Synthesis and complexing ability of 2-(2-ethoxycarbonyl-3-oxo-3- polyfluoroalkylprop-1-enylamino) benzoic acids

Article abstract of DOI:10.1007/s11172-009-0161-9

The condensation of ethyl 2-ethoxymethylidene-3-oxo-3- polyfluoroalkylpropionates with 2-aminobenzoic acid occurs at the ethoxymethylidene substituent and gives 2-(2-ethoxy-carbonyl-3-oxo-3- polyfluoroalkylprop-1-enylamino)benzoic acids. These compounds s

Full text of DOI:10.1007/s11172-009-0161-9

Russian Chemical Bulletin, International Edition, Vol. 58, No. 6, pp. 1241—1247, June, 2009
1241
Synthesis and complexing ability of
2ꢀ(2ꢀethoxycarbonylꢀ3ꢀoxoꢀ3ꢀpolyfluoroalkylpropꢀ1ꢀenylamino)
benzoic acids*
Yu. S. Kudyakova, M. V. Goryaeva, Ya. V. Burgart, V. I. Saloutin, and P. A. Slepukhin
I. Ya. Postovsky Institute of Organic Synthesis, Ural Branch of the Russian Academy of Sciences,
22/20 ul. S. Kovalevskoi, 620041 Ekaterinburg, Russian Federation.
Fax: +7 (343) 374 5954. Eꢀmail: saloutin@ios.uran.ru
The condensation of ethyl 2ꢀethoxymethylideneꢀ3ꢀoxoꢀ3ꢀpolyfluoroalkylpropionates with
2ꢀaminobenzoic acid occurs at the ethoxymethylidene substituent and gives 2ꢀ(2ꢀethoxyꢀ
carbonylꢀ3ꢀoxoꢀ3ꢀpolyfluoroalkylpropꢀ1ꢀenylamino)benzoic acids. These compounds serve
as new O,N,Oꢀtridentate ligands capable of forming nickel(II) and copper(II) complexes.
Key words: 2ꢀethoxymethylideneꢀ3ꢀoxoꢀ3ꢀpolyfluoroalkylpropionates, 2ꢀaminobenzoic
acid, ligands, nickel complexes, copper complexes, organofluorine compounds.
1,3ꢀDicarbonyl compounds and their amino derivaꢀ
tives are commonly recognized as templates for the
formation of metal complexes.1—5 The complexing ability
of these compounds is responsible for various aspects
of their practical use, including for the separation of
mixtures of rareꢀearth metals, for the extraction fluoroꢀ
metric determination of elements, and as shiftꢀreagents in
NMR spectroscopy.1,2 Metal chelates of 1,3ꢀdicarbonyl
compounds are used as antioxidants, lubricating oil addiꢀ
tives, and catalysts for the oxidation, addition, and polyꢀ
merization,1,2 as well as for the preparation of metal oxide
coatings, the introduction of metals into highꢀtemperaꢀ
ture superconducting films,6,7 and the design of electroꢀ
luminescent diodes.8
that the latter compounds, unlike nonfluorinated anaꢀ
logs,10 do not form stable metal complexes.
In the present study, we used 2ꢀaminobenzoic acid,
whose carboxy group can serve as an additional coordinaꢀ
tion center, as the nucleophilic agent in the reactions
with ethyl 2ꢀethoxymethylideneꢀ3ꢀoxoꢀ3ꢀfluoroalkylꢀ
propionates 1a—c.
Thus, esters 1a—c easily undergo the condensation
with 2ꢀaminobenzoic acid at the ethoxymethylidene
substituent in diethyl ether at room temperature to form
2ꢀ(2ꢀethoxycarbonylꢀ3ꢀoxoꢀ3ꢀpolyfluoroalkylpropꢀ1ꢀenylꢀ
amino)benzoic acids 2a—c (Scheme 1). Products 2a—c
are crystalline compounds, which were isolated and
purified by the crystallization from ethanol.
Nowadays, the design of multidentate ligands capable
of forming coordination clusters and supramolecular strucꢀ
tures assumes great importance.9 Functionalized derivaꢀ
tives of 1,3ꢀdicarbonyl compounds containing reactive
groups, which assist in introducing additional coordinaꢀ
tion centers into the molecules, are convenient building
blocks for this purpose. Readily accessible 2ꢀalkoxyꢀ
methylideneꢀ3ꢀoxoalkanoates can be used as such comꢀ
pounds. A series of monoꢀ,10 biꢀ,11ꢀ13 triꢀ,14 and hexaꢀ
dentate ligands were synthesized starting from nonfluoriꢀ
nated alkyl 2ꢀethoxymethylideneꢀ3ꢀoxoalkanoates.15
Previously, we have synthesized ethyl 2ꢀethoxymethylꢀ
ideneꢀ3ꢀoxoꢀ3ꢀpolyfluoroalkylpropionates and used these
compounds in the reactions with various monoamines to
prepare ethyl 2ꢀalkylꢀ and ethyl 2ꢀ(het)arylaminomethylꢀ
ideneꢀ3ꢀoxoꢀ3ꢀpolyfluoroalkylpropionates.16 It was found
Scheme 1
RF = CF3 (a), H(CF2)2 (b), C3F7 (c).
