On the mechanism of the chemiluminescent condensation of aniline with butyraldehyde catalyzed by LnCl3 ? 6H2O

Article abstract of DOI:10.1134/S0023158410040129

The mechanism of the chemiluminescent condensation of aniline with butyraldehyde into 3-ethyl-2-propylquinoline catalyzed by LnCl₃ ? 6H₂O (Ln = Tb, Ho) is reported. A likely scheme of the catalytic condensation of aniline with butyraldehyde has been developed by simulation of separate steps of the reaction using chemiluminescence and photoluminescence methods and quantum-chemical calculations of the heats of these steps.

Full text of DOI:10.1134/S0023158410040129

ISSN 0023ꢀ1584, Kinetics and Catalysis, 2010, Vol. 51, No. 4, pp. 534–541. © Pleiades Publishing, Ltd., 2010.
Original Russian Text © R.G. Bulgakov, S.P. Kuleshov, A.R. Makhmutov, U.M. Dzhemilev, 2010, published in Kinetika i Kataliz, 2010, Vol. 51, No. 4, pp. 558–565.
On the Mechanism of the Chemiluminescent Condensation
of Aniline with Butyraldehyde Catalyzed by LnCl3 · 6H O
2
R. G. Bulgakov, S. P. Kuleshov, A. R. Makhmutov, and U. M. Dzhemilev
Institute of Petrochemistry and Catalysis, Russian Academy of Sciences, Ufa, 450075 Bashkortostan, Russia
eꢀmail: ink@anrb.ru
Received July 3, 2009
Abstract—The mechanism of the chemiluminescent condensation of aniline with butyraldehyde into 3ꢀ
ethylꢀ2ꢀpropylquinoline catalyzed by LnCl · 6H O (Ln = Tb, Ho) is reported. A likely scheme of the cataꢀ
3
2
lytic condensation of aniline with butyraldehyde has been developed by simulation of separate steps of the
reaction using chemiluminescence and photoluminescence methods and quantumꢀchemical calculations of
the heats of these steps.
DOI: 10.1134/S0023158410040129
It was found earlier [1] that the condensation of ing to an earlier reported procedure [3]. A solution of
aniline (
pylquinoline (
1
) with butyraldehyde (
2
) into 3ꢀethylꢀ2ꢀproꢀ the catalyst for the condensation of
1 with 2 was preꢀ
3) catalyzed by LnCl3
⋅
6H O crystalline pared by dissolving the crystalline hydrate (0.2 mmol)
2
hydrates is accompanied by chemiluminescence (CL). in DMF (3 ml) at room temperature.
Chemiluminescence is also observed in the absence of
The condensation of
0ꢀml quartz cell equipped with a reflux condenser
and a liquid inlet assembly. The cell, placed in a
chemiluminescence chamber, was filled with a soluꢀ
1 with 2 was carried out in a
the crystalline hydrates. However, it is important that
the yield of compound and the CL brightness in the
presence of the catalyst are much higher; i.e., the catꢀ
alytic formation of and CL are interrelated. The
2
3
3
tion of the catalyst (3 ml) and compound
and compound (25 mmol) was charge into the liquid
inlet device. The chamber was hermetically sealed,
and compound was forced into the cell with an Ar
1 (10 mmol),
nature of the emitter of this CL depends on the nature
of the lanthanide (Ln = Tb, Eu, or Ho). For the crysꢀ
talline hydrates of Tb and Eu, the CL emitters are the
2
2
3+
3+
excited ions Tb * and Eu *, respectively. They are
flow. The reaction was conducted under bubbling
argon, and CL was measured simultaneously. The
presumably generated due to energy transfer from the
3
triplet excited state of the final product
3
(
С Н N*
)
1
4
17
reactions of compounds
carried out similarly. In the first case, compound
placed in the liquid inlet device. In the second case,
1
with
5
and
4
with
2
were
[
1]. In the case of the holmium crystalline hydrate, the
5
was
3
3+
CL emitter is С Н N* because Ho does not lumiꢀ
14
17
nesce in solutions.
