catena-Poly[[bis­(2-chloro­pyrazine-κN4)cadmium]-di-μ-thio­cyanato-κ2N:S;κ2S:N]

Wöhlert, S.; Jess, I.; Näther, C.

doi:10.1107/S1600536813006338

metal-organic compounds

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ISSN: 2056-9890

Volume 69| Part 4| April 2013| Page m195

doi:10.1107/S1600536813006338

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catena-Poly[[bis(2-chloropyrazine-κN⁴)cadmium]-di-μ-thiocyanato-κ²N:S;κ²S:N]

Susanne Wöhlert,^a ^* Inke Jess ^a and Christian Näther ^a

^aInstitut für Anorganische Chemie, Christian-Albrechts-Universität Kiel, Max-Eyth-Strasse 2, 24118 Kiel, Germany
^*Correspondence e-mail: swoehlert@ac.uni-kiel.de

(Received 4 March 2013; accepted 5 March 2013; online 9 March 2013)

Reaction of cadmium thiocyanate with 2-chloropyrazine leads to the polymeric title compound, [Cd(NCS)₂(C₄H₃ClN₂)₂]_n. The Cd^II cation, which is located on a center of inversion, is coordinated by two N-bonded and two S-bonded thiocyanate anions and by two N-bonded 2-chloropyrazine ligands within a slightly distorted octahedron. The Cd^II cations are linked into chains along the a axis by bridging thiocyanate anions.

Related literature

For the background to this work and the synthesis of bridging thiocyanato coordination polymers, see: Wöhlert et al. (2012 , 2013 ).

Experimental

Crystal data

[Cd(NCS)₂(C₄H₃ClN₂)₂]
M_r = 457.63
Triclinic, $[P \overline 1]$
a = 5.7151 (6) Å
b = 6.7625 (8) Å
c = 11.2915 (13) Å
α = 76.895 (9)°
β = 82.639 (9)°
γ = 73.068 (8)°
V = 405.70 (8) Å³
Z = 1
Mo Kα radiation
μ = 1.93 mm⁻¹
T = 293 K
0.17 × 0.15 × 0.10 mm

Data collection

Stoe IPDS-2 diffractometer
Absorption correction: numerical (X-SHAPE and X-RED32; Stoe & Cie, 2008 ) T_min = 0.551, T_max = 0.719
5777 measured reflections
1592 independent reflections
1492 reflections with I > 2σ(I)
R_int = 0.068

Refinement

R[F² > 2σ(F²)] = 0.029
wR(F²) = 0.072
S = 1.02
1592 reflections
97 parameters
H-atom parameters constrained
Δρ_max = 0.56 e Å⁻³
Δρ_min = −0.49 e Å⁻³

Table 1
Selected bond lengths (Å)

Cd1—N1	2.287 (3)
Cd1—N12	2.417 (2)
Cd1—S1ⁱ	2.7071 (9)
Symmetry code: (i) x-1, y, z.

Data collection: X-AREA (Stoe & Cie, 2008); cell refinement: X-AREA; data reduction: X-AREA; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: XP in SHELXTL (Sheldrick, 2008) and DIAMOND (Brandenburg, 2011 ); software used to prepare material for publication: XCIF in SHELXTL and publCIF (Westrip, 2010 ).

Supporting information

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536813006338/bt6896sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536813006338/bt6896Isup2.hkl

checkCIF report

Comment top

Recently we have reported on the synthesis and characterization of cadmium(II) thiocyanato coordination polymers with different neutral N-donor co-ligands. For [Cd(NCS)₂(4-ethylpyridine)₂]_n a one-dimensional structure was observed, in which the metal cations are octahedrally coordinated by two N and two S atoms of the thiocyanato anions and two N atoms of the co-ligands all of them in an all-trans coordination (Wöhlert et al., 2013). In contrast, for [Cd(NCS)₂(pyridine)₂]_n, three different modifications were obtained in which the anionic ligands are all-trans, all-cis or cis-cis-trans coordinated (Wöhlert et al., 2012). To investigate the influence of the neutral co-ligand in more detail, 2-chloropyrazine was selected, which can act as a bidentate as well as a monodentate ligand. Therefore, cadmium(II) thiocyanate was reacted with 2-chloropyrazine in water which results in the formation of single crystals suitable for structure determination.

