Unexpected formation and crystal structure of tetra­kis­(1H-pyrazole-κN2)­palladium(II) dichloride

Wagner, T.; Christiansen, N.; Hrib, C.G.; Kaufmann, D.E.; Edelmann, F.T.

doi:10.1107/S160053681402460X

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Volume 70| Part 12| December 2014| Pages 486-488

doi:10.1107/S160053681402460X

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Unexpected formation and crystal structure of tetrakis(1H-pyrazole-κN²)palladium(II) dichloride

Thomas Wagner,^a Nena Christiansen,^b Cristian G. Hrib,^a Dieter E. Kaufmann ^b and Frank T. Edelmann ^a ^*

^aChemisches Institut, Otto-von-Guericke-Universität Magdeburg, Universitätsplatz 2, D-39106 Magdeburg, Germany, and ^bInstitut für Organische Chemie, Technische Universität Clausthal, Leibnizstrasse 6, D-38678 Clausthal-Zellerfeld, Germany
^*Correspondence e-mail: frank.edelmann@ovgu.de

Edited by M. Weil, Vienna University of Technology, Austria (Received 24 October 2014; accepted 10 November 2014; online 15 November 2014)

The title salt, [Pd(C₃H₄N₂)₄]Cl₂, was obtained unexpectedly by the reaction of palladium(II) dichloride with equimolar amounts of 1-chloro-1-nitro-2,2,2-tris(pyrazolyl)ethane in methanol solution. The Pd²⁺ cation is located on an inversion centre and has a square-planar coordination sphere defined by four N atoms of four neutral pyrazole ligands. The average Pd—N distance is 2.000 (2) Å. The two chloride anions are not coordinating to Pd²⁺. They are connected to the complex cations through N—H⋯Cl hydrogen bonds. In addition, C—H⋯Cl hydrogen bonds are observed, leading to a three-dimensional linkage of cations and anions.

Keywords: crystal structure; palladium(II); homoleptic metal–pyrazole complex; hydrogen bonding; solvolytic ligand degradation.

CCDC reference: 1033485

1. Chemical context

Transition metal complexes containing pyrazole or substituted pyrazoles as ligands are of current interest due to their supramolecular arrangements (Lumme et al., 1988 ; Takahashi et al., 2006 ; Casarin et al., 2007 ; Alsalme et al., 2013 ). In the course of an investigation on the coordination chemistry of various azolyl-nitrochloroalkanes (Zapol'skii & Kaufmann, 2008 ), we have previously studied the reaction of copper(II) perchlorate hexahydrate with equimolar amounts of 1-chloro-1-nitro-2,2,2-tris(pyrazolyl)ethane, Cl(NO₂)CH—C(C₃H₃N₂)₃ (Fig. 1) in methanol solution (Edelmann et al., 2008 ). Quite unexpectedly, a complete degradation of the starting material took place during the course of this reaction. As a result, the dark-blue compound trans-bis(perchlorato)-tetrakis(pyrazole)copper(II), [Cu(C₃H₄N₂)₄(ClO₄)₂], was isolated. The formation of free pyrazole could only be explained by a solvolytic degradation of the starting material. This degradation must have taken place to a large extent as the isolated yield was 64% (Edelmann et al., 2008).

Figure 1
Structure diagram of the starting material 1-chloro-1-nitro-2,2,2-tris(pyrazolyl)ethane.

We have now carried out a closely related reaction of 1-chloro-1-nitro-2,2,2-tris(pyrazolyl)ethane with palladium(II) dichloride in methanol solution. Structure determination of the yellow reaction product using X-ray analysis surprisingly again revealed the presence of a homoleptic pyrazole complex. The structure of the resultant title compound, [Pd(C₃H₄N₂)₄]Cl₂ is presented here. An elemental analysis of the title compound was also in very good agreement with the composition C₁₂H₁₆Cl₂PdN₈. In this case, too, the yield was fairly high (56%), indicating a far-reaching decomposition of the starting material. Apparently, the ligand degradation of azolyl-nitrochloroalkanes in the presence of transition metal salts is a more common phenomenon than originally anticipated.