The NH proton of acids 2a—c is rather labile and can
be involved in different tautomeric transformations, as
well as in interꢀ and intramolecular hydrogen bonding.
Due to this fact, acids 2a—c can be involved in ketoꢀenol
* Dedicated to Academician O. N. Chupakhin on the occasion
of his 75th birthday.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1207—1212, June, 2009.
1066ꢀ5285/09/5806ꢀ1241 © 2009 Springer Science+Business Media, Inc.

1242
Russ.Chem.Bull., Int.Ed., Vol. 58, No. 6, June, 2009
Kudyakova et al.
and aminoꢀimino tautomerism and can exist as iminoꢀ
ketone (IK), iminoꢀenol (IE), and/or aminoꢀketone (AK)
tautomers. In addition, the AK tautomer can exhibit Z,E
isomerism resulting from different positions of the substiꢀ
tuents with respect to the C=C bond. The Z isomer (ZꢀAK)
is stabilized by an intramolecular hydrogen bond with the
involvement of the ethoxycarbonyl substituent, whereas
the E isomer (EꢀAK) is stabilized by an intramolecular
hydrogen bond with the polyfluoroacyl fragment.
Fig. 2. Hydrogen bonds in the crystal structure of compound 2a
along the diagonal of the ab plane based on the Xꢀray diffraction
data.
the NH group. These IR spectroscopic data are in better
agreement with the AK isomers of acids 2a—c, which was
confirmed by the Xꢀray diffraction study of compound 2a
(Figs 1 and 2).
According to the Xꢀray diffraction data, acid 2a exists
in the crystal as the sꢀcis,sꢀcis conformer of the EꢀAK
isomer with the trifluoromethyl and ethoxy substituents
in adjacent positions. The NH hydrogen atom is involved in
two intramolecular hydrogen bonds with the oxygen atom
of the trifluoroacetyl substituent (N(1)—H(1)...O(5)) and
the oxygen atom of the carboxy group (N(1)—H(1)...O(1))
(see Fig. 1, Table 1).
In the crystal structure, molecules 2a form chains
through strong intermolecular hydrogen bonds between
the oxygen atom of the ethoxycarbonyl fragment of one
molecule and the hydrogen atom of the carboxy group of
another molecule O(2)—H(2)...O(3) #1 [x + 1, y + 1, z]
(see Fig. 2, Table 1).
The solidꢀstate structures of acids 2a—c were studied
by IR spectroscopy and Xꢀray diffraction. Thus, the
IR spectra of compounds 2a—c show three groups of
intense absorption bands at 1709—1702, 1691—1682, and
1663—1640 cm–1 assigned to the stretching vibrations of
three nonequivalent carbonyl groups (CO2Et, CO2H, and
RFC=O, respectively) and intense absorption bands at
3150—3086 cm–1 corresponding to the stretching vibraꢀ
tions of NH and OH groups involved in hydrogen bondꢀ
ing.17 The lowꢀfrequency shift of the absorption bands of
the carbonyl groups is attributed to their conjugation with
the C=C bond and the involvement of two of these groups
in the formation of intramolecular hydrogen bonds with
Then the structures of compounds 2a—c were studied
in a chloroform solution by IR and NMR spectroscopy.
In the IR spectra of compounds 2a—c recorded in a
3% CHCl3 solution, the absorption bands of virtually all
characteristic groups are substantially broadened. This fact
indicates that the acids undergo structural changes upon
dissolution.
1
The H NMR spectra of compounds 2a—c measured
in CDCl3 show two sets of signals, the signals for the
protons of the NH and CH= groups being observed at low
field (δCH ≈ 8.51—8.72, δNH ≈ 12.78—13.60) as doublets with
the spinꢀspin coupling constant of ~14 Hz. The 19F NMR
spectra of compounds 2a—c are also characterized by the
doubling of the resonances for the fluorine nuclei. It can
F(1)
O(5)
C(11)
O(1)
F(3)
C(10)
O(2)
C(9)
C(12)
F(2)
C(1)
Table 1. Parameters of D—H...A hydrogen bonds in the crystal
packing of compound 2a
C(8)
O(4)
C(2)
C(6)
C(5)
N(1)
D—H...А
D—H
H...A
D—H...A
/deg
D...A
C(7)
O(3)
C(13)
/Å
C(14)
C(3)
Å
N(1)—H(1)...O(1) 0.89(2) 1.93(2) 137.3(1.4) 2.656(2)
N(1)—H(1)...O(5) 0.89(2) 2.10(2) 124.4(1.4) 2.711(2)
O(2)—H(2)...O(3)#1 0.92(2) 1.75(2) 166.1(1.9) 2.648(2)
C(4)
Fig. 1. Molecular structure of compound 2a with displacement
Note: The symmetry code#1: [x + 1, y + 1, z].
ellipsoids drawn at the 50% probability level.

