Cl
k
H3C
2
+
O–
O•
O
Cl
H3C
H3C
H3C
H3C
H3C
H3C
O
H3C
O–
k
3
(III)
(IV)
+
O•
O
Cl
…
Cl•
H3C
O•
Cl• + Cl–
Cl–2
(V)
O
O–
H3C
H3C
+ Cl–2
+ Cl2
O•
(VI)
H3C
H3C
O
H3C
O–
O–
H3C
+ CH3COCH•2
(VII)
….
+ CH3COCH3
O•
H3C
H3C
OH
Scheme 3.
Reactions (I) and (II) belong to the catalytic pathꢀ ical anion resulting from the reaction of DMD with
way of the process, and the electronꢀtransfer reaction the oxidized form of the catalyst (reaction (III)) and
−
Cl2
(III), which occurs simultaneously with reaction (II),
with the radical anion
(reaction (VI)) is rapidly
initiates the chain of transformations leading to the
irreversible consumption of the Cl– catalyst. The cataꢀ
lytic exothermic reaction (II), which yields 1О2, is
dominant [20]. However, endothermic electron transꢀ
fer (III), which makes a small contribution to the overꢀ
all reaction (see Table 1), occurs in parallel. One of the
products of this interaction (DMD radical anion) is
likely consumed in its reaction with the solvent.
Another product of redox reaction (III) (2ꢀchloroxyꢀ
isopropyl radical) converts the catalyst into its inactive
form. We did not study this process but formally repreꢀ
sented it as steps (IV)–(VI).
and irreversibly consumed without 1О2 formation (for
example, via solvent oxidation). Thirdly, the 2ꢀchloꢀ
rooxyꢀ2ꢀhydroxy propane alcoholate concentration is
considered to be approximately quasiꢀstationary.
For the above reaction scheme, it is easy to set up a
system of differential equations describing the joint
consumption of the reactants:
k1(2k2 + 3k3)[DMD][Cl−]
d[DMD]
(2)
−
=
,
dt
(k2 + k3)
2k1k3[DMD][Cl−]
d[Cl−]
dt
(3)
−
=
.
(k2 + k3)
The following assumptions were made in the
kinetic analysis of the reaction scheme. Firstly, reacꢀ
The ratio of Eqs. (2) and (3) leads to the following
tion (III) is accepted to be the rateꢀdetermining step of expression relating the current concentrations of the
the redox process. Secondly, it is assumed that the radꢀ reactants:
KINETICS AND CATALYSIS Vol. 53
No. 1
2012

KINETICS AND MECHANISM OF THE HIGHLY EFFICIENT GENERATION
49
[Cl–] = [Cl–]0 +
γ
([DMD] – [DMD]0),
(4)
t
, s
0
2
4
6
8
10
12
14
2k3
k3
≈
1.0
0.8
0.6
0.4
0.2
0
where
is the quantity characterizing
γ =
2k2 + 3k3 k2
the ratio of the contributions from reactions (II) and
(III). The physical meaning of this quantity can also
be interpreted as an indicator of catalyst resistance to
poisoning in side processes. Evidently, for an ideal catꢀ
alyst
γ
= 0. By substituting Eq. (4) into Eq. (2), one can
exclude the chloride ion concentration from this
equation. Taking into account that
k
2 ӷ
k3, we obtain
2
d[DMD]
–ꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀ
dt
1
(5)
2
=
2k ([Cl–] – γ[DMD] )[DMD] + 2k γ[DMD] .
0
1
0
1
0
10
20
30
40
50
t
, s
Thus, for the above scheme of the process with the
1
above assumptions taken into account, the order of the
reaction with respect to the DMD concentration can
vary from 1 to 2, depending on the reaction condiꢀ
tions. This conclusion is consistent with the kinetics of
the process studied by the IRCL method (see above).
