Poly[cadmium(II)-μ-4,4′-oxydianiline-N:N′-di-μ-thiocyanato-N:S]

The title polymeric complex, [Cd(SCN)₂(C₁₂H₁₂N₂O)], exhibits a three-dimensional framework in which each Cd^II atom is bridged by two η-1,3-(SCN)⁻ groups, forming a double-stranded chain. The unique Cd^II atom lies on an inversion centre and the coordination sphere is completed by two terminal N atoms from two different 4,4′-oxy­dianiline (4,4′-Oda) ligands, furnishing a CdS₂N₄ octahedral geometry. Adjacent polymeric double-stranded chains are linked via the 4,4′-Oda ligands, which lie across twofold rotation axes.

S1. Comment

In the past two decades, polymeric Lewis base adducts of cadmium(II) thiocyanate, [Cd(SCN)₂(L)₂]_n (where L is 2-, 3- or 4-methylpyridine, benzylamine, dibenzylamine, tri-m-tolyphosphine or 1H-1,2,4-triazole), exhibiting one-dimensional double-stranded chain structures comprising (–N—C—S—Cd)₂ eight-membered rings in a chair conformation, have been documented (Ram et al., 1981; Taniguchi et al., 1987; Taniguchi & Ouchi, 1987). Recently, these one-dimensional chains have been linked into a two-dimensional hydrogen-bonded network by means of the bifunctional ligands imidazole and nicotinic acid (Chen et al., 1999; Yang et al., 2001). We report here the title covalent polymeric complex, [Cd(SCN)₂(4,4'-Oda)]_n, (I), where the organic ligand 4,4'-Oda (4,4'-Oda is 4,4'-oxydianiline) links the one-dimensional chains into a three-dimensional framework. \sch

In compound (I), the Cd^II ion is located at an inversion centre, and is octahedrally coordinated by a pair of S atoms from two (SCN)^- groups, a pair of N atoms from another two (SCN)^- groups and a pair of N atoms from two 4,4'-Oda organic ligands. Each pair of adjacent metal atoms is bridged by a pair of (SCN)^- groups through opposite ends, resulting in a double-stranded chain comprising eight-membered (–N—C—S—Cd)₂ rings in a chair conformation, with a Cd—Cd atom separation of 6.215 Å (Fig. 1). Within each unit cell, two such chains, related by the C-centring operation, run parallel to [110] at z = 1/2, and a further pair of chains, generated from the first pair by the twofold rotation axes, run parallel to [100] at z = 0.

As expected, adjacent double-stranded chains are linked by the 4,4'-Oda ligands, which lie across twofold rotation axes with a dihedral angle between the two aryl rings of 85.3 (3)°. This results in a three-dimensional framework, in which each double-stranded chain between adjacent layers runs towards the intercross direction, respectively *please explain*, with a Cd—Cd atom separation of 13.566 Å, as shown in Fig. 2. Each 4,4'-Oda ligand links one [110] chain to one [110] chain.

Related literature

For related literature, see: Chen et al. (1999); Ram et al. (1981); Taniguchi & Ouchi (1987); Taniguchi, Sugita & Ouchi (1987); Yang et al. (2001).

S2. Experimental

A hot ethanol-water (1:1 v/v) solution (5 ml) of 4,4'-oxydianiline (0.50 g, 2.5 mmol) was added to an aqueous solution (5 ml) of Cd(SCN)₂ (0.57 g, 2.5 mmol). After vigorous stirring, the solution was adjusted to pH 5 by addition of dilute HNO₃ and the resulting solution was allowed to evaporate at room temperature for 6 d, resulting in the formation of colourless crystals of (I) (yield 56%). IR data (ν, cm^-1): 3329 (m), 3237 (s), 3149 (m), 3017 (w), 2869 (w), 2115 (versus), 1876 (w), 1590 (m), 1499 (s), 1211 (s), 1094 (w), 991 (s), 925 (w), 828 (w), 785 (m), 573 (m), 523 (m), 439 (w). Elemental analysis, found: C 39.5, H 2.9, N 12.9, S 14.9%; calculated for C₁₄H₁₂CdN₄OS₂: C 39.2, H 2.8, N 13.1, S 15.0%.

S3. Refinement

All H atoms were treated as riding, with C—H = 0.96 Å.

Computing details

Data collection: SHELXTL-Plus (Siemens, 1990); cell refinement: SHELXTL-Plus; data reduction: SHELXTL-Plus; program(s) used to solve structure: SHELXS86 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL-Plus; software used to prepare material for publication: SHELXL97.

Figures

	Fig. 1. A view of the coordination environment in (I), with 30% probability displacement ellipsoids [symmetry codes: (i) -x, -y, 1 - z; (ii) 1/2 - x, -1/2 - y, 1 - z; (iii) x - 1/2, 1/2 + y, z].
	Fig. 2. A view of the three-dimensional framework of (I); the 4,4'-oxydianiline ligand is simplified to a stick for clarity.

poly[Cadmium(II)-µ-4,4'-oxydianiline-N:N'-di-µ-thiocyanato-N:S]

Crystal data

[Cd(C12H12N2O)(CNS)2]	F(000) = 848
Mr = 428.80	Dx = 1.809 Mg m^−3
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
a = 9.441 (4) Å	Cell parameters from 25 reflections
b = 8.085 (3) Å	θ = 7–14°
c = 20.666 (11) Å	µ = 1.66 mm^−1
β = 93.490 (1)°	T = 293 K
V = 1574.5 (12) Å^3	Block, colourless
Z = 4	0.38 × 0.35 × 0.29 mm