Fluorinated O,N,Oꢀtridentate ligands
Russ.Chem.Bull., Int.Ed., Vol. 58, No. 6, June, 2009
1243
Table 2. Content of the Z and E isomers in soluꢀ
tions of compounds 2a—c in CDCl3 according
to the NMR
be concluded that in a chloroform solution, compounds
2a—c exist as mixtures of Z and E isomers of the AK
tautomer, as opposed to the solid state, in which only one
isomeric form (EꢀAK) is observed.
Comꢀ
pound
RF
Content (%)
It is known that compounds containing functional
groups at the double bond, which are responsible for the
polarization of this bond or its involvement in the conjuꢀ
gation system, have a substantially lower barrier to rotaꢀ
tion about the C=C bond.18,19 This is particularly typical
of enamino ketones, the soꢀcalled pushꢀpull olefins, which
contain electronꢀwithdrawing substituents on one side and
electronꢀdonating substituents on another side. In these
compounds, the formally double C=C bond has a partial
singleꢀbond character due to the electron delocalization.
As a result, the barrier to rotation about the double bond
is substantially lower than that in normal olefins.18 In the
case under consideration, the crystallization affords
apparently only the conformational E isomer, which is
partially isomerized to the Z isomer upon dissolution.
Presumably, the isomerization occurs through the resoꢀ
nance structures I and II (Scheme 2).
E
Z
2a
2b
2c
CF3
(CF2)2H
C3F7
62
60
53
38
40
47
of the CF3 and αꢀCF2 groups of the Z isomer containing
the free polyfluoroacyl group are characterized by a
downfield shift with respect to the corresponding signals
of the hydrogenꢀbonded polyfluoroacyl group in the
E isomer. Thus, the 19F NMR spectrum of compound 2a
recorded in CDCl3 shows a signal of the trifluoromethyl
group at δ 89.79 assigned to the Z isomer and a signal at
δ 88.91 assigned to the E isomer. The similar assignment
was made for compounds 2b,c.
Therefore, we showed that compounds 2a—c exist in
a CDCl3 solution as mixtures of Z and E isomers, with
the more stable E isomer predominating (Table 2). An
increase in the length of the polyfluoroalkyl substituent
leads to an increase in the percentage of the Z isomer.
We investigated the complexing ability of acids 2a—c
with respect to transition metal cations. The structures of
these compounds suggest that they can form metal comꢀ
plexes through the coordination with the involvement of
the O,N,Oꢀtridentate fragment and the salt formation at
the carboxy substituent.
Scheme 2
Scheme 3
R = 2ꢀC6H4CO2H
The assignment of the Z and E isomers in the 1H NMR
spectra of compounds 2a—c was made based on the data
obtained previously for esters of 2ꢀalkylꢀ, 2ꢀarylꢀ, and
2ꢀhetarylaminomethylideneꢀ3ꢀoxoꢀ3ꢀpolyfluoroalkylꢀ
propionic acids,16 according to which the CH and NH
protons of the E isomer are observed at lower field comꢀ
pared to the corresponding protons of the Z isomer. The
large shifts δNH for the E isomer are indicative of a stronꢀ
ger intramolecular hydrogen bond in this isomer and,
consequently, of the higher stability of the E isomer.
Based on the analysis of the 19F NMR spectroscopic
data for 2ꢀalkylꢀ, 2ꢀarylꢀ, and 2ꢀhetarylaminomethylꢀ
ideneꢀ3ꢀoxoꢀ3ꢀpolyfluoroalkylpropionates,16 the signals
(for 3d)
3: RF = CF3, M = Ni (a), Cu (b); RF = (CF2)2H, M = Ni (c), Cu (d);
RF = C3F7, M = Ni (e), Cu (f).

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Russ.Chem.Bull., Int.Ed., Vol. 58, No. 6, June, 2009
Kudyakova et al.
Table 3. Selected geometric parameters of the coordination unit
in the crystal packing of compound 4
The treatment of acids 2a—c with nickel(II) and
copper(II) salts afforded compounds 3a—f (Scheme 3).
The elemental analysis data for compounds 3a—f
dried at 60 °C correspond to the composition ML•H2O,
where L is the dideprotonated ligand. The elemental
analysis data obtained after careful drying of compounds
3 at 170—180 °C are consistent with the composition ML.
A comparative analysis of the IR spectra of ligands
2a—c and complexes 3a—f revealed substantial differꢀ
ences in the absorption band regions corresponding to the
vibrations of the carbonyl group of the acidic fragment.
Thus, the band of the carbonyl group of the carboxy subꢀ
stituent in ligands 2 is observed at 1663—1640 cm–1,
whereas the absorption of the carbonyl groups of comꢀ
plexes 3 is manifested at 1589—1583 cm–1, which is
indicative of their carboxylate nature. The vibrations of
the ethoxycarbonyl group in ligands 2 and complexes 3
are observed in almost the same regions (1709—1702 cm–1).
