Binary α-unsaturated palladium carboxylates and their complexes with morpholine derivatives: The Crystal structure of palladium carbamoyl crotonate (OC4H8NH)2Pd[OC4H8N(C=O)](MeCH=CHCO2)·H2O, a product of the first inner-sphere amination reaction of α-unsaturated palladium carbonyl carboxylates with morpholine

Article abstract of DOI:10.1134/S0036023615070050

Binary α-unsaturated palladium carboxylates have been synthesized by substitution of α-unsaturated acids RCOOH (R is CH₂=C(Me), MeCH=CH, PhCH=CH) for the acetate ion in Pd₃(μ-MeCOO)₆. These carboxylates react with amines A (A is morpholine (M), methylmorpholine (MM), or thiomorpholine (MS)) to give trans-Pd(A)₂(RCOO)₂ similar to trans-A₂(MeCO₂)₂. The structures of the trans-Pd(A)₂(RCOO)₂ complexes (R is MeCH=CH; A is M, MM, MS) have been determined by X-ray crystallography. The effect of solvent on the crystal structure of the complexes has been demonstrated for trans-(MeCH=CHCO₂)₂Pd(C₄H₉NO)₂ as an example. The amination reaction of palladium carbonyl crotonate with a secondary amine, morpholine, has been studied for the first time. The reaction involves disproportionation of Pd(I) into Pd(0) and Pd(II) and leads to the first unsaturated palladium(II) carbamoyl carboxylate - palladium carbamoyl crotonate trans-(OC₄H₈NH)₂Pd[OC₄H8NC(=O)](MeCH=CHCO₂)·H₂O, as well as to trans-M₂Pd(MeCH=CHCO₂)₂ and (C₄H₁₀NO)⁺(MeCH=CHCO₂)^-. The structures of these compounds have been proved by X-ray crystallography.

Full text of DOI:10.1134/S0036023615070050

ISSN 0036ꢀ0236, Russian Journal of Inorganic Chemistry, 2015, Vol. 60, No. 7, pp. 848–860. © Pleiades Publishing, Ltd., 2015.
Original Russian Text © I.A. Efimenko, P.V. Ankudinova, L.G. Kuz’mina, A.V. Churakov, N.A. Ivanova, L.I. Demina, O.S. Erofeeva, 2015, published in Zhurnal Neorganicheskoi
Khimii, 2015, Vol. 60, No. 7, pp. 935–948.
Binary αꢀUnsaturated Palladium Carboxylates
and Their Complexes with Morpholine Derivatives:
the Crystal Structure of Palladium Carbamoyl Crotonate
(OC4H8NH)2Pd[OC4H8N(C=O)](MeCH=CHCO2)
⋅
H2O,
a Product of the First InnerꢀSphere Amination Reaction
of
α
ꢀUnsaturated Palladium Carbonyl Carboxylates
with Morpholine
I. A. Efimenko, P. V. Ankudinova, L. G. Kuz’mina, A. V. Churakov, N. A. Ivanova,
L. I. Demina, and O. S. Erofeeva
Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences,
Leninskii pr. 31, Moscow, 119991 Russia
eꢀmail: ines@igic.ras.ru
Received February 2, 2015
Abstract—Binary
ated acids RCOOH (R is CH2=C(Me), MeCH=CH, PhCH=CH) for the acetate ion in Pd3(
These carboxylates react with amines A (A is morpholine (M), methylmorpholine (MM), or thiomorpholine
(MS)) to give transꢀPd(A)2(RCOO)2 similar to transꢀA2(MeCO2)2. The structures of the trans
Pd(A)2(RCOO)2 complexes (R is MeCH=CH; A is M, MM, MS) have been determined by Xꢀray crystallogꢀ
raphy. The effect of solvent on the crystal structure of the complexes has been demonstrated for trans
α
ꢀunsaturated palladium carboxylates have been synthesized by substitution of
α
ꢀunsaturꢀ
μ
ꢀMeCOO)6.
ꢀ
ꢀ
(MeCH=CHCO2)2Pd(C4H9NO)2 as an example. The amination reaction of palladium carbonyl crotonate
with a secondary amine, morpholine, has been studied for the first time. The reaction involves disproportionꢀ
ation of Pd(I) into Pd(0) and Pd(II) and leads to the first unsaturated palladium(II) carbamoyl carboxylate—
palladium carbamoyl crotonate transꢀ(OC4H8NH)2Pd[OC4H8NC(=O)](MeCH=CHCO2) H2O, as well as
⋅
to transꢀM2Pd(MeCH=CHCO2)2 and (C4H10NO)+(MeCH=CHCO2)–. The structures of these compounds
have been proved by Xꢀray crystallography.
DOI: 10.1134/S0036023615070050
At present, palladium carboxylates attract attenꢀ rocene) [13], the binuclear
tion of coordination chemists because of revealing CH2=C(Ме)CH2CO2)( ꢀCH2=C(Ме)CH2)Pd (PPh3
(
PPh3)2Pd(μꢀ
μ
)
new trends and properties in a series of aliphatic pallaꢀ complex [14], and the only binary cyclic palladium
dium complexes [1], as well as due to their practical tiglate Pd3MeCH=CH(Me)CO2)6 [15]. Recently, we
application as catalysts (or their precursors) of organic have described the synthesis and spectral characꢀ
reactions [2–7]. In the chemistry of platinum metals, teristics of palladium carbonyl and nitrosyl carꢀ
a few unsaturated carboxylates containing double boxylates and have synthesized palladium carbonyl
and triple bonds in the carboxylate ligand have been and nitrosyl carboxylates Pd4(
described: heterometallic Os and Ru complexes with Pd4(μꢀNO)2(μꢀRCO2)6 where
acetylcarboxylic acid [8], platinum heterocarboxyꢀ MeCH=C(Me) [16], CH2=CH, CH2=C(Me)
late complex Pt4(MeCO2)(CH=CHCO2)4 [9], and transꢀMeCH=CH, PhH=CH, and trans
polynuclear ruthenium complexes with unsaturated MeCH=C(Me). The structures of the Pd4(
acids [10]. CO)4( ꢀMeCH=CHCO2)4 and Pd4( ꢀNO)2( ꢀ
μꢀCO)4(μꢀRCO2)4 and
,
R =
trans
ꢀ
,
ꢀ
ꢀ
μ
μ
μ
μ
CH2=CH(Me)CO2)6 complexes have been proved by
Xꢀray crystallography [17]. No information is availꢀ
able on unsaturated palladium carboxylates with
nitrogenꢀcontaining ligands.
