New chiral metal complexes based on 2-ethoxymethylidene-3-oxo-3- polyfluoroalkylpropionates

Article abstract of DOI:10.1134/S107042801103002X

Ethyl 2-ethoxymethylidene-3-oxo-3-polyfluoroalkylpropionates reacted with (1S,2S)-1,2-diphenylethane-1,2-diamine to give diethyl 2,2′-{[(1S,2S)- diphenylethane-1,2-diyl]bis[iminomethylidene]}bis(3-oxo-3-polyfluoroalkyl) alkanoates which were used as ligands to obtain chiral complexes with transition metals.

Full text of DOI:10.1134/S107042801103002X

ISSN 1070-4280, Russian Journal of Organic Chemistry, 2011, Vol. 47, No. 3, pp. 331–339. © Pleiades Publishing, Ltd., 2011.
Original Russian Text © Yu.S. Kudyakova, M.V. Goryaeva, Ya.V. Burgart, V.I. Saloutin, 2011, published in Zhurnal Organicheskoi Khimii, 2011, Vol. 47,
No. 3, pp. 339–346.
New Chiral Metal Complexes Based on 2-Ethoxymethylidene-
3-oxo-3-polyfluoroalkylpropionates
Yu. S. Kudyakova, M. V. Goryaeva, Ya. V. Burgart, and V. I. Saloutin
Postovskii Institute of Organic Synthesis, Ural Division, Russian Academy of Sciences,
ul. S. Kovalevskoi/Akademicheskaya, 22/20, Yekaterinburg, 620041 Russia
e-mail: saloutin@ios.uran.ru
Received May 4, 2010
Abstract—Ethyl 2-ethoxymethylidene-3-oxo-3-polyfluoroalkylpropionates reacted with (1S,2S)-1,2-diphenyl-
ethane-1,2-diamine to give diethyl 2,2′-{[(1S,2S)-diphenylethane-1,2-diyl]bis[iminomethylidene]}bis(3-oxo-3-
polyfluoroalkyl)alkanoates which were used as ligands to obtain chiral complexes with transition metals.
DOI: 10.1134/S107042801103002X
Asymmetric metal complex catalysis acquires in-
creasing importance in coordination and organic chem-
istry, as well as for the manufacture of medicines,
herbicides, and food additives. Classical chiral cata-
lysts are C2-symmetric metal complexes with salen-
type ligands [1, 2]. Such complexes showed a high
catalytic activity in asymmetric Diels–Alder reactions,
epoxidation, oxirane ring opening, cyanation of
imines, and consecutive nucleophilic addition [2].
tion and therapy of diseases related to radical-induced
damage of cells and tissues [3]. Optically active man-
ganese(III) complex obtained from ethyl 2-ethoxy-
methylidene-3-oxobutanoate and (S,S)-1,2-diphenyl-
ethane-1,2-diamine (an acyclic analog of salen-type
metal complexes) was patented as catalyst for the
preparation of optically active epoxides [4]. We pre-
viously demonstrated prospects in using ethyl 2-ethoxy-
methylidene-3-oxo-3-polyfluoroalkylpropionates I as
templates for the synthesis of tri- and tetradentate
Schiff base ligands via reactions with 2-aminobenzoic
acid [5], o-phenylenediamine [6], and ethylenediamine
[7]. We have found no published data on reactions of
Salen metal complexes derived from (S,S)- and
(R,R)-1,2-diphenylethane-1,2-diamine and salicylalde-
hyde were used to develop synthetic catalytic free
radical scavengers useful as antioxidants for preven-
Scheme 1.
Ph
N
Ph
N
O
O
Et2O
H
H
·
·
·
·
·
·
EtO
O
O
OEt
RF
RF
OEt
OEt
Ph
NH2
Ph
IIa–IIc
M(OAc)2
EtOH, Δ
+
RF
Ph
N
Ph
N
H2N
O
O
Ia–Ic
O
O
Ni(OAc)2, EtOH
M
EtO
O
O
OEt
RF
RF
IIIa–IIIf
I, II, RF = CF3 (a), HCF2CF2 (b), C3F7 (c); III, RF = CF3, M = Ni (a), Cu (b); RF = HCF2CF2, M = Ni (c), Cu (d);
RF = C3F7, M = Ni (e), Cu (f).
331

KUDYAKOVA et al.
332
F3a
bonds have similar parameters: d(O3a · · · H1b) =
C12a
F4a
d(O3aa · · · H1bb) = 1. 82(6) Å; ∠ N1aH1bO3a
=
=
∠ N 1 a a H 1 b b O 3 a a = 1 2 9 . 2 2 ° , ∠ C 1 0 a O 3 a H 1 b
∠C10aaO3aaH1bb = 105.42°.