In this work, we simulated separate steps of the compound
condensation of with catalyzed by НоCl3
and TbCl3
compound
4
1
was introduced into the cell instead of
. When the cyclization of compound
6
6
1
2
⋅
6H O was studied, the cell contained a solution of
6H O using luminescence techniques and (5 mmol) in DMF (1.5 ml) and the liquid inlet device
2
⋅
2
quantum chemical calculations (AM1/RHF method) contained a solution of the crystalline hydrate
of the heats of possible steps of CL generation and sugꢀ (0.2 mmol) in DMF (1.5 ml).
gested a probable mechanism for the formation of
the ground and electronꢀexcited states.
3 in
The Ln3+ content was determined by titration with
EDTA [4], and the water contents of the crystalline
hydrate and reaction products were determined by the
Fischer method [4]. The products of all condensation
reactions were analyzed on a Carlo Erba GC 6000
EXPERIMENTAL
Crystalline hydrates were reagent grade. Other chromatograph (column 3 m in length and 4 mm in
reagents and dimethylformamide (DMF) were highꢀ diameter, PEGꢀ6000 stationary liquid phase (15%) on
purity grade. Amines
tilled in vacuo (10 Torr) at 70 and 91°С, respectively. matograph (column 3 m in length and 4 mm in diamꢀ
Aldehyde and benzaldehyde ( ) were distilled from eter, SEꢀ30 stationary liquid phase (5%) on Chromaꢀ
hydroquinone [2] under atmospheric pressure, and ton NꢀAWꢀHMDS). The elemental analysis of the
DMF was purified as described in [2] with subsequent LnCl3 4DMF complex was carried out on a Carlo
1 and 2,6ꢀxylidine (4) were disꢀ Chromaton NꢀAWꢀDMCS) and a CHROM 5 chroꢀ
2
5
⋅
distillation
nylimino)methyl]heptane (
from
BaO.
4ꢀAnilinoꢀ3ꢀ[(pheꢀ Erba 106 CHN analyzer. Photoluminescence (PL)
6) was synthesized accordꢀ spectra were recorded on an Aminko Bowman specꢀ
534

ON THE MECHANISM OF THE CHEMILUMINESCENT CONDENSATION
535
2PrCHO
2
CatꢀLn
O
OH
Et CatꢀLn
Pr
Et
Pr
Et
Pr
Et
Pr
[
O]
O
+
–
H O, –H
2
NH
N
H
N
NH2
1
7
3
Scheme 1.
.
.
+
N
NHPh
NPh
HP hP h
10b
CH2
HC
+
+
+H+
+H ; –H
2
+ 2CH CHO
3
–2H O
2
9
N
CH3
N
H
CH3
N
H
CH3
NH2
10a
1
NHPh
NHPh
H
[
O]
H+
–PhNH2
–H2
–
+
NH CH3
N
CH3
N
CH3
N
CH3
H
H
11
Scheme 2.
trofluorimeter. The lifetime of the terbium ion products [1, 9]. We identified compound
3
(target
3+
(
τ
Tb *) was measured with an LGIꢀ23 pulsed nitroꢀ product) and
gen laser ( = 337 nm, measurement error of 10%). the products of condensation between
N
ꢀbutylaniline (
8
) (<5%, byꢀproduct) as
and . We
in the reaction cataꢀ
described earlier [5]. CL spectra were recorded using lyzed by CatꢀLn [7] and its absence in the reaction catꢀ
λ
1
2
exc
The setup and procedure for CL measurements were believe that the formation of
7
cutꢀoff light filters [6].
alyzed by the crystalline hydrate [1, 9] are due to the
fact that the synthesis condition in the former case
(
CatꢀLn, 100°С, 6 h) [7] are much more severs than
RESULTS AND DISCCUSION
were used in catalysis by the crystalline hydrate (20°С
,
<
5 min) [1, 9]. This conclusion is confirmed by our
There has been only one mechanistic study on
reactions of aromatic amines with aldehydes catalyzed
by metal complexes [7], in which a likely mechanism
experimental results obtained for solutions of
2 and
the crystalline hydrate combined at 20 and 100°С
Product forms only at 100°С (60% yield).