As for unsaturated palladium carboxylates, only
five structurally characterized compounds with such
anions are known: the mononuclear
(P Pr3)2Pd(MeCH=C(CH2CH=CH–CH=CH2)CO2)2
[11] and (dppf)Pd(cis HO2CCH=CHCO2)2 [12]
'
ꢀ
In the present paper, we report the synthesis of
α
complexes, the polymeric {[dppf)Pd(RCO2)]+CF3SO3}n binary
ꢀunsaturated palladium carboxylates and the
complex (dppf is 1,1'ꢀbis(diphenylphosphino)ferꢀ results of studying the reactions of secondary
848

BINARY
α
ꢀUNSATURATED PALLADIUM CARBOXYLATES
849
amines—morpholine derivatives—with both binary 550 cm–1 were recorded on a Nicolet NEXUS IR FT
palladium carboxylates and palladium carbonyl crotoꢀ spectrophotometer equipped with a Pike diamond
nate. The latter reaction has led, for the first time, to ATR sampling accessory. The samples were applied to
αꢀunsaturated palladium carbamoyl carboxylate, a a diamond crystal without additional preparation.
product of amination of the coordinated CO molecule This sampling procedure made it possible to avoid side
in palladium carbonyl crotonate.
processes initiated by grinding the samples with minꢀ
eral oil and by compacting the samples into pellets
with KBr.
The Raman spectra of the complexes were
recorded on a LabRAMꢀ300 laser spectrophotometer
(He–Ne laser excitation at 632.8 nm with a power of
no more than 0.3 mW to avoid sample degradation).
EXPERIMENTAL
Initial compounds and methods of investigation.
The following reagents were used: 98% cinnamic acid,
98% crotonic acid, 99.5% acrylic and methacrylic
acids, morpholine C4H9NO, 4ꢀmethylmorpholine
C5H11NO, and thiomorpholine C4H9NS (ACROS
Organics); NaOH (pure for analysis); CHCl3, benꢀ
zene, toluene, diethyl ether, hexane, petroleum ether,
and methylene chloride; acetic, nitric, and formic
acids (all chemically pure, Khimmed).
Synthesis of Binary Palladium Carboxylates
New method of synthesis of Pd3( ꢀMeCO2)6 (1). In
μ
a 1000ꢀmL heatꢀresistant glass beaker, 14 g of
(NH3)4PdCl4 was dissolved in 250 mL of distilled
water; then, 350 mL of formic acid was added, and the
reaction mixture was refluxed for 2 h until the formaꢀ
tion of palladium black (sponge) in a transparent colꢀ
orless solution. The solution was carefully decanted,
and palladium black was washed in the same beaker
Palladium complexes with acids were synthesized
from palladium acetate Pd3(μꢀМеCO2)6 (1) obtained by
our new original method, palladium tiglate Pd3(
МеCO2)6 synthesized as described in ]15], and palladium
carbonyl crotonate synthesized as described in [17].
Analysis for C, H, N was carried out on a Carlo
Erba Instruments CHNS OEA 1108 analyzer.
μꢀ
with water (7
(AgNO3 test) and, then, with acetic acid (2
×
500 mL) to remove chlorine traces
200 mL).
×
The activated black with a small amount of acetic acid
was placed into a 1000ꢀmL twoꢀneck roundꢀbottom
flask; then, 300 mL of acetic acid and 1.5 mL of HNO3
were added, and the mixture was refluxed for 4 h until
complete disappearance of brown nitrogen oxides.
The hot orange brown solution was filtered through a
Schott filter (no. 40) to remove the unreacted pallaꢀ
dium metal; the solution was concentrated in a rotary
evaporator to 25 mL and cooled until a crystalline preꢀ
cipitate formed. The resulting orange precipitate was
filtered off through a Schott filter (no. 40) and dried
first in air with the use of a waterꢀjet pump for 1 h and
then in a vacuum at 93 Pa for 2 h to constant weight.
The product was an orange crystalline powder. The
yield was 6.24 g (45% based on the introduced pallaꢀ
dium).
Singleꢀcrystal Xꢀray diffraction analysis of comꢀ
pounds was carried out on a Bruker SMART APEX II
automated diffractometer (Mo
0.71073 Å, graphite monochromator,
K
radiation,
λ
=
α
ω
scan). The
structures were solved by direct methods and refined
anisotropically by fullꢀmatrix leastꢀsquares calculations
on F2 for all nonꢀhydrogen atoms (SHELXTLꢀPlus). All
hydrogen atoms in structure 12 were located from a
difference Fourier synthesis and refined isotropically;
in structures 10 and 17, all hydrogen atoms were introꢀ
duced in calculated positions and refined as riding on
their parent atoms. In structures 8, 8а, 16, and 18, the
H atoms bonded to the carbon atoms were placed in
calculated positions and refined as riding of these
atoms, while the amine hydrogen atoms were located
from electron density maps and refined isotropically.
The crystal characteristics and experimental and
refinement details are summarized in Table 1. The
structural data were deposited with the Cambridge
Crystallographic Data Centre (CCDC 1043133–
1043139).
The contents of C, H, and N in C4H6O4Pd deterꢀ
mined in samples of five independent syntheses carꢀ
ried out in analytical laboratories at (a) the Institute of
General and Inorganic Chemistry, RAS, and (b) the
Institute of Organic Chemistry, RAS, are summarized
in Table 2.
Powder Xꢀray diffraction analysis was carried out
The elemental analysis data for these samples conꢀ
firm the synthesis of pure palladium acetate (Table 2).
on
a
Bruker D8 ADVANCE diffractometer
(Cu
K radiation, Ni filter, LynxEye detector) of the
α
IR (cm–1): 1594 s, νas(COO); 1415 s, νs(COO)
.
Shared Facility Center at the Institute of General and
Inorganic Chemistry, RAS.
The IR absorption spectra of the compounds in the
range 4000–225 cm–1 were recorded on a Nicolet
NEXUS IR FT spectrophotometer. Samples were
ground with mineral oil. The resulting mulls were
placed between KRSꢀ5 plates.
Pd3( ꢀCH2=C(Me)CO2)6 (3). A 1.5ꢀfold excess (as
μ
calculated for palladium) of methacrylic (2ꢀmethyꢀ
lacrylic) acid (254 mL, 3 mmol) was introduced into a
solution of 224 mg (1 mmol) of Pd3(МеСO2)6 in
30 mL of toluene under stirring and heating (45–
50°C). The color of the reaction mixture changed to
The multiple attenuated total reflectance (MATR) dark orange are remained unaltered for 2 h. Then, the
IR spectra of the complexes in the range 4000– solution was filtered from the palladium metal through
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850
EFIMENKO et al.
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BINARY
α
ꢀUNSATURATED PALLADIUM CARBOXYLATES
851
Table 2. Analytical characteristics of Pd3(μꢀMeCO2)6 samples
C*
H**
N
Sample no.
found, %
found, %
found, %
a
b
a
b
a
b
1
21.24
21.29
21.29
21.39
21.53
21.23
21.14
21.21
21.19
21.30
2.69
2.63
2.90
2.75
2.49
2.87
2.84
2.87
2.92
2.58
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
2
3
4
5
*
Calculated 21.39%.