2. Structural commentary

In the crystal structure of the title compound, the Pd²⁺ ion is located on an inversion centre and is bonded to four neutral pyrazole ligands within a square-planar coordination environment (Fig. 2). The average Pd—N distance in the [Pd(pyrazole)₄]²⁺ cation is 2.000 (2) Å. This is exactly the same value as found for the Cu—N distance in trans-bis(perchlorato)-tetrakis(pyrazole)copper(II) [2.000 (1) Å; Edelmann et al., 2008]. The two chloride anions are not coordinating to the Pd²⁺ cation. This is in marked contrast to the analogous copper(II) complex [Cu(pyrazole)₄Cl₂] (Xing et al., 2006 ), in which the Cu²⁺ ion is six-coordinated by four N atoms from four pyrazole ligands and two Cl⁻ ions. The same octahedral coordination has also been reported for the manganese(II) analog [Mn(pyrazole)₄Cl₂] (Lumme, 1985 ).

Figure 2
The coordination sphere of Pd²⁺ and the Cl⁻ counter-ions in the title compound. Displacement ellipsoids represent the 50% probability level. [Symmetry code (A): −x + $[{1\over 2}]$ , −y + $[{1\over 2}]$ , −z.]

3. Supramolecular features

In the title compound, the crystal packing is stabilized by two N—H⋯Cl hydrogen bonds (Table 1) between the complex cations and the Cl⁻ counter-anions (Fig. 3). Weaker C—H⋯Cl hydrogen bonds are also observed, stabilizing a three-dimensional network. The crystal structures of the formally analogous complexes [M(pyrazole)₄Cl₂] show related features. In the structures with M = Mn and Cu and an octahedral coordination of the metal cation, the crystal structures likewise exhibit N—H⋯Cl and C—H⋯Cl hydrogen bonds which, in combination, yield three-dimensional networks.

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N2—H2N⋯Cl	0.87 (2)	2.50 (3)	3.254 (3)	145 (3)
N4—H4N⋯Cl	0.88 (2)	2.33 (2)	3.147 (3)	156 (4)
C1—H1⋯Clⁱ	0.95	2.75	3.625 (4)	153
C4—H4⋯Clⁱⁱ	0.95	2.73	3.656 (4)	164
Symmetry codes: (i) $[x, -y, z+{\script{1\over 2}}]$ ; (ii) $[-x+{\script{1\over 2}}, -y-{\script{1\over 2}}, -z]$ .

Figure 3
A packing diagram of the title compound. Dashed lines indicate N—H⋯Cl hydrogen-bonding interactions.

4. Relation with other compounds

Various closely related homoleptic metal–pyrazole complexes are known from the literature (Misra et al., 1998 ; Reedijk, 1969 ; Sastry et al., 1986 ). Analogous complexes of composition [M(pyrazole)₄Cl₂] have previously been reported for M = Mn, Fe, Co, Ni, and Cu (Daugherty & Swisher, 1968 ; Bagley et al., 1970 ; Nicholls & Warburton, 1970 , 1971 ; Lumme, 1985; Sun et al., 2001 ; Xing et al., 2006). Generally, these compounds are prepared in a more straightforward manner by treatment of the transition metal dichlorides with four equivalents of pyrazole in suitable solvents such as methanol. While the analogous nickel(II) complex has been studied frequently (Daugherty & Swisher, 1968; Nicholls & Warburton, 1970), to the best of our knowledge neither the title compound nor the platinum homologue [Pt(pyrazole)₄]Cl₂ have ever been reported.