Based on the above results, we believe that the conꢀ
densation of with catalyzed by the crystalline
hydrate differs from Scheme 1 and the first step of this
reaction is the formation of a Schiff base. Schiff bases
form readily in reactions of aldehydes and primary
amines even below room temperature [10].
.
7
of the condensation of
threeꢀcomponent system LnCl –Ph P–DMF (Catꢀ
1
with
Ln) is discussed (Scheme 1).
According to Scheme 1, the first step of the reacꢀ
2 into 3 catalyzed by the
3
3
1
2
tion is the interaction of two molecules of yielding 2ꢀ
ethylꢀ2ꢀhexenal ( ), which then reacts with . This
mechanism is based on the known scheme of the conꢀ
densation of with acetaldehyde catalyzed by HCl [8]
omitted here), which is alternative to Scheme 2.
Scheme 1 was confirmed [7] by the experiment in
which product was obtained by the condensation of
catalyzed by CatꢀLn (100°С, 6 h, ethanol,
4% yield). Unlike Selimov et al. [7], we studied the
2
7
1
The possibility of the direct interaction between
and without the intermediate formation of the aldeꢀ
hyde dimer was confirmed by earlier works in which
the mechanism of the condensation of with acetalꢀ
dehyde ( ) catalyzed by HCl is presented [8, 11]
Scheme 2).
According to Scheme 2, the Schiff base
was absent from the reaction ylideneaniline forms in the first step. ꢀEthylideneꢀ
1
1
2
(
1
3
9
1
8
with 7
(
same reaction catalyzed by the crystalline hydrate and
found that compound
Nꢀethꢀ
7
N
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5
36
BULGAKOV et al.
ICL, arb. units
ICL, arb. units
3
2
1
0
1
6
2
8
4
0
2
1
1
a
0
10
20
30
40
50
60
, s
3
00 350 400 450 500 550 600 650
λ
t
, nm
Fig. 2. Chemiluminescence spectra for the reaction of
Fig. 1. Chemiluminescence kinetics in the reaction of
aniline (10 mmol) with butyraldehyde (25 mmol) cataꢀ
aniline (10 mmol) with butyraldehyde (25 mmol) cataꢀ
lyzed by HoCl · 6Н О (0.2 mmol) in DMF at 20°С: (1)
3 2
lyzed by HoCl · 6Н О (0.2 mmol) in DMF at 20°С
.
first and (
2) second maxima (Fig. 1). The CL spectra were
3
2
(a) The instant butyraldehyde was added.
measured using a set of vutꢀoff light filters.
aniline exists in solution in two forms, namely, the value decreases from 1300 to 800
±
80
µ
s. This suggests
4L with
4L to
nucleophilic molecule of enamine (10a) and the elecꢀ that a more complicated complex of Tb
trophilic molecule of aldimine (10b). In 2ꢀmethꢀ forms upon the addition of a solution of Tb
ylquinoline (11) formation, the quinoline ring results
⋅
1
1.
⋅
In the present work, we also obtained new data on
from the autocondensation of two Schiff base moleꢀ
cules and subsequent transformations as shown in
Scheme 2. For this reason, we used Scheme 2 when
selecting model reactions for identifying the lightꢀ
CL accompanying the catalytic condensation of
with . Two maxima were found in the time depenꢀ
dence of the CL intensity in the reaction of with in
DMF catalyzed by HoCl · 6H O CL1): a narrow one
1
2
1
2
(
3
2
emitting of the condensation of
1 with 2.