** Calculated 2.69%.
a Schott filter (no. 40). The filtrate was concentrated orange powder was 180 mg (65% based on the introꢀ
in a rotary evaporator to 5 mL. To the resulting viscous duced palladium).
oil, diethyl ether (5 mL), hexane (10 mL), and methꢀ
For C8H10O4Pd anal. calcd. (%): C, 34.71; H, 3.62.
ylene chloride (5 mL) were successively added, and
Found (%): C, 34.51; H, 3.37.
the newly formed orange solution was concentrated in
Raman (cm–1): 1653,
IR (cm–1): 1652,
(C=С); 1568, νas(COO); 1406,
νs(COO)
Pd3( ꢀPhCH=CHCO2)6 (5). A sixfold excess (as
ν(C=С)).
a rotary evaporator. To the resulting brown oil, 10 mL
of methylene chloride and 10 mL of hexane were
added, and the solution was concentrated in a rotary
evaporator to 5 mL; then, 20 mL of hexane was added,
and the solution was concentrated again until an
orange crystalline precipitate formed. The resulting
orange powder was recrystallized from acetone with
the addition of hexane to remove possible impurities of
the unreacted acid and was dried in a vacuum at 93 Pa
for 2 h to constant weight. The yield of an orange powꢀ
der was 166 mg (60% based on the introduced pallaꢀ
dium).
ν
.
μ
calculated for palladium) of cinnamic (transꢀ3ꢀpheꢀ
nylpropenoic) acid (1332 mg, 9 mmol) was gradually
added to a solution of Pd3(МеСO2)6 (224 mg, 1 mmol)
in 30 mL of toluene under stirring and heating to 45–
65°C. The color of the reaction mixture changed to
dark orange. The synthesis was carried for 2 to 72 h.
The resulting solution was filtered through a Schott filꢀ
ter (no. 40) from palladium metal. The filtrate was
concentrated in a rotary evaporator until the formaꢀ
tion of 5 mL of dark brown viscous oil, to which 5 mL
of diethyl ether and then 10 mL of hexane were added.
The mother liquor was decanted from the resulting
light orange precipitate, which was washed with hexꢀ
For C8H10O4Pd anal. calcd. (%): C, 34.71; H, 3.62.
Found (%): C, 34.33; H, 3.55.
Raman (cm–1): 1643,
IR (cm–1): 1643,
νs(COO)
Pd3(
ν
(C=С)
.
ν
(C=С); 1574, νas(COO); 1407,
.
ane (
2 10 mL) and dried in a vacuum at 93 Pa to conꢀ
×
μ
ꢀMeCH=CHCO2)6 (4). A 1.5ꢀfold excess (as
stant weight. To remove an unreacted acid excess, the
product (a light orange powder) was recrystallized two
to five times from acetone with the addition of hexane
and dried in a vacuum at 93 Pa for 2 h to constant
weight. The yield of the final product—an orange
powder—was 50 mg (13% based on the introduced
palladium).
calculated for palladium) of crotonic (transꢀ2ꢀ
butenoic) acid (258 mg, 3 mmol) was poured into a
solution of Pd3(MeCO2)6 (224 mg, 1 mmol) in 30 mL
of toluene under stirring and heating to 45–50°C. The
color of the reaction mixture changed to dark orange
and remained unaltered for 2 h. Then, the solution was
filtered from the palladium metal through a Schott filꢀ
ter (no. 40). The filtrate was concentrated in a rotary
evaporator until the formation of 5 mL of a dark brown
viscous oil; then, 5 mL of diethyl ether (for dissolving
the unreacted acid residues) and 10 mL of hexane were
added. The mother liquor was decanted from the
deposited orange precipitate, which was washed with
For C18H14O4Pd anal. calcd. (%): C, 53.94;
H, 3.50.
Found (%): C, 52.09; H, 3.60.
Raman (cm–1): 1635,
ν
(C=С)
.
IR (cm–1): 1632,
νs(COO)
Pd3(
ν
(C=С); 1570, νas(COO); 1389,
.
hexane (
2 10 mL) and dried in a vacuum at 93 Pa for
×
μ
ꢀ(Me)CH=CH(Me)CO2)6 (6). The synthesis
was described elsewhere [15].
2 h to constant weight. The product—a light orange
powder—was recrystallized from acetone with the
addition of hexane to remove possible impurities of the
transꢀ(CH2=C(Me)CO2)2Pd(C4H9NO)2 (7). Morꢀ
unreacted acid and was dried in a vacuum at 93 Pa for pholine (173 mL, 2 mmol) was introduced into a soluꢀ
2 h to constant weight. The yield of the resulting tion of palladium methacrylate (276 mg, 1 mmol) in
RUSSIAN JOURNAL OF INORGANIC CHEMISTRY Vol. 60 No. 7 2015

852
EFIMENKO et al.
30 mL of toluene under stirring. This induced a
change in the solution color from orange to greenꢀyelꢀ νs(COO)
IR (cm–1): 1636,
(C=С); 1588 νas(COO); 1352,
ν
.
low, which did not change within 1 h of synthesis. The
solution was filtered through a Schott filter (no. 40)
from palladium metal and concentrated in a rotary
evaporator until dry. The yellow precipitate was
transꢀ(MeCH=CHCO2)2Pd(C5H11NO)2
4ꢀMethylmorpholine (220 mL, 2 mmol) was introꢀ
duced into a solution of palladium crotonate Pd3(
МеCH=CHCO2)6 (276 mg, 1 mmol) in 30 mL of tolꢀ
uene under stirring. The solution color did not change
over a period of 1 h. The solution was filtered through
a Schott filter (no. 40) from palladium metal and conꢀ
centrated in a rotary evaporator to 5 mL. Then, 10 mL
of hexane was added, and a precipitate was separated
from the mother liquor by decantation. The resulting
(10).
μꢀ
washed with hexane (
2
×
10 mL) and dried in a vacꢀ
uum at 93 Pa for 2 h to constant weight. The yield of
the final product—a yellowꢀgreen powder—was 382
mg (85% based on the introduced palladium).
For C16H28N2O6Pd anal. calcd. (%): C, 42.67;
H, 6.22; N, 6.22.
green precipitate was washed with hexane (
2 10 mL)
×
Found (%): C, 42.98; H, 6.54; N, 6.36.
and dried in a vacuum at 93 Pa for 2 h to constant
weight. The yield of the final product—a green powꢀ
der—was 310 mg (65% based on the introduced palꢀ
ladium).
Raman (cm–1): 1640,
IR (cm–1): 1641,
(C=С); 1568, νas(COO); 1354,
νs(COO)
ν(C=С).
ν
.
For C18H32N2O6Pd anal calcd. (%): C, 45.19;
H, 6.69; N, 5.86.
transꢀ(MeCH=CHCO2)2Pd(C4H9NO)2 (8). Morꢀ
pholine (173 mL, 2 mmol) was introduced into a soluꢀ
tion of palladium crotonate Pd3( ꢀCH3CH=CHCO2)6
μ
Found (%): C, 45.29; H, 6.91; N, 6.07.
Raman (cm–1): 1659,
ν
(C=С)
.
(276 mg, 1 mmol) in 30 mL of toluene under stirring.
This induced a change in the solution color to yellowꢀ
orange, which did not change within 1 h of synthesis.
The solution was filtered through a Schott filter
(no. 40) from palladium metal and concentrated in a
rotary evaporator until dry. The yellow precipitate was
IR (cm–1): 1656,
νs(COO)
ν(C=С); 1600, νas(COO); 1336,
.