5. Synthesis and crystallization

Solid palladium(II) dichloride (0.28 g, 1.6 mmol) was added to a solution of 1-chloro-1-nitro-2,2,2-tris(pyrazolyl)ethane (0.50 g, 1.6 mmol) in methanol (100 ml). After stirring for 48 h at room temperature, a small amount of unreacted PdCl₂ was removed by filtration. Crystallization from the clear filtrate at 276–279 K for 14 d afforded bright-yellow crystals of the title compound. Yield: 0.4 g (56%). Analysis calculated for C₁₂H₁₆Cl₂PdN₈: C 32.06%; H 3.59%; N 24.92%; Cl 15.77%; found: C 31.55%; H 3.38%; N 25.13%; Cl 15.25%. IR (KBr): 3090vs, 2977vs, 2371m, 1798w, 1772w, 1632w, 1518m, 1487m, 1472s, 1401m, 1367s, 1312m, 1264m, 1251m, 1209w, 1181vs, 1169m, 1139s, 1123s, 1078vs, 1052vs, 983m, 956m, 913m, 908m, 899m, 886m, 878m, 779vs, 739s, 615s, 606s cm⁻¹.

6. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2. The hydrogen atoms attached to carbon were included using a riding model, with C—H = 0.95 Å, and with U_iso(H) = 1.2U_eq(C). The hydrogen atoms attached to nitrogen were refined with a restrained distance N—H = 0.88 (2) Å and with U_iso(H) = 1.2U_eq(N).

Table 2
Experimental details

Crystal data
Chemical formula	[Pd(C₁₂H₁₆N₈)]Cl₂
M_r	449.63
Crystal system, space group	Monoclinic, C2/c
Temperature (K)	150
a, b, c (Å)	13.797 (3), 9.6560 (19), 14.174 (3)
β (°)	117.80 (3)
V (Å³)	1670.4 (6)
Z	4
Radiation type	Mo Kα
μ (mm⁻¹)	1.44
Crystal size (mm)	0.40 × 0.40 × 0.20

Data collection
Diffractometer	Stoe IPDS 2T
Absorption correction	Multi-scan (Blessing, 1995 )
T_min, T_max	0.562, 0.750
No. of measured, independent and observed [I > 2σ(I)] reflections	7700, 2253, 2030
R_int	0.054
(sin θ/λ)_max (Å⁻¹)	0.686

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.039, 0.094, 1.12
No. of reflections	2253
No. of parameters	112
No. of restraints	2
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	1.79, −1.73
Computer programs: X-AREA and X-RED32 (Stoe, 2008 ), SHELXS97, SHELXL97 and XP (Sheldrick, 2008 ).

Supporting information

CCDC reference: 1033485

Crystal structure: contains datablocks I, New_Global_Publ_Block. DOI: 10.1107/S160053681402460X/wm5084sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S160053681402460X/wm5084Isup2.hkl

checkCIF report

Chemical context top

Transition metal complexes containing pyrazole or substituted pyrazoles as ligands are of current interest due to their supramolecular arrangements (Lumme et al., 1988; Takahashi et al., 2006; Casarin et al., 2007; Alsalme et al., 2013). In the course of an investigation on the coordination chemistry of various azolyl-nitrochloroalkanes (Zapol'skii & Kaufmann, 2008), we have previously studied the reaction of copper(II) perchlorate hexahydrate with equimolar amounts of 1-chloro-1-nitro-2,2,2-tris(pyrazolyl)ethane, Cl(NO₂)CH—C(C₃H₃N₂)₃ (Fig. 1) in methanol solution (Edelmann et al., 2008). Quite unexpectedly, a complete degradation of the starting material took place during the course of this reaction. As a result, the dark-blue compound trans-bis(perchlorato)-tetrakis(pyrazole)copper(II), [Cu(C₃H₄N₂)₄(ClO₄)₂], was isolated. The formation of free pyrazole could only be explained by a solvolytic degradation of the starting material. This degradation must have taken place to a large extent as the isolated yield was 64% (Edelmann et al., 2008).

