Role of association of Yanovskii anionic σ adducts in their oxidation with quinones

Article abstract of DOI:10.1023/A:1020442609484

In oxidation of 1,3-dinitro- and 1,3,5-trinitrobenzene acetonate σ adducts (Yanovskii complexes) with sodium, potassium, and tetrabutylammonium cations in acetonitrile and tetrahydrofuran (290-313 K), ion pairs are less reactive than free ions, which is e

Full text of DOI:10.1023/A:1020442609484

Russian Journal of General Chemistry, Vol. 72, No. 6, 2002, pp. 928 932. Translated from Zhurnal Obshchei Khimii, Vol. 72, No. 6, 2002,
pp. 992 996.
Original Russian Text Copyright
2002 by Kurenkova, Alifanova, Atroshchenko, Lapina, Tarasova, Akhromushkina, Kaminskii, Gitis.
Role of Association of Yanovskii Anionic
in Their Oxidation with Quinones
Adducts
Yu. V. Kurenkova, E. N. Alifanova, Yu. M. Atroshchenko, O. Yu. Lapina,
E. Yu. Tarasova, I. M. Akhromushkina, A. Ya. Kaminskii, and S. S. Gitis
Tolstoi Tula State Pedagogical University, Tula, Russia
Received September 4, 2000
Abstract In oxidation of 1,3-dinitro- and 1,3,5-trinitrobenzene acetonate adducts (Yanovskii complexes)
with sodium, potassium, and tetrabutylammonium cations in acetonitrile and tetrahydrofuran (290 313 K), ion
pairs are less reactive than free ions, which is explained by charge redistribution in the ring of the adducts,
decreasing the electron-donor power of the associated anion. Separation of the apparent rate constants into
ionic and ion-pair contributions showed that the reactivity of the ion pairs depends on the radius of their cation.
The revealed kinetic regularities are interpreted on the basis of AM1 semiempirical quantum-chemical calcula-
tions of the ions and ion pairs with lithium cation.
Anionic adducts of electron-deficient arenes exist
in solutions as solvated ions and ion pairs of different
types with different abilities to solvolysis [1] and re-
actions with electrophiles [2] and oxidants [3]. Ho-
wever, the role of association in oxidation of ad-
ducts, which is one of efficient ways of introduction
of C C bonds in aromatic systems, have scarcely been
studied. Moreover, there has been lack of information
in literature about quantitative characteristics of the
metric study of the kinetics of oxidation of sodium
(a), potassium (b), and tetrabutylammonium (c) 1-
acetonyl-2,4-dinitro-6-X-cyclohexa-2,5-dienides [X =
H (I), NO (II)] with 1,4-benzoquinone (III) and
2
2,3,5,6-tetrabromo-1,4-benzoquinone (IV) in MeCN
and THF.
The oxidation reaction has an overall second order
and involves formation of a donor acceptor ion-pair
intermediate V whose accumulation and consumption
can be followed by the absorbance in the region of
12000 cm 1 [4].
ions and ion pairs of
adducts.
In this connection we performed a spectrophoto-
O
O
CH2COCH3
NO2
OH
H
CH COCH
H
CH COCH3
2
3
2
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
X
NO2
X
NO2
X
Y
Y
+
+
NO Ct+
+
O
NO2
O Ct+
2
O
NO Ct
2
Ia Ic, IIa IIc
III, IV
Va Vc, VIa VIc
VII, VIII
IXa IXc,
Xa Xc
+
+
+
+
X = H (I, V, VII), NO (II, VI, VIII); Y = H (III, V, IX), Br (IV, VI, X); Ct = Na (a), K (b), [N(C H ) ] (c).
2
4 9 4
In acetonitrile ( 36.0), where adducts are mostly
present as free ions, the rate constant is independent
The reactivity of ions and ion pairs was estimated
by the Acree equation [5].
of the concentration of
0
adducts [k (Ib) (2.19
2
.06) 10 1 l mol s (298 K)]. In THF the rate
1
1
kapp = ki + k (1
).
ip
constant decreases with increasing concentration of
adducts (Table 1), on account of increasing fraction
of the tight ion pair.
Here kapp is the apparent second-order rate constant,
k and k are the oxidation rate constants of ions and
i
ip
1
070-3632/02/7206-0928$27.00 2002 MAIK Nauka/Interperiodica

