Synthesis and Structure of [Pd(NH3)4][cis-Pd(NH 3)2(SO3)2][Pd(NH3) 3(SO3)]·H2O

Article abstract of DOI:10.1023/A:1023360723314

A new palladium compound [Pd(NH₃)₄][cis-Pd(NH ₃)₂(SO₃)₂][Pd(NH₃) ₃(SO₃)]·H₂O (I) was synthesized and its structure was studied by X-ray powder diffraction method. In the course of the synthesis, the initial trans-diamminesulfite anionic complex is transformed into the cis-configuration. Further heating in aqueous solution results in isomerization of a substance into a neutral complex [Pd(NH₃) ₃(SO₃)]. Crystals I are triclinic: a = 10.3297(2) A, b = 14.1062(3) A, c = 6.8531(1) A, α = 101.36(0)°, β = 92.74(0)°, γ = 92.71(0)°, space group P1. Structure I consists of the columns with alternating cis-[Pd(NH ₃)₂(SO₃)₂]^2- and [Pd(NH₃)₃(SO₃)] complexes and [Pd(NH ₃)₄]²⁺ ions between the columns.

Full text of DOI:10.1023/A:1023360723314

Russian Journal of Coordination Chemistry, Vol. 29, No. 4, 2003, pp. 256–260. Translated from Koordinatsionnaya Khimiya, Vol. 29, No. 4, 2003, pp. 274–279.
Original Russian Text Copyright © 2003 by Mulagaleev, Soloviev, Blokhin, Kirik.
Synthesis and Structure
of [Pd(NH3)4][cis-Pd(NH3)2(SO3)2][Pd(NH3)3(SO3)] · H2O
R. F. Mulagaleev, L. A. Soloviev, A. I. Blokhin, and S. D. Kirik
Institute of Chemistry and Chemical Technology, Siberian Division, Russian Academy of Sciences, Krasnoyarsk, Russia
Received January 24, 2002
Abstract—A new palladium compound [Pd(NH3)4][cis-Pd(NH3)2(SO3)2][Pd(NH3)3(SO3)] · H2O (I) was synthe-
sized and its structure was studied by X-ray powder diffraction method. In the course of the synthesis, the initial
trans-diamminesulfite anionic complex is transformed into the cis-configuration. Further heating in aqueous
solution results in isomerization of a substance into a neutral complex [Pd(NH3)3(SO3)]. Crystals I are triclinic:
a = 10.3297(2) Å, b = 14.1062(3) Å, c = 6.8531(1) Å, α = 101.36(0)°, β = 92.74(0)°, γ = 92.71(0)°, space group P1 .
Structure I consists of the columns with alternating cis-[Pd(NH3)2(SO3)2]2– and [Pd(NH3)3(SO3)] complexes and
[Pd(NH3)4]2+ ions between the columns.
The syntheses of two-complex platinum and palla- the trans-diamminedichloride palladium(II) (1 g) were
dium aminosulfite compounds by means of sulfitization each suspended in 20 ml of distilled water in two bea-
of the respective tetraammine chlorides [M(NH3)4]Cl2 kers. Ammonium hydroxide was added by drops to one
with sodium sulfite were described in [1–4]. The reac- beaker to dissolve the suspension, such that excess
tions were carried out in aqueous solutions and, ammonium hydroxide would be avoided. The obtained
depending on the temperature and stoichiometric ratio [Pd(NH3)4]Cl2 solution was cooled with ice to 5°ë.
of the initial reagents, different reaction products were Na2SO3 crystals (1.2 g) were added to the second bea-
obtained. In particular, for platinum, [Pt(NH3)4][trans- ker until the suspension was dissolved. The trans-
Pt(NH3)2(SO3)2] · 2H2O was isolated at room tempera- Na2[Pd(NH3)2(SO3)2] solution was also cooled to 5°ë.
ture. The formation of this trans-configuration is When these two cooled solutions were mixed, a white
explained in [1–4] as a characteristic manifestation of a precipitate formed almost immediately. It was filtered
strong trans-effect of a sulfite group. In the case of pal- off and washed with cold water. After the mother liquor
ladium, the two-complex compound is stable at the was allowed to stand at room temperature, the molecu-
lowered temperature, whereas at room temperature, lar complex [Pd(NH3)3(SO3)] precipitated [7]. The
[Pd(NH3)3(SO3)] is formed. The synthesis of compound under study was dried in air at room temper-
[Pt(NH3)4][trans-Pt(NH3)2(SO3)2] · 2H2O via the ion ature. When the synthesis was carried out with cooling
exchange between [Pt(NH3)4]Cl2 and trans- to a lower temperature, the crystallization time
Na2[Pt(NH3)2(SO3)2] is described in [5]. With the aim to increased and the compound formed in the lower yield.