The absorption bands of the carbonyl groups of the
polyfluoroacyl moieties in complexes 3 are characterized
by small lowꢀfrequency shifts (1690—1680 cm–1) comꢀ
pared to the corresponding bands of free ligands 2 (1691—
1682 cm–1). The IR spectra of completely dried comꢀ
pounds 3a—f show also broadened absorption bands in
the 3460—3128 cm–1 region corresponding to the stretchꢀ
ing vibrations of the hydroxy groups of a coordinated
water molecule. The difficulties in eliminating water from
complexes 3a—f are apparently attributed to the fact that
the coordination number 4 is most typical of the divalent
copper cation, and the water molecule is required for the
saturation of the copper coordination sphere.
Bond
d/Å
Angle
ω/deg
Cu(1)—O(1)
Cu(1)—N(1)
Cu(1)—O(3)
Cu(1)—N(2)
1.925(3)
O(1)—Cu(1)—O(3)
147.52(14)
177.77(19)
91.46(12)
90.11(14)
90.33(12)
89.08(14)
1.935(4) N(1)—Cu(1)—N(2)
1.942(2) O(1)—Cu(1)—N(1)
2.014(3) N(1)—Cu(1)—O(3)
Cu(1)—O(2)#1 2.219(3) O(1)—Cu(1)—N(2)
O(3)—C(10)
C(9)—C(10)
C(9)—C(13)
N(1)—C(13)
O(1)—C(1)
1.259(4) O(3)—Cu(1)—N(2)
1.393(5)
1.420(5)
1.297(5) O(3)—Cu(1)—O(2)#1 107.87(14)
1.274(4) N(2)—Cu(1)—O(2)#1 89.46(13)
C(13)—N(1)—Cu(1) 125.2(3)
O(1)—Cu(1)—O(2)#1 104.60(11)
N(1)—Cu(1)—O(2)#1 88.81(12)
C(7)—N(1)—Cu(1)
117.6(3)
C(10)—O(3)—Cu(1) 129.7(3)
C(1)—O(1)—Cu(1)
C(10)—C(9)—C(13)
127.6(2)
120.0(4)
C(14)—N(2)—Cu(1) 124.6(3)
C(18)—N(2)ꢀCu(1) 117.4(3)
Note: The symmetry code#1: [#1 x, –y, z + 1/2], #2: [x, –y,
z – 1/2].
To confirm the structures of products 3a—f, we synꢀ
thesized complex 4 from compound 3d and pyridine (see
Scheme 3). The Xꢀray diffraction study of complex 4
showed that the molecule contains a tridentate unit, in
which the copper(II) cation is coordinated by the hydroxy
oxygen atom, the nitrogen atom of the aminobenzoic
fragment, and the oxygen atom of the fluoroacyl substituꢀ
ent (Fig. 3). The saturation of the coordination sphere of
the copper(II) cation is achieved as a result of coordinaꢀ
tion by the nitrogen atom of pyridine serving as a coꢀ
ligand. The coordination environment of the copper(II)
1
Unfortunately, we failed to interpret the H NMR
spectra of complexes 3a—f because of a strong broadening
of the signals. In addition, we failed to grow crystals of
complexes 3a—f suitable for Xꢀray diffraction.
O(2)
C(3)
С(1)
C(18)
C(17)
С(2)
O(2)
C(4)
C(5)
C(16)
C(15)
Cu(1)
N(1)
N(2)
C(7)
C(14)
C(6)
O(3)
C(10)
C(9)
C(13)
F(2)
F(3)
F(4)
C(11)
С(8)
С(19)
O(5)
F(1)
С(20)
C(12)
O(4)
Fig. 3. Molecular structure of compound 4 with displacement
Fig. 4. Molecular packing of compound 4 along the c axis.
ellipsoids drawn at the 50% probability level.

Fluorinated O,N,Oꢀtridentate ligands
Russ.Chem.Bull., Int.Ed., Vol. 58, No. 6, June, 2009
1245
measured on a Xcalibur 3 diffractometer at 295(2) K (ω/2θ
scanning technique, MoꢀKα radiation, graphite monochromaꢀ
tor, CCD detector), 2870 independent reflections (Rint = 0.0290),
1948 reflections with Fo > 4σ(Fo). The analytical absorption
correction was applied using a multifaceted crystal model. The
structure was solved by direct methods and refined by the leastꢀ
squares method with the use of the SHELXLꢀ97 program packꢀ
age20 to R1 = 0.0295, wR2 = 0.0470, and GOOF = 1.002 (based
on reflections with I > 2σ(I)).