Single crystals of 10 suitable for Xꢀray crystallograꢀ
phy were obtained by keeping a solution of the comꢀ
plex in a mixture of 15 mL of benzene with 5 mL of
hexane at room temperature for three days.
washed with hexane (
2 10 mL) and dried in a vacuum
×
at 93 Pa for 2 h to constant weight. The yield of the
final product—a yellowꢀgreen powder—was 338 mg
(75% based on the introduced palladium).
transꢀ(PhCH=CHCO2)2Pd(C5H11NO)2
(11).
4ꢀMethylmorpholine (220 mL, 2 mmol) was introꢀ
duced under stirring into a solution of palladium cinꢀ
namate (400 mg, 1 mmol) in 30 mL of toluene. This
induced a change in the solution color to yellowꢀ
green, which did not change within 1 h of synthesis.
The solution was filtered through a Schott filter (no.
40) from palladium metal and concentrated in a rotary
evaporator to 5 mL. Then, 10 mL of hexane was
added, which led to the formation of a green precipiꢀ
tate. The latter was separated from the mother liquor
by decantation. The resulting green precipitate was
For C16H28N2O6Pd anal. calcd. (%): C, 42.67; H,
6.22; N, 6.22.
Found (%): C, 42.21; H, 6.98; N, 6.41.
Raman (cm–1): 1654,
IR (cm–1): 1656,
(C=С); 1582, νas(COO); 1348,
νs(COO); 3209, 3259, (NH)
Single crystals of for Xꢀray crystallography were
ν(C=С).
ν
ν
.
8
obtained by keeping a solution of the complex in
15 mL of benzene with the addition of 5 mL of hexane
at room temperature for three days.
washed with hexane (
2 × 10 mL) and dried in a vacuum
at 93 Pa for 2 h to constant weight. The yield of the
final product—a green powder—was 291 mg (65%
based on the introduced palladium).
For C28H36N2O6Pd anal. calcd. (%): C, 55.81;
H, 5.98; N, 4.65.
transꢀ(PhCH=CHCO2)2Pd(C4H9NO)2 (9). Morꢀ
pholine (173 mL, 2 mmol) was added under stirring to
a
solution of palladium cinnamate Pd3( ꢀ
μ
PhCH=CHCO2)6 (400 mg, 1 mmol) in 30 mL of tolꢀ
uene, which was accompanied by a change in color to
yellow. The reaction gave a yellow precipitate, which
was collected on a Schott filter (no. 16), washed with
5 mL of toluene and 5 mL of petroleum ether, and
dried in a vacuum at 93 Pa for 2 h to constant weight.
The yield of the final product—a light yellow powꢀ
der—was 258 mg (45% based on the introduced palꢀ
ladium).
Found (%): C, 55.95; H, 6.33; N, 4.93.
Raman (cm–1): 1639,
ν
(C=С)
.
IR (cm–1): 1636,
νs(COO)
transꢀ(CH2=C(Me)CO2)2Pd(C5H11NO)2
ν
(C=С); 1576, νas(COO); 1336,
.
(12).
4ꢀMethylmorpholine (220 mL, 2 mmol) was introꢀ
duced under stirring into a solution of palladium
methacrylate (276 mg, 1 mmol) in 30 mL of toluene.
This induced a change in the solution color to brown,
which did not change within 2 h of synthesis. Then,
the solution was filtered through a Schott filter
(no. 40) from palladium metal and concentrated in a
For C26H32N2O6Pd anal. calcd. (%): C, 54.35;
H, 5.57; N, 4.88.
Found (%): C, 54.37; H, 5.33; N, 4.93.
Raman (cm–1): 1638,
(C=С).
ν
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BINARY
α
ꢀUNSATURATED PALLADIUM CARBOXYLATES
853
rotary evaporator until dry. The resulting green precipꢀ carbonyl crotonate (219 mg, 1 mmol) in 20 mL of tolꢀ
itate was washed with hexane ( 10 mL) and dried in uene. The yellowꢀorange color of the reaction mixture
2
×
a vacuum at 93 Pa for 2 h to constant weight. The yield changed, which was accompanied by deposition of
of the final product—a green powder—was 334 mg palladium black for 1 h. then, the solution was cooled
(70% based on the introduced palladium).
For C18H32N2O6Pd anal. calcd. (%): C, 45.19;
H, 6.69; N, 5.86.
to 4°С and filtered through a Schott filter (no. 40)
from palladium metal. To the resulting pale green filꢀ
trate, 5 mL of hexane was added, and the solution was
allowed to stand at 4°C for 14 days. Crystals of pallaꢀ
Found (%): C, 44.84: H, 7.00; N, 6.00.
dium carbamoyl crotonate 16 and morpholonium croꢀ
tonate 17 were formed. After these crystals were isoꢀ
lated, 10 mL of methylene chloride was added to the
Raman (cm–1): 1641,
ν
(C=С)
.
IR (cm–1): 1641,
νs(COO)
ν(C=С); 1592, νas(COO); 1328,
.
mother liquor, which was allowed to stand at
three days for crystallization. This led to the formaꢀ
tion of crystals of the aminate complex trans
(МеCH=CHCO2)2Pd(C4H9NO)2 8a).
Spectra data for palladium carbamoyl crotonate (16).
Raman (cm–1): 1659,
(C=C)).
IR (cm–1): 1576,
(CO) (carbamoyl moiety); 1657,
(C=C); 1543, νas(COO); 1345, νs(COO); 3031,
(CH=); 3171, (NH); 3402, (H2O)).
Spectral data for morpholonium crotonate
4°C for
transꢀ(MeCH=CHCO2)2Pd(C4H9NS)2 (13). Thiꢀ
omorpholine (201 mL, 2 mmol) was introduced under
stirring into a solution of palladium crotonate Pd3( ꢀ
МеCH=CHCO2)6 (276 mg, 1 mmol) in 30 mL of benꢀ
zene. This induced a change in the solution color to
yellow, which did not change within 1 h of synthesis.
Then, the solution was filtered through a Schott filter
(no. 40) from palladium metal and concentrated in a
rotary evaporator until dry. The resulting yellow preꢀ
ꢀ
(
μ
ν
ν
ν
ν
ν
ν
cipitate was washed with hexane (
2 10 mL) and dried
×
(
C4H10NO)+(МеCH=CHCOO)– (17
.
in a vacuum at 93 Pa for 2 h to constant weight. The
yield of the final product—a yellow powder—was 409
mg (85% based on the introduced palladium).
For C16H28N2S2O4Pd anal. calcd. (%): C, 39.80;
H, 5.80; N, 5.80; S, 13.30.
IR (cm–1): 1656,
νs(COO)
Spectral data for 8а
ν
(C=С); 1516, νas(COO); 1375,
.
.
Raman (cm–1): 1654,
IR (cm–1): 1656,
(C=С); 1580, νas(COO); 1348,
νs(COO); 3181, (NH)).
ν(C=С).
Found (%): C, 39.40; H, 5.88; N, 6.00; S, 13.50.
Raman (cm–1):
ν
(C=С) 1651.
(C=С) 1661; νas(COO) 1568,
(Pd–N) 296.