ROLE OF ASSOCIATION OF YANOVSKII ANIONIC
ADDUCTS
929
Table 1. Second-order rate constants for oxidation of
adducts Ia Ic and IIa IIc in THF (298 K)
Ia
IIa
Ib
4
cad 10 , M
k2 10, l mol 1 s 1
k2 10 , l mol 1 s 1
2
k2 10, l mol 1 s 1
7.14
6.66
5.55
3.33
2.22
1.33
0.67
0.62
0.50
0.33
1.71 0.08
1.83 0.04
1.91 0.10
1.98 0.06
2.33 0.11
0.275
0.283
0.305
0.374
0.435
2.94 0.09
3.47 0.13
3.63 0.08
4.54 0.11
5.05 0.09
5.23 0.12
5.37 0.09
0.179
1.00 0.02
1.03 0.01
1.18 0.03
1.99 0.01
2.52 0.13
3.54 0.25
0.310
0.334
0.407
0.471
0.557
0.674
0.185
0.203
0.263
0.322
0.415
0.588
2.63 0.12
2.67 0.14
2.87 0.09
0.637
0.648
0.685
7.74 0.04
11.7 0.40
0.728
0.781
5.50 0.29
0.678
IIa
Ic
IIc
4
cad 10 , M
k2 10 , l mol s 1
2
1
k2 10, l mol 1 s 1
k2 10 , l mol 1 s 1
2
7.14
6.66
5.55
3.33
2.22
1.33
0.67
0.62
0.50
0.33
2.44 0.02
3.08 0.03
3.06 0.01
4.53 0.13
0.286
0.294
0.317
0.388
1.78 0.06
2.01 0.02
2.10 0.05
2.13 0.03
2.39 0.06
2.54 0.13
2.58 0.02
0.472
0.483
0.514
0.601
0.669
0.751
0.842
0.398 0.024
0.729 0.051
0.843 0.032
0.991 0.012
1.03 0.02
1.29 0.05
1.57 0.08
2.30 0.03
2.40 0.14
2.98 0.70
0.448
0.459
0.484
0.576
0.644
0.728
0.825
0.833
0.858
0.897
9.81 0.15
29.2 1.4
39.7 1.3
0.535
0.653
0.694
2.72 0.08
3.21 0.12
0.873
0.908
61.8 2.2
0.763
ion pairs, respectively, and
degree of adducts, determined by conductometry.
is the dissociation
nitrobenzene
adducts is not linear (Fig. 1), and,
therefore, the apparent rate constants are impossible
separate into ionic and ion-pair contributions by the
Akri equation.
The k values for adducts Ia Ic are higher than
i
kip, and k increase in the order K+ > Na
+
>
ip
+
[
N(C H ) ] . This result can be explained in terms of
The plots of lnk /k on ln K (K is the dissociation
4
9 4
i
ip
d
d
the increasing radius of solvated cation, which
enhances steric hindrances to formation of inter-
mediate V and thus slows down the reaction. The
constant) for adducts Ia Ic (Fig. 2) are straight lines
with positive slopes, which, too, suggests that the re-
activity of ion pairs increases with increasing degree
of binding of the anion with the cation.
dependence of kapp/(1
) on /(1
) for 1,3,5-tri-
5
4
1
0
0
0
.0
.8
.6
.4
0.6
1
0
0
.4
.2
2
3
2
1
0
0
.2
0
0
4.35
0
.35
1.35
2.35
(1
3.35
/
)
11
10
9
8
7
log Kd
Fig. 1. Plot of k /(1
) vs. /(1
) for adducts.
app
(
1) Compound Ia and (2) compound IIa.
Fig. 2. Plot of ln k /k vs. ln K for
adducts Ia Ic.
i
ip
d
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 72 No. 6 2002

