Poly[bis(sulfolane-κO)di-μ₂-thio­cyanato-cadmium(II)]

In the title complex, [Cd(SCN)₂(C₄H₈O₂S)₂]_n, the Cd^II atom, on an inversion centre, is within a distorted N₂S₂O₂ octa­hedron and the five-membered ring has a distorted envelope conformation. In the crystal structure, neighbouring Cd atoms are connected by –SCN– bridges, leading to the formation of an infinite three-dimensional –Cd–NCS–Cd– network.

Key indicators

• Single-crystal X-ray study
• T = 294 K
• Mean [sigma](C-C) = 0.004 Å
• R factor = 0.020
• wR factor = 0.056
• Data-to-parameter ratio = 20.0

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT153_ALERT_1_C The su's on the Cell Axes are Equal (x 100000) .        500 Ang.
PLAT154_ALERT_1_C The su's on the Cell Angles are Equal (x 10000)         500 Deg.

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   2 ALERT level C = Check and explain
   0 ALERT level G = General alerts; check

   2 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   0 ALERT type 2 Indicator that the structure model may be wrong or deficient
   0 ALERT type 3 Indicator that the structure quality may be low
   0 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

---

S1. Comment

A variety of polymeric structures of the monometallic thiocyanates of the IIB metals and of their Lewis base adducts are interesting themes of structural chemistry and nonlinear optics (Lipkowski, 1990; Wang, et al., 2000; Chenskaya et al., 2000; Zhu et al., 2006). According to the hard and soft acids and bases (HSAB) theory (Pearson, 1966), cadmium is a rather soft metal, although its softness is less than that of mercury or lead. Therefore, it is expected that the N and S atoms of the thiocyanate ion are able to bond easily with Cd, and that SCN-bridged polymeric complexes are stable (Yamaguchi et al., 1985; Taniguchi et al., 1986, 1987; Taniguchi & Ouchi, 1987a,b; Ouchi & Taniguchi, 1988; Ozutsmi et al., 1989). In the present work, the title sulfolane adduct of Cd(SCN)₂, (I), has been characterized.

In (I), the Cd^II atom is within a distorted N₂S₂O₂ octahedron (Fig. 1). The Cd—N, Cd—O and Cd—S bonds are shorter, longer and shorter, respectively, than the sums of the ionic radii, i.e. 2.41, 2.30 and 2.79 Å, respectively (Shannon, 1976). The bond angles (Table 1) deviate significantly from ideal octahedral geometry. The C—N—Cd and C—S—Cd bond angles (close to 180° and 90°, respectively) show that the these groups are quasi-linear and significantly bent, respectively.

The five-membered S1/C1–C4 ring is not planar, having a distorted envelope conformation, with C2 as the flap atom displaced by 0.589 (3) Å from the mean plane of the other four atoms. It has also a pseudo twofold axis passing through atom S1 and the mid-point of the C2—C3 bond, as evidenced by the torsion angles (Table 1).

In the crystal structure, neighbouring Cd atoms are connected by –SCN– bridges, which leads to the formation of an infinite three-dimensional –Cd—NCS—Cd–network.

Related literature

For related literature, see: Chenskaya et al. (2000); Lipkowski (1990); Ouchi & Taniguchi (1988); Ozutsmi et al. (1989); Pearson (1966); Shannon (1976); Taniguchi et al. (1986, 1987); Taniguchi & Ouchi (1987a,b); Wang et al. (2000); Yamaguchi et al. (1985); Zhu et al. (2006).