ν
ν
IR (cm–1):
ν
In the reaction of carbonyl crotonate with thioꢀ
morpholine, analogous to the reaction with morphoꢀ
line, palladium carbonyl crotonate was completely
reduced to Pd(0). Only crystals of thiomorpholonium
crotonate (C4H10NS)+(МеCH=CHCOO)– (18) were
isolated from the mother liquor; the structure of 18
was also confirmed by Xꢀray crystallography.
νs(COO) 1343,
ν
Single crystals of 13 suitable for Xꢀray crystallograꢀ
phy were obtained by keeping a solution of the comꢀ
plex in a mixture of 15 mL of benzene with 5 mL of
hexane at room temperature for three days.
[(MeCH=CHCO2)Pd(
morpholine (101 mL, 1 mmol) was introduced under
stirring into a solution of palladium crotonate Pd3(
μ
ꢀC4H9NS)]2 (14). Thioꢀ
μ
ꢀ
МеCH=CHCO2)6 (276 mg, 1 mmol) in 30 mL of benꢀ
zene, which led to the change and color and formation
of a yellow precipitate. The reaction mixture was
allowed to stand for 1 h until the precipitation was
complete. The precipitate was filtered off through a
RESULTS AND DISCUSSION
Among binary palladium carboxylates, aliphatic
palladium carboxylates and especially Pd3(
μ
ꢀ
CH3CO2)6 ( are most studied [1]. As for binary pallaꢀ
1
)
dium complexes with unsaturated acids, almost no
information on their synthesis and properties is availꢀ
able, although it is evident that studying catalytic proꢀ
cesses involving unsaturated organic molecules
requires knowing their transformations in the presꢀ
ence of palladium.
Schott filter (no. 16), washed with toluene (
2
×
10 mL)
and petroleum ether (bp = 40–60 ), and dried in a
°C
vacuum at 93 Pa for 2 h to constant weight. The yield
of the final product—a yellow powder—was 208 mg
(55% based on the introduced palladium).
For C12H19NSO4Pd anal. calcd. (%): C, 38.00;
H, 5.01; N, 3.60; S, 8.40.
Binary palladium complexes with unsaturated
carboxylic acids that have the
Ka’s of aliphatic acids with electronꢀreleasing subꢀ
stituents have been synthesized and studied: cinꢀ
namic ꢀphenylacrylic) acid trans
(Ph)CH=CHCOOH ( Ka = 4.44), methacrylic (2ꢀ
transꢀ(OC4H8NH)2Pd[OC4H8NC(=O)](MeCH= methylpropenoic) acid CH2=C(Ме)COOH (pKa
pKa’s in the range of
Found (%): C, 38.00; H, 5.02; N, 3.77; S, 8.53.
p
Raman (cm–1): 1660,
ν
(C=С)
(C=С); 1570, νas(COO); 1345,
(Pd–N); 344, (Pd–S)
.
IR (cm–1): 1660,
νs(COO); 290,
ν
(
β
ꢀ
ν
ν
.
p
=
CHCO2) H2O (16). Morpholine (173 mL, 2 mmol) 4.66), and crotonic (transꢀ2ꢀbutenoic) acid transꢀ
⋅
was added under stirring to a solution of palladium MeCH=CHCOOH (pKa = 4.69).
RUSSIAN JOURNAL OF INORGANIC CHEMISTRY Vol. 60 No. 7 2015

854
EFIMENKO et al.
Table 3. Spectral data for
α
ꢀunsaturated palladium carboxylates
Raman, cm–1
3–6
IR, cm–1
Complex
ν
(C=C)
ν
(C=C)
νas(CO2)
νs(CO2)
Δν
Pd3(
Pd3(
Pd3(
Pd3(
μ
μ
μ
μ
ꢀCH2=C(Me)CO2)6 (
ꢀMeCH=CHCO2)6 (
ꢀPhCH=CHCO2)6 (
ꢀ(Me)CH=CH(Me)CO2)6 (
3
)
1652
1653
1635
–
1652
1652
1632
1656
1574
1568
1570
1582
1407
1406
1389
1414
167
162
181
168
4)
5
)
6) [15]
Only one complex with an unsaturated carboxylic to that of palladium tiglate Pd3(
acid—palladium tiglate Pd3(μꢀMeCH=C(Me)CO2)6 complexes contain a trinuclear metallacycle on the
has been structurally characterized [15]. The complex sides of which the corresponding carboxylate groups are
contains a trinuclear metallacycle on the sides of arranged in pairs. Complexes are readily soluble
μꢀRCO2)6 (6). Thus,
—
3–5
3–5
which the bridging carboxylate groups are located. and stable in nonpolar solvents. However, attempts to
The Pd–Pd distances in this complex are within carbonylate them in a benzene solution led to the
3.093–3.171 Å and do not differ from the Pd–Pd disꢀ reduction of the complexes to Pd(0).
tances in palladium acetate
Pd–Pd distance is 3.164 Å [1].
Binary ꢀunsaturated palladium carboxylates have
been synthesized by substitution of acetate groups in
with ꢀunsaturated acids:
Pd3( ꢀMeCO2)6 + RCO2H
MeCO2H, where R = CH2=C(Ме), MeCH=CH, PdCl2L2 (L2 is 2,2'ꢀbipyridine (bipy) or 1,10ꢀphenanꢀ
1, in which the average
It has been reported [19] that the carbamoyl moiꢀ
ety =N–C(=O)– is generated by conversion of secꢀ
ondary amines to carbamoyl chlorides, intermediates
in the synthesis of carbamates and urea, through the
formation of palladium carbamoyl complexes
α
1
α
μ
→
Pd3( ꢀRCO2)6 + PdCl(2 – x)(CONRR')xL2 (x = 1, 2) in the reaction of
μ
PhCH=CH, or MeCH=C(Me).
The above palladium ꢀcarboxylates were syntheꢀ
sized from palladium acetate , produced by our origꢀ
inal procedure. This acetate was free from HNO3
decomposition products and afforded high yields and
purity of a target complex, which we failed to achieve
using commercial palladium acetate.
throline (phen)) with NHRR' (where NRR' is
СH2(CH2)4N (piperidine) or CH2(CH2OCH2)CH2N
(morpholine)) with carbon oxide. The use of unsaturꢀ
ated palladium carboxylates in analogous processes
can open new possibilities for the known reactions, for
example, allows one to bypass the stage of formation of
complexes with stabilizing diamines, bipyridine and
phenanthroline, and to use the already synthesized
aminate complexes, in particular, with secondary
amines, as initial compounds for carbonylation.
α
1
It should be noted that different methods, includꢀ
ing multistage, timeꢀconsuming processes [18], have
been used to purify commercial palladium acetate
In the procedure developed by us, the initial comꢀ
pound for synthesis of palladium acetate is
(NH4)2PdCl4; the ammonia in this complex promotes trans
2.
We have synthesized aminate complexes of
ꢀunsaturated carboxylates with secondary amines
1
α
ꢀ
PdA2(RCO2)2 (A is morpholine (M) C4H9NO
,
the intramolecular reduction of palladium and faciliꢀ methylmorpholine (MM) C5H11NO, or thiomorphoꢀ
tates the washing of the product from the traces of line (MS) C4H9NS). The spectral characteristics of
outerꢀsphere chloride ions.
these complexes are presented in Table 4.