The complete crystallographic data for compounds 2c and 4
were deposited with the Cambridge Crystallographic Data
Centre (CCDC 720575 and CCDC 720576) and can be obꢀ
tained, free of charge, on application to www.ccdc.cam.ac.uk/
conts/retrieving.html (orwww.ccdc.cam.ac.uk/conts/retrieving.html
CCDC, 12 Union Road, Cambridge CB2 1EZ, UK; fax:
+44 1223 336033; eꢀmail: deposit@ccdc.cam.ac.uk).
atom can be described as a distorted square pyramid, whose
apical position is occupied by the oxygen atom O(2) #1
[x, –y, z + 1/2] of the adjacent molecule. The dihedral
angle between the planes of the O(1)—Cu(1)—N(1) and
O(3)—Cu(1)—N(1) fragments is 32.46°. The chelate ring
at the tetrafluoroethyl substituent is characterized by a
high degree of electron density delocalization, which is
reflected in an essential equalization of the pairs of the
C(9)—C(13), C(9)—C(10) and O(3)—C(10), N(1)—C(13)
bond lengths. Principal geometric parameters of the coꢀ
ordination unit are presented in Table 3.
The crystal packing of complex 4 consists of polyꢀ
meric chains formed as a result of the additional coordinaꢀ
tion of the copper ion by the oxygen atom of the carboxyꢀ
late group of the adjacent molecule (Fig. 4).
To sum up, we have performed reactions of fluoroꢀ
alkylated 2ꢀethoxymethylideneꢀ3ꢀoxo esters 1 with 2ꢀaminoꢀ
benzoic acid giving new O,N,Oꢀtridentate ligands capable
of coordinating transition metal cations.
Reaction of ethyl 2ꢀethoxymethylideneꢀ3ꢀoxoꢀ3ꢀpolyfluoroꢀ
alkylpropionates 1 with 2ꢀaminobenzoic acid (general procedure).
A mixture of ester 1 (4 mmol) and 2ꢀaminobenzoic acid
(4 mmol) in Et2O (10 mL) was stirred at room temperature for
2—4 h. Then the reaction mixture was concentrated, and the
precipitate that formed was crystallized from ethanol and dried.
(2E)ꢀ2ꢀ(2ꢀEthoxycarbonylꢀ4,4,4ꢀtrifluoroꢀ3ꢀoxobutꢀ1ꢀenylꢀ
amino)benzoic acid (2a). The yield was 0.98 g (74%), m.p. 175—
176 °C. IR, ν/cm–1: 3150 (NH); 2999 (C—H); 1704 (CO2Et);
1682 (CORF); 1640 (CO2H); 1609, 1579 (C=C, NH); 1206—1145
Experimental
The melting points were measured in open capillaries on a
Stuart SMP3 meltingꢀpoint apparatus. The diffuse reflectance
IR spectra were recorded on a Perkin Elmer Spectrum One
Fourierꢀtransform IR spectrometer in the 400—4000 cm–1 reꢀ
gion. The NMR spectra were measured on Bruker DRXꢀ400
spectrometers (400 MHz for 1H and 376 MHz for 19F) with
1
(C—F). H NMR (CDCl3), δ, E isomer (62%): 1.36 (t, 3 H,
OCH2CH3, 3J = 7.2 Hz); 4.33 (q, 2 H, OCH2CH3, 3J = 7.2 Hz);
7.34 (ddd, 1 H, H(4´), 3JH(4´),H(3´) = 7.9 Hz, 3JH(4´)—H(5´) = 7.7 Hz,
4JH(4´)—H(6´) = 1.0 Hz); 7.55 (dd, 1 H, H(6´), 3JH(6´),H(5´)= 8.4 Hz,
4JH(6´)—H(4´) = 1.0 Hz); 7.70 (ddd, 1 H, H(5´), 3JH(5´),H(6´) = 8.4 Hz,
1
SiMe4 and C6F6 as the internal standard for H and 19F NMR,
4
3J(5´),H(4´) = 7.7 Hz, JH(5´),H(3´) = 1.5 Hz); 8.24 (dd, 1 H,
3
4
respectively. The chemical shifts and the spinꢀspin coupling
constants were measured with an accuracy of 0.01 ppm and
0.1 Hz, respectively. The elemental analysis was carried out on
an automated Perkin Elmer PEꢀ2400 series II CHNSꢀO
elemental analyzer. The course of the reactions was monitored
by TLC on Sorbfil PTSKhꢀAFꢀVꢀUF plates.