930
KURENKOVA et al.
(a)
0
.097
0
.095
H
H
H 0.101
H 0.084
0
.290
O
0
.327
O
0.105
0.136
C
0
.126
H
C
H 0.135
H
.214 C
H
C
0.271
.232
0.094
C
0.270
0.245
.086
0
0
0
.213
C
H0
0.116 H
H
0
.382
0
.106
0.009
O
H
O 0.437
0
.047
0.130
N 0.576
H
0
.106 H
.255
N 0.588
.344
O
0
.380
0
0
.200
.070
0.209
0.047
0
O 0.437
0
0
.096
0
.038
H
H
H0.179
0
.242
H0.152
0.147
0
.132
0
.034
N 0.545
N 0.599
O
0.487
O
O
0.480
O
Li
0
.449
0.444
0
.721
(b)
0
.089
H
0
.087
H
H 0.096
H0.106
0.267
0.274
0
.297
O
O
0
.270
0.120
0
.114
C
C
H
H
C0
0.108
H
C
C
.235 H
0.240
0
.144
H
0.114
0
.391
0
0.144
C 0
.215
0.207
0.357
O
H
0.091
0.391
0.096
O
H
H
O
O 0.343
.581
N
N 0.578
N
N 0.567
0
.569
0
.059
0.019
0
.297
O 0.424
0.205
0.202
0.032
O 0.289
O
O 0.389
0
.424
0
.035
0
.080
0.080
0.358
H
.171
H0.170
H
H
0
.353
0
.170
0.270
N 0.566
0
0
.171
N 0.600
O
.424
O
0.425
O 0.463 O 0.464
Li
0
0
.749
Fig. 3. Atomic charges in the anions and ion pairs of adducts, calculated by the AM1 method. (a) Structure I and (b) struc-
ture II.
It should be noted that dissociation stronger affects
the rates of oxidation of 1,3,5-trinitrobenzene ad-
ducts compared with 1,3-dinitrobenzene adducts.
Thus, as the concentration of adducts changes from
highest occupied molecular orbital (EHOMO) for ion
pairs and ions are 8.08 and 4.83 eV, respectively,
which suggests a lower electron-donor ability of ion
pairs compared with free ions.
.14 10 4 to 3.33 10 M, the oxidation rate con-
5
7
It is interesting that on addition of dibenzo-18-
crown-6 (XI) the oxidation rate decreases, whereas
the bathochromic shifts of the absorption maxima of
adducts points to formation of solvent-separated ion
pairs and solvated ions from the tight ion pairs
stant of adduct IIc increases 7.4 times and that of
adduct Ic, 1.8 times.
One of the reasons for the reduced reactivity of ion
pairs compared with an ions may lie in the charge
redistribution induced by association of the anion
with the cation, which, according to [6], involves
(
Table 2). This is apparently explained by formation
of so-called crown-separated ion pairs in which
the metal cations are located in the crown ether cavity,
but the distance between the cation and the anion
oxygen atoms of the 4-NO group. The AM1 semi-
2
empirical calculation of the ions and ion pairs of
aducts I and II with lithium cation located at a
+
+
remains unchanged: Ct An + XI
Ct XIAn .
distance of 2.42
from oxygen atoms of the 4-NO2
group placed increased negative charge on the 4-NO2
Analysis of the activation parameters of oxidation
group and reduced negative charge on the ring and the of adducts Ia Ic, measured in the range 290 313 K
(6)-NO groups (Figs. 3a and 3b). The energy of the in THF (Table 3), showed that the energy E and the
2
2
a
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 72 No. 6 2002