obtain adequate crystals for [Pd(NH3)4][trans-
Compound I forms white finely crystalline powder
Pd(NH3)2(SO3)2] · 2H2O, we used the method described
poorly soluble in water. When dry, the compound is sta-
in [5], since it is most suitable for monitoring the crys-
ble at room temperature. When the powder or its aque-
tallization conditions. The resulting compound with the
ous solution is heated, [Pd(NH3)3(SO3)] is formed.
expected composition Pd(NH3)3(SO3) had an unusual
structure that corresponded to the formula
The crystal structure of I was solved and refined by
[Pd(NH3)4][cis-Pd(NH3)2(SO3)2][Pd(NH3)3(SO3)] · H2O
X-ray powder diffraciton method. The experimental
(I). It is likely that the author of [4] isolated the same
data were obtained on a DRON-4-07 diffractometer at
compound but assigned different structure to it. This
20°ë (CuKα radiation, graphite monochromator). In
work was undertaken with the aim to synthesize com-
order to minimize the effect of the preferred orienta-
plex I and to study it by X-ray powder diffraction
tion, the sample was prepared by spreading the powder
method.
on the plane of a single-crystal silicon plate cut in the
nonreflecting direction. Scanning was carried out in the
range of 2θ from 6° to 80° at a step of 0.02° and record
EXPERIMENTAL
time 10 s. The unit cell parameters were found from
Complex I was synthesized by the procedure similar X-ray powder diffraction pattern using the program [8].
to that in [4]. All initial compounds were prepared The structure was solved and refined with the program
using procedures described in [6]. The reagent grade package based on the modified and supplemented ver-
chemicals were used in the synthesis. Two samples of sion of the DBWC-9006PC program [9]. Positions of
1070-3284/03/2904-0256$25.00 © 2003 åÄIä “Nauka /Interperiodica”

SYNTHESIS AND STRUCTURE
257
I, pulses
7000
6000
5000
4000
3000
2000
1000
0
1
2
10
20
30
40
50
60
70
2θ, deg
Fig. 1. Experimental and calculated X-ray powder diffraction patterns after refinemnt of structure I.
the metal atoms and orientations of ligands were between the coordination bonds deviate by no more
located from the Patterson synthesis. The remaining than 5° from the standard value of 90°, the SPdS angle
non-hydrogen atoms were located from the Fourier being the largest, which is explained by mutual steric
synthesis. The Rietveld method [10] was used for refin-
ing the crystal structure. Hydrogen atoms were located
geometrically with account of the structures of ammo-
nia and water molecules and of the analysis of the most
probable hydrogen bonding system. Hydrogen atoms
were rigidly fixed at the respective N and O atoms.
effect of two sulfite groups. An average Pd–S bond
length (2.291(6) Å) in the known trans-diamminedis-
ulfite palladium complexes [11, 12] coincides within
the limits of the standard deviations with that in com-
pound I (2.28(2) Å). However, the Pd–N bonds in the
The refined experimental and calculated X-ray pat-
terns are shown in Fig. 1. Data on the crystal structure
of I are presented in Table 1. Atomic coordinates and
thermal parameters are listed in Table 2, while the bond
lengths and angles are given in Table 3.
Table 1. Crystal data and R factors for structure I
Space group
P1
a, Å
10.3297(2)
14.1062(3)
6.8531(1)
101.36(0)
92.74(0)
92.71(0)
976.3(4)
2
b, Å
c, Å
RESULTS AND DISCUSSION
α, deg
β, deg
γ, deg
V, Å3
Z
Crystals I (Fig. 2) consist of the complex anions cis-
[Pd(NH3)2(SO3)2]2–, neutral complexes [Pd(NH3)3(SO3)],
complex cations [Pd(NH3)4]2+, and water molecules. A
fragment of structure I is shown in Fig. 3.
No data are available in the literature on the geome-
try of the cis-[Pd(NH3)2(SO3)2]2– complexes. The Pd
atom in this anion has almost planar coordination envi-
ronment of two S atoms of two sulfite groups, and two
N atoms of two ammonia molecules. The angles
ρ(calcd), g/cm3
2.486
Rwp
0.0697
Rb
0.0330
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 29 No. 4 2003

258
MULAGALEEV et al.
Table 2. Atomic coordinates and thermal parameters for
structure I
ate from 90°, probably, due to the effect of hydrogen
bonds.