F1a
C10a
C11a
C2a
O3a
O1a
C3a
C1a
F2a
C13a
Comparison of the IR spectra of bis-esters IIa–IIc
(mineral oil) revealed no appreciable differences.
Compounds IIa–IIc characteristically showed in the
IR spectra absorption bands corresponding to stretch-
ing vibrations of the ester carbonyl groups (1710–
1706 cm–1), carbonyl groups in the polyfluoroacyl
fragments (1688–1683 cm–1), and associated NH
groups (3242–3213 cm–1). These findings also indicat-
ed E,E-bis-enaminoketone structure of IIa–IIc, stabi-
lized by two intramolecular hydrogen bonds.
C4a
C6a
C7a
C9a
O2a
C5a
C8a
C14a
N1a
C15a
C15c
C7aa
C14b
C8aa
O2aa
C9aa
O3aa
C5aa
C6aa
C1aa
C4aa
C3aa
N1aa
C13b
O1aa
F2aa
F1aa
C12b
C2aa
C11b
Taking into account the presence of two double
C=C bonds in molecules IIa–IIc, Z,Z and Z,E struc-
tures are also possible (in addition to E,E). Unlike the
E isomer in which the intramolecular hydrogen bond
involves carbonyl oxygen atom in the polyfluoroacyl
fragment, analogous hydrogen bond in the Z isomer is
formed with participation of the ester carbonyl group.
F4aa
F3aa
Fig. 1. Structure of the molecule of diethyl 2,2′-{(1S,2S)-
diphenylethane-1,2-diylbis[iminomethylidene]}bis(4,4,5,5-
tetrafluoro-3-oxopentanoate) (IIb) according to the X-ray
diffraction data.
In fact, unlike crystalline state, the 1H and 19F NMR
spectra of IIa–IIc in CDCl3 revealed the presence of
E,E, Z,Z, and Z,E isomers (see Experimental). Signals
were assigned to particular isomers on the basis of
general relations found by us previously for a large
series of ethyl 2-alkyl(aryl, hetaryl)aminomethylidene-
3-polyfluoroalkyl-3-oxopropionates [8]. Chemical
fluoroalkyl-containing ethyl 2-ethoxymethylidene-3-
oxopropionates I with asymmetric ethane-1,2-di-
amines.
The goal of the present work was to synthesize new
chiral C2-symmetric ligands by reaction of esters Ia–Ic
with (1S,2S)-1,2-diphenylethane-1,2-diamine. We
found that esters Ia–Ic react with (1S,2S)-1,2-di-
phenylethane-1,2-diamine in ethanol at room tempera-
ture to produce bis-esters IIa–IIc as a result of con-
densation of one diamine molecules with two mole-
cules of ester I at the ethoxymethylidene substituent
(Scheme 1).
1
shifts of the CH and NH protons in the H NMR
spectra are indicative: signals of these protons in the
E isomer appear in a weaker field relative to those of
the Z isomer. Larger δNH values for the E isomer
suggest stronger intramolecular hydrogen bond therein
and hence higher stability of that isomer. In the
19F NMR spectra, signals from fluorine atoms in the
α-CF3 and α-CF2 groups of the Z isomer are located in
a weaker field as compared to the corresponding
signals of the E isomer.
The structure of compounds IIa–IIc in the crys-
talline state was studied by IR spectroscopy and X-ray
analysis. According to the X-ray diffraction data,
molecule IIb in crystal exists as E,E isomer of bis-
(enaminoketone) tautomer characterized by S,S-con-
figuration (Fig. 1). The carbonyl oxygen atoms in both
fluoroacyl fragments are involved in intramolecular
hydrogen bonds O3a···H1b and O3aa···H1bb with the NH
protons in the ethylenediamine bridge; the hydrogen
Bis-esters IIa–IIc in CDCl3 solution are charac-
terized by different ratios of the E,E, Z,Z, and Z,E
isomers. Presumably, the E,Z and Z,Z isomers appear
in solution via partial isomerization of the E,E isomer
Ph
Ph
Ph
Ph
Ph
Ph
O
N
N
O
O
N
N
O
O
N
N
O
H
H
H
H
H
H
·
·
·
·
·
·
·
·
·
·
·
·
·
·
·
·
·
·
EtO
O
O
OEt
RF
O
O
RF
EtO
O
O
RF
RF
RF
EtO
OEt
RF
OEt
EE
ZZ
ZE
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NEW CHIRAL METAL COMPLEXES BASED ON 2-ETHOXYMETHYLIDENE-...