According to analytical data, the ratio Pd : RCOO =
1 : 2 persists in the resulting carboxylates. The spectroꢀ
Comparison of the νas(СО2) and νs(СО2) frequenꢀ
cies of
pholine, 4ꢀmethylmorpholine, and thiomorpholine
14) (Table 4) points to a weak effect of the conjuꢀ
COO group
double bond of methacrylic, crotonic, and cinnamic monodentately bound to palladium: their vibrational
acids is not involved in the bonding of the ꢀcarboxyꢀ frequencies correlate with analogous frequencies for
late ion to palladium; i.e., the (C=С) values for these 14 and the (MeCO2)2Pd(C4H9NO)2 complex [20].
α
ꢀunsaturated palladium carboxylates with morꢀ
scopic data for complexes
Table 3.
3–5 are summarized in
(7–
The Raman and IR spectra have shown that the gated double bond on the character of the
⎯
α
ν
complexes remain close to the values observed for the According to Xꢀray crystallographic data, the conjugaꢀ
initial acids and palladium tiglate [15]. The stretching tion of the C(2)=C(3) double bond of the coordinated
vibration frequencies νas(CO2) and νs(CO2) and the acid residue with the СОО– moiety in 10 lacking
splitting Δν = 162–181 = cm–1 for the synthesized hydrogen bonds follows from the value of the torsion
carboxylates, as well as their coincidence with the corꢀ angle O(1)C(1)C(2)C(3) = 173.11° close to the perfect
responding frequencies of palladium tiglate [15], are straight angle (180°). The
evidence that the carboxylate ligands are bridging, which 13 is the same being 296 cm–1. It should be noted that
has been proved by structural data [15]; this fact allows us the reaction of palladium crotonate with thiomorphoꢀ
to conclude that complexes have a structure similar line C4H9NS at the reagent ratio Pd : MS = 1 : 2 gives the
ν(Pd–N) frequency for 7–
4
3–5
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BINARY
α
ꢀUNSATURATED PALLADIUM CARBOXYLATES
855
Table 4. Spectral data for transꢀaminate complexes of
for comparison 15 and [20]
α
ꢀunsaturated carboxylic acids 7–14 and complexes with acetic acid
IR, cm–1
Raman,
ν
Complex
cm–1
(C=C)
ν
(C=C)
νas(CO2)
νs(CO2)
Δν
(CH2=C(Me)CO2)2Pd(C4H9NO)2
(7)
1640
1654
1638
1659
1639
1641
1661
1660
–
1641
1656
1636
1656
1636
1641
1661
1660
–
1568
1582
1588
1600
1576
1592
1568
1570
1591
1575
1354
1348
1352
1336
1336
1328
1343
1345
1378
1338
214
234
236
264
240
264
225
225
213
237
(MeCH=CHCO2)2Pd(C4H9NO)2
(PhCH=CHCO2)2Pd (C4H9NO)2
(9)
(8)
(MeCH=CHCO2)2Pd(C5H11NO)2
(10)
(PhCH=CHCO2)2Pd(C5H11NO)2
(11)
(CH2=C(Me)CO2)2Pd(C5H11NO)2
(
12
)
(MeCH=CHCO2)2Pd(C4H9NS)2
(
13)
[(MeCH=CHCO )Pd(C4H9NS)]2
(14)
2
(MeCO2)2Pd(C4H9NS)2
(15)
(MeCO2)2Pd(C4H9NO)2
⋅
H2O [20]
–
–
Table 5. Selected bond lengths (Å) in complexes
8,
8a,
10,
12, and 16–18
Complex
Pd–N
Pd–O
C=C
C–O(Pd)
C–Oterm
NH⋅⋅⋅O
(MeCH=CHCO2)2Pd(C4H9NO)2 (
8
)
2.054(2)
2.052(2)
2.122(5)
2.059(1)
2.004(1)
2.009(1)
2.028(5)
2.010(1)
1.288(3)
1.293(3)
1.332(9)
1.306(3)
1.283(2)
1.289(2)
1.313(7)
1.291(2)
1.227(2)
1.235(2)
1.245(8)
1.234(2)
2.771(2)
3.023(2)
–
(MeCH=CHCO2)2Pd(C4H9NO)2 (8a
)
(MeCH=CHCO2)2Pd(C5H11NO)2 (10
)
(CH2=C(Me)CO2)2Pd(C5H11NO)2 (12
)
3.091(2)
(OC4H8NH)2Pd[OC4H8NC(=O)]
MeCH=CHCO2)
⋅
H2O (16
)
2.077(2)
2.077(2)
2.138(2)
1.316(3)
1.314(8)
1.266(3)
1.250(3)
2.813(3)
3.017(3)
(C4H10NO)+(MeCH
=
CHCO2)– (17
)
–
–
–
–
–
1.257(6
1.277(6)
2.707(5)
2.628(5)
(C4H10NS)+(MeCH=CHCO2)– (18
)
–
1.315(5)–
1.329(5)
1.251(4)– 2.675(4)–
1.275(4)
2.694(4)
(MeCO2)2Pd(C4H9NO)2 H2O [20]
⋅
2.047(4)
2.017(3)
–
1.272(5)
1.238(6)
3.038(7)
(MeCH=CHCO2)2Pd(C4H9NS)2 complex (13) in at 296 cm–1) and the sulfur atom (
which thiomorpholine coordinated through the nitroꢀ with retention of the monodentate coordination of the
gen atom rather than through the sulfur atom, like in crotonate ions, but in the cis position, νas(СО2)
compounds with morpholine and 4ꢀmethylmorphoꢀ 1570 cm–1 and νs(СО2) = 1345 cm–1. The probable
line ( and 10, respectively). The reaction at the ratio structure of complex 14 is shown in Fig. 1. It should be
Pd : MS = 1 : 1 leads to the binuclear complex noted that the νas(СО2) and νs(СО2) values for monoꢀ
[(MeCH=CHCO2)Pd(C4H9NS)]2 (14 with the and binuclear complexes with thiomorpholine 13 and
bridging thiomorpholine molecules coordinated to 14 do not change and point to the lack of the effect of
ν
(Pd–S) at 344 cm–1),
=
8
)
palladium through both the nitrogen atom (ν(Pd–N) the position of the carboxylate groups on their spectral
CH3CH=CH(O=)CO
OC(=O)CH=CHCH3
OC(=O)CH=CHCH3
S
NH
S
Pd
Pd
CH3CH=CH(O=)CO
NH
Fig. 1. Complex [(MeCH=CHCO ) Pd(C H NS)] (14).
2
2 2
4
9
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856
EFIMENKO et al.