The crystal structure of [Cd(NCS)₂(2-chloropyrazine)₂]_n consists of cadmium(II) cations that are located on centers of inversion as well as of thiocyanato anions and 2-chloropyrazine ligand in general position. Each cadmium(II) cation is coordinated by two N-bonded and two S-bonded thiocyanato anions as well as two 2-chloropyrazine ligands within a slightly distorted octahedral geometry (Fig. 1). The CdN₄S₂ distances ranges from 2.287 (3) Å to 2.7071 (9) Å with angles arround the cadmium(II) cation between 87.75 (8) ° to 92.25 (8) ° and of 180 ° (Tab. 1). In the crystal structure the cadmium(II) cations are connected through µ-1,3 bridging thiocyanato anions into one-dimensional polymeric chains, in which all thiocyanato anions and the 2-chloropyrazine ligand are trans-coordinated (Fig. 2). The intrachain cadmium-cadmium separation amounts to 5.7151 (6) Å, whereas the shortest interchain Cd—Cd distance is 11.2915 (13) Å. This structural motiv is frequently found in cadmium thiocyanato coordination compounds and might represent the most stable coordination. However, in this context it is noted that for [Cd(NCS)₂(pyridine)₂]_n, the form with a cis-cis-trans coordination represents the thermodynamic stable form at room-temperature and this might be an exception (Wöhlert et al., 2012).

Related literature top

For the background to this work and the synthesis of bridging thiocyanato coordination polymers see Wöhlert et al. (2012, 2013).

Experimental top

CdSO₄x8/3H₂O, Ba(NCS)₂x3H₂O and 2-chloropyrazine were obtained from Alfa Aesar. All chemicals were used without further purification. Cd(NCS)₂ was prepared by the reaction of equimolar amounts of CdSO₄x8/3H₂O with Ba(NCS)₂x3H₂O in water. The resulting precipitate of BaSO₄ were filtered off and the filtrate were concentrated to complete dryness resulting in white residues of Cd(NCS)₂. The purity was checked by XRPD and CHNS analysis. 0.1 mmol (22.0 mg) Cd(NCS)₂ and 0.4 mmol (32.0 µL) 2-chloropyrazine were reacted in 1 ml water. Colorless single crystals of the title compound were obtained after three days.

Computing details top

Data collection: X-AREA (Stoe & Cie, 2008); cell refinement: X-AREA (Stoe & Cie, 2008); data reduction: X-AREA (Stoe & Cie, 2008); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: XP in SHELXTL (Sheldrick, 2008) and DIAMOND (Brandenburg, 2011); software used to prepare material for publication: XCIF in SHELXTL (Sheldrick, 2008) and publCIF (Westrip, 2010).

Figures top

	Fig. 1. : Crystal structure of the title compound with labeling and displacement ellipsoids drawn at the 50% probability level. Symmetry code: i = -x + 1, -y + 1, -z; ii = x - 1, y, z; iii = -x + 2, -y + 1, -z.
	Fig. 2. : Crystal structure of the title compound with view along the b-axis (orange = cadmium, blue = nitrogen, yellow = sulfur, green = chloro, grey = carbon, white = hydrogen).

catena-Poly[[bis(2-chloropyrazine-κN⁴)cadmium]-di-µ-thiocyanato-κ²N:S;κ²S:N] top

Crystal data top

[Cd(NCS)₂(C₄H₃ClN₂)₂]	Z = 1
M_r = 457.63	F(000) = 222
Triclinic, P1	D_x = 1.873 Mg m⁻³
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 5.7151 (6) Å	Cell parameters from 5777 reflections
b = 6.7625 (8) Å	θ = 1.9–26.0°
c = 11.2915 (13) Å	µ = 1.93 mm⁻¹
α = 76.895 (9)°	T = 293 K
β = 82.639 (9)°	Block, colourless
γ = 73.068 (8)°	0.17 × 0.15 × 0.10 mm
V = 405.70 (8) Å³

Data collection top

Stoe IPDS-2 diffractometer	1592 independent reflections
Radiation source: fine-focus sealed tube	1492 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.068
ω scan	θ_max = 26.0°, θ_min = 1.9°
Absorption correction: numerical (X-SHAPE and X-RED32; Stoe & Cie, 2008)	h = −7→7
T_min = 0.551, T_max = 0.719	k = −8→8
5777 measured reflections	l = −13→13

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)] = 0.029	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.072	H-atom parameters constrained
S = 1.02	w = 1/[σ²(F_o²) + (0.0411P)²] where P = (F_o² + 2F_c²)/3
1592 reflections	(Δ/σ)_max < 0.001
97 parameters	Δρ_max = 0.56 e Å⁻³
0 restraints	Δρ_min = −0.49 e Å⁻³