333
upon dissolution of crystalline sample. Facile isomer-
ization of bis-esters IIa–IIc about the C=C bond may
be rationalized as follows. Due to the presence of
functional groups with different electron-withdrawing
powers, the C=C bond constitutes a part of polarized
conjugated system where the barrier to rotation about
double C=C bond is considerably reduced [9]. As we
showed previously [8], the ability of E isomer to
undergo isomerization upon dissolution to produce
a mixture of Z and E isomers is a common feature of
ethyl 2-alkyl(aryl, hetaryl)aminomethylidene-3-oxo-3-
polyfluoroalkylpropionates.
complexes IIIa–IIIf have the composition ML where
L is doubly deprotonated ligand.
1
The H and 19F NMR spectra of nickel(II) com-
plexes IIIa, IIIc, and IIIe turned out to be informative
from the viewpoint of structure determination. In the
1H NMR spectra of the complexes the diamagnetic
shift of signals from the CH protons in the ethylene-
diamine fragment was δ ~4.40–4.45 ppm (δ ~4.69–
4.80 ppm for free ligands IIa–IIc), indicating partici-
pation of that fragment in the formation of coordina-
tion entity. In the 19F NMR spectra we observed
a downfield shift of signal from the α-fluorine atom
relative to the corresponding signals of all isomers of
free ligands IIa–IIc (see Experimental), which resulted
from coordination of nickel(II) ion at the carbonyl
oxygen atom in the fluoroacyl group.
Bis-esters IIa–IIc are potential tetradentate (N2O2)
ligands and are capable of forming coordination com-
pounds with transition metal salts. By reaction of
ligands IIa–IIc with nickel(II) and copper(II) acetates
we obtained metal complexes IIIa–IIIf (Scheme 1).
Complexes III can also be obtained by template syn-
thesis from esters Ia–Ic and (1S,2S)-1,2-diphenyl-
ethane-1,2-diamine in the presence of metal ion tem-
plate. However, only nickel(II) ion turned out to be
an appropriate template; in such a way (by three-
component reaction) we synthesized nickel complexes
IIIa, IIIc, and IIIe.
The structure of complexes IIIa and IIIc was
determined by X-ray analysis (Figs. 2, 4). According to
the X-ray diffraction data, the coordination entity con-
sists of two carbonyl oxygen atoms in the fluoroacyl
groups and two nitrogen atoms of the ethylenediamine
bridge (tetradentate coordination mode). The same
coordination mode was typical of metal complexes
synthesized previously on the basis of esters I and
1,2-diamines (o-phenylenediamine [6] and ethylene-
diamine [7]). The S,S configuration of the chiral
centers is conserved in complexes IIIa and IIIc, and
the ethoxycarbonyl groups are nonequivalent and are
The structure of complexes IIIa–IIIf was studied
1
by X-ray diffraction and IR spectroscopy, and H and
19F NMR spectra of the nickel complexes were meas-
ured. According to the data of elemental analysis,
C23
C15
C16
C14
C24
C13
C19
C22
C6
C5
C17
C21
C7
C26
C25
C18
N1
C20
N2
O3
O6
C4
C11
C3
C12
C8
Ni1
C28
O4
O5
C9
C27
C2
O2
O1
F4
C10
C1
F2
F3
F6
F5
F1
Fig. 2. Structure of the molecule of (1S,2S)-diphenylethane-1,2-diylbis{[2-ethoxycarbonyl-4,4,4-trifluoro-3-oxobut-1-en-1-yl]-
azanide}nickel(II) (IIIa) according to the X-ray diffraction data.
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 47 No. 3 2011

KUDYAKOVA et al.
334
6.756 Ǻ
a
c
6.756 Ǻ
0
6.756 Ǻ
6.756 Ǻ
6.756 Ǻ
b
6.756 Ǻ
Fig. 3. Crystal packing of complex IIIa (a view along the crystallographic a axis; hydrogen atoms are not shown for the sake of
simplicity).
oriented trans. Nonequivalence of the ester groups also
follows from the IR spectra of all metal complexes
IIIa–IIIf, which contained two high-frequency car-
bonyl bands in the region 1723–1689 cm–1.
Tetradentate N2O2 coordination of the ligand in
complex IIIa gives rise to one five- and two six-
membered chelate rings. The central nickel(II) ion has
a distorted square–planar configuration. The carbon
C11
C12
C19
C20
C18
C17
C10
C13
C9
C21
C14
C16
C8
C23
C15
N2
C7
O2
N1
O3
C32
C22
C1
O3
C2
C3
C27
Ni1
C24
C26
O6
O1
O4
C28
C29
C25
F7
C4
F9
F5
C5
F10
F6
F8
F4
C30
F11
C31
F14
F3
C6
F12
F13
F2
F1
Fig. 4. Structure of molecule A of [(1S,2S)-diphenylethane-1,2-diyl]bis{[2-ethoxycarbonyl-4,4,5,5,6,6,6-heptafluoro-3-oxohex-1-en-
1-yl]azanide}nickel(II) (IIIe) according to the X-ray diffraction data.