The analytical solution of Eq. (5) for the DMD conꢀ
centration takes the form
Fig. 6. Decay kinetics of IRCL from
reaction between DMD and the chloride ion: (
О forming in the
2
1
) [DMD] =
0
–3
–
–4
6.0
×
10 mol/l, [Cl ] = 4.8
×
10 mol/l, concentraꢀ
0
tion ratio of 12.6, acetone, 288 K; (
2
) [DMD] = 6.0
×
0
–3
–
–5
10 mol/l, [Cl ] = 6.8
×
10 mol/l, concentration ratio
0
of 88.5, acetone, 303 K. The solid line is the fit to Eq. (12).
log2
4.0
k
1[l mol–1 s–1
]
–log
γ
4.0
[DMD]0(kI + kII[DMD])
1
(6)
ln
kI [DMD](kI + kII[DMD]0)
= t,
3.5
3.0
2.5
2.0
1.5
1.0
3.5
3.0
2.5
2.0
1.5
1.0
where kI and kII are the apparent firstꢀ and secondꢀ
order rate constants, respectively. The physical meanꢀ
ing of these constants is defined by the equations
k
I = 2k
1([Cl–]0 –
γ
[DMD]0),
(7)
(8)
kII = 2k1γ.
A relationship between the current DMD concenꢀ
tration and ICL should be established for quantitative
description of the experimental curves of IRCL intenꢀ
sity decay with time. According to Eq. (1), ICL is proꢀ
portional to the rate of the catalytic process and, at the
initial point in time, is
3.1
3.2
3.3
1000/
3.4
, K–1
3.5
3.6
T
I0
=
ϕCL2k1[
DMD]0[Cl–]0.
(9)
The coefficient 2 reflects the stoichiometry of
DMD consumption and singlet oxygen accumulation.
Taking into account the change in the concentration
Fig. 7. Temperature dependence of the rate constant
2k and
1
rate constant ratio = 1/ in chlorideꢀinduced DMD
k
/
k
γ
2
3
4
–4
decomposition (
[
n
ꢀBu NCl] = (0.5–8.0)
×
10 mol/l,
0
–3
[
Cl–] during the process (Eq. (4)), we can state that the
[DMD] = 6.0
×
10 mol/l, acetone).
0
IRCL intensity is related to the DMD concentration
by the nonlinear equation
2
ICL
[DMD]
[DMD]0
[DMD]
[DMD]
ꢀꢀꢀꢀꢀ = ꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀ – γꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀ + γꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀ. (11)
ICL = ϕ(2k ([Cl–] – γ[DMD] )[DMD]
[Cl–]
[DMD] [Cl–]
0
I0
1
0
0
0
0
(10)
2
+
2k1γ[DMD] ).
Solving the quadratic equation (11) for the DMD
concentration and substituting the resulting equation
into Eq. (7), we finally obtain
Thus, the normalized IRCL intensity is related to
the current DMD concentration in a complicated
way:
KINETICS AND CATALYSIS Vol. 53
No. 1
2012

50
OVCHINNIKOV et al.
Table 2. Secondꢀorder rate constants of the reaction between DMD and the chloride ion (2
k
1) and the rate constant ratio
k3 k2 ) at various temperatures
/
(
γ
ꢀBu)4NCl]0
104, mol/l
×
T
, K
2k1
×
10–2, L mol–1 s–1
γ × 102
[(n
283
288
292
1.0
1.0
1.2
1.2
2.0
3.2
3.2
4.8
6.5
8.0
–
–
–
–
1.37 0.05
1.02 0.03
0.89 0.02
1.16 0.05
4.01 0.06
4.50 0.04
4.15 0.05
4.34 0.02
3.77 0.01
4.11 0.02
–
–
–
–
–
–
4.2 0.3
1.1 0.2
–
1.0
1.0
1.2
2.0
2.0
3.2
4.8
4.8
6.5
6.5
1.40 0.03
1.12 0.01
1.44 0.01
1.65 0.03
–
–
5.96 0.05
6.12 0.05
4.55 0.02
5.31 0.01
4.83 0.01
4.94 0.01
4.62 0.01
–
–
–
–
–
–
5.2 0.6
1.4 0.2
–
1.1
1.3
1.8
1.8
2.0
2.5
2.5
3.4
3.4
4.7
4.7
2.03 0.02
5.06 0.01
6.58 0.03
5.02 0.01
5.38 0.07
5.20 0.07
–
5.73 0.01
6.54 0.02
6.27 0.01
6.04 0.01
–
1.68 0.02
1.29 0.01
–
–
2.19 0.02
–
1.47 0.02
–
–
5.8 0.6
1.7 0.4
9.09 0.03
297
1.2
1.5
1.5
2.2
2.7
2.7
3.3
4.0
4.0
4.9
4.9
6.0
1.13 0.01
1.15 0.01
1.33 0.01
2.43 0.01
–
10.5 0.1
11.9 0.1
10.9 0.1
7.74 0.02
9.57 0.08
8.97 0.05
9.84 0.07
8.64 0.02
10.1 0.1
10.3 0.1
8.92 0.07
–
1.92 0.03
–
–
2.0 0.1
1.4 0.1
–
9
2
1.6 0.5
KINETICS AND CATALYSIS Vol. 53
No. 1
2012

KINETICS AND MECHANISM OF THE HIGHLY EFFICIENT GENERATION
51
Table 2. (Contd.)