Structural commentary top

In the crystal structure of the title compound, the Pd²⁺ ion is located on an inversion centre and is bonded to four neutral pyrazole ligands within a square-planar coordination environment (Fig. 2). The average Pd—N distance in the [Pd(pyrazole)₄]²⁺ cation is 2.000 (2) Å. This is exactly the same value as found for the Cu—N distance in trans-bis(perchlorato)-tetrakis(pyrazole)copper(II) (2.000 (1) Å; Edelmann et al., 2008). The two chloride anions are not coordinating to the Pd²⁺ cation. This is in marked contrast to the analogous copper(II) complex [Cu(pyrazole)₄Cl₂] (Xing et al., 2006) in which the Cu²⁺ ion is six-coordinated by four N-atoms from four pyrazole ligands and two Cl^- ions. The same octahedral coordination has also been reported for the manganese(II) analog [Mn(pyrazole)₄Cl₂] (Lumme, 1985).

Supramolecular features top

In the title compound, the crystal packing is stabilized by two N—H···Cl hydrogen bonds (Table 1) between the complex cations and the Cl^- counter anions (Fig. 3). Weaker C—H···Cl hydrogen bonds are also observed, stabilizing a three-dimensional network. The crystal structures of the formally analogous complexes [M(pyrazole)₄Cl₂] show related features. In the structures with M = Mn and Cu and an octahedral coordination of the metal, the crystal structures likewise exhibit N—H···Cl and C—H···Cl hydrogen bonds which, in combination, yield three-dimensional networks.

Relation with other compounds top

Various closely related homoleptic metal pyrazole complexes are known from the literature (Misra et al., 1998; Reedijk, 1969; Sastry et al., 1986). Analogous complexes of composition [M(pyrazole)₄Cl₂] have previously been reported for M = Mn, Fe, Co, Ni, and Cu (Daugherty & Swisher, 1968; Bagley et al., 1970; Nicholls & Warburton, 1970, 1971; Lumme, 1985; Sun et al., 2001; Xing et al., 2006). Generally, these compounds are prepared in a more straightforward manner by treatment of the transition metal dichlorides with four equivalents of pyrazole in suitable solvents such as methanol. While the analogous nickel(II) complex has been studied frequently (Daugherty & Swisher, 1968; Nicholls & Warburton, 1970), to the best of our knowledge neither the title compound nor the platinum homologue [Pt(pyrazole)₄]Cl₂ have ever been reported.

Synthesis and crystallization top

Refinement top

Related literature top

For representative supramolecular structures of transition metal pyrazole complexes, see: Lumme et al. (1988); Takahashi et al. (2006); Casarin et al. (2007); Alsalme et al. (2013). For similar reactions, see: Edelmann et al. (2008); Zapol'skii & Kaufmann (2008). For other homoleptic transition metal pyrazole complexes, see: Misra et al. (1998); Reedijk (1969); Sastry et al. (1986). For analogous [M(pyrazole)₄]Cl₂ complexes with M = Mn, Fe, Co, Ni, Cu, see: Daugherty & Swisher (1968); Bagley et al. (1970); Nicholls & Warburton (1970, 1971); Lumme (1985); Sun et al. (2001); Xing et al. (2006).

Computing details top

Data collection: X-AREA (Stoe, 2008); cell refinement: X-AREA (Stoe, 2008); data reduction: X-RED32 (Stoe, 2008); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: XP (Sheldrick, 2008); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures top

Structure diagram of the starting material 1-chloro-1-nitro-2,2,2-tris(pyrazolyl)ethane.

The coordination sphere of Pd²⁺ and the Cl^- counter-ions in the title compound. Displacement ellipsoids represent the 50% probability level. [Symmetry code (A): -x + 1/2, -y + 1/2, -z.]

A packing diagram of the title compound. Dashed lines indicate N—H···Cl hydrogen-bonding interactions.