S2. Experimental

Cd(SCN)₂ was prepared by the reaction of Cd(NO₃)₂.4H₂O (6.170 g, 20 mmol) and NH₄SCN (3.045 g, 40 mmol) in water (6 ml). The crystalline powder of Cd(SCN)₂ (3.438 g, 15 mmol) was dissolved in water (50 ml) at about 313 K, and then sulfolane (2.5 ml) was added. The mixture was left standing at room temperature, yielding colourless crystals of (I) suitable for X-ray vrystal structure analysis. IR (Nicolet 20 SX FTIR spectrometer; cm^-1): 2945.88 and 2878.38 [ν(CH)], 2107.92 and 2078.99 [ν(CN)], 1447.39, 1409.78, 1384.71, 1290.21 and 1254.53 [δ(HCH)], 1204.39, 1145.57, 1108.92, 1086.75, 1031.78, 991.28, 672.10, 570.85 and 516.85 [ν(SO)], 967.17 and 907.39 [2δ(SCN)], 735.75[ν(CS)], 465.75, 418.50 and 407.89 [δ(SCN)]. Raman (NXR FT-Raman spectrometer using InGaAs laser at 1064 nm, cm^-1): 3008.5, 2977.6 and 2947.9 [ν(CH)], 2107.0 [ν(CN)], 1450.5, 1253.0 [δ(HCH)], 1132.8, 1095.2, 1073.9, 1026.2, 666.5 and 561.5 [ν(SO)], 967.0 and 877.3 [2δ(SCN)], 777.9 and 734.0 [ν(CS)], 476.9 and 444.9 [δ(SCN)], 385.5 [ν(CdN)], 260.9 [ν(CdO)], 193.7, 161.7 and 129.0 [ν(CdS)].

S3. Refinement

H atoms were positioned geometrically, with C—H = 0.97 Å, and constrained to ride on their parent atoms, with U_iso(H) = 1.2U_eq(C).

Computing details

Data collection: APEX2 (Bruker, 2005); cell refinement: APEX2; data reduction: APEX2; program(s) used to solve structure: SIR97 (Altomare et al., 1999); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL (Bruker, 1997); software used to prepare material for publication: WinGX (Farrugia, 1999).

Figures

Fig. 1. A fragment of the polymeric structure of (I), with the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level. Atoms N1A, O2A, S2A and S2B are at the symmetry positions (1 - x, -y, 1 - z), (1 - x, -y, 1 - z), (x - 1, y, z) and (2 - x, -y, 1 - z), respectively.

Poly[Bis(sulfolane-κO)di-µ₂-thiocyanato-cadmium(II)]

Crystal data

[Cd(SCN)2(C4H8O2S)2]	Z = 1
Mr = 468.89	F(000) = 234
Triclinic, P1	Dx = 1.830 Mg m^−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71069 Å
a = 5.9138 (1) Å	Cell parameters from 3568 reflections
b = 8.5561 (2) Å	θ = 2.4–27.6°
c = 9.4413 (2) Å	µ = 1.79 mm^−1
α = 115.246 (1)°	T = 294 K
β = 96.147 (1)°	Prism, colourless
γ = 94.512 (1)°	0.31 × 0.23 × 0.19 mm
V = 425.48 (2) Å^3

Data collection

Bruker APEXII CCD area-detector diffractometer	1937 independent reflections
Radiation source: fine-focus sealed tube	1881 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.014
φ and ω scans	θmax = 27.6°, θmin = 2.4°
Absorption correction: multi-scan (APEX2; Bruker, 2005)	h = −7→6
Tmin = 0.585, Tmax = 0.710	k = −10→11
3857 measured reflections	l = −12→12

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.020	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.056	H-atom parameters constrained
S = 1.08	w = 1/[σ^2(Fo^2) + (0.0333P)^2 + 0.1407P] where P = (Fo^2 + 2Fc^2)/3
1937 reflections	(Δ/σ)max = 0.017
97 parameters	Δρmax = 0.42 e Å^−3
0 restraints	Δρmin = −0.62 e Å^−3