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NEW CHIRAL METAL COMPLEXES BASED ON 2-ETHOXYMETHYLIDENE-...
335
C12a
C18a
C17a
C11a
C10a
C9a
C19a
C13a
C20a
C21a
C14a
C16a
C15a
C8a
C23a
N1a
C32a
O2a
C1a
O3a
N2a
O5a
C22a
C7a
C2a
Ni1a
C26a
C27a
C28a
C24a
O1a
O6a
C3a
C4a
C5a
O4a
F6a
F7a
C25a
F9a
F11a
C29a
F8a
F5a
F4a
C30a
F10a
F12a
C31a
F14a
F13a
C6a
F2a
F1a
F3a
Fig. 5. Structure of molecule B of [(1S,2S)-diphenylethane-1,2-diyl]bis{[2-ethoxycarbonyl-4,4,5,5,6,6,6-heptafluoro-3-oxohex-1-en-
1-yl]azanide}nickel(II) (IIIe) according to the X-ray diffraction data.
atoms in the ethylene bridge deviate from the mean-
square plane of the coordination entity by 0.273–
0.283 Å, and the central carbon atoms in the six-
membered chelate rings deviate from that plane by
0.010–0.369 Å. Electron density in the six-membered
chelate rings is strongly delocalized, and the bonds
therein are considerably leveled. The difference in the
Ni–X bond lengths (X = N, O) does not exceed 0.04 Å,
and the corresponding differences for the C–X (X =
N, O) and C–C bonds are 0.009 and 0.047 Å, respec-
tively. These data do not allow us to speak about
iminoenolate or ketoenaminate structure of the ligand.
The C–N bonds in the five-membered metal ring, as
well as the C–CO2Et bonds, are slightly shorter than
the corresponding standard single bonds, indicating
a weak conjugation between those bonds and electron
system of the six-membered chelate rings.
(Figs. 4, 5); the structure of the coordination entity in
these molecules is similar to that of complex IIIa.
However, complex IIIe is characterized by larger
deviations of carbon atoms in the ethylenediamine
bridge from the mean-square plane (0.215–0.474 Å);
deviations of the central carbon atoms in the six-
membered chelate rings range from 0.044 to 0.638 Å;
in addition, spatial orientation of the ethoxycarbonyl
groups is different from that typical of IIIa. Crystal
packing of complex IIIe is formed by layers consisting
of two chains of molecules which are arranged alter-
nately with a small shear relative to each other along
the b axis (Fig. 6). Molecules in one chain are turned
through an angle of 180° with respect to those in the
other chain, so that the fluoroalkyl and phenyl substit-
uents are oriented oppositely.
Thus we have found that ethyl 2-ethoxymethyli-
dene-3-oxo-3-polyfluoroalkylpropionates I are con-
venient building blocks for the synthesis of chiral
ligands and metal complexes.
Molecules IIIa in crystal are packed into layers in
which the plane of the coordination entity of one mole-
cule is orthogonal to the corresponding plane of the
other molecule (Fig. 3), and the molecules are oriented
in the “head-to-tail” mode. The distance between the
laters is 6.756 Å.
EXPERIMENTAL
Unlike trifluoromethyl-substituted derivative IIIa,
tetrafluoroethyl analog IIIe in crystal exists as two
crystallographically independent molecules A and B
The melting points of compounds IIa, IIb, and
IIIa–IIId were determined in open capillaries on
a Stuart SMP3 instrument. The IR (diffuse reflectance)
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 47 No. 3 2011

KUDYAKOVA et al.
336
b
0
a
c
Fig. 6. Crystal packing of complex IIIe (a view along the crystallographic b axis; hydrogen atoms are not shown for the sake of
simplicity).
spectra were measured on a Perkin–Elmer Spectrum
One spectrometer with Fourier transform. The NMR
spectra were recorded from solutions in CDCl3 on
a Bruker DRX-400 spectrometer (1H: 400 MHz, TMS;
19F: 376 MHz, C6F6). The elemental compositions
were determined on a Perkin–Elmer 2400 Series 2
CHNS-O EA 1108.4 analyzer. The progress of reac-
tions was monitored by TLC on Sorbfil PTSKh-AF-V-
UF plates.
characterized by F0 > 4σ(F0). The structure was solved
by the direct method with subsequent Fourier syn-
theses using SHELXS-97 software package [10] and
was refined by the least-squares procedure in full-
matrix anisotropic approximation for all non-hydrogen
atoms (SHELXL-97) [10] up to R1 = 0.0498, wR2 =
0.1136; goodness of fit 1.019 [for reflections with
I > 2σ(I)]; 590 refined parameters.
