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Each of two square-planar PdII ions in the title compound, [Pd2Cl4(μ-Haet-S)2]·2H2O (Haet = 2-ammonio­ethane­thiol­ate, C2H7NS), which was obtained by rearrangement of [Pd2{Pd(aet-N,S)2}4]4+ in acidic solution, is coordinated by two bridging S atoms from two Haet ligands and by two terminal Cl atoms, forming the dinuclear structure. Since the complex is situated on a center of symmetry, the two monodentate Haet arms are located on opposite sides of the central Pd2S2 square plane, i.e. the present complex is the anti isomer. The S—C—C—N torsion angle is 177.3 (6)° and some intermolecular hydrogen bonds are observed.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270101015736/oa1118sup1.cif
Contains datablocks mu991108, I

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270101015736/oa1118Isup2.hkl
Contains datablock I

CCDC reference: 179255

Comment top

It has been recognized that the PdII ion readily forms an S-bridged Pd2S2Cl4 core by reaction with disulfide compounds, such as disulfidebiphenyl (Karet & Kostić, 1998). Using the corresponding reaction with cystamine, the dinuclear complex with 2-ammonioethanethiolate (Haet) (Efimenko et al., 2000) has been synthesized. This complex exhibits some intramolecular hydrogen bonds involving the ammonio groups of the bridging ligands. On the other hand, during the course of our synthetic investigation of S-bridged polynuclear complexes containing square-planar [Pd(aet-N,S)2] units as building blocks (Yamada et al., 2000a,b), we found geometrically different structure of the Haet complex. We describe here, therefore, the crystal structure of [Pd2(µ-Haet-S)2Cl4].2H2O, (I), which occupies a center of symmetry in the unit cell.

The complex molecule in (I) consists of two square-planar Pd atoms, two S-bridging monodentate ligands and four terminal Cl atoms (Fig. 1). The fact that there are no no counter-ions in the crystal implies that the dinuclear complex is neutral. Namely, the terminal N atoms of the S-bridging ligands are protonated during the reaction and exist as NH3+ groups. This unusual monodentate coordination mode resulting from the protonation of the aet ligands influences the stereochemistry of the dinuclear complex (see below).

Although the overall S-bridged PdII dinuclear structure, [Pd2(µ-Haet-S)2Cl4], of the complex in (I) is similar to that of the complex reported by Efimenko et al. (2000), notable differences are observed in the geometry for the bridging Haet ligands. The two monodentate Haet arms of the previously reported complex are located on the same side of the central Pd2S2 square plane, i.e. the complex adopts a syn form with a twofold axis through the center of the Pd2S2 square plane. On the other hand, the two monodentate Haet arms are located on opposite sides of the central Pd2S2 square plane (Fig. 1), i.e. the complex adopts an anti form with an inversion center at the center of the Pd2S2 square plane. According to the differences in the geometry, the two PdS2Cl2 planes are bend over the S—S line (dihedral angle = 138°) in the syn isomer and adopt a coplanar conformation in the anti isomer. The two bridging benzenethiolate ligands in [Pd2(µ-SPh)2Cl4]2- are located on the same side of the central Pd2S2 square plane, but the Pd2S2Cl4 core is nevertheless essentially planar (Karet & Kostić, 1998). Hence, it can be considered that the dihedral angle between two PdS2Cl2 planes depends not only on the geometry of the bridging S atoms, but also on weak interactions, such as ππ-stacking or hydrogen-bonding interactions.

The bond distances and angles of the Pd2S2Cl4 core in syn- and anti-[Pd2(µ-Haet-S)2Cl4] are almost the same (Table 1), although the Pd—S—Pd angle [97.54 (9)°] in the anti isomer in (I) is somewhat larger than that [91.73 (3)°] in the syn isomer (Efimenko et al., 2000). Moreover, the Pd—S and Pd—Cl distances are comparable with those in other PdII complexes, such as [Pd2(µ-SPh)2Cl4]2- (Karet & Kostić, 1998) or [PdCl2{Co(aet)2(en)}]+ (Konno et al., 1998), which can be regarded as a fixed anti form. The Pd···Pd distance [3.423 (1) Å] in the anti isomer is considerably longer than that [3.271 (1) Å] in the syn isomer; there is no evidence of a Pd—Pd bond in these cases. The bond distances involving the bridging Haet ligands in syn- and anti-[Pd2(µ-Haet-S)2Cl4] also agree with one another. However, the angles of the Haet arms in these complexes are clearly different, that is, the S—C—C—N torsion angles are 55° for the syn isomer and 177.3 (6)° for the anti isomer. Consequently, the S and N atoms take a `trans form' with respect to the C—C bond in the anti isomer in (I), and they take a `cis form' in the syn isomer.

