Poly[(acetonitrile-κN)-μ3-thiocyanato-κ3 N:S:S-μ2-thiocyanato-κ2 N:S-cadmium]

The asymmetric unit of the title compound, [Cd(NCS)2(CH3CN)]n, consists of one CdII cation, two thiocyanate anions and one acetonitrile ligand, all in general positions. The CdII cation is coordinated by three N atoms of two thiocyanate anions and one acetonitrile ligand, as well as three S atoms of symmetry-related thiocyanate anions within a slightly distorted octahedral coordination environment. The CdII cations are linked by μ-1,3(N,S) and μ-1,1,3(S,S,N) thiocyanate anions into layers that are located in the ab plane.

The asymmetric unit of the title compound, [Cd(NCS) 2 (CH 3 CN)] n , consists of one Cd II cation, two thiocyanate anions and one acetonitrile ligand, all in general positions. The Cd II cation is coordinated by three N atoms of two thiocyanate anions and one acetonitrile ligand, as well as three S atoms of symmetry-related thiocyanate anions within a slightly distorted octahedral coordination environment. The Cd II cations are linked by -1,3(N,S) and -1,1,3(S,S,N) thiocyanate anions into layers that are located in the ab plane.
Data collection: X-AREA (Stoe & Cie, 2008); cell refinement: X-AREA; data reduction: X-AREA; program(s) used to solve structure: SHELXS92 (Sheldrick, 2008); program(s) used to refine structure: SHELXL92 (Sheldrick, 2008); molecular graphics: XP in SHELXTL (Sheldrick, 2008) and DIAMOND (Brandenburg, 2011); software used to prepare material for publication: SHELXTL and publCIF (Westrip, 2010). The structure determination of the title compound was performed as part of a project on the synthesis of new coordination polymers based on transition metal thiocyanates and the investigations on their magnetic properties (Boeckmann et al. (2010(Boeckmann et al. ( , 2011). Within this project, we have reacted cadmium(II)thiocyanate with 4-tert-butylpyridine in acetonitrile, which resulted in the formation of crystals of the title compound by accident. In the crystal structure the Cd cations are surrounded by three N atoms of two N-bonded µ-1,3-briding thiocyanato anions and one acetonitril ligand as well as three S atoms of three S-bonded µ-1,1,3-bridging thiocyanato anions in a slightly distorted octahedral geometry ( Fig. 1 and Tab. 1). The Cd···N distances range from 2.2544 (28) Å to 2.3396 (28) Å, the Cd···S distances from 2.6254 (9) Å to 2.8781 (8) Å (Table 1). The Cd cations are linked into dimeric units by pairs of µ-1,3-briding thiocyanato anions that are further connected into chains by single µ-1,3-briding anionic ligands. These chains are further connected by pairs of µ-1,1,3-bridging thiocyanato anions into layers which are parallel to the crystallographic a-b-plane.

Experimental
The title compound was obtained accidently during the reaction of 68.6 mg Cd(NCS) 2 (0.30 mmol) with 11.1 µL 4-tertbutylpyridine (0.08 mmol) in 1.0 ml acetonitrile at RT in a closed 3 ml snap cap vial. After several months colourless blocks of the title compound were obtained.

Refinement
The H atoms were positioned with idealized geometry, allowed to rotate but not to tip and were refined isotropic with U iso (H) = 1.5 U eq (C) of the parent atom using a riding model with C-H = 0.98 Å.  Crystal structure of the title compound with labelling and displacement ellipsoids drawn at the 50% probability level.

Poly[(acetonitrile-κN)-µ 3 -thiocyanato-κ 3 N:S:S-µ 2 -thiocyanato-κ 2 N:S-cadmium]
Crystal data  where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max = 0.001 Δρ max = 1.09 e Å −3 Δρ min = −0.89 e Å −3 Extinction correction: SHELXL92 (Sheldrick, 2008), Fc * =kFc[1+0.001xFc 2 λ 3 /sin(2θ)] -1/4 Extinction coefficient: 0.0100 (7) Special details 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 F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > σ(F 2 ) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.