Single crystals of compound IIIa were obtained by
crystallization from ethanol–acetone (3:1). The X-ray
diffraction data were acquired on an Xcalibur 3 dif-
fractometer equipped with a CCD detector [ω/2θ
scanning, λ(MoKα) = 0.71073 Å, 295(2) K, graphite
monochromator]. The positions of hydrogen atoms
were determined experimentally and were refined in
isotropic approximation. C28H24F6N2NiO6. M 657.20.
Orthorhombic crystals, space group P212121; unit cell
parameters: a = 10.5838(9), b = 11.3541(12), c =
23.703(3) Å; α = β = γ = 90°; V = 2848.4(5) Å3; Z = 4;
Initial esters Ia and Ib were synthesized according
to the procedure described in [8].
Single crystals of compound IIb were obtained by
crystallization from ethanol. The X-ray diffraction data
were acquired on an Xcalibur 3 diffractometer
equipped with a CCD detector [ω scanning, λ(MoKα)
0.71073 Å, 120(2) K, graphite monochromator]. The
positions of hydrogen atoms were determined experi-
mentally and were refined in isotropic approximation.
C30H28F8N2O6. M 664.55. Tetragonal crystals, space
group P41212; unit cell parameters: a = 21.6122(11),
b = 21.6122(11), c = 19.7421(7) Å; α = β = γ = 90°;
V = 9221.3(7) Å3; Z = 4; dcalc = 1.253 g/cm3; μ(MoKα) =
0.107 cm–1; F(000) = 3648. Total of 26716 reflection
intensities were measured, 5238 of which were inde-
pendent (Rint = 0.0645) and 2911 reflections were
d
calc = 1.533 g/cm3; μ(MoKα) = 0.765 cm–1; F(000) =
1344. Total of 9824 reflection intensities were meas-
ured, 6398 of which were independent (Rint = 0.0304);
3390 reflections with F0 > 4σ(F0). The structure was
solved by the direct method with subsequent Fourier
syntheses (SHELXS-97) [10] and was refined by the
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NEW CHIRAL METAL COMPLEXES BASED ON 2-ETHOXYMETHYLIDENE-...
337
least-squares procedure in full-matrix anisotropic ap-
proximation for all non-hydrogen atoms (SHELXL-97)
[10] up to R1 = 0.0383, wR2 = 0.0668; goodness of fit
1.011 [for reflections with I > 2σ(I)]; 388 refined
parameters.
4.80 m (2H, CH), 7.03–7.35 m (10H, C6H5); E,E:
1.27 t (6H, CH2CH3, J = 7.0 Hz), 8.08 d (2H, =CH, J =
13.6 Hz), 11.14 br.m (2H, NH); E,Z: 1.26 t and 1.34 t
(3H each, CH2CH3, J = 7.1 Hz), 7.83 d and 8.04 d (1H
each, =CH, J = 13.6 Hz), 10.40 br.m and 11.14 br.m
(2H, NH); Z,Z: 1.33 t (6H, CH2CH3, J = 7.1 Hz),
7.85 d (2H, =CH, J = 13.6 Hz), 10.14 br.m (2H, NH).
19F NMR spectrum, δF, ppm: E,E: 88.95 s (6F, CF3);
E,Z: 89.76 s and 88.97 s (3F each, CF3); Z,Z: 89.71 s
(6F, CF3). Found, %: C 53.55; H 4.49; F 17.56; N 3.76.
C28H26F6N2O6. Calculated, %: C 56.00; H 4.36;
F 18.98; N 4.66.
Single crystals of compound IIIe were obtained by
crystallization from chloroform. The X-ray diffraction
data were acquired on an Xcalibur 3 diffractometer
equipped with a CCD detector [ω/2θ scanning,
λ(MoKα) = 0.71073 Å, 110(2) K, graphite mono-
chromator]. The positions of hydrogen atoms were de-
termined experimentally and were refined in isotropic
approximation. C32H24F14N2NiO6. M 857.24. Mono-
clinic crystals, space group C2; unit cell parameters:
a = 24.4275(9), b = 15.1545(5), c = 19.2321(5) Å; β =
106.358(3); V = 6831.3(4) Å3; Z = 8; dcalc = 1.667 g×
cm–3; μ(MoKα) = 0.692 cm–1; F(000) = 3456. Total of
23625 reflection intensities were measured, 13174 of
which were independent (Rint = 0.0214); 9991 reflec-
tions with F0 > 4σ(F0). The structure was solved by the
direct method with subsequent Fourier syntheses
(SHELXS-97) [10] and was refined by the least-
squares procedure in full-matrix anisotropic approxi-
mation for all non-hydrogen atoms (SHELXL-97) [10]
up to R1 = 0.0271, wR2 = 0.0446; goodness of fit
1.007 [for reflections with I > 2σ(I)]; 991 refined
parameters.