(
(
Imax = 6.0
Imax = 8.0
×
108 photon s ml ) and a broad one
–1
–1
Since the crystalline hydrate catalyst of the conꢀ
108 photon s ml ) (Fig. 1). The CL
–1
–1
×
1
densation of with is loaded into the reactor as a
1
2
spectrum in the time interval of the first maximum
contains one diffuse peak at 490 nm, while that
observed in the time interval of the second maximum
shows peaks at 450 and 515 nm (Fig. 2). Therefore,
DMF solution, before simulation of the reactions it
was interesting to identify the initial form of the lanꢀ
thanide reacting with the other reactants. The dissoluꢀ
tion of the crystalline hydrate in DMF produces colorꢀ
less homogeneous solutions. It was found for
1
2
two different CL emitters (E1 and E1 ) are generated in
the reaction of with and they are responsible for the
remains after the removal of DMF from these soluꢀ first and second CL peaks, respectively. The maxima
1
2
TbCl3 6H O as an example that a syrupy liquid
⋅
2
2
tions. According to elemental analysis data and the
Fischer determination of the water content, this liquid
in the CL spectrum caused by emission from E1 fall in
the region where the known phosphorescence of quinꢀ
oline is observed [13] (Fig. 2). The two strongest maxꢀ
1
3+
is the TbCl3 · 4DMF complex (Tb
value for the Tb · 4L complex (1300
that for TbCl · 6Н О (425 40 s). Based on data of
·
4L). The
τ
Tb *
µ
s) is larger than
ima in the CL spectrum (455
±
25 and 512
±
25 nm)
1
±
µ
3
2
and phosphorescence spectrum (455 and 500 nm)
other authors [12], we explain this by the removal of
2
the water molecules, which are quenchers of Tb3
+
spectra are close together. This indicates that the E1
emitter is the triplet excited state of
3
1
. The other stable
, and ꢀbutyꢀ
), as well as the Ho ion, do not luminesce
in the spectral range of CL [14–16] and, hence, canꢀ
photoluminescence, from the coordination sphere of
3+
participants of the reaction, namely,
,
2
N
the Tb ion upon the dissolution of TbCl3
DMF. Thus, the lanthanide is involved in catalytic laniline (
condensation in the form of the Tb 4L complex.
⋅
6Н О in
2
3+
8
⋅
1
1
1
2
1
1
1
When solutions of Tb
4L are mixed with solutions not be CL
⋅
emitters such as
E
or
E
. The
E
emitter is
with
Tb * with a short lifetime. This is indicated by the initial
1
of
1
in a ratio of 1 : 100, the PL of terbium (+3) is comꢀ a labile intermediate of the condensation of
1
2
3+
pletely quenched, whereas at the 1 : 1 ratio the
τ
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2010

ON THE MECHANISM OF THE CHEMILUMINESCENT CONDENSATION
NC H5
537
6
Et
Et
Et
Tb · 4L
2
+ 2O
NH2
2
Et
Et
Et
N
N
H
6
N
1
2
12
3
Scheme 3.
portion of the CL curve, which is like a flash of light
1
NH2
COH
1
2
N
(
Fig. 1). Since E1 and E1 emit in the same spectral
+
–
H O
2
range (Fig. 2), it can be assumed that they are similar
in nature.
1
5
13
1
In order to identify E1 and elucidate the mechaꢀ
nism of the formation of
ically excited states, the three possible steps of the synꢀ
thesis of were simulated and CL was sought and
3 in the ground and electronꢀ
Scheme 4.
3
recorded (Scheme 3).
The simulation of the hypothetical steps of heteroꢀ
cyclization was complicated by the fast reaction of
with catalyzed by Tb 4L (<5 min at the 100% conꢀ
version of ) [1, 9]. This is likely due to the high instaꢀ
bility of the intermediates. To solve this problem, simꢀ
ulation in two cases was carried out for compounds
that are most similar in nature to the starting reactants
and hypothetical intermediates and are converted into
more stable products.
1
2
⋅
Me
Me
Et
1
N
Me
Me
Me
H N
2
H
2
+ 2
N
H
Pr
Et
–2H O
2
O
Me
When studying the possibility of CL generation in the
4
2
14
first step of the condensation of
which yields the Schiff base ꢀbutylideneaniline (12),
a compound readily undergoing further autocondenꢀ
sation [3], aldehyde was taken instead of aldehyde
1 with 2 (Scheme 3),
N
Scheme 5.