Crystal data top

[Cd(NCS)₂(C₄H₃ClN₂)₂]	γ = 73.068 (8)°
M_r = 457.63	V = 405.70 (8) Å³
Triclinic, P1	Z = 1
a = 5.7151 (6) Å	Mo Kα radiation
b = 6.7625 (8) Å	µ = 1.93 mm⁻¹
c = 11.2915 (13) Å	T = 293 K
α = 76.895 (9)°	0.17 × 0.15 × 0.10 mm
β = 82.639 (9)°

Data collection top

Stoe IPDS-2 diffractometer	1592 independent reflections
Absorption correction: numerical (X-SHAPE and X-RED32; Stoe & Cie, 2008)	1492 reflections with I > 2σ(I)
T_min = 0.551, T_max = 0.719	R_int = 0.068
5777 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.029	0 restraints
wR(F²) = 0.072	H-atom parameters constrained
S = 1.02	Δρ_max = 0.56 e Å⁻³
1592 reflections	Δρ_min = −0.49 e Å⁻³
97 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
Cd1	0.5000	0.5000	0.0000	0.04055 (12)
N1	0.7466 (5)	0.7003 (4)	0.0217 (3)	0.0512 (6)
N12	0.6360 (5)	0.2497 (4)	0.1840 (2)	0.0457 (6)
C12	0.5473 (6)	0.0818 (5)	0.2234 (3)	0.0485 (7)
H12	0.4340	0.0591	0.1794	0.058*
C11	0.6252 (7)	−0.0574 (5)	0.3298 (3)	0.0502 (8)
C14	0.8718 (8)	0.1294 (6)	0.3560 (3)	0.0623 (9)
H14	0.9856	0.1502	0.4005	0.075*
C13	0.8027 (7)	0.2699 (6)	0.2508 (3)	0.0545 (8)
H13	0.8726	0.3819	0.2247	0.065*
N11	0.7817 (7)	−0.0377 (5)	0.3977 (3)	0.0590 (7)
Cl11	0.5080 (2)	−0.27337 (15)	0.37726 (10)	0.0755 (3)
S1	1.14072 (16)	0.73906 (13)	0.12925 (8)	0.0535 (2)
C1	0.9108 (6)	0.7182 (4)	0.0647 (3)	0.0404 (6)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Cd1	0.03692 (19)	0.04198 (17)	0.04287 (19)	−0.01361 (12)	−0.01125 (13)	−0.00014 (12)
N1	0.0460 (16)	0.0474 (13)	0.0632 (17)	−0.0154 (12)	−0.0118 (13)	−0.0089 (12)
N12	0.0451 (15)	0.0484 (13)	0.0416 (14)	−0.0117 (11)	−0.0087 (11)	−0.0031 (11)
C12	0.0487 (18)	0.0482 (15)	0.0459 (16)	−0.0095 (13)	−0.0086 (14)	−0.0057 (13)
C11	0.060 (2)	0.0455 (15)	0.0418 (16)	−0.0124 (14)	−0.0037 (15)	−0.0052 (12)
C14	0.071 (3)	0.071 (2)	0.0480 (18)	−0.0249 (19)	−0.0237 (18)	−0.0015 (16)
C13	0.059 (2)	0.0546 (17)	0.0511 (19)	−0.0204 (15)	−0.0145 (16)	−0.0011 (14)
N11	0.072 (2)	0.0601 (16)	0.0431 (14)	−0.0183 (15)	−0.0143 (14)	0.0004 (12)
Cl11	0.1033 (9)	0.0591 (5)	0.0665 (6)	−0.0365 (5)	−0.0086 (6)	0.0031 (4)
S1	0.0426 (5)	0.0638 (5)	0.0620 (5)	−0.0142 (4)	−0.0100 (4)	−0.0250 (4)
C1	0.0381 (16)	0.0394 (13)	0.0452 (16)	−0.0123 (11)	−0.0033 (13)	−0.0088 (12)

Geometric parameters (Å, º) top

Cd1—N1	2.287 (3)	C12—H12	0.9300
Cd1—N1ⁱ	2.287 (3)	C11—N11	1.303 (5)
Cd1—N12ⁱ	2.417 (2)	C11—Cl11	1.730 (3)
Cd1—N12	2.417 (2)	C14—N11	1.341 (5)
Cd1—S1ⁱⁱ	2.7071 (9)	C14—C13	1.364 (5)
Cd1—S1ⁱⁱⁱ	2.7071 (9)	C14—H14	0.9300
N1—C1	1.158 (4)	C13—H13	0.9300
N12—C12	1.338 (4)	S1—C1	1.636 (3)
N12—C13	1.342 (4)	S1—Cd1^iv	2.7071 (9)
C12—C11	1.381 (4)