Diethyl 2,2′-{(1S,2S)-diphenylethane-1,2-diylbis-
[iminomethylidene]}bis(4,4,5,5-tetrafluoro-3-oxo-
pentanoate) (IIb). Yield 0.94 g (71%), light yellow
oily substance; a mixture of E,E (65%), E,Z (26%),
and Z,Z isomers (9%). IR spectrum, ν, cm–1: 3239
(N–H), 2983 (C–H), 1710 (C=O, ester), 1683 (C=O),
1639 (C=C), 1592, 1579 (δNH), 1226–1096 (C–F).
1H NMR spectrum, δ, ppm: 4.69–4.79 m (2H, CH),
7.03–7.35 m (10H, C6H5); E,E: 1.27 t (6H, CH2CH3,
J = 7.1 Hz), 4.18 m (4H, OCH2, AB system, ΔAB
=
0.01, JAB = 10.8, 7.1 Hz), 6.70 t.t (2H, HCF2, J = 53.7,
5.7 Hz), 8.02 d (2H, =CH, J = 13.6 Hz), 11.25 br.m
(2H, NH); E,Z: 1.26 t and 1.34 t (3H each, CH2CH3,
J = 7.1 Hz), 4.37 q and 4.29 q (2H each, OCH2, J =
7.1 Hz), 6.26 t.t and 6.66 t.t (1H each, HCF2, J = 53.7,
5.7 Hz), 7.78 d and 7.95 d (1H each, =CH, J =
13.6 Hz), 10.25 br.m and 11.25 br.m (1H each, NH);
Z,Z: 1.37 t (6H, CH2CH3, J = 7.1 Hz), 4.29 q.d (4H,
OCH2, J = 7.1, 1.2 Hz), 6.27 t.t (2H, HCF2, J = 53.7,
5.7 Hz), 7.79 d (2H, =CH, J = 13.6 Hz), 10.25 br.m
The complete sets of crystallographic data for com-
pounds IIb, IIIa, and IIIe were deposited to the
Cambridge Crystallographic Data Centre (entry
nos. CCDC 771 843, 771842, and 771844, respec-
tively) and are available at www.ccdc.cam.ac.uk/conts/
retrieving.html (or CCDC, 12 Union Road, Cambridge
CB2 1EZ, UK; fax: +44 1223 336033; e-mail:
deposit@ccdc.cam.ac.uk).
19
(2H, NH). F NMR spectrum, δF, ppm: E,E: 24.3 d.m
(4F, HCF2, J = 53.7 Hz), 39.66 m (4F, CF2); E,Z:
22.17 d.m and 24.00 d.m (2F each, HCF2, J =
53.7 Hz), 39.77 m and 41.20 m (2F each, CF2); Z,Z:
22.16 d.m (4F, HCF2, J = 53.7 Hz), 41.21 m (4F, CF2).
Found, %: C 50.52; H 4.03; F 23.12; N 3.70.
C30H28F8N2O6. Calculated, %: C 54.22; H 4.25;
F 22.87; N 4.22.
Bis-esters IIa–IIc (general procedure). A mixture
of 4 mmol of ester Ia–Ic and 0.42 g (2 mmol) of
(1S,2S)-1,2-diphenylethane-1,2-diamine in 15 ml of
ethanol was stirred for 10 h at room temperature. The
solvent was distilled off, and the residue was subjected
to column chromatography on silica gel using chloro-
form as eluent.
Diethyl 2,2′-{(1S,2S)-diphenylethane-1,2-diylbis-
[iminomethylidene]}bis(4,4,5,5,6,6,6-heptafluoro-3-
oxohexanoate) (IIc). Yield 1.10 g (69%), light yellow
oily substance; a mixture of E,E (28%), E,Z (46%),
and Z,Z isomers (26%). IR spectrum, ν, cm–1: 3242
(N–H), 2986 (C–H), 1706 (C=O, ester), 1688 (C=O),
1637 (C=C), 1595, 1581 (δNH), 1228–1119 (C–F).