ROLE OF ASSOCIATION OF YANOVSKII ANIONIC
ADDUCTS
931
Table 2. Dependence of the oxidation rate of adduct Ib
changes in the activation enthalpy H and entropy
decrease with increasing radius R of solvated
on the concentration of crown ether (c ) in THF (298 K)
S
ce
cation. Thus, as R and, consequently, the dissociation
constant of adduct increase (Table 4), the entropy
difference between the starting and transition state
increases, and, since the reaction is entropy-controlled,
it is slowed down.
c /c
k2 10, l mol 1 s 1
max, nm
ad ce
0
5.34 0.12
5.39 0.18
4.65 0.05
2.49 0.15
2.65 0.98
541.1
542.3
543.4
549.9
556.2
1
1
1
1
: 0.2
: 1
: 5
Thus, we found that ion pairs of adducts are less
reactive than free ions, which is explained by the fact
that association increases the negative charge on the
: 10
Table 3. Termodynamic parameters of oxidation of
adducts Ia Ic in THF (298 K)
Cation
Ea, kJ/mol
H , kJ/mol
S , kJ mol 1 K 1
S T, kJ/mol
G , kJ/mol
+
Na
K
[
50.8 0.7
48.1 0.8
29.2 2.6
48.4 0.2
45.6 0.5
26.7 2.1
97.8 0.7
101.1 1.2
168.4 2.6
29.1
30.1
50.2
77.0 0.4
75.2 0.7
77.1 1.0
0.435
0.415
0.472
+
+
N(C H ) ]
4 9 4
Table 4. Dissociation constants (K ), ionic (k ), and ion-pair (k ) rate constants of oxidation of adducts Ia Ic (298 K)
d
i
ip
5
ki 10, l mol 1 s 1
kip 10, l mol 1 s 1
Adduct
Kd 10 , M
r
ki/kip
Ia
Ib
Ic
7.46
2.60
30.1
3.54 0.18
5.07 0.10
3.32 0.21
1.14 0.28
4.56 0.37
0.272 0.093
0.997
0.985
0.999
3.1
1.3
12
ring and decreases the negative charge on the 4-NO2
group. The reactivity of ion pairs decreases with
increasing ionic radius of their cation.
the HyperChem 4.5 program, AM1 semiempirical
method, Polak Ribiere optimization algorithm,
gradient 10 .
4
EXPERIMENTAL
The Yanovskii adducts and quinones were syn-
thesized by the procedures in [9] and [10], respecti-
vely. Their structures were proved by electronic, H
NMR, and IR spectroscopy. The solvents were puri-
fied according to [11], and their purities were control-
led by the refractive indices measured on an IRF-22
refractometer.
1
Kinetic and spectral measurements were performed
on a Specord M-40 spectrophotometer by the proce-
dure in [7] in temperature-controlled cells 0.1 to 5 cm
thick. The rates of oxidation of adducts were fol-
lowed by the decrease of optical density in their
absorption maxima. All measurement were performed
under pseudo-first-order conditions at 50 100-fold
excesses of oxidant.
ACKNOWLEDGMENTS
The work was financially supported by the Russian
Foundation for Basic Research (project no. 01-03-
Conductometric measurements were performed be
means of an R-5010 ac bridge and a specially
designed cell with parallel-plate platinum electrodes.
The concentrations were measured to an accuracy of
9
6002).
REFERENCES
0
.2% and the electrical conductivities, 0.8 2%,
depending on concentration. The and K ( 0 is
equivalent electrical conductivity) were calculated by
the program in [8].
0
d
1
. Glaz, A.I., Gitis, S.S., and Kaminskii, A.Ya., Izv. Sib.
Otd. Akad. Nauk SSSR, Ser. Khim., 1990, vol. 4, no. 2,
pp. 100 108.
Quantum-chemical calculations were performed by
2. Alifanova, E.N., Atroshchenko, Yu.M., Kamin-
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 72 No. 6 2002

932
KURENKOVA et al.
skii, A.Ya., Gitis, S.S., Grudtsyn, Yu.D., Naso-
Zh. Obshch. Khim., 2001, vol. 71, no. 2, pp. 300 309.
7. Savinova, L.N., Akhromushkina, I.M., Atroshchen-
ko, Yu.M., Gitis, S.S., and Kaminskii, A.Ya., Zh. Org.
Khim., 1993, vol. 29, no. 5, pp. 994 950.
nov, S.N., Alekhina, N.N., and Illarionova, L.V.,
Zh. Org. Khim., 1993, vol. 29, no. 7, pp. 1412 1418.
3
4
. Kurenkova, Yu.V., Alifanova, E.N., Atroshchen-
ko, Yu.M., Akhromushkina, I.M., Gitis, S.S., and
Kaminskii, A.Ya., Zh. Obshch. Khim., 2001, vol. 71,
no. 4, pp. 644 649.
8
. Kalugin, O.N. and V’yunnik, I.N., Zh. Obshch. Khim.,
990, vol. 60, no. 6, pp. 1213 1219.
9. Gitis, S.S. and Kaminskii, A.Ya., Zh. Obshch. Khim.,
963, vol. 33, no. 10, pp. 3297 3300.
1
1
. Atroshchenko, Yu.M., Akhromushkina, I.M., Gi-
tis, S.S., Nevodchikov, V.I., Savinova, L.N., Druzh-
kov, I.O., Kaminskii, A.Ya., and Nechet, O.V., Zh.
Obshch. Khim., 1993, vol. 63, no. 8, pp. 1843 1848.
1
1
0. Houben, J., Die Methoden der organishchen Chemie,
Leipzig: Thieme, 1930. Translated under the title
Metody organicheskoi khimii, vol. 3, issue 2, Moscow:
ONTI, 1935, p. 197.
1. Organic Solvents: Physical Properties and Methods of
Purification, Weissberger, A., Proskauer, E.S., Rid-
dick, J.A., and Toops, E.E., Jr., Eds., New York:
Interscience, 1955.
5
6
. Solov’yanov, A.A. and Beletskaya, I.P., Usp. Khim.,
1
978, vol. 47, no. 5, pp. 819 844.
. Alifanova, E.N., Kalnin’sh, K.K., Chudakov, P.V.,
Kaminskii, A.Ya., Kutsenko, A.D., and Gitis, S.S.,
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 72 No. 6 2002