In the present anti isomer, no intramolecular hydrogen bonds are observed. This is inconsistent with the fact that the NH3+ group of the Haet ligand in the syn isomer is close to both the terminal Cl atom and the bridging S atom [the N···Cl and N···S contact distances are 3.19 (4) and 3.10 (3) Å, repectively; Efimenko et al., 2000]. Alternatively, the NH3+ group in the anti isomer is close to the water molecule [the N1···O1 contact distance is 2.81 (1) Å]. Considering that the O1···O1i contact distance [2.86 (1) Å; symmetry code: (i) -x + 1, -y + 1, -z] is also short, each complex molecule is linked by intermolecular hydrogen bonds through the two water molecules to form a one-dimensional row in the crystal. Further, the NH3+ group is close to the Cl atom of the complex molecule in the neighboring row [the N1···Cl1ii contact distance is 3.186 (8) Å; symmetry code: (ii) x - 1, y, z]. Accordingly, it has become apparent that the structural differences between the syn and anti isomers of [Pd2(µ-Haet-S)2Cl4] greatly influence the crystal lattice.

Related literature top

For related literature, see: Efimenko et al. (2000); Karet & Kostić (1998); Konno et al. (1994, 1998); Yamada et al. (2000a, 2000b).

Experimental top

An orange solution containing [Pd2{Pd(aet)2}4]Br4.6H2O (Konno et al., 1994; 0.040 g, 0.024 mmol) in 1.0 mol dm-3 HCl (30 ml) was stirred at room temperature overnight. After removing the unreacted materials by filtration, the filtrate was poured onto a gel-filtration column of Sephadex G-10. Two yellow bands were eluted with 1.0 mol dm-3 HCl and the first band concentrated to dryness. The resulting orange powder was redissolved in a 1.0 mol dm-3 HCl and allowed to stand at room temperature for several days. A small amount of orange crystals were collected.

Refinement top

H atoms bonded to C or N atoms were fixed geometrically and allowed to ride on their attached atoms [C—H = N—H = 0.95 Å; Uiso = 1.2Ueq(C,N)]. The H atoms of the water molecule were not included in the calculations.

Computing details top

Data collection: WinAFC (Rigaku Corporation, 1999); cell refinement: WinAFC; data reduction: TEXSAN (Molecular Structure Corporation, 1999); program(s) used to solve structure: SIR92 (Altomare et al., 1994); program(s) used to refine structure: TEXSAN; software used to prepare material for publication: TEXSAN.