The starting ethyl 2ꢀethoxymethylideneꢀ3ꢀoxoꢀ3ꢀpolyfluoroꢀ
alkylpropionates 1a—c were synthesized according to a proceꢀ
dure described previously.16
H(3´), JH(3´),H(4´) = 7.9 Hz, JH(3´),H(5´) = 1.5 Hz); 8.72 (d,
1 H, CH, 3J = 13.9 Hz); 13.60 (d, 1 H, NH, 3J = 13.9 Hz); 13.87
3
(br.s, 1 H, OH); Z isomer (38%): 1.38 (t, 3 H, OCH2CH3, J =
= 7.1 Hz); 4.40 (q, 2 H, OCH2CH3, 3J = 7.1 Hz); 7.30 (ddd, 1 H,
H(4´), 3 JH(4´),H(3´) = 8.0 Hz, 3 JH(4´),H(5´) = 7.6 Hz, 4JH(4´),H(6´)
=
3
= 1.0 Hz); 7.48 (dd, 1 H, H(6´), JH(6´)—H(5´)= 8.5 Hz,
4JH(6´)—H(4´) = 1.0 Hz); 7.69 (ddd, 1 H, H(5´), JH(5´),H(6´)
=
3
= 8.5 Hz, 3J(5´),H(4´) = 7.6 Hz, JH(5´),H(3´) = 1.5 Hz); 8.22 (dd,
4
3
4
1 H, H(3´), JH(3´),H(4´) = 8.0 Hz, JH(3´),H(5´) = 1.5 Hz); 8.55
3
3
Single crystals of compound 2c were obtained by crystallizaꢀ
(d, 1 H, CH, J = 13.8 Hz); 13.03 (d, 1 H, NH, J = 13.8 Hz);
13.87 (br.s, 1 H, OH). 19F NMR (CDCl3), δ, E isomer (62%):
88.91 (s, CF3); Z isomer (38%): 89.79 (s, CF3). Found (%):
C, 50.72; H, 3.58; F, 17.13; N, 4.17. C14H12F3NO5. Calcuꢀ
lated (%): C, 50.76; H, 3.65; F, 17.21; N, 4.23.
tion from ethanol, C14H12F3NO5, M = 331.25, triclinic crystals,
–
space group P1, a = 7.2980(5) Å, b = 8.9895(6) Å, c =
= 11.4924(7) Å, α = 93.665(5)°, β = 90.261(5)°, γ = 105.204(6)°,
V = 725.91(8) Å3, Z = 2, dcalc = 1.515 g cm–3, μ(MoꢀKα) =
= 0.139 cm–1, F(000) = 340. A total of 7061 reflections were
measured on a Xcalibur 3 diffractometer at 295(2) K (ω/2θ
scanning technique, MoꢀKα radiation, graphite monochromaꢀ
tor, CCD detector), 3437 independent reflections (Rint = 0.0250),
1910 reflections with Fo > 4σ(Fo). The structure was solved by
direct methods and refined by the leastꢀsquares method with
the use of the SHELXLꢀ97 program package20 to R1 = 0.0378,
wR2 = 0.0813, and GOOF = 1.002 (based on reflections with
I > 2σ(I)).
(2E)ꢀ2ꢀ(2ꢀEthoxycarbonylꢀ4,4,5,5ꢀtetrafluoroꢀ3ꢀoxopentꢀ
1ꢀenylamino)benzoic acid (2b). The yield was 1.13 g (78%),
m.p. 183—185 °C. IR, ν/cm–1: 3150, 3086 (NH); 2986 (C—H);
1709 (CO2Et); 1692 (CORF); 1656 (CO2H); 1608, 1585, 1569
(C=C, NH); 1233—1079 (C—F). 1H NMR ((CD3)2SO), δ,
3
E isomer (61%): 1.29 (t, 3 H, OCH2CH3, J = 7.1 Hz); 4.23
(q, 2 H, OCH2CH3, 3J = 7.1 Hz); 6.99 (tt, 1 H, H(CF2)2, 2JH,F
=
=
=
= 52.7 Hz, 3JH—F = 5.7 Hz); 7.38 (br.t, 1 H, H(4´), 3 JH(4´),H(3´)
3
= JH(4´),H(5´) = 7.7 Hz); 7.74 (ddd, 1 H, H(5´), JH(5´),H(6´)
= 8.2 Hz, 3J(5´),H(4´) = 7.7 Hz, 4JH(5´),H(3´) = 1.4 Hz); 7.83 (br.d,
Single crystals of compound 4 were obtained by crystallizaꢀ
tion from ethanol, C20H16F4N2O5Cu, M = 503.89, monoclinic
crystals, space group Cc, a = 15.4178(16) Å, b = 17.493(2) Å,
c = 9.3890(10) Å, α = 90.00°, β = 103.885(10)°, γ = 90.00°,
V = 2009.5(4) Å3, Z = 4, dcalc = 1.666 g cm–3, μ(MoꢀKα) =
= 1.160 cm–1, F(000) = 1020. A total of 4938 reflections were
3
1 H, H(6´), JH(6´),H(5´)= 8.2 Hz); 8.04 (dd, 1 H, H(3´),
4
3JH(3´),H(4´) = 7.7 Hz, JH(3´),H(5´) = 1.4 Hz); 8.65 (d, 1 H, CH,
3
3J = 14.0 Hz); 13.57 (d, 1 H, NH, J = 14.0 Hz); 13.90 (br.s,
1 H, OH); Z isomer (39%): 1.31 (t, 3 H, OCH2CH3, 3J = 7.1 Hz);
3
4.33 (q, 2 H, OCH2CH3, J = 7.1 Hz); 6.88 (tt, 1 H, H(CF2)2,

1246
Russ.Chem.Bull., Int.Ed., Vol. 58, No. 6, June, 2009
Kudyakova et al.