On the whole, geometrical parameters of a neutral
[Pd(NH3)3(SO3)] molecule are close to those for
[Pd(NH3)3(SO3)] [14]. Some deviations include an
increase in the Pd–S distance by 0.05 Å and a decrease
in the average Pd–N distance (2.05(3) Å) as compared
to analogous data (2.11(2) Å) [14].
Atom
x
y
z
B, Å2
Pd(1)
Pd(2)
Pd(3)
S(1)
0.2374(5) 0.8373(3)
0.2377(5) 0.3480(4)
0.2354(5) 0.8093(3)
0.9799(8)
0.1521(8)
0.4628(7)
1.068(3)
1.174(5)
1.176(4)
0.882(5)
0.396(2)
0.597(5)
0.330(5)
0.294(4)
0.399(2)
0.412(5)
0.552(5)
0.196(5)
0.973(4)
0.999(4)
0.907(4)
0.526(4)
0.535(4)
–0.105(4)
0.409(5)
0.317(4)
0.010(4)
0.267(3)
3.8(2)
4.5(2)
2.8(2)
4.7(4)
4.6(4)
4.6(4)
4.6(4)
4.7(4)
4.6(4)
4.6(4)
4.6(4)
4.7(4)
4.6(4)
4.6(4)
4.6(4)
4.2(5)
4.2(5)
4.2(5)
4.2(5)
4.2(5)
5.0(6)
5.0(6)
5.0(6)
5.0(6)
4(1)
A peculiar feature of compound I is that its structure
0.251(2)
0.130(3)
0.368(3)
0.246(3)
0.393(2)
0.433(3)
0.506(3)
0.341(3)
0.068(2)
1.003(1)
1.027(2)
1.040(2)
1.047(2)
0.700(1)
0.685(2)
0.747(2)
0.607(2)
0.697(1)
0.753(2)
0.641(2)
0.630(2)
0.817(2)
0.833(2)
0.684(2)
0.917(2)
0.924(2)
0.244(2)
0.437(2)
0.255(2)
0.447(2)
0.497(2)
consists
of
columns
of
alternating
cis-
[Pd(NH3)2(SO3)2]2– anions and neutral [Pd(NH3)3(SO3)]
molecules. The columns are directed along the c axis
and have zigzag elements with the Pd(1)···Pd(3) dis-
O(11)
O(12)
O(13)
S(2)
tances being 3.410(8) and 3.486(7)
Å
and
Pd(1)···Pd(3)···Pd(1) angle being 167.1(2)°. The
[Pd(NH3)3(SO3)] complexes occupy the space-saving
anti-position with respect to the cis-[Pd(NH3)2(SO3)2]2–
anions; the torsion S–Pd···Pd–S angle is close to 130°.
One can notice that the columns form corrugated planes
parallel to the x0z axis, such that each column is sur-
rounded by two closest columns.
The most probable hydrogen bonding system was
established by analyzing the N···O and O···O distances
(Table 3) and the Pd–N···O, O···N···O, and O···O···O
angles. In the cationic complex, each nitrogen atom,
except for N(7), forms three hydrogen bonds linking a
cation with the remaining complexes and water mole-
cules. Hydrogen bonds of the anionic and neutral com-
plexes are realized between the neighboring columns
and inside the column. Hydrogen bonds inside the col-
umn are likely to favor stabilization of the cis-configu-
ration of the anion in the course of crystallization.
Water molecules are also connected to the columns by
the O(1)···O(21) and O(1)···O(23) hydrogen bonds.
O(21)
O(22)
O(23)
S(3)
O(31) –0.057(3)
O(32)
O(33)
N(1)
N(2)
N(3)
N(4)
N(5)
N(6)
N(7)
N(8)
N(9)
O(w)
0.057(3)
0.064(3)
0.037(3)
0.428(3)
0.233(3)
0.095(3)
0.375(3)
0.270(3)
0.213(3)
0.274(3)
0.191(3)
0.580(3)
Proceeding from the synthesis and analysis of the
crystal structure of I, one can suggest the mechanism of
transformation of the initial trans-diamminedisulfite
complex into the cis-configuration, taking into account
that the trans-diamminedisulfitopalladate(II) anion
undergoes dissociation and hydration in aqueous solu-
tion:
trans-[Pd(NH3) (SO3) ]2–+ H2O
2
2
(1)
trans-[Pd(NH3) (SO3)(H2O)] + SO32–.