Figures top
[Figure 1] Fig. 1. A view of the complex molecule of (I) with the labeling of the non-H atoms. Displacement ellipsoids are shown at the 50% probability level and H atoms are drawn as small circles of arbitrary radii.
(I) top
Crystal data top
[Pd2Cl4(C2H7NS)2]·2H2ODx = 2.268 Mg m3
Mr = 544.93Mo Kα radiation, λ = 0.7107 Å
Monoclinic, P21/cCell parameters from 25 reflections
a = 7.449 (1) Åθ = 11.2–14.1°
b = 8.941 (3) ŵ = 3.17 mm1
c = 11.984 (2) ÅT = 296 K
β = 91.68 (1)°Prismatic, orange
V = 797.8 (3) Å30.15 × 0.10 × 0.08 mm
Z = 2
Data collection top
Rigaku AFC-7S
diffractometer
Rint = 0.063
ω–2θ scansθmax = 27.5°
Absorption correction: ψ scan
(North et al., 1968)
h = 09
Tmin = 0.729, Tmax = 0.776k = 011
1970 measured reflectionsl = 1515
1833 independent reflections3 standard reflections every 150 reflections
982 reflections with F2 > 2σ(F2) intensity decay: 0.1%
Refinement top
Refinement on F2 w = 1/[σ2(Fo2) + {0.03[max(Fo2,0) + 2Fc2]/3}2]
R[F2 > 2σ(F2)] = 0.044(Δ/σ)max = 0.0002
wR(F2) = 0.108Δρmax = 1.11 e Å3
S = 0.97Δρmin = 1.05 e Å3
1833 reflectionsExtinction correction: Zachariasen (1967), type 2, Gaussian isotropic
74 parametersExtinction coefficient: 0.0034 (9)
H-atom parameters not refined
Crystal data top
[Pd2Cl4(C2H7NS)2]·2H2OV = 797.8 (3) Å3
Mr = 544.93Z = 2
Monoclinic, P21/cMo Kα radiation
a = 7.449 (1) ŵ = 3.17 mm1
b = 8.941 (3) ÅT = 296 K
c = 11.984 (2) Å0.15 × 0.10 × 0.08 mm
β = 91.68 (1)°
Data collection top
Rigaku AFC-7S
diffractometer
982 reflections with F2 > 2σ(F2)
Absorption correction: ψ scan
(North et al., 1968)
Rint = 0.063
Tmin = 0.729, Tmax = 0.7763 standard reflections every 150 reflections
1970 measured reflections intensity decay: 0.1%
1833 independent reflections
Refinement top
R[F2 > 2σ(F2)] = 0.04474 parameters
wR(F2) = 0.108H-atom parameters not refined
S = 0.97Δρmax = 1.11 e Å3
1833 reflectionsΔρmin = 1.05 e Å3
Special details top

Refinement. Refinement using reflections with F2 > -10.0 σ(F2). The weighted R-factor (wR) and goodness of fit (S) are based on F2. R-factor (gt) are based on F. The threshold expression of F2 > 2.0 σ(F2) is used only for calculating R-factor (gt).