1H NMR spectrum, δ, ppm: 4.68–4.78 m (2H, CH),
7.00–7.40 m (10H, C6H5); E,E: 1.26 t (6H, CH2CH3,
J = 7.1 Hz), 4.19 q (4H, OCH2, J = 7.1 Hz), 8.02 d
(2H, CH, J = 13.6), 11.02 br.m (2H, NH, J = 13.6 Hz);
Diethyl 2,2′-{(1S,2S)-diphenylethane-1,2-diylbis-
[iminomethylidene]}bis(4,4,4-trifluoro-3-oxobutan-
oate) (IIa). Yield 0.89 g (74%), light yellow oily
substance; a mixture of E,E (43%), E,Z (44%), and Z,Z
isomers (13%). IR spectrum, ν, cm–1: 3237 (N–H),
2985 (C–H), 1708 (C=O, ester), 1683 (C=O), 1641
1
(C=C), 1594, 1581 (δNH), 1235–1162 (C–F). H NMR
spectrum, δ, ppm: 4.17–4.23 m (4H, OCH2), 4.76–
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KUDYAKOVA et al.
338
E,Z: 1.25 t and 1.31 t (3H each, CH2CH3, J = 7.1 Hz),
4.19 q.d and 4.28 q.d (2H each, OCH2, J = 7.1,
0.8 Hz), 7.71 d and 7.96 d (1H each, =CH, J =
13.6 Hz), 10.33 br.m and 11.04 br.m (1H each, NH);
Z,Z: 1.32 t (6H, CH2CH3, J = 7.1 Hz), 4.29 q.d (4H,
OCH2, J = 7.1, 1.2 Hz), 7.70 d (2H, CH, J = 13.5 Hz),
10.28 br.m (2H, NH). 19F NMR spectrum, δF, ppm:
E,E: 38.18 m (4F, β-CF2), 48.33 m (4F, α-CF2), 81.55 t
(6F, CF3, J = 9.6 Hz); E,Z: 37.49 m and 38.17 m (2F
each, β-CF2), 48.34 m and 48.99 m (2F each, α-CF2),
81.54 t and 81.57 t (3F each, CF3, J = 9.6 Hz); Z,Z:
37.39 m (4F, β-CF2), 48.92 m (4F, α-CF2), 81.58 t (6F,
CF3, J = 9.6 Hz). Found, %: C 47.03; H 3.45; F 33.37;
N 3.12. C32H26F14N2O6. Calculated, %: C 48.01;
H 3.27; F 33.22; N 3.50.
[(1S,2S)-Diphenylethane-1,2-diyl]bis[(2-ethoxy-
carbonyl-4,4,5,5-tetrafluoro-3-oxopent-1-en-1-yl)-
azanide]nickel(II) (IIIc). Yield 2.99 g (83%) (a),
1.08 g (75%) (b); red–orange powder, mp 182–184°C.
IR spectrum, ν, cm–1: 3067, 3037 (C–H), 1718, 1698
(C=O, ester), 1610 (C=C), 1500, 1474 (C=Carom),
1
1077–1260 (C–F). H NMR spectrum, δ, ppm: 1.88 t
(6H, CH2CH3, J = 7.1 Hz), 4.12 q (4H, OCH2, J =
7.1 Hz), 4.44 s (2H, CH), 6.33 t.t (2H, HCF2, J = 53.6,
5.5 Hz), 7.29 s (2H, =CH), 7.36–7.52 m (10H, C6H5).
19F NMR spectrum, δF, ppm: 23.46 d.m (4F, HCF2, J =
53.6 Hz), 42.70 m (4F, CF2). Found, %: C 49.73;
H 3.43; F 21.43; N 3.72. C30H26F8N2NiO6. Calculated,
%: C 49.96; H 3.63; F 21.07; N 3.88.
[(1S,2S)-Diphenylethane-1,2-diyl]bis[(2-ethoxy-
carbonyl-4,4,5,5-tetrafluoro-3-oxopent-1-en-1-yl)-
azanide]copper(II) (IIId). Yield 2.87 g (79%) (a),
dark violet powder, mp 193–195°C. IR spectrum, ν,
cm–1: 3067, 3035 (C–H), 1710, 1692 (C=O, ester),
1618 (C=C), 1504, 1470 (C=Carom), 1254–1067 (C–F).
Found, %: C 49.58; H 3.69; F 21.43; N 3.80.
C30H26CuF8N2O6. Calculated, %: C 49.63; H 3.61;
F 20.93; N 3.86.