Special details

Experimental. IR (Nicolet 20 SX FTIR spectrometer; cm^-1): 2945.88 and 2878.38 [ν(CH)], 2107.92 and 2078.99 [ν(CN)], 1447.39, 1409.78, 1384.71, 1290.21 and 1254.53 [δ(HCH)], 1204.39, 1145.57, 1108.92, 1086.75, 1031.78, 991.28, 672.10, 570.85 and 516.85 [ν(SO)], 967.17 and 907.39 [2δ(SCN)], 735.75[ν(CS)], 465.75, 418.50 and 407.89 [δ(SCN)]. Raman (NXR FT-Raman spectrometer using InGaAs laser at 1064 nm, cm^-1): 3008.5, 2977.6 and 2947.9 [ν(CH)], 2107.0 [ν(CN)], 1450.5, 1253.0 [δ(HCH)], 1132.8, 1095.2, 1073.9, 1026.2, 666.5 and 561.5 [ν(SO)], 967.0 and 877.3 [2δ(SCN)], 777.9 and 734.0 [ν(CS)], 476.9 and 444.9 [δ(SCN)], 385.5 [ν(CdN)], 260.9 [ν(CdO)], 193.7, 161.7 and 129.0 [ν(CdS)].

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 (Ų)

	x	y	z	Uiso*/Ueq
Cd1	0.5000	0.0000	0.5000	0.03334 (8)
S1	0.31205 (8)	0.13344 (6)	0.20978 (6)	0.03717 (11)
S2	1.32208 (8)	0.25374 (7)	0.72442 (6)	0.04356 (13)
O1	0.2601 (3)	−0.0393 (2)	0.0826 (2)	0.0583 (4)
O2	0.4885 (3)	0.1593 (2)	0.3410 (2)	0.0489 (4)
N1	0.8515 (3)	0.1461 (2)	0.6227 (2)	0.0418 (4)
C1	0.0585 (4)	0.2137 (3)	0.2838 (3)	0.0474 (5)
H1A	−0.0782	0.1404	0.2130	0.057*
H1B	0.0545	0.2189	0.3882	0.057*
C2	0.0768 (5)	0.3954 (3)	0.2911 (3)	0.0604 (6)
H2A	0.1752	0.4783	0.3875	0.072*
H2B	−0.0737	0.4329	0.2900	0.072*
C3	0.1777 (5)	0.3854 (3)	0.1473 (3)	0.0559 (6)
H3A	0.0662	0.3217	0.0518	0.067*
H3B	0.2221	0.5016	0.1571	0.067*
C4	0.3848 (4)	0.2918 (3)	0.1400 (3)	0.0507 (5)
H4A	0.5189	0.3727	0.2069	0.061*
H4B	0.4167	0.2357	0.0322	0.061*
C5	1.0453 (3)	0.1882 (2)	0.6641 (2)	0.0313 (3)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cd1	0.01888 (11)	0.03835 (12)	0.04516 (12)	0.00468 (7)	0.00290 (7)	0.02091 (9)
S1	0.0352 (2)	0.0394 (2)	0.0443 (2)	0.01258 (19)	0.00901 (19)	0.0234 (2)
S2	0.0227 (2)	0.0446 (3)	0.0495 (3)	0.00226 (19)	0.00154 (19)	0.0089 (2)
O1	0.0628 (11)	0.0463 (8)	0.0592 (9)	0.0139 (8)	0.0077 (8)	0.0165 (7)
O2	0.0399 (8)	0.0564 (9)	0.0595 (9)	0.0059 (7)	0.0001 (7)	0.0359 (8)
N1	0.0239 (8)	0.0412 (8)	0.0523 (9)	0.0050 (6)	0.0061 (7)	0.0129 (7)
C1	0.0368 (11)	0.0630 (13)	0.0554 (12)	0.0179 (10)	0.0174 (9)	0.0338 (11)
C2	0.0557 (15)	0.0549 (13)	0.0758 (16)	0.0272 (12)	0.0236 (13)	0.0273 (12)
C3	0.0543 (14)	0.0506 (12)	0.0758 (16)	0.0154 (11)	0.0105 (12)	0.0386 (12)
C4	0.0526 (13)	0.0558 (12)	0.0649 (13)	0.0190 (10)	0.0239 (11)	0.0410 (11)
C5	0.0281 (9)	0.0300 (8)	0.0364 (8)	0.0073 (6)	0.0075 (7)	0.0139 (6)

Geometric parameters (Å, º)