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
Pd10.68536 (9)0.44120 (8)0.43119 (6)0.0283 (2)
Cl10.7901 (3)0.4937 (3)0.2517 (2)0.0462 (7)
Cl20.9194 (4)0.2732 (3)0.4737 (2)0.0547 (9)
S10.4609 (3)0.6140 (3)0.4108 (2)0.0294 (6)
O10.312 (1)0.474 (1)0.0091 (7)0.104 (4)
N10.1654 (10)0.3422 (10)0.1990 (7)0.046 (2)
C10.320 (1)0.554 (1)0.2942 (7)0.040 (3)
C20.289 (1)0.388 (1)0.2924 (8)0.040 (3)
H10.05260.39010.20650.0548*
H20.21540.37040.13000.0548*
H30.14950.23690.20060.0548*
H40.20680.60260.29850.0474*
H50.37530.58170.22700.0474*
H60.23780.35900.36090.0475*
H70.40070.33900.28450.0475*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Pd10.0250 (3)0.0335 (4)0.0264 (3)0.0023 (4)0.0033 (2)0.0018 (4)
Cl10.044 (1)0.066 (2)0.029 (1)0.009 (1)0.010 (1)0.004 (1)
Cl20.044 (2)0.063 (2)0.058 (2)0.024 (1)0.008 (1)0.013 (1)
S10.032 (1)0.029 (1)0.028 (1)0.001 (1)0.0026 (10)0.0015 (10)
O10.134 (9)0.118 (9)0.058 (5)0.032 (8)0.029 (6)0.018 (5)
N10.026 (4)0.052 (6)0.058 (5)0.001 (4)0.015 (4)0.025 (5)
C10.043 (5)0.038 (5)0.037 (5)0.010 (6)0.005 (4)0.003 (5)
C20.032 (5)0.048 (6)0.039 (5)0.002 (5)0.007 (4)0.008 (5)
Geometric parameters (Å, º) top
Pd1—Cl12.357 (2)S1—C11.806 (9)
Pd1—Cl22.346 (3)N1—C21.48 (1)
Pd1—S12.285 (3)C1—C21.50 (1)
Pd1—S1i2.267 (2)
Cl1···N1ii3.186 (8)O1···N12.81 (1)
Cl1···N1iii3.188 (9)O1···O1iv2.86 (2)
Cl1···O1iv3.208 (9)O1···C23.49 (1)
Cl2···O1v3.19 (1)O1···C13.49 (1)
Cl2···N1vi3.380 (8)Pd1···Pd1i3.423 (1)
Cl1—Pd1—Cl293.55 (9)Pd1—S1—Pd1i97.54 (9)
Cl1—Pd1—S191.62 (9)Pd1—S1—C1106.8 (3)
Cl1—Pd1—S1i170.40 (9)Pd1—S1i—C1i107.3 (3)
Cl2—Pd1—S1173.35 (9)S1—C1—C2113.1 (7)
Cl2—Pd1—S1i92.94 (9)N1—C2—C1112.1 (8)
S1—Pd1—S1i82.46 (9)
Pd1—S1—Pd1i—Cl1i52.3 (6)Cl1—Pd1—S1i—C1i162.6 (6)
Pd1—S1—Pd1i—Cl2i175.2 (1)Cl2—Pd1—S1—C1157.2 (9)
Pd1—S1—Pd1i—S1i0.0Cl2—Pd1—S1i—C1i64.9 (4)
Pd1—S1—C1—C240.6 (7)S1—Pd1—S1i—Pd1i0.0
Pd1—S1i—Pd1i—Cl1i172.41 (10)S1—Pd1—S1i—C1i110.3 (4)
Pd1—S1i—Pd1i—Cl2i46.5 (9)S1—Pd1i—S1i—Pd10.0
Pd1—S1i—Pd1i—S10.0S1—Pd1i—S1i—C1i110.7 (4)
Pd1—S1i—C1i—C2i63.1 (7)S1—C1—C2—N1177.3 (6)
Cl1—Pd1—S1—C161.7 (3)
Symmetry codes: (i) x+1, y+1, z+1; (ii) x+1, y, z; (iii) x+1, y+1/2, z+1/2; (iv) x+1, y+1, z; (v) x+1, y1/2, z+1/2; (vi) x+1, y+1/2, z+1/2.

Experimental details

Crystal data
Chemical formula[Pd2Cl4(C2H7NS)2]·2H2O
Mr544.93
Crystal system, space groupMonoclinic, P21/c
Temperature (K)296
a, b, c (Å)7.449 (1), 8.941 (3), 11.984 (2)
β (°) 91.68 (1)
V3)797.8 (3)
Z2
Radiation typeMo Kα
µ (mm1)3.17
Crystal size (mm)0.15 × 0.10 × 0.08
Data collection
DiffractometerRigaku AFC-7S
diffractometer
Absorption correctionψ scan
(North et al., 1968)
Tmin, Tmax0.729, 0.776
No. of measured, independent and
observed [F2 > 2σ(F2)] reflections
1970, 1833, 982
Rint0.063
(sin θ/λ)max1)0.650
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.044, 0.108, 0.97
No. of reflections1833
No. of parameters74
No. of restraints?
H-atom treatmentH-atom parameters not refined
Δρmax, Δρmin (e Å3)1.11, 1.05

Computer programs: WinAFC (Rigaku Corporation, 1999), WinAFC, TEXSAN (Molecular Structure Corporation, 1999), SIR92 (Altomare et al., 1994), TEXSAN.

Selected geometric parameters (Å, º) top
Pd1—Cl12.357 (2)Pd1—S12.285 (3)
Pd1—Cl22.346 (3)Pd1—S1i2.267 (2)
Cl1—Pd1—Cl293.55 (9)S1—Pd1—S1i82.46 (9)
Cl1—Pd1—S191.62 (9)Pd1—S1—Pd1i97.54 (9)
Cl1—Pd1—S1i170.40 (9)Pd1—S1—C1106.8 (3)
Cl2—Pd1—S1173.35 (9)Pd1—S1i—C1i107.3 (3)
Cl2—Pd1—S1i92.94 (9)
Symmetry code: (i) x+1, y+1, z+1.
 

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