2J = 52.4 Hz, 2J = 5.6 Hz); 7.32 (br.t, 1 H, H(4´), 3JH(4´),H(3´)
=
=
(CO2Et); 1682 (CORF); 1656, 1645 (C=C); 1588 (COO–);
1259—1080 (C—O, C—F). Found (%): C, 42.87; H, 2.58;
F, 18.07; N, 3.29. C15H11F4NO5Ni. Calculated (%): C, 42.90;
H, 2.64; F, 18.10; N, 3.34.
2ꢀ(2ꢀEthoxycarbonylꢀ4,4,5,5ꢀtetrafluoroꢀ3ꢀoxopentꢀ1ꢀenylꢀ
aminato)benzoatocopper(II) (3d). The yield was 1.13 g (89%),
m.p. 197—199 °C. IR, ν/cm–1: 3071, 2985 (C—H); 1708 (CO2Et);
1685 (CORF); 1617 (C=C); 1585 (COO–); 1227—1096 (C—O,
C—F). Found (%): C, 42.41; H, 2.60; F, 17.88; N, 3.20.
C15H11F4NO5Cu. Calculated (%): C, 42.41; H, 2.61; F, 17.89;
N, 3.30.
2ꢀ(2ꢀEthoxycarbonylꢀ4,4,5,5,6,6,6ꢀheptafluoroꢀ3ꢀoxohexꢀ
1ꢀenylaminato)benzoatonickel(II) (3e). The yield was 1.24 g
(85%), t.decomp. 310—315 °C. IR, ν/cm–1: 2985 (C—H); 1704
(CO2Et); 1688 (CORF); 1637 (C=C); 1590 (COO–); 1225—1117
(C—O, C—F). Found (%): C, 39.25; H, 2.03; F, 27.18; N, 2.90.
C16H10F7NO5Ni. Calculated (%): C, 39.38; H, 2.07; F, 27.25;
N, 2.87.
2ꢀ(2ꢀEthoxycarbonylꢀ4,4,5,5,6,6,6ꢀheptafluoroꢀ3ꢀoxohexꢀ
1ꢀenylaminato)benzoatocopper(II) (3f). The yield was 1.21 g
(82%), m.p. 188—189 °C. IR, ν/cm–1: 3075, 2986 (C—H); 1702
(CO2Et); 1690 (CORF); 1651 (C=C); 1584 (COO–); 1216—1119
(C—O, C—F). Found (%): C, 38.95; H, 2.00; F, 26.88; N, 23.78.
C16H10F7NO5Cu. Calculated (%): C, 39.00; H, 2.05; F, 26.99;
N, 2.84.
3
= JH(4´),H(5´) = 7.6 Hz); 7.69 (ddd, 1 H, H(5´), JH(5´),H(6´)
3
4
= 8.5 Hz, J(5´),H(4´) = 7.6 Hz, JH(5´),H(3´) = 1.4 Hz); 7.78
3
(br.d, 1 H, H(6´), JH(6´),H(5´)= 8.5 Hz); 8.03 (dd, 1 H, H(3´),
3JH(3´),H(4´) = 7.6 Hz, 4JH(3´)—H(5´) = 1.4 Hz); 8.51 (d, 1 H, CH,
3J = 14.2 Hz); 12.78 (d, 1 H, NH, J = 14.2 Hz); 13.90 (br.s,
3
1 H, OH). 19F NMR ((CD3)2SO), δ, E isomer (61%): 25.21 (dt,
2 F, CF2H, J = 52.7 Hz, J = 8.0 Hz); 41.46 (m, 2 F, CF2);
Z isomer (39%): 24.48 (dt, 2 F, CF2H, J = 52.4 Hz, J = 8.2 Hz);
42.24 (m, 2 F, CF2). Found (%): C, 49.52; H, 3.57; F, 20.75;
N, 3.77. C15H13F4NO5. Calculated (%): C, 49.60; H, 3.61;
F, 20.92; N, 3.86.