Complexes IIIa–IIIf (general procedures).
a. A mixture of 5 mmol of compound IIa–IIc and
10 mmol of nickel(II) or copper(II) acetate in 20 ml of
ethanol was heated for 5 min under reflux. The mixture
was filtered while hot, the filtrate was cooled, and the
precipitate was filtered off and recrystallized from
ethanol.
b. A mixture of 4 mmol of ester Ia–Ic, 0.42 g
(2 mmol) of (1S,2S)-1,2-diphenylethane-1,2-diamine,
and 0.3 g (2 mmol) of nickel(II) acetate in 25 ml of
ethanol was heated for 15 min under reflux. The
mixture was then poured into 50 ml of cold water and
extracted with chloroform (2×30 ml). The extract was
evaporated, and the residue was crystallized from
ethanol.
[(1S,2S)-Diphenylethane-1,2-diyl]bis[(2-ethoxy-
carbonyl-4,4,5,5,6,6,6-heptafluoro-3-oxohex-1-en-1-
yl)azanide]nickel(II) (IIIe). Yield 3.26 g (76%) (a),
1.20 g (70%) (b); red–orange powder, mp 162–163°C.
IR spectrum, ν, cm–1: 3065, 3038 (C–H), 1723, 1698
(C=O, ester), 1610 (C=C), 1499, 1455 (C=Carom),
1
1224–1026 (C–F). H NMR spectrum, δ, ppm: 1.86 t
(6H, CH2CH3, J = 7.1 Hz), 4.11 q (4H, OCH2, J =
7.1 Hz), 4.45 s (2H, CH), 7.20 s (2H, =CH), 7.43 m
(10H, C6H5). 19F NMR spectrum, δF, ppm: 37.69 m
(4F, β-CF2), 51.07 m (4F, α-CF2), 81.45 t (6F, CF3, J =
9.9 Hz). Found, %: C 44.58; H 2.78; F 30.89; N 3.23.
C32H24F14N2NiO6. Calculated, %: C 44.84; H 2.81;
F 31.03; N 3.27.
(1S,2S)-Diphenylethane-1,2-diylbis[(2-ethoxy-
carbonyl-4,4,4-trifluoro-3-oxobut-1-en-1-yl)aza-
nide]nickel(II) (IIIa). Yield 2.79 g (85%) (a), 1.03 g
(78%) (b); red–orange powder, mp 227–228°C. IR
spectrum, ν, cm–1: 1709, 1689 (C=O, ester), 1605
(C=C), 1488, 1475 (C=Carom), 1287–1080 (C–F).
1H NMR spectrum, δ, ppm: 1.21 t (6H, CH2CH3, J =
7.1 Hz), 4.14 q (4H, OCH2, J = 7.1 Hz), 4.40 s (2H,
CH), 7.40 s (2H, =CH), 7.42–7.70 m (10H, C6H5).
19F NMR spectrum: δF 93.89 ppm, s (6F, CF3). Found,
%: C 51.40; H 3.32; F 17.05; N 4.13. C28H24F6N2NiO6.
Calculated, %: C 51.17; H 3.68; F 17.34; N 4.26.
[(1S,2S)-Diphenylethane-1,2-diyl]bis[(2-ethoxy-
carbonyl-4,4,5,5,6,6,6-heptafluoro-3-oxohex-1-en-1-
yl)azanide]copper(II) (IIIf). Yield 3.45 g (80%) (a),
dark violet powder, mp 180–182°C. IR spectrum, ν,
cm–1: 3070, 3037 (C–H), 1707 br (C=O, ester), 1619
(C=C), 1517, 1490 (C=Carom), 1257–1117 (C–F).
Found, %: C 45.66; H 2.97; F 31.43; N 2.70.
C32H24CuF14N2O6. Calculated, %: C 44.58; H 2.81;
F 30.85; N 3.25.
(1S,2S)-Diphenylethane-1,2-diylbis[(2-ethoxy-
carbonyl-4,4,4-trifluoro-3-oxobut-1-en-1-yl)aza-
nide]copper(II) (IIIb). Yield 2.95 g (89%) (a), violet
powder, mp 198–199°C. IR spectrum, ν, cm–1: 1713,
1690 (C=O, ester), 1605 (C=C), 1513, 1489 (C=Carom),
1232–1110 (C–F). Found, %: C 50.20; H 3.48;
F 17.07; N 3.97. C28H24CuF6N2O6. Calculated, %:
C 50.80; H 3.65; F 17.22; N 4.23.
This study was performed under financial support
by the Russian Foundation for Basic Research (project
no. Ural 10-03-96017) and by the Presidium of the
Ural Division, Russian Academy of Sciences (program
nos. 09-P-3-1013, 09-S-3-1002).
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NEW CHIRAL METAL COMPLEXES BASED ON 2-ETHOXYMETHYLIDENE-...
339
6. Kudyakova, Yu.S., Goryaeva, M.V., Burgart, Ya.V., and
Saloutin, V.I., Izv. Ross. Akad. Nauk, Ser. Khim., 2010,
p. 1544.
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