, K
ꢀBu)4NCl]0
104, mol/l
×
T
2k1
×
10–2, L mol–1 s–1
γ × 102
[(n
303
0.7
0.9
1.2
1.6
2.1
2.1
2.9
3.8
3.8
5.1
5.1
–
–
–
1.10 0.1
1.07 0.01
1.39 0.02
0.93 0.02
14.5 0.1
12.9 0.1
16.0 0.2
14.4 0.1
13.9 0.1
14.5 0.1
13.5 0.1
12.8 0.1
–
1.11 0.05
–
–
–
–
–
14
1
1.2 0.2
307
1.3
1.3
2.0
2.0
2.0
2.0
3.3
3.3
24.0 0.2
23.9 0.1
19.7 0.1
21.0 0.2
21.7 0.2
–
1.93 0.04
1.31 0.01
–
1.18 0.03
1.70 0.03
1.27 0.06
1.90 0.1
–
–
20.6 0.1
22
2
1.5 0.3
316
0.9
0.9
3.8
–
1.26 0.03
1.26 0.02
–
28.2 0.2
25.9 0.1
27
2
1.26 0.04
–3
Note: Reaction conditions: acetone as the solvent; [DMD] = 6.0 10 mol/l. Dashes mean that, in this case, the kinetic curve is lowꢀ
×
0
sensitive to variation of the rate constant or the ratio of constants. The correlation factor of nonlinear approximation is at least
0.994 (the typical value is 0.999).
2 I
4γ CL [DMD]20
I0
1
(12)
ln
= t.
2k1([Cl−]0 − γ[DMD]0)
2
⎛
⎞
I
([Cl−]0 − γ[DMD]0)2 + 4γ CL [Cl−]0[DMD]0 − ([Cl−]0 − γ[DMD]0)
⎜
⎝
⎟
⎠
I0
Equation (12) accounts for the observed variable mental factors, and the reactants are partially conꢀ
reaction order. In the limiting case of the absence of sumed during this period. The results of regression
the irreversible consumption of the catalyst in the side analysis indicate that the observed maximum CL
process, Eq. (12) reduces to a firstꢀorder kinetic equaꢀ intensity is underestimated to an extent of 10–20%.
tion with the apparent rate constant equal to
2k
1[Cl–]0
.
Equation (12) describes, with a high correlation factor,
Indeed, using the Lopital–Bernoulli rule, it can the dependence of the IRCL intensity on the reaction
readily be shown that the limit of the ratio in the logaꢀ time under various experimental conditions (temperꢀ
rithmic term tends to ICL
The secondꢀorder rate constant
constant ratio were determined by nonlinear regresꢀ
sion analysis, approximating the observed dependence
of CL on (Table 2). The initial intensity I0 was optiꢀ
/
I
0 at γ →
0
.
2
ature, ratio of the initial concentrations of the reacꢀ
tants), indicating that the generalized scheme proꢀ
posed for the interaction of DMD with the chloride
ion is valid (Scheme 3). The experimental curves and
approximations obtained using Eq. (12) are shown in
Fig. 6 by way of example.
k1 and the rate
γ
I
t
mized along with these kinetic constants. This was
necessary for adequate description of the kinetic
The activation energy E1act and preexponential facꢀ
curves, because a certain time (~1 s; see Experimental) tor A1 of the catalytic decomposition of DMD by the
is required for the CL intensity to reach its maximum. chloride ion were derived from the temperature
This time is due to mixing of the reactants and instruꢀ dependence of the rate constant 2k1 (Table 2, Fig. 7):
KINETICS AND CATALYSIS Vol. 53
No. 1
2012

52
OVCHINNIKOV et al.