2
trans-complexes [11, 12] (average length 2.069(9) Å)
are somewhat shorter than similar bonds in I (2,11(2)
Å). Although this difference only slightly exceeds the
standard deviation, one can suggest that an increase in
the Pd–N distance is caused by the trans-labilizing
effect of the sulfite group. Geometrical parameters of
the sulfite groups in cis-[Pd(NH3)2(SO3)2]2– are almost
the same as those in trans-diamminedisulfite palladium
[11, 12].
It is obvious that equilibrium (1) should be significantly
shifted to the left due to a high affinity of Pd(II) toward
sulfite group. However, the particles that can interact
with the sulfite ions (in particular, the [Pd(NH3)4]2+
complex cations) can shift equilibrium (1) toward the
aqua complex. As a result of an increased trans-effect
of its sulfite group, this complex is rearranged into the
cis-configuration or adds ammonia. Ammonia is
obtained due to the interaction of [Pd(NH3)4]2+ and
In the [Pd(NH3)4]2+ complex cation of structure I,
the Pd–N distances are close to those in
SO32– with the formation of a stable triamminesulfite
[Pd(NH3)4]C2O4 [13] and in [Pd(NH3)4]Cl2 · H2O [7]. complex. The final reaction products are in fact the
At the same time, the NPdN angles substantially devi- result of this activity. Evidently, the fixation of cis-com-
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 29 No. 4 2003

SYNTHESIS AND STRUCTURE
Table 3. Selected bond lengths and angles in structure I*
259
Bond
d, Å
2.07(3) N(2) O(22)
...
Bond
d, Å
Angle
ω, deg
Angle
ω, deg
#2
...
Pd(1)–N(1)
Pd(1)–N(2)
Pd(1)–N(3)
Pd(2)–N(4)
Pd(2)–N(5)
Pd(3)–N(6)
Pd(3)–N(7)
Pd(3)–N(8)
Pd(3)–N(9)
Pd(1)–S(1)
Pd(2)–S(2)
Pd(2)–S(3)
S(1)–O(11)
S(1)–O(12)
S(1)–O(13)
S(2)–O(21)
S(2)–O(22)
S(2)–O(23)
S(3)–O(31)
S(3)–O(32)
S(3)–O(33)
N(1)–O(11)#1
2.87(5) S(1)Pd(1)N(1)
3.12(4) S(1)Pd(1)N(2)
2.91(4) N(1)Pd(1)N(3)
2.89(5) N(3)Pd(1)N(2)
3.06(4) S(1)Pd(1)N(3)
3.14(5) N(1)Pd(1)N(2)
3.06(4) S(2)Pd(2)S(3)
3.21(4) N(4)Pd(2)N(5)
2.85(5) S(2)Pd(2)N(5)
2.76(4) S(3)Pd(2)N(4)
2.98(4) S(2)Pd(2)N(4)
2.94(4) S(3)Pd(2)N(5)
2.99(4) N(6)Pd(3)N(8)
2.99(5) N(6)Pd(3)N(9)
3.21(4) N(7)Pd(3)N(8)
3.03(4) N(7)Pd(3)N(9)
3.27(4) N(6)Pd(3)N(7)
2.98(4) N(8)Pd(3)N(9)
3.10(4)
98(1)
91(1)
84(1)
86(1)
O(11)S(1)O(12)
O(12)S(1)O(13)
O(13)S(1)O(11)
O(21)S(2)O(22)
115(2)
106(2)
108(2)
105(2)
122(2)
104(2)
103(2)
110(2)
108(2)
104(1)
113(1)
110(1)
102(1)
109(2)
112(1)
106(2)
113(1)
115(1)
1.97(3) N(2) O(21)
...
2.12(3) N(3) O(32)
#2
...
2.15(3) N(3) O(33)
...
2.08(3) N(4) O(13)
177.3(9) O(22)S(2)O(23)
169(1) O(23)S(2)O(21)
95.1(7) O(31)S(3)O(32)
86(1) O(32)S(3)O(33)
#3
...
2.11(3) N(4) O(11)
...
1.99(3) N(5) O(13)
#3
#4
#5
#6
...
1.93(3) N(5) O(12)
...
1.92(3) N(6) O(22)
91.2(9) O(33)S(3)O(31)
87.7(9) Pd(1)S(1)O(11)
177.3(9) Pd(1)S(1)O(12)
...
2.29(1) N(6) O(13)
...
2.30(2) N(6) O(31)
...
2.26(2) N(7) O(23)
174(1)
90(1)
95(1)
84(1)
90(1)
175(1)
174(1)
Pd(1)S(1)O(13)
Pd(2)S(2)O(21)
Pd(2)S(2)O(22)
Pd(2)S(2)O(23)
Pd(2)S(3)O(31)
Pd(2)S(3)O(32)
Pd(2)S(3)O(33)
#7
#7
#5
...