Tetrakis(1H-pyrazole-κN²)palladium(II) dichloride top

Crystal data top

[Pd(C₁₂H₁₆N₈)]Cl₂	F(000) = 896
M_r = 449.63	449.6
Monoclinic, C2/c	D_x = 1.788 Mg m⁻³
Hall symbol: -C 2yc	Mo Kα radiation, λ = 0.71073 Å
a = 13.797 (3) Å	Cell parameters from 15423 reflections
b = 9.6560 (19) Å	θ = 2.7–29.6°
c = 14.174 (3) Å	µ = 1.44 mm⁻¹
β = 117.80 (3)°	T = 150 K
V = 1670.4 (6) Å³	Prism, yellow
Z = 4	0.40 × 0.40 × 0.20 mm

Data collection top

Stoe IPDS-2T diffractometer	2253 independent reflections
Radiation source: fine-focus sealed tube	2030 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.054
Detector resolution: 6.67 pixels mm^-1	θ_max = 29.2°, θ_min = 2.7°
ω–scans	h = −18→18
Absorption correction: multi-scan (Blessing, 1995)	k = −13→13
T_min = 0.562, T_max = 0.750	l = −17→19
7700 measured reflections

Refinement top

Refinement on F²	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F² > 2σ(F²)] = 0.039	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.094	H atoms treated by a mixture of independent and constrained refinement
S = 1.12	w = 1/[σ²(F_o²) + (0.049P)² + 4.2172P] where P = (F_o² + 2F_c²)/3
2253 reflections	(Δ/σ)_max < 0.001
112 parameters	Δρ_max = 1.79 e Å⁻³
2 restraints	Δρ_min = −1.73 e Å⁻³

Crystal data top

[Pd(C₁₂H₁₆N₈)]Cl₂	V = 1670.4 (6) Å³
M_r = 449.63	Z = 4
Monoclinic, C2/c	Mo Kα radiation
a = 13.797 (3) Å	µ = 1.44 mm⁻¹
b = 9.6560 (19) Å	T = 150 K
c = 14.174 (3) Å	0.40 × 0.40 × 0.20 mm
β = 117.80 (3)°

Data collection top

Stoe IPDS-2T diffractometer	2253 independent reflections
Absorption correction: multi-scan (Blessing, 1995)	2030 reflections with I > 2σ(I)
T_min = 0.562, T_max = 0.750	R_int = 0.054
7700 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.039	2 restraints
wR(F²) = 0.094	H atoms treated by a mixture of independent and constrained refinement
S = 1.12	Δρ_max = 1.79 e Å⁻³
2253 reflections	Δρ_min = −1.73 e Å⁻³
112 parameters