N1—Cd1—N1ⁱ	180.0	C12—N12—Cd1	120.7 (2)
N1—Cd1—N12ⁱ	88.62 (10)	C13—N12—Cd1	122.4 (2)
N1ⁱ—Cd1—N12ⁱ	91.38 (10)	N12—C12—C11	119.6 (3)
N1—Cd1—N12	91.38 (10)	N12—C12—H12	120.2
N1ⁱ—Cd1—N12	88.62 (10)	C11—C12—H12	120.2
N12ⁱ—Cd1—N12	180.00 (15)	N11—C11—C12	124.5 (3)
N1—Cd1—S1ⁱⁱ	92.25 (8)	N11—C11—Cl11	117.2 (2)
N1ⁱ—Cd1—S1ⁱⁱ	87.75 (8)	C12—C11—Cl11	118.2 (3)
N12ⁱ—Cd1—S1ⁱⁱ	91.06 (7)	N11—C14—C13	122.5 (4)
N12—Cd1—S1ⁱⁱ	88.94 (7)	N11—C14—H14	118.7
N1—Cd1—S1ⁱⁱⁱ	87.75 (8)	C13—C14—H14	118.7
N1ⁱ—Cd1—S1ⁱⁱⁱ	92.25 (8)	N12—C13—C14	121.3 (3)
N12ⁱ—Cd1—S1ⁱⁱⁱ	88.94 (7)	N12—C13—H13	119.4
N12—Cd1—S1ⁱⁱⁱ	91.06 (7)	C14—C13—H13	119.4
S1ⁱⁱ—Cd1—S1ⁱⁱⁱ	180.00 (4)	C11—N11—C14	115.1 (3)
C1—N1—Cd1	150.2 (2)	C1—S1—Cd1^iv	96.53 (11)
C12—N12—C13	116.9 (3)	N1—C1—S1	178.3 (3)

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

Experimental details

Crystal data
Chemical formula	[Cd(NCS)₂(C₄H₃ClN₂)₂]
M_r	457.63
Crystal system, space group	Triclinic, P1
Temperature (K)	293
a, b, c (Å)	5.7151 (6), 6.7625 (8), 11.2915 (13)
α, β, γ (°)	76.895 (9), 82.639 (9), 73.068 (8)
V (Å³)	405.70 (8)
Z	1
Radiation type	Mo Kα
µ (mm⁻¹)	1.93
Crystal size (mm)	0.17 × 0.15 × 0.10

Data collection
Diffractometer	Stoe IPDS2 diffractometer
Absorption correction	Numerical (X-SHAPE and X-RED32; Stoe & Cie, 2008)
T_min, T_max	0.551, 0.719
No. of measured, independent and observed [I > 2σ(I)] reflections	5777, 1592, 1492
R_int	0.068
(sin θ/λ)_max (Å⁻¹)	0.617

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.029, 0.072, 1.02
No. of reflections	1592
No. of parameters	97
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.56, −0.49

Computer programs: X-AREA (Stoe & Cie, 2008), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), XP in SHELXTL (Sheldrick, 2008) and DIAMOND (Brandenburg, 2011), XCIF in SHELXTL (Sheldrick, 2008) and publCIF (Westrip, 2010).

Selected bond lengths (Å) top

Cd1—N1	2.287 (3)	Cd1—S1ⁱ	2.7071 (9)
Cd1—N12	2.417 (2)

Symmetry code: (i) x−1, y, z.

Acknowledgements

We gratefully acknowledge financial support by the DFG (project No. NA 720/3–1) and the State of Schleswig–Holstein. We thank Professor Dr Wolfgang Bensch for access to his experimental facility.

References

Brandenburg, K. (2011). DIAMOND. Crystal Impact GbR, Bonn, Germany. Google Scholar
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Stoe & Cie (2008). X-AREA, X-RED32 and X-SHAPE. Stoe & Cie, Darmstadt, Germany. Google Scholar
Westrip, S. P. (2010). J. Appl. Cryst. 43, 920–925. Web of Science CrossRef CAS IUCr Journals Google Scholar
Wöhlert, S., Boeckmann, J., Jess, I. & Näther, C. (2012). CrystEngComm, 14, 5412–5420. Google Scholar
Wöhlert, S., Jess, I. & Näther, C. (2013). Z. Anorg. Allg. Chem. 639, 385–391. Google Scholar

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