(2E)ꢀ2ꢀ(2ꢀEthoxycarbonylꢀ4,4,5,5,6,6,6ꢀheptafluoroꢀ3ꢀoxoꢀ
hexꢀ1ꢀenylamino)benzoic acid (2c). The yield was 1.19 g (69%),
m.p. 155—156 °C. IR, ν/cm–1: 3120, 3107 (NH); 2995 (C—H);
1702 (CO2Et); 1691 (CORF); 1663 (CO2H), 1650, 1607, 1573
1
(C=C, NH); 1241—1126 (C—F). H NMR (CDCl3), δ: 1.27
(br.t, 3 H, OCH2CH3, 3J = 7.0 Hz); 8.04 (br.d, 1 H, H(3´),
3JH(3´),H(4´) = 7.7 Hz); 13.92 (br.s, 1 H, OH); E isomer (53%):
3
4.21 (q, 2 H, OCH2CH3, J = 7.2 Hz); 7.38 (br.t, 1 H, H(4´),
3JH(4´),H(3´)
=
3JH(4´),H(5´) = 7.7 Hz); 7.73 (ddd, 1 H, H(5´),
3
3JH(5´),H(6´) = 8.2 Hz, JH(5´),H(4´) = 7.7 Hz); 7.85 (br.d, 1 H,
3
3
H(6´), JH(6´),H(5´) = 8.2 Hz); 8.66 (d, 1 H, CH, J = 14.2 Hz);
13.53 (d, 1 H, NH, 3J = 14.2 Hz); Z isomer (47%): 4.30 (q, 2 H,
3
3
OCH2CH3, J = 7.1 Hz); 7.33 (br.t, 1 H, H(4´), JH(4´),H(3´)
=
=
3
3
= JH(4´),H(5´) = 7.7 Hz); 7.70 (ddd, 1 H, H(5´), JH(5´),H(6´)
Pyridine[2ꢀ(2ꢀethoxycarbonylꢀ4,4,5,5ꢀtetrafluoroꢀ3ꢀoxoꢀ
pentꢀ1ꢀenylaminato)benzoato]copper(II) (4). A mixture of comꢀ
plex 3d (0.5 mmol) and pyridine (0.5 mmol) in ethanol (10 mL)
was refluxed for 2 h. Then the reaction mixture was concenꢀ
trated. The crystals that formed were filtered off. The yield
was 0.24 g (94%), m.p. 234—235 °C. IR, ν/cm–1: 3091, 2990
(C—H); 1703 br. (CO2Et, CORF); 1627, 1607 (C=C); 1586
(COO–); 1220—1096 (C—O, C—F). Found (%): C, 47.52;
H, 3.13; F, 14.98; N, 5.45. C20H16F4N2O5Cu. Calculated (%):
C, 47.67; H, 3.20; F, 15.08; N, 5.56.
3
4
= 8.2 Hz, JH(5´),H(4´) = 7.7 Hz, JH(5´),H(3´) = 1.4 Hz); 7.80
3
(br.d, 1 H, H(6´), JH(6´),H(5´) = 8.2 Hz); 8.51 (d, 1 H, CH,
3J = 14.2 Hz); 12.83 (d, 1 H, NH, J = 14.2 Hz). 19F NMR
3
((CD3)2SO), δ, E isomer (53%): 39.66 (m, 2 F, CF2); 49.71
(m, 2 F, CF2); 82.99 (t, 2 F, CF3, J = 9.2 Hz); Z isomer (47%):
39.18 (m, 2 F, CF2); 50.09 (m, 2 F, CF2); 42.24 (m, 2 F, CF2);
82.96 (t, 2 F, CF3, J = 9.5 Hz). Found (%): C, 44.54; H, 2.79;
F, 30.65; N, 3.15. C16H12F7NO5. Calculated (%): C, 44.56;
H, 2.80; F, 30.84; N, 3.25.
Synthesis of complexes 3a—f (general procedure). A mixture
of acid 2a—c (2 mmol) and nickel (or copper) acetate (2 mmol)
in ethanol (10 mL) was refluxed for 30 min. Then the reaction
mixture was poured into water (20 mL). In the case of comꢀ
pounds 3b,d,f, the precipitate that formed was filtered off and
crystallized from ethanol. Products 3a,c,e were extracted with
chloroform, the extracts were concentrated, and the products
were isolated by column chromatography using chloroform as
the eluent.
This study was financially supported by the Council
on Grants of the President of the Russian Federation
(Program for State Support of Leading Scientific Schools
of the Russian Federation, Grant NShꢀ3758.2008.3).
References
2ꢀ(2ꢀEthoxycarbonylꢀ4,4,4ꢀtrifluoroꢀ3ꢀoxobutꢀ1ꢀenylꢀ
aminato)benzoatonickel(II) (3a). The yield was 1.05 g (90%),
m.p. 167—168 °C. IR, ν/cm–1: 2987 (C—H); 1702 (CO2Et);
1680 (CORF); 1644, 1638, 1610, (C=C, NH); 1589 (COO–);
1275—1162 (C—O, C—F). Found (%): C, 43.26; H, 2.58;
F, 14.60; N, 3.56. C14H10F3NO5Ni. Calculated (%): C, 43.35;
H, 2.60; F, 14.69; N, 3.61.
2ꢀ(2ꢀEthoxycarbonylꢀ4,4,4ꢀtrifluoroꢀ3ꢀoxobutꢀ1ꢀenylꢀ
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C—F). Found (%): C, 42.78; H, 2.51; F, 14.40; N, 3.53.
C14H10F3NO5Cu. Calculated (%): C, 42.81; H, 2.57; F, 14.51;
N, 3.57.
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Received March 25, 2009;
in revised form April 23, 2009