Cd1—N1^i	2.251 (2)	C1—H1B	0.9700
Cd1—N1	2.251 (2)	C2—C3	1.513 (4)
Cd1—O2	2.4192 (17)	C2—H2A	0.9700
Cd1—O2^i	2.4192 (17)	C2—H2B	0.9700
Cd1—S2^ii	2.6875 (11)	C3—C4	1.507 (3)
Cd1—S2^iii	2.6875 (11)	C3—H3A	0.9700
S2—Cd1^iv	2.6875 (11)	C3—H3B	0.9700
O1—S1	1.4341 (19)	C4—S1	1.785 (2)
O2—S1	1.4580 (17)	C4—H4A	0.9700
C1—C2	1.521 (3)	C4—H4B	0.9700
C1—S1	1.785 (2)	C5—N1	1.147 (3)
C1—H1A	0.9700	C5—S2	1.644 (2)
C2—C1—S1	103.85 (16)	N1^i—Cd1—N1	180.00 (10)
C2—C1—H1A	111.0	N1^i—Cd1—O2	90.81 (7)
S1—C1—H1A	111.0	N1—Cd1—O2	89.19 (7)
C2—C1—H1B	111.0	N1^i—Cd1—O2^i	89.19 (7)
S1—C1—H1B	111.0	N1—Cd1—O2^i	90.81 (7)
H1A—C1—H1B	109.0	O2—Cd1—O2^i	180.0
C1—C2—C3	107.17 (19)	N1^i—Cd1—S2^ii	88.25 (6)
C1—C2—H2A	110.3	N1—Cd1—S2^ii	91.75 (6)
C3—C2—H2A	110.3	O2—Cd1—S2^ii	89.81 (6)
C1—C2—H2B	110.3	O2^i—Cd1—S2^ii	90.19 (6)
C3—C2—H2B	110.3	N1^i—Cd1—S2^iii	91.75 (6)
H2A—C2—H2B	108.5	N1—Cd1—S2^iii	88.25 (6)
C4—C3—C2	106.69 (19)	O2—Cd1—S2^iii	90.19 (6)
C4—C3—H3A	110.4	O2^i—Cd1—S2^iii	89.81 (6)
C2—C3—H3A	110.4	S2^ii—Cd1—S2^iii	180.00 (2)
C4—C3—H3B	110.4	C5—N1—Cd1	165.48 (15)
C2—C3—H3B	110.4	S1—O2—Cd1	127.40 (10)
H3A—C3—H3B	108.6	O1—S1—O2	116.68 (11)
C3—C4—S1	105.34 (16)	O1—S1—C4	111.75 (13)
C3—C4—H4A	110.7	O2—S1—C4	108.46 (12)
S1—C4—H4A	110.7	O1—S1—C1	111.28 (13)
C3—C4—H4B	110.7	O2—S1—C1	109.89 (12)
S1—C4—H4B	110.7	C4—S1—C1	96.99 (11)
H4A—C4—H4B	108.8	C5—S2—Cd1^iv	101.40 (7)
N1—C5—S2	178.52 (17)
O2—Cd1—N1—C5	−101.9 (7)	C2—C1—S1—C4	−15.3 (2)
O2^i—Cd1—N1—C5	78.1 (7)	C2—C1—S1—O1	−131.90 (18)
S2^ii—Cd1—N1—C5	−12.1 (7)	C1—C2—C3—C4	−48.4 (3)
S2^iii—Cd1—N1—C5	167.9 (7)	C2—C3—C4—S1	35.0 (3)
N1^i—Cd1—O2—S1	−5.53 (13)	C3—C4—S1—C1	−11.2 (2)
N1—Cd1—O2—S1	174.47 (13)	C3—C4—S1—O1	105.05 (19)
S2^ii—Cd1—O2—S1	82.72 (13)	C3—C4—S1—O2	−124.95 (19)
S2^iii—Cd1—O2—S1	−97.28 (13)	Cd1—O2—S1—O1	−54.85 (16)
S1—C1—C2—C3	37.9 (2)	Cd1—O2—S1—C4	177.92 (11)
C2—C1—S1—O2	97.29 (18)	Cd1—O2—S1—C1	73.02 (15)

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