catena-Poly[ammonium (cadmium-tri-μ-thio­cyanato-κ4 S:N;κ2 N:S)–1,4,10,13,16-hexa­oxa­cyclo­octa­decane (1/1)]

V Ramesh; K Rajarajan; K Sendil Kumar; A Subashini; M NizamMohideen

doi:10.1107/S1600536812004898

. 2012 Feb 24;68(Pt 3):m335–m336. doi: 10.1107/S1600536812004898

catena-Poly[ammonium (cadmium-tri-μ-thiocyanato-κ⁴ S:N;κ² N:S)–1,4,10,13,16-hexaoxacyclooctadecane (1/1)]

V Ramesh ^a, K Rajarajan ^b, K Sendil Kumar ^a, A Subashini ^a, M NizamMohideen ^c,^*

PMCID: PMC3297278 PMID: 22412468

Abstract

In the title compound, {(NH₄)[Cd(NCS)₃]·C₁₂H₂₄O₆}_n, the Cd²⁺ ion, the ammonium cation, one of the SCN⁻ ligands and the macrocycle are located on mirror planes. The thiocyanate anions act as bridging ligands between the Cd^II ions, leading to a polymeric chain arrangement extending along [001] around a twofold screw axis. The ammonium ions are contained within the bowl of the macrocycle via extensive N—H⋯O hydrogen bonding.

Related literature

For a singly bridged cadmium thiocyanate complex, see: Bose et al. (2004 ▶). For a triply bridged cadmium thiocyanate complex, see: Chen et al. (2002 ▶). For an S-bound terminal thiocyanate cadmium complex, see: Nfor et al. (2006 ▶). For polymeric structures of complexes, see: Lobana et al. (2008 ▶). For the structures and properties of cadmium compounds, see: Gu et al. (2011 ▶); Zheng et al. (2004 ▶); Rajesh et al. (2004 ▶). For bond lengths and angles of related compounds, see: Nawaz et al. (2010 ▶).

Experimental

Crystal data

(NH₄)[Cd(NCS)₃]·C₁₂H₂₄O₆
M _r = 568.99
Orthorhombic,
a = 14.7568 (6) Å
b = 15.4378 (6) Å
c = 10.6383 (5) Å
V = 2423.54 (18) Å³
Z = 4
Mo Kα radiation
μ = 1.20 mm⁻¹
T = 293 K
0.30 × 0.25 × 0.20 mm

Data collection

Bruker Kappa APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 2004 ▶) T _min = 0.716, T _max = 0.796
11323 measured reflections
2483 independent reflections
2445 reflections with I > 2σ(I)
R _int = 0.019

Refinement

R[F ² > 2σ(F ²)] = 0.013
wR(F ²) = 0.034
S = 1.09
2483 reflections
154 parameters
5 restraints
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.20 e Å⁻³
Δρ_min = −0.36 e Å⁻³
Absolute structure: Flack (1983 ▶), 7607 Friedel pairs
Flack parameter: 0.005 (15)

Data collection: APEX2 (Bruker, 2004 ▶); cell refinement: APEX2 and SAINT (Bruker, 2004 ▶); data reduction: SAINT and XPREP (Bruker, 2004 ▶); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 (Farrugia, 1997 ▶) and Mercury (Macrae et al., 2006 ▶); software used to prepare material for publication: WinGX (Farrugia, 1999 ▶), PLATON (Spek, 2009 ▶) and publCIF (Westrip, 2010 ▶).

Supplementary Material

Crystal structure: contains datablock(s) global, I. DOI: 10.1107/S1600536812004898/zb2021sup1.cif

e-68-0m335-sup1.cif^{(21.8KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536812004898/zb2021Isup2.hkl

e-68-0m335-Isup2.hkl^{(122KB, hkl)}

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N3—H3E⋯O2	0.89 (1)	2.03 (1)	2.9130 (19)	174 (3)
N3—H3D⋯O4	0.90 (1)	2.05 (3)	2.892 (3)	155 (5)

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Acknowledgments

The authors thank Dr Babu Vargheese, SAIF, IIT, Madras, India, for his help in collecting the X-ray intensity data.

supplementary crystallographic information

Comment

Thiocyanate anion is known to bind the cadmium ion in different modes: terminal N-bound, terminal S-bound (Nfor et al. 2006) or N:S-bridging ligand. As a bridging ligand, it may give rise to a singly bridged (Bose et al. 2004), doubly bridged or triply bridged (Chen et al. 2002) cadmium complex. Cadmium(II) complexes with thiones possess a variety of structures ranging from four- to six-coordinate species with tetrahedral and octahedral environments for the CdII atom, respectively. In some cases, these units further aggregate to form polymeric structures (Lobana et al., 2008). The interest in cadmium compounds was provoked by their luminescent properties (Zheng et al., 2004), magnetic and catalytic properties (Gu et al., 2011) and non-linear optical properties (Rajesh et al., 2004). Herein, we report the synthesis and crystal structure of cadmium complex, the title compound, (I), coordinated by nitrogen and sulfur.

A perspective view of compound (I) with the atom-numbering scheme is shown in Fig. 1. The Cd^II ions are bridged by a pair of thiocyanate N:S-bridging ligands around a twofold screw axis. Two trans-N:S-bridging thiocyanates complete the N3S3 donor set around the Cd atom. The thiocyanate anions function as bridging ligands between the Cd^II centres, leading to a chain-like arrangement expanding along [001]. The thiocyanate ligands are almost linear.

The Cd—S bond lengths are 2.747 (4) and 2.728 (4) Å. These are in agreement with those reported for related compounds (Nawaz et al., 2010). The bond distances of N-bonded NCS groups [Cd—N(NCS) 2.347 (4) and 2.375 (4) Å]. These values agree well with those observed in [Cd(NCS)₂(1-vinylimidazole)₄] (Gu et al., 2011). The values of the bond angles around cadmium are close to those expected for a regular octahedral geometry, the largest angular deviation being observed for the N2 –Cd1- N1 angle [93.34 (5)°].

The parameters of hydrogen bonds are given in the Table 1. The thiocyanate anions function as bridging ligands between the CdII centres, leading to a chain-like arrangement are parallel to one another and expanding along [001]. The ammonium molecules also participate in extensive N—H···O hydrogen bonding, as shown in Fig. 2.

Experimental

The mixture of 18-crown-6 (C₁₂H₂₄O₆), CdCl₂ and NH₄SCN (molar ratio 1:1:3) were thoroughly dissolved in double distilled water and stirred for 5 h to obtain a homogeneous mixture. The colorless single crystals were obtained after the filtrate had been allowed to stand at room temperature for three weeks.