(a)
(b)
C(8)
C(8A)
C(7A)
O(3)
C(7)
C(6)
C(6A)
O(3A)
C(4A)
C(5)
O(2)
C(2A)
C(1A)
C(5A)
O(2A)
C(3A)
N(1A)
O(1A)
O(1A)
N(1A)
C(2A)
C(3)
C(1)
C(4A)
C(3A)
C(1A)
C(4)
Pd(1)
C(2)
Pd(1)
O(3)
O(1)
O(1)
C(2)
N(1)
N(1)
O(2A)
C(5A)
C(3)
O(2)
C(1)
C(4)
C(5)
C(7A)
C(6)
C(7)
O(3A)
C(6A)
C(8)
C(8A)
Fig. 2. Molecular structure of polymorphs
8
. Thermal ellipsoids are drawn at the 50% probability level. Here and in Figs. 3, 5,
(from C H ) and (b) 8а (from СH Cl ).
and 7, dashed lines show hydrogen bonds. (a)
8
6
6
2
2
characteristics. This is likely a result of the complex ing to Xꢀray crystallographic data, all aminate comꢀ
plexes of palladium ꢀcarboxylates with morpholine
α
electron density redistribution in the O2PdNS system
of complex 14
derivatives— 8а 10, and 12—are centrosymmetric
8,
,
.
monomers in which the palladium atom has a typical
squareꢀplanar environment composed of the nitrogen
atoms of two coordinated molecules of morpholine
Single crystals of palladium complexes 8, 10, and
12 have been studied by Xꢀray crystallography. Figꢀ
ures 2–5 show the structures of these complexes, and
Table 5 presents the bond lengths in transꢀaminate
(or its derivatives) and two oxygen atoms of the trans
ꢀ
arranged terminal crotonate groups. Noteworthy is the
elongation of the Pd–N bond in complex 10 with
methylmorpholine to 2.122(5) Å as compared with
complexes of αꢀunsaturated carboxylic acids. Accordꢀ
complex 8 with morpholine (2.054(2) Å), which is eviꢀ
dence of steric hindrances caused by coordination of
4ꢀmethylmorpholine to palladium, which can be
explained by the existence of the methyl substituent at
the nitrogen atom located in the equatorial position,
whereas the N(1)–Pd(1) bond in in axial orientation
to the morpholine ring with a chair conformation.
Pd(1C)
Pb(1B)
a
In crystal structure of
8, only intramolecular
hydrogen bonds NH⋅⋅⋅O are observed (Fig. 2), while in
its polymorph 8а and compound 12, all hydrogen
bonds are intermolecular and combine neighboring
complexes into layers (Figs. 2, 3, and 5; Table 5).
Pd(1E)
Pd(1)
Pd(1F)
It has turned out that the carbonylation of the synꢀ
thesized aminate
αꢀunsaturated palladium carboxyꢀ
late complexes is accompanied by their reduction to
Pd(0). Therefore, we have used a new approach to the
synthesis of palladium carbamoyl carboxylates
through the amination of reaction of palladium carboꢀ
nyl crotonate with a secondary amine, morpholine.
0
c
Pd(1D)
Pd(1A)
b
The reaction of palladium carbonyl crotonate Pd4(
μꢀ
CO)4( ꢀMeCH=CHCO2) with morpholine was
μ
accomplished in toluene at room temperature. Pallaꢀ
dium carbonyl crotonate was synthesized through the
substitution of the acetate ion in palladium carbonyl
Fig. 3. Layers in structure 8а
.
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BINARY
α
ꢀUNSATURATED PALLADIUM CARBOXYLATES
857
(a)
(b)
C(4A)
C(4)
C(3A)
C(5A)
S(1)
C(6A)
C(3)
C(2)
C(1)
O(3A)
C(9A)
C(2A)
O(2A)
C(6)
C(1A)
O(1A)
O(2)
C(7A)
C(8)
C(5)
N(1A)
C(8A)
O(1)
C(7)
Pd(1)
N(1)
Pd(1)
O(1A)
C(8)
N(1)
C(7)
O(3)
O(2A)
O(1)
N(1A)
C(5A)
C(9)
O(2)
C(7A)
C(1A)
C(2A)
C(3A)
C(8A)
C(1)
C(5)
C(6)
C(2)
C(6A)
C(3)
C(4A)
S(1A)
C(4)
Fig. 4. Molecular structure of complexes (a) 10 and (b) 12. Thermal ellipsoids are drawn at the 50% probability level.
c
0
a
b
Fig. 5. Layers in structure 12
.
carboxylate with appropriate acid to give Pd4(
CO)4( ꢀМеСН=СНCO2) [17].
μꢀ
СНСО2)
(
⋅
Н2О (16) and morpholonium crotonate
C4H10NO)+(МеСН=СНСОО)– (17). After separaꢀ
μ
tion of these crystals, the addition of methylene
chloride to the mother liquor gives the third type of
The reaction scheme is shown in Fig. 6. First, pallaꢀ
dium carbonyl crotonate disproportionates to give Pd(0)
and a Pd(II) complex. After separation of palladium
metal, two types of single crystals were obtained from
crystal 8а of the same composition as the trans
MeCH=CHCO2)2Pd(C4H8NO)2 complex ( ). Howꢀ
ever, Xꢀray crystallography has shown that the reaction
ꢀ
(
8
the mother liquor at 4°С: palladium carbamoyl crotoꢀ
nate transꢀ(OC4H8NH)2Pd[OC4H8NC(=O)](МеСН= leads to isomer 8а of complex 8.
RUSSIAN JOURNAL OF INORGANIC CHEMISTRY Vol. 60 No. 7 2015

858
EFIMENKO et al.
Pd(0)
trans
ꢀ
(OC4H8NH)2Pd[OC4H8NC(=O)](MeCH=CHCO2) H2O (16)
⋅
C H ONH
4
8
Pd4(
μ
ꢀCO)4(μꢀMeCH=CHCO2)4
(C4H10NO)+2(MeCH=CHCO2)– (17
)
C H Me
6
5
Pd(MeCH=CHCO2)2(C4H9NO)2 (8а) (point group Pccn
)
Fig. 6. Scheme of transformations of palladium carbonyl crotonate in the reaction with morpholine.
The spectral characteristics of reaction products 16
,
8а
,
and 17 are summarized in Table 6. The (С=С),
ν
C(12)
O(1)
νas(СО2), and νs(СО2) frequencies for all these comꢀ
pounds are nearly identical. The vibrational frequenꢀ
cies of the coordinated morpholine molecules in 8а
C(11)
and 16 also do not differ from the (NH) values for
ν
C(14)
C(13)
other complexes (Table 4) with transꢀarranged amines
coordinated to palladium through the nitrogen atoms.
N(1)
O(4)
In complex 16 (Fig. 7), the palladium atom has a
squareꢀplanar environment with transꢀarranged atoms
N–Pd–N and O–Pd–C. The palladium atom is
bonded to two transꢀarranged morpholine molecules
with a somewhat elongated Pd–N distance (2.077(2) Å)
as compared with the Pd–N distance in complex 8а
(2.052(2) Å).
C(34)
C(1)
C(33)
N(3)
O(3)
Pd(1)
N(2)
C(32)
C(21)
C(31)
C(22)
The Pd–C distances are somewhat shortened
(1.958(2) Å) as compared with the Pd–C distances in
the initial palladium carbonyl crotonate (1.980(2)–
1.986(2) Å [17]).