5
2.
In this case, stable Schiff base 13 forms as the final
reaction product (Scheme 4).
Therefore, the second step of the condensation of
with (Scheme 3) is not accompanied by CL.
1
2
It was found that the reaction between
1 and 5 catꢀ
According to Scheme 3, product 3 results from the
alyzed by Tb 4L is not accompanied by CL. Since the
⋅
catalytic transformation of . Intermediate was
6
6
Schiff bases 12 (Scheme 3) and 13 (Scheme 4) form
via the formation of the same type of C=N bond and,
hence, with similar heats of reaction, it can be inferred
that the formation of Schiff base 12 via the reaction
obtained by an independent method [3], which made
it possible to verify the possibility of its cyclization catꢀ
alyzed by TbCl3
⋅
6H O in DMF (Scheme 6). Comꢀ
2
pound , 4ꢀanilinoꢀ3ꢀethylꢀ2ꢀpropylꢀ1,2,3,4ꢀtetꢀ
1, 3
between
1 and 2 (Scheme 3) does not generate CL
rahydroquinoline (15), and 3ꢀethylꢀ2ꢀpropylꢀ1,2ꢀ
dihydroquinoline (16) were identified as the cyclizaꢀ
tion products in 2 : 1 : 1 : 1 ratios (Scheme 6).
either.
Another possible CLꢀemitting step is the condenꢀ
sation of two molecules of Schiff base 12 into
Scheme 3). To study the possibility of CL generation
in this step, amine was condensed with
in the presꢀ 5.4
ence of the crystalline hydrate catalyst (Scheme 5). (Fig. 3) is described by a curve with a broad maximum.
Amine was taken instead of
because this reaction The CL spectrum (Fig. 3) coincides with the known
Scheme 5) yields stable compound 14, whereas the spectrum of CL [1] recorde for the reaction of
reaction of with
(Scheme 3) produces compound catalyzed by TbCl3 6H O and contains the luminesꢀ
, which undergoes further cyclization [17]. No CL cence maxima of Tb * (490 and 540 nm). Therefore,
6
(
The cyclization of 6 is accompanied by CL (I =
max
8
–1
–1
4
2
×
10 photon s ml ) (CL ), whose kinetics
2
4
1
2
(
1 with 2
1
2
⋅
2
3+
6
3+
was observed in the reaction represented by Scheme 5. the CL and CL emitter is the Tb * ion.
2
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538
BULGAKOV et al.
NHC H5
NC H5
6
6
Et Ln · 4L
Et
+
Et
+
Et
+
NH2
N
Pr
N
Pr
N
Pr
N
Pr
H
H
H
6
15
16
3
1
Scheme 6.
Thus, of the three simulated reactions, only the [20]) as the difference between the enthalpies of forꢀ
0
cyclization of
that the CL appearing upon the condensation of
catalyzed by the crystalline hydrate, whose emitter is
6
is accompanied by CL. This suggests mation (
fH ) of the final products and the starting
Δ
0
1
with
compounds for steps 1–4. The following
were obtained:
Δ
rH values
2
3+
Tb *, is due to the cyclization of
According to earlier studies [8, 17, 18], the cyclizaꢀ
tion of can proceed via two routes (Schemes 7, 8).
6 (Scheme 3).
0
=
Δ
f
Н0
(17) –
Δ
Н0
(6)
f
Δ H1
r
6
=
63.3 – 34.2 = 29.1 kcal/mol,
To see which of these reactions (Schemes 7, 8) is
thermodynamically more favorable as a CL exciter,
0
2
Н0
(16) +
Δ
f
Н0
(1) –
Δ
Н0
(17)
f
0
Δ H
r
=
Δ
f
the heats of the reactions (
Δ
rH ) were calculated by the
AM1/RHF method [19] (Hyperchem 5.0 program
=
8.1 + 20.8 – 63.3 = –34.4 kcal/mol,
0
3
Н0
(15) –
Δ
Н0
(6)
f
6
Δ H
r
=
Δ
f
(
a)
=
13.9 – 34.2 = –20.3 kcal/mol,
1
0
Δ H4
=
Δ
f
Н0
(16) +
Δ
f
Н0
(1
) –
8.1 + 20.8 – 13.9 = 15.0 kcal/mol
Thus, the cyclization of 17 into 16 with the simulꢀ
Δ
Н0
(15)
f
r
4
2
=
.