E1act
=
46 4 kJ/mol, log
A
1 = 11.1 0.7 [L mol–1 s–1]. remains to be unity, but it causes the app versus [Cl–]0
k
The value of the preexponential factor is typical of straight line to intercept some segment on the concenꢀ
bimolecular reactions in the liquid phase. A compariꢀ tration axis (Fig. 3). At a 50–100ꢀfold excess of DMD
son between the apparent activation energy and the over the catalyst, the Cl– concentration decreases conꢀ
strength of the peroxide bond in DMD for its siderably during the process and, as a result, DMD
homolytic cleavage (95 kJ/mol [46]) demonstrates consumption obeys a complicated kinetic law.
that the chloride ion acts as a catalyst, i.e., a compoꢀ
nent of the system lowering the energy barrier for the
reaction examined.
Note that the low activation energy of the catalytic
process is fairly consistent with the theoretical value
Thus, the reaction scheme (I)–(VI) accounts for
the basic regularities observed for DMD decomposiꢀ
tion in the presence of chloride ions. The reaction proꢀ
ceeds via two pathways, namely, the catalytic decomꢀ
position of the peroxide yielding singlet oxygen (major
pathway) and the oxidation of the chloride ion resultꢀ
ing in its withdrawal from the catalytic cycle (minor
pathway).
obtained by quantum chemical calculations [20],
≠
according to which H = 17 kJ/mol. In view of the
Δ
difficulty of taking into account the solvation of the
reactants, especially for anionic intermediates, the
agreement between the theory and the experiment is
satisfactory.
ACKNOWLEDGMENTS
This work was supported by the Russian Foundaꢀ
tion for Basic Research, project no. 09ꢀ03ꢀ00831a.
Correlation between the Catalytic and “Dark” Pathways
of the Reaction
REFERENCES
The results of the kinetic analysis along with the
chemiluminescence and theoretical estimates confirm
the conclusion about the minor contribution of the
side “dark” pathway (reaction (III)) to the total rate of
disappearance of the 2ꢀchloroxyisopropyl anionic
intermediate. In the temperature range examined, the
1. Wasserman, H.H. and Murray, R.W., Organic Chemisꢀ
try: Singlet Oxygen, New York: Academic, 1979, vol. 40.
2. Frimer, A.A., Singlet Oxygen, Boca Raton, Fla.: CRC,
1985.
3. Adam, W. and Wirth, T., Acc. Chem. Res., 1999, vol. 32,
p. 703.
rate constant ratio = k3/k2 (Table 2, Fig. 7) is almost
γ
4. Schweitzer, C. and Schmidt, R., Chem. Rev., 2003,
temperatureꢀindependent, being 0.014 0.003; i.e.,
the proportion of the “dark” pathway does not exceed
1.5%.
vol. 103, p. 1685.
5. Cadet, J., Ravanat, J.ꢀL., Martinez, G.R.,
Medeiros, M.H.G., and Di Mascio, P., Photochem.
Photobiol., 2006, vol. 82, p. 1219.
6. Skovsen, E., Snyder, J.W., and Ogilby, P.R., Photochem.
Photobiol., 2006, vol. 82, p. 1187.
In spite of the small value of
rate of the process, /[DMD] =
the slope ratio of the plot of ln(ICL
γ
, the instant reduced
1[Cl–], determined by
0) versus (Fig. 4) at
w
2k
/
I
t
a considerable excess of the dioxirane over the catalyst,
decreases substantially in the experiment. This fact is
seemingly in conflict with kinetic conceptions, but it
allows a simple explanation in the framework of the
above kinetic model. Equation (4) describes the stoꢀ
ichiometry of reactant disappearance, which is deterꢀ
7. Schmidt, R., Photochem. Photobiol., 2006, vol. 82,
p. 1161.
8. Krasnovsky, A.A., Jr., Biochemistry (Moscow), 2007,
vol. 72, p. 1065.
9. Krasnovsky, A.A., Jr., J. Photochem. Photobiol., A
,
2008, vol. 196, p. 210.
10. Minaev, B.F., Russ. Chem. Rev., 2007, vol. 76, p. 989.
11. Adam, W., Kazakov, D.V., and Kazakov, V.P., Chem.
Rev., 2005, vol. 105, p. 3371.