Special details top

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > σ(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
Pd	0.2500	0.2500	0.0000	0.01539 (11)
Cl	0.09118 (6)	−0.02409 (9)	−0.06859 (6)	0.02881 (17)
N1	0.2363 (2)	0.2373 (2)	0.1343 (2)	0.0190 (5)
N2	0.1606 (2)	0.1607 (3)	0.1453 (2)	0.0225 (5)
H2N	0.116 (3)	0.109 (4)	0.093 (2)	0.027*
N3	0.36913 (18)	0.1080 (3)	0.05645 (18)	0.0189 (4)
N4	0.3490 (2)	−0.0279 (3)	0.0486 (2)	0.0234 (5)
H4N	0.2803 (18)	−0.054 (5)	0.015 (2)	0.028*
C1	0.1706 (3)	0.1749 (3)	0.2435 (2)	0.0269 (6)
H1	0.1268	0.1311	0.2702	0.032*
C2	0.2560 (3)	0.2644 (3)	0.2984 (3)	0.0284 (7)
H2	0.2832	0.2944	0.3702	0.034*
C3	0.2943 (2)	0.3019 (3)	0.2264 (2)	0.0234 (5)
H3	0.3529	0.3642	0.2412	0.028*
C4	0.4419 (3)	−0.0999 (4)	0.0945 (3)	0.0302 (6)
H4	0.4484	−0.1979	0.0986	0.036*
C5	0.5262 (3)	−0.0071 (4)	0.1346 (3)	0.0316 (7)
H5	0.6023	−0.0271	0.1721	0.038*
C6	0.4771 (2)	0.1239 (3)	0.1089 (2)	0.0267 (6)
H6	0.5148	0.2099	0.1263	0.032*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Pd	0.01373 (15)	0.01505 (16)	0.01795 (15)	0.00207 (9)	0.00784 (11)	0.00096 (9)
Cl	0.0255 (3)	0.0302 (4)	0.0336 (3)	−0.0083 (3)	0.0162 (3)	−0.0104 (3)
N1	0.0183 (10)	0.0186 (12)	0.0216 (10)	0.0018 (8)	0.0105 (9)	0.0021 (8)
N2	0.0227 (11)	0.0210 (12)	0.0275 (11)	−0.0027 (9)	0.0149 (9)	−0.0005 (9)
N3	0.0160 (10)	0.0175 (11)	0.0222 (10)	0.0035 (8)	0.0080 (8)	0.0017 (8)
N4	0.0199 (10)	0.0173 (11)	0.0329 (12)	0.0025 (9)	0.0122 (9)	0.0016 (10)
C1	0.0286 (14)	0.0259 (16)	0.0322 (14)	0.0049 (12)	0.0192 (12)	0.0057 (12)
C2	0.0299 (15)	0.0337 (18)	0.0213 (13)	0.0118 (12)	0.0117 (12)	0.0023 (11)
C3	0.0202 (12)	0.0248 (14)	0.0218 (12)	0.0037 (11)	0.0069 (10)	−0.0016 (11)
C4	0.0303 (14)	0.0252 (16)	0.0391 (16)	0.0093 (12)	0.0195 (13)	0.0067 (13)
C5	0.0216 (13)	0.0325 (18)	0.0392 (16)	0.0134 (12)	0.0128 (12)	0.0094 (13)
C6	0.0158 (11)	0.0238 (15)	0.0342 (15)	0.0005 (10)	0.0063 (11)	−0.0009 (12)

Geometric parameters (Å, º) top

Pd—N3	1.999 (2)	N4—H4N	0.875 (19)
Pd—N3ⁱ	1.999 (2)	C1—C2	1.372 (5)
Pd—N1ⁱ	2.002 (3)	C1—H1	0.9500
Pd—N1	2.002 (3)	C2—C3	1.399 (4)
N1—C3	1.327 (4)	C2—H2	0.9500
N1—N2	1.347 (3)	C3—H3	0.9500
N2—C1	1.340 (4)	C4—C5	1.365 (5)
N2—H2N	0.869 (18)	C4—H4	0.9500
N3—C6	1.327 (4)	C5—C6	1.400 (4)
N3—N4	1.336 (3)	C5—H5	0.9500
N4—C4	1.332 (4)	C6—H6	0.9500

N3—Pd—N3ⁱ	180.00 (11)	N2—C1—C2	107.4 (3)
N3—Pd—N1ⁱ	89.89 (10)	N2—C1—H1	126.3
N3ⁱ—Pd—N1ⁱ	90.11 (10)	C2—C1—H1	126.3
N3—Pd—N1	90.11 (10)	C1—C2—C3	105.4 (3)
N3ⁱ—Pd—N1	89.89 (10)	C1—C2—H2	127.3
N1ⁱ—Pd—N1	180.0 (2)	C3—C2—H2	127.3
C3—N1—N2	106.7 (2)	N1—C3—C2	109.7 (3)
C3—N1—Pd	128.7 (2)	N1—C3—H3	125.2
N2—N1—Pd	124.51 (19)	C2—C3—H3	125.2
C1—N2—N1	110.8 (3)	N4—C4—C5	107.4 (3)
C1—N2—H2N	130 (3)	N4—C4—H4	126.3
N1—N2—H2N	119 (3)	C5—C4—H4	126.3
C6—N3—N4	107.2 (2)	C4—C5—C6	105.7 (3)
C6—N3—Pd	130.1 (2)	C4—C5—H5	127.2
N4—N3—Pd	122.71 (18)	C6—C5—H5	127.2
C4—N4—N3	110.9 (3)	N3—C6—C5	108.8 (3)
C4—N4—H4N	132 (3)	N3—C6—H6	125.6
N3—N4—H4N	117 (3)	C5—C6—H6	125.6