taneous elimination of is the most exothermic reacꢀ
1
tion. This process is likely responsible for the appearꢀ
ance of CL upon the condensation of
1
with
2. The
1
*
350
700
energy Eexc necessary for the excitation of the E1
emitter, as estimated from the position of the maxiꢀ
6
4
2
0
t
, s
b)
mum (
λ
max
≈
490 nm, 2.53 eV) in the CL spectrum
1
(
(
Fig. 2, spectrum
1), is ~60 kcal/mol. Since Eexc =
⎯
Δ
H0
+
Eact (where Eact is the activation energy of the
r
2
reaction) [21], the formation of excited compound 16
via Scheme 6 will be possible if Eact is not lower than
2
5.6 kcal/mol. Because there are no Eact data for this
reaction in the literature, Eact was calculated from the
known Polanyi equation Eact = 0.32 – 26.9 (where
D
D
is the bond dissociation energy) to be 28.6 kcal/mol.
Therefore, Eexc = 34.4 + 28.6 = 63.0 kcal/mol, which
is quite sufficient for the excitation of intermediate 16
via Scheme 7 (step 2). Another product of this reaction
450
500
, nm
550
600
λ
is aniline, which cannot be the CL emitter, because,
1
according to spectroscopic data [14, 15], the generaꢀ
Fig. 3. Chemiluminescence (a) kinetics and (b) spectra for
the cyclization of compound catalyzed by TbCl3 6H O
in DMF. The CL spectra were measured using a set of cutꢀ
off light filters.
tion of its singlet and triplet states requires ES
5 kcal/mol and ET = 76 kcal/mol, respectively, which
is higher than Eexc
=
6
⋅
2
9
.
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ON THE MECHANISM OF THE CHEMILUMINESCENT CONDENSATION
539
NC H5
NHC H5
6
6
Et
Et
Et
+
Δ
rH10
Step 1
Δ
rH20
Step 2
C H NH
6
5
2
N
H
Pr
N
Pr
N
H
Pr
H
6
17
Scheme 7.
16
1
NC H5
NHC H5
6
6
Et
Et
Et
+
Δ
rH30
Step 3
Δ
rH40
Step 4
C H NH
6
5
2
N
Pr
N
H
Pr
N
H
Pr
H
6
15
16
1
Scheme 8.
Based on the obtained results, we suggest the folꢀ tion of
1
with
2 (catalyzed by HoCl · 6H O) in the
3 2
lowing simplified scheme of CL excitation in the conꢀ
1
presence of 3 synthesized separately and introduced
densation of
hydrate:
1
with
2
catalyzed by the crystalline
into the system before the reaction. In this case, the
CL spectrum observed in the region of the first maxiꢀ
3
2
*
mum is due to emission from E1 . Thus, we found
3
Ln ⋅4L
1
1
*
С Н NH + C H O ⎯⎯⎯→ E
,
(I) that the Ln3+ ion accepts energy from intermediate 16
6
5
2
4
8
3
1
1
1
1
rather than product
The above results of the simulation of possible
chemiluminescent steps of the condensation of with
2 catalyzed by the crystalline hydrate suggest the folꢀ
3 (as was assumed earlier [1]).
*
E → E + hν1,
(II)
(III)
(IV)
3
1
1
2
1
1
1
3
2
1
2
1
*
*
E + E → E + E → E + hν
,
2
1
3
1
3+
1
1
3+*
3+
*
E + Tb → E + Tb → Tb + hν3,
1
lowing probable mechanism for the formation of
(Scheme 10).