12. Kazakov, D.V., Kazakov, V.P., Maistrenko, G.Ya.,
mined by the value of
readily derive the dependence of the chloride ion conꢀ
version
= ([Cl–]0 – [Cl–])/[Cl–]0 on the DMD conꢀ
γ. From this equation, one can
ξ
version. Let us estimate the value of
conversion:
ξ
at 90% dioxirane
Mal’zev, D.V., and Schmidt, R., J. Phys. Chem. A
2007, vol. 111, p. 4267.
,
0.9γ[DMD]0
(13)
ξ =
.
[Cl−]0
13. Adam, W., Curci, R., and Edwards, J.O., Acc. Chem.
Res., 1989, vol. 22, no. 6, p. 205.
14. Murray, R.W., Chem. Rev., 1989, vol. 89, p. 1187.
At a 50ꢀfold excess of DMD over the chloride ions,
= 63%; i.e., nearly two thirds of the catalyst is irreꢀ
ξ
versibly consumed in the redox process. Therefore,
during the reaction the apparent rate constant of cataꢀ
lytic decomposition, kapp
15. Kazakov, V.P., Voloshin, A.I., and Kazakov, D.V., Russ.
Chem. Rev, 1999, vol. 68, p. 253.
16. Adam, W., SahaꢀMöller, C.R., and Zhao, C.ꢀG., Org.
React., 2002, vol. 61, p. 219.
17. Nagel, V., Duschek, F., Kiefer, W., Gorth, F.,
Golsch, D., Adam, W., Ferrer, M., and Messeguer, A.,
Asian J. Spectrosc., 1998, p. 35.
18. Adam, W., Kiefer, W., Schlucker, S., SahaꢀMoller, C.,
Kazakov, D.V., Kazakov, V.P., and Latypova, R.R., in
= 2k
1[Cl–], decreases almost
by a factor of 3, thus inducing a considerable decrease
in the DMD consumption rate. According to Eq. (13),
at [DMD]0 : [Cl–]0
≤
10 the chloride ion conversion
does not exceed 13%. In this case, the introduced perꢀ
turbation exerts almost no effect on the reaction order
with respect to the DMD concentration, which
KINETICS AND CATALYSIS Vol. 53
No. 1
2012

KINETICS AND MECHANISM OF THE HIGHLY EFFICIENT GENERATION
53
Bioluminescence and Chemiluminescence: Progress and 35. Koch, W. and Holthausen, M.C., A Chemist’s Guide to
Current Applications, Stanley, P.E. and Kricka, L.J.,
Eds., Singapore: World Scientific, 2002, p. 129.
Density Functional Theory, Weinheim: WileyꢀVCH,
2001, p. 293.
36. Becke, A.D., J. Chem. Phys., 1993, vol. 98, no. 7,
19. Adam, W., Kiefer, W., Kazakov, D.V., Kazakov, V.P.,
Latypova, R.R., and Schlücker, S., Photochem. Photoꢀ
biol. Sci., 2004, vol. 3, p. 182.
p. 5648.
37. Lee, C., Yang, W., and Parr, R.G., Phys. Rev. B: Conꢀ
dens. Matter, 1988, vol. 37, p. 785.
20. Ovchinnikov, M.Yu., Khursan, S.L., Kazakov, D.V.,
and Adam, W., J. Photochem. Photobiol., A, 2010,
vol. 210, p. 100.
38. Jensen, F., Introduction to Computational Chemistry
,
Chichester: Wiley, 1999, p. 428.
39. Frisch, M.J., Trucks, G.W., Schlegel, H.B.,
Scuseria, G.E., Robb, M.A., Cheeseman, J.R., Zakrzeꢀ
wski, V.G., Montgomery, J.A., Stratmann, R.E.,
Burant, J.C., Dapprich, S., Millam, J.M., Daniels, A.D.,
Kudin, K.N., Strain, M.C., Farkas, O., Tomasi, J.,
Barone, V., Cossi, M., Cammi, R., Mennucci, B.,
Pomelli, C., Adamo, C., Clifford, S., Ochterski, J.,
Petersson, G.A., Ayala, P.Y., Cui, Q., Morokuma, K.,
Malick, D.K., Rabuck, A.D., Raghavachari, K., Foresꢀ
man, J.B., Cioslowski, J., Ortiz, J.V., Baboul, A.G.,
Stefanov, B.B., Liu, G., Liashenko, A., Piskorz, P.,
Komaromi, I., Gomperts, R., Martin, R.L., Fox, D.J.,
Keith, T., AlꢀLaham, M.A., Peng, C.Y., Nanayakkara, A.,
Challacombe, M., Gill, P.M.W., Johnson, B., Chen, W.,
Wong, M.W., Andres, J.L., Gonzalez, C., HeadꢀGorꢀ
don, M., Replogle, E.S., and Pople, J.A., Gaussian 03
Revision D02, Pittsburgh, Pa.: Gaussian Inc., 2004.