C(23)
C(24)
O(7)
O(6)
C(2)
O(5)
O(2)
C(3)
The Pd–O distances to the monodentately coordiꢀ
nated carboxylate group are 2.138(2) Å in complex 16
and 2.009(1) Å in aminate complex 8a. The elongation
of the Pd–O bond by 0.13 Å can be a result of the
effect of the trans carbamoyl ligand, as well as of an
intricate system of rather short hydrogen bonds
involving solvate water molecules, which form heir
chains along the ac diagonal (Fig. 8).
C(4)
C(5)
Fig. 7. Molecular structure of complex 16. Thermal ellipꢀ
soids are drawn at the 50% probability level.
The second product of the reaction of morpholine
and palladium carbonyl crotonate is morpholonium
crotonate (C4H10NO)+(МеCH=CHCOO)–
(
17).
Formation of the morpholonium cation C6H8ONH2+
as a result of hydrogen bonding with the carbonyl oxyꢀ band of morpholonium crotonate, which is observed
gen atoms of the crotonate anion is accompanied by a
+
lowꢀfrequency shift of the
stretching vibration
−NH2 −
Table 6. Spectral characteristics (cm–1) of compounds 8a
, 16, and 17
IR, cm–1
s(CO2) (NH)
Raman,
cm–1
(C=C)
Compound
ν
(CO)
ν
ν
(C=C)
ν
as(CO2)
ν
ν
ν
(H2O)
carbamoyl
(C4H9NO)2Pd(MeCH=CHCO2)2 (8a
)
1654
1659
1656
1656
1580
1513
1348
1345
3182
–
–
(OC4H8NH)2Pd[OC4H8NC(=O)](MeCH=CHCO2
)
⋅
3171
1576
3402
H2O (16
)
(C4H10NO)+(MeCH=CHCO2)– (17
)
–
1656
1516
1375
–
–
–
RUSSIAN JOURNAL OF INORGANIC CHEMISTRY Vol. 60 No. 7 2015

BINARY
α
ꢀUNSATURATED PALLADIUM CARBOXYLATES
859
It should be noted that, when thiomorpholine was
added to a solution of palladium carbonyl crotonate,
only
(
thiomorpholonium
crotonate
C4H10NS)+(МеCH=CHCOO)– (18) was isolated.
Xꢀray crystallographic data for compounds 17 and
18 demonstrate that the morpholinium and thiomorꢀ
pholinium cations in crystals are linked with crotonate
anions through strong, almost linear hydrogen bonds
NH⋅⋅⋅O to form chains (Fig. 9, Table 4).
a
The third product of amination of palladium carbamꢀ
oyl crotonate is the transꢀ(C4H9NО)2Pd(МеCH=
CHCO2)2 complex (8а) of the same composition as
complex
crystal and powder diffraction data: a crystal of comꢀ
plex obtained from benzene (Fig. 2a) belongs to
point group 21/ , whereas a crystal of complex 8а
obtained from CH2Cl2 belongs to point group Pccn
(Fig. 2b). This difference is due to formation of differꢀ
ent types of hydrogen bonds: only intramolecular
hydrogen bonds NH⋅⋅⋅O are formed in the crystal
8 but differing from it according to singleꢀ
c
0
8
Р
n
b
Fig. 8. Hydrogenꢀbonded chains in structure 16
.
structure of
8, whereas exclusively intermolecular
hydrogen bonds are formed in the structure of comꢀ
as a moderate broad band with several submaxima in
plex 8а; i.e., the type of hydrogen bond network and,
the range 2000–2600 cm–1. Selected bond lengths in hence, the type of crystal lattice is determined in this
complexes 8а
,
16,
17,
and 18 are presented in Table 5. case by the nature of the solvent.
(a)
b
N(1B)
O(3A)
a
(b)
0
N(1)
O(2A)
O(3)
O(2)
b
N(1A)
c
c
0
a
Fig. 9. Hydrogenꢀbonded chains in structures (a) 17 and (b) 18
.
RUSSIAN JOURNAL OF INORGANIC CHEMISTRY Vol. 60 No. 7 2015

860
EFIMENKO et al.
6. I. Ara, L. R. Falvello, J. Forniers, et al., Inorg. Chim.
Thus, when studying the interaction of a secondary
Acta 359, 4574 (2006).
7. S. Hermans, C. Diverehy, O. Demoulin, et al., J. Catal.
243, 239 (2006).
8. K. I. Hardcastle, T. McPhilips, A. J. Arce, et al., J. Org.
Met. Chem. 389, 361 (1990).
9. M. Ohash and A. Yagyu, Xu Qinghong, et al., Chem.
amine—morpholine—with palladium carbonyl croꢀ
tonate, we discovered a new reaction of formation of
the carbamoyl moiety =N–C(=O)– as a result of
innerꢀsphere transformations of the coordinated carꢀ
bonyl in palladium carbonyl crotonate under the
action of morpholine, which lead to palladium carꢀ
bamoyl crotonate. The transꢀ(OC4H8NH)2Pd
[OC4H8NC(=O)](МеCH=CHCO2)
is the first transitionꢀmetal carbamoyl carboxylate
complex where the anion is an ꢀunsaturated carboxꢀ
ylate ion. Knowledge of the structure and properties of
complex 16 can contribute to the understanding of the
mechanisms of carbonylation reactions catalyzed by
palladium carboxylates [21].
Lett. 35, 954 (2006).
10. W. Zh. Chen, J. D. Protasiewicz, C. A. Davis, et al.,
⋅ H2Ocomplex (16)
Inorg. Chem. 46, 3775 (2007).
11. Y. C. Neo, J. S. L. Yeo, P. M. N. Low, et al., J. Org. Met.
α
Chem. 638, 159 (2002).
12. A. Behr, R. He, K. D. Juszak, et al., Chem. Bes. 119
,
991 (1986).
13. P. Teo, L. L. Koh, and T. S. A. Hor, Inorg. Chem. 47
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6464 (2008).
ACKNOWLEDGMENTS
14. D. P. Hruskewycz, Janguo Wu, N. Hazari, et al., J. Am.
Chem. Soc. 133, 3280 (2011).
15. T. A. Stromnova, K. Yu. Monakhov, and J. Campora,
We are grateful to L.A. Leites for recording and
interpretation of Raman spectra and to O.N. Shishilov
for participation in discussions of some results.
Inorg. Chim. Acta 360, 4111 (2007).
16. T. A. Stromnova, O. N. Shishilov, M. V. Dayneko, et al.,
J. Organomet. Chem. 691, 3730 (2006).
17. O. N. Shishilov, P. V. Ankudinova, E. V. Nikitenko,
et al., J. Organomet. Chem. 767, 112 (2014).
18. I. P. Stolyarov, L. I. Demina, and N. V. Cherkashina,
Russ. J. Inorg. Chem. 56, 1532 (2011).
19. M. Aresta, P. Giannoccaro, I. Tommasi, et al., Organoꢀ
metallics 19, 3879 (2000).
20. O. N. Shishilov, T. A. Stromnova, A. V. Churakov, et al.,
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π
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Translated by G. Kirakosyan
RUSSIAN JOURNAL OF INORGANIC CHEMISTRY Vol. 60 No. 7 2015