3
where Ln · 4L = LnCl · 4DMF (Ln = Tb, Ho),
3
1
E1 is 3ꢀethylꢀ2ꢀpropylꢀ1,2ꢀdihydroquinoline,
The dissolution of the crystalline hydrate catalyst in
2
DMF (I) produces the LnCl · 4DMF complex (
τ
and E1 is 3ꢀethylꢀ2ꢀpropylquinoline.
3
3+
Tb * = 1300
±
130
80
µ
s), which forms complex
A
3+
Scheme 9.
(
τ
Tb * = 800
molecules
in free and reacts with
Schiff base in the aldimine form (12). Complex
reacts with via reaction (IIIb) to form the Schiff base
in the enamine form (12') as a component of complex
±
µ
s) with a small proportion of
is
via reaction (IIIa) to form a
1
via reaction (II). The major portion of 1
2
In this scheme, the first step is the formation of the
A
3
E
1
1
*
triplet excited molecule
vated, in a way depending on the nature of the crystalꢀ
line hydrate catalyst. When the crystalline hydrate is
(I), which is then deactiꢀ
2
B
B
. The two forms of Schiff bases 12 and 12' in complex
react via reaction (IV) yielding compound 17
HoCl3
⋅
6H O, phosphorescence (II) is observed and
2
2
energy is transferred to E1 to bring it into the triplet
excited state, which is also deactivated with phosphoꢀ
rescence emission (III). For the Tb crystalline
hydrate, energy transfer to the Tb ion brings it into
the emitting excited state (reaction (IV)). Energy
(Scheme 7), which is bound with Ln into complex
C.
Next, complex simultaneously undergoes cyclizaꢀ
C
tion and elimination via reaction (V) to evolve a rather
large amount of energy (~64 kcal/mol), As a result,
3+
compound 17 is formed in the ground and excited
3
E
1
1
2
2
*
transfer from
to E1 (product
3
) is confirmed by states (CL emitter E1 ) and complex
A
is formed,
the high intensity of the first CL peak in the condensaꢀ which starts a new catalytic cycle. The oxidative conꢀ
KINETICS AND CATALYSIS Vol. 51
No. 4
2010

540
BULGAKOV et al.
LnCl · 6H O +
3
хDMF
→
LnCl · 4DMF + 6(Н О) · (DMF)m + (
х
– 6m)DMF
(I)
II)
2
3
2
,
+
Ln · 4L
(
NH2
NH2
Ln
1
A
·
L
O
,
+
Et –H O
2
(IIIa)
Et
NH2
N
1
2
12
(
aldimine form
)
O
+
H
N
Et –H
O
2
,
Et
(IIIb)
NH2
A
2
Б
Ln
·
L
·
Ln L
1
2'
(enamine form
)
Ph
H
H
B
12
N
Ph N
Et
Ln
·
L
Et
Ln
N
·
L
,
(IV)
Et
Et
N
H
B
12'
B
Ph
H
N
·
Ln L
Et
Et
+
,
(
V)
Et
Et
N
N
N
NH2
Ln
H
H
C
16
A
·
L
Et
Et
[
O]
Et –2H
(VI)
Et
N
H
16
3
where Ln · L = Ln ·
хDMF (Ln = Tb, Ho;
x
≤
4).
Scheme 10.
version of 17 into the target product
is possible due to the presence of the following oxidizꢀ to suggest a probable scheme for the formation of 3ꢀ
ethylꢀ2ꢀpropylquinoline in the condensation of
3 via reaction (VI) methods and thermodynamic calculations allowed us
ers in the reaction system: dissolved oxygen, comꢀ
pound 12, and excess compound
aniline with butyraldehyde catalyzed by LnCl3 6H O.
⋅
2.
2
ACKNOWLEDGMENTS
CONCLUSIONS
The simulation of separate steps of the reaction
This work was supported by the Russian Foundaꢀ
using the chemiluminescence and photoluminescence tion for Basic Research, project no. 05ꢀ03ꢀ97906.
KINETICS AND CATALYSIS Vol. 51
No. 4
2010

ON THE MECHANISM OF THE CHEMILUMINESCENT CONDENSATION
541
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