N3—Pd—N1—C3	84.2 (3)	N1—Pd—N3—N4	83.8 (2)
N3ⁱ—Pd—N1—C3	−95.8 (3)	C6—N3—N4—C4	−0.4 (3)
N1ⁱ—Pd—N1—C3	−138 (100)	Pd—N3—N4—C4	−178.5 (2)
N3—Pd—N1—N2	−97.9 (2)	N1—N2—C1—C2	0.1 (3)
N3ⁱ—Pd—N1—N2	82.1 (2)	N2—C1—C2—C3	0.4 (3)
N1ⁱ—Pd—N1—N2	40 (100)	N2—N1—C3—C2	0.9 (3)
C3—N1—N2—C1	−0.6 (3)	Pd—N1—C3—C2	179.0 (2)
Pd—N1—N2—C1	−178.9 (2)	C1—C2—C3—N1	−0.8 (3)
N3ⁱ—Pd—N3—C6	127 (100)	N3—N4—C4—C5	0.4 (4)
N1ⁱ—Pd—N3—C6	86.1 (3)	N4—C4—C5—C6	−0.3 (4)
N1—Pd—N3—C6	−93.9 (3)	N4—N3—C6—C5	0.2 (4)
N3ⁱ—Pd—N3—N4	−55 (100)	Pd—N3—C6—C5	178.1 (2)
N1ⁱ—Pd—N3—N4	−96.2 (2)	C4—C5—C6—N3	0.1 (4)

Symmetry code: (i) −x+1/2, −y+1/2, −z.

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N2—H2N···Cl	0.87 (2)	2.50 (3)	3.254 (3)	145 (3)
N4—H4N···Cl	0.88 (2)	2.33 (2)	3.147 (3)	156 (4)
C1—H1···Clⁱⁱ	0.95	2.75	3.625 (4)	153
C4—H4···Clⁱⁱⁱ	0.95	2.73	3.656 (4)	164

Symmetry codes: (ii) x, −y, z+1/2; (iii) −x+1/2, −y−1/2, −z.

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N2—H2N···Cl	0.869 (18)	2.50 (3)	3.254 (3)	145 (3)
N4—H4N···Cl	0.875 (19)	2.33 (2)	3.147 (3)	156 (4)
C1—H1···Clⁱ	0.95	2.75	3.625 (4)	153
C4—H4···Clⁱⁱ	0.95	2.73	3.656 (4)	164

Symmetry codes: (i) x, −y, z+1/2; (ii) −x+1/2, −y−1/2, −z.

Experimental details

Crystal data
Chemical formula	[Pd(C₁₂H₁₆N₈)]Cl₂
M_r	449.63
Crystal system, space group	Monoclinic, C2/c
Temperature (K)	150
a, b, c (Å)	13.797 (3), 9.6560 (19), 14.174 (3)
β (°)	117.80 (3)
V (Å³)	1670.4 (6)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	1.44
Crystal size (mm)	0.40 × 0.40 × 0.20

Data collection
Diffractometer	Stoe IPDS2T diffractometer
Absorption correction	Multi-scan (Blessing, 1995)
T_min, T_max	0.562, 0.750
No. of measured, independent and observed [I > 2σ(I)] reflections	7700, 2253, 2030
R_int	0.054
(sin θ/λ)_max (Å⁻¹)	0.686

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.039, 0.094, 1.12
No. of reflections	2253
No. of parameters	112
No. of restraints	2
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	1.79, −1.73

Computer programs: X-AREA (Stoe, 2008), X-RED32 (Stoe, 2008), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), XP (Sheldrick, 2008).

Acknowledgements

Financial support of this work by the Otto-von-Guericke-Universität Magdeburg is gratefully acknowledged.

References

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Volume 70| Part 12| December 2014| Pages 486-488

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