1.50(4) N(7) O(32)
...
1.41(3) N(8) O(31)
...
1.52(4) N(8) O(12)
...
1.48(4) N(9) O(33)
#4
...
1.45(4) N(9) O(1)
#6
#8
...
1.43(3) N(9) O(33)
...
1.54(4) N(8) O(21)
...
1.44(4) O(1) O(23)
2.97(4)
#8
...
1.52(3) O(1) O(21)
2.90(4)
3.15(4)
#1
#2
#3
#4
#5
#6
#7
* Symmetry operations: –x, 2 – y, 2 – z; x, y, 1 + z; x, y, –1 + z; 1 – x, 1 – y, –z; x, –1 + y, –1 + z; –x, 1 – y, –z; –x, 1 – y, 1 – z;
#8
1 – x, 1 – y, 1 – z.
plex is realized due to hydrogen bonding with be the most advantageous process due to a specific
[Pd(NH3)3(SO3)] resulting in the formation of poorly
packing of complexes that provides the energy gain as
soluble groups. The formation of crystals I is likely to a result of the higher structural compatibility of the
N(1)
O(11)
N(3)
O(32)
N(8)
O(31) Pd(1)
N(7)
N(2)
S(1)
O(12)
O(13)
Pd(3)
S(3)
O(33)
O(23)
Pd(2)
N(9)
N(4)
O(21)
N(6)
S(2)
N(5)
O(1)
O(22)
Fig. 2. Crystal structure I.
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 29 No. 4 2003

260
MULAGALEEV et al.
bound into a weakly soluble [Pd(NH3)4][trans-
Pd(NH3)2(SO3)2] · 2H2O compound. In this case, the
concentration of a free trans-[Pd(NH3)2(SO3)2]2– anion
is low and equilibrium (1) is thus inessential. When the
trans-Na2[Pd(NH3)2(SO3)2] solution is used as the ini-
tial carrier of the sulfite group, the concentration of
[Pd(NH3)2(SO3)(H2O)] attains the value at which the
transformations proceed further and give compound I.
x
REFERENCES
z
1. Gel’fman, M.I. and Gordon, N.N., Koord. Khim., 1986,
y
vol. 12, no. 3, p. 376.
2. Gel’fman, M.I. and Gordon, N.N., Zh. Neorg. Khim.,
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3. Gel’fman, M.I. and Gordon, N.N., Zh. Neorg. Khim.,
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Fig. 3. Packing of structural units in crystal I.
4. Earwicker, G.F., J. Chem. Soc., 1960, no. 6, p. 2620.
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as compared to the [Pd(NH3)4]2+ and trans-
[Pd(NH3)2(SO3)2]2– complexes.
6. Sintez kompleksnykh soedinenii metallov platinovoi
gruppy, Spravochnik (Syntheses of Complex Com-
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The interpretation based on the hydrolysis of the
Pd(II) trans-diamminedisulfite complex agrees with
the data on the hydrolysis of the Pt(II) trans- and cis-
diamminedihalides [15, 16]. The estimation of the
instability constants of the Pt(II) trans- and cis-diam-
minedihalides shows that the trans-compounds are
hydrolyzed to a greater extent than the cis-complexes.
The amminesulfite complexes are likely to exhibit the
same tendencies. However, unlike the halide com-
plexes, the trans–cis and the cis–trans transformations
are accompanied here by the formation of a stable non-
electrolytic [Pd(NH3)3(SO3)] complex.
8. Visser, J.W., J. Appl. Crystallogr., 1969, vol. 2, no. 2,
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Zh. Neorg. Khim., 1999, vol. 44, no. 10, p. 1606.
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13. Solovyov, L.A., Blokchina, M.L., Kirik, S.D., et al.,
Powder Diffraction, 1996, vol. 11, no. 1, p. 13.
[Pd(NH3)4][cis-Pd(NH3)2(SO3)2][Pd(NH3)3(SO3)]
·
14. Spinler, M.A. and Becka, L.N., J. Chem. Soc., Sect. A,
H2O or [Pd(NH3)4][trans-Pd(NH3)2(SO3)2] · 2H2O
depends on whether the hydrolysis (1) is an essential or
inessential process. In the presence of [Pd(NH3)4]Cl2
and reactive Na2SO3 sulfitizing agent, the trans-
[Pd(NH3)2(SO3)2]2– anion is rapidly formed and is
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