21. Ovchinnikov, M.Yu., Khursan, S.L., and Kazakov, D.V.,
Izv. Akad. Nauk, Ser. Khim., 2011, no. 1, p. 29.
22. Sam, D.J. and Simmons, H.E., J. Am. Chem. Soc.
1974, vol. 96, p. 2252.
,
23. Gordon, A.J. and Ford, R.A., A Handbook of Practical
Data, Techniques, and References, New York: Wiley,
1972.
24. Murray, R.W. and Jeyaraman, R., J. Org. Chem., 1985,
vol. 50, p. 2847.
25. Adam, W., Chan, Y.ꢀY., Cremer, D., Gauss, J.,
Scheutzow, D., and Schindler, M., J . Org. Chem., 1987,
vol. 52, p. 2800.
26. Wasserman, H.H. and Larsen, D.L., J. Chem. Soc.,
Chem. Commun., 1972, vol. 5, p. 253.
27. Turro, N.J., Chow, M.ꢀF., and Rigaudy, J., J. Am.
Chem. Soc., 1981, vol. 103, p. 7218.
40. Chemcraft. http://www.chemcraftprog.com
41. Kazakov, D.V., Voloshin, A.I., Kazakov, V.P., Shereꢀ
shovets, V.V., and Kabal’nova, N.N., Khimiya i
khemilyuminestsentsiya dioksiranov (Chemistry and
Chemiluminescence of Dioxiranes), Moscow: Nauka,
1999.
42. Khursan, S.L., Grabovskii, S.A., Kabal’nova, N.N.,
Galkin, E.G., and Shereshovets, V.V., Izv. Akad. Nauk,
Ser. Khim., 2000, no. 8, p. 1344.
43. Baron, N.M., Ponomareva, A.M., Ravdel’, A.A., and
Timofeeva, Z.N., Kratkii spravochnik fizikoꢀkhimiꢀ
cheskikh velichin (Concise Handbook of Physicochemical
Data), St. Petersburg: Ivan Fedorov, 2003.
28. Sharipov, G.L., Kazakov, V.P., and Tolstikov, G.A.,
Khimiya
i
khemilyuminestsentsiya 1,2ꢀdioksetanov
(Chemistry and Chemiluminescence of 1,2ꢀDioxetꢀ
anes), Moscow: Nauka, 1990, p. 174.
29. Gibert, M., Ferrer, M., SanchezꢀBaeza, F., and Mesꢀ
seguer, A., Tetrahedron, 1997, vol. 53, p. 8643.
30. Spravochnik khimika (Chemist’s Handbook), Moscow:
Khimiya, 1965, vol. 4, p. 744.
31. Baboul, A.G., Curtiss, L.A., Redfern, P.C., and Raghaꢀ
vachari, K., J. Chem. Phys., 1999, vol. 110, p. 7650.
32. Miertus, S., Scrocco, E., and Tomasi, J., Chem. Phys.
1981, vol. 55, p. 117.
33. Miertus, S. and Tomasi, J., Chem. Phys., 1982, vol. 65,
p. 239.
,
44. NIST Chemistry WebBook. http://webbook.nist.gov
45. Yu, X.ꢀY., J. Phys. Chem. Ref. Data, 2004, vol. 33,
p. 747.
34. Cossi, M., Barone, V., Cammi, R., and Tomasi, J., 46. Cremer, D., Kraka, E., and Szalay, P.G., Chem. Phys.
Chem. Phys. Lett., 1996, vol. 255, p. 327.
Lett., 1998, vol. 292, p. 97.
KINETICS AND CATALYSIS Vol. 53
No. 1
2012