Data collection

Siemens R3m diffractometer	1433 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.021
Graphite monochromator	θmax = 27.0°, θmin = 3.3°
ω scans	h = 0→12
Absorption correction: semi-empirical (using intensity measurements) based on ψ-scan (Kopfman & Huber, 1968)	k = 0→10
Tmin = 0.555, Tmax = 0.618	l = −27→26
1833 measured reflections	2 standard reflections every 200 reflections
1717 independent reflections	intensity decay: none

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)] = 0.030	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.083	H-atom parameters constrained
S = 1.07	w = 1/[σ^2(Fo^2) + (0.0504P)^2 + 0.4572P] where P = (Fo^2 + 2Fc^2)/3
1717 reflections	(Δ/σ)max < 0.001
103 parameters	Δρmax = 0.49 e Å^−3
0 restraints	Δρmin = −0.36 e Å^−3

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 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	0.0000	0.0000	0.5000	0.02878 (15)
C1	0.1479 (3)	−0.3798 (4)	0.53864 (15)	0.0270 (6)
C2	0.1891 (4)	0.0104 (4)	0.64003 (15)	0.0279 (6)
C3	0.1521 (4)	−0.1143 (5)	0.68226 (17)	0.0384 (8)
H3A	0.0538	−0.1407	0.6861	0.080*
C4	0.2560 (4)	−0.2005 (4)	0.71909 (17)	0.0389 (8)
H4A	0.2301	−0.2878	0.7476	0.080*
C5	0.3977 (3)	−0.1604 (4)	0.71383 (15)	0.0296 (7)
C6	0.4359 (4)	−0.0382 (4)	0.67143 (17)	0.0331 (7)
H6A	0.5343	−0.0118	0.6678	0.080*
C7	0.3311 (4)	0.0463 (4)	0.63408 (17)	0.0317 (7)
H7A	0.3576	0.1297	0.6040	0.080*
N1	0.0760 (3)	−0.2677 (3)	0.52703 (15)	0.0364 (7)
N2	0.0815 (3)	0.0997 (3)	0.60249 (13)	0.0309 (6)
O1	0.5000	−0.2531 (4)	0.7500	0.0379 (8)
S1	0.24723 (10)	−0.54422 (12)	0.55763 (6)	0.0440 (3)
H2B	−0.0009	0.1039	0.6219	0.080*
H2A	0.1173	0.2011	0.5959	0.080*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cd1	0.0293 (2)	0.0264 (2)	0.0298 (2)	0.00725 (13)	−0.00561 (12)	0.00048 (13)
C1	0.0246 (15)	0.0250 (15)	0.0316 (16)	0.0005 (12)	0.0042 (12)	0.0020 (13)
C2	0.0320 (16)	0.0274 (15)	0.0237 (14)	−0.0002 (13)	−0.0025 (12)	−0.0027 (12)
C3	0.0298 (17)	0.048 (2)	0.0368 (19)	−0.0087 (15)	−0.0030 (14)	0.0064 (16)
C4	0.0396 (19)	0.042 (2)	0.0339 (19)	−0.0101 (16)	−0.0036 (15)	0.0126 (16)
C5	0.0323 (16)	0.0273 (16)	0.0277 (16)	0.0014 (13)	−0.0093 (13)	−0.0023 (13)
C6	0.0263 (16)	0.0380 (18)	0.0349 (17)	−0.0002 (13)	0.0013 (13)	−0.0004 (14)
C7	0.0321 (17)	0.0292 (15)	0.0340 (17)	−0.0001 (13)	0.0035 (13)	0.0033 (13)
N1	0.0350 (15)	0.0282 (15)	0.0463 (17)	0.0064 (12)	0.0044 (13)	0.0053 (13)
N2	0.0297 (14)	0.0314 (14)	0.0313 (14)	0.0023 (11)	−0.0011 (11)	−0.0015 (11)
O1	0.0417 (19)	0.0290 (17)	0.0406 (19)	0.000	−0.0181 (16)	0.000
S1	0.0277 (4)	0.0306 (4)	0.0747 (7)	0.0084 (3)	0.0113 (4)	0.0211 (4)

Geometric parameters (Å, º)

Cd1—N1	2.338 (3)	C3—H3A	0.9600
Cd1—N1^i	2.338 (3)	C4—C5	1.387 (5)
Cd1—N2^i	2.352 (3)	C4—H4A	0.9599
Cd1—N2	2.352 (3)	C5—C6	1.383 (5)
Cd1—S1^ii	2.7544 (13)	C5—O1	1.402 (3)
Cd1—S1^iii	2.7544 (13)	C6—C7	1.396 (5)
C1—N1	1.149 (4)	C6—H6A	0.9600
C1—S1	1.660 (3)	C7—H7A	0.9600
C2—C7	1.384 (5)	N2—H2B	0.8978
C2—C3	1.392 (5)	N2—H2A	0.9002
C2—N2	1.435 (4)	O1—C5^iv	1.402 (3)
C3—C4	1.391 (5)	S1—Cd1^v	2.7544 (13)
N1—Cd1—N1^i	180.0	C5—C4—C3	119.4 (3)
N1—Cd1—N2^i	88.66 (10)	C5—C4—H4A	120.2
N1^i—Cd1—N2^i	91.34 (10)	C3—C4—H4A	120.4
N1—Cd1—N2	91.34 (10)	C6—C5—C4	120.4 (3)
N1^i—Cd1—N2	88.66 (10)	C6—C5—O1	121.5 (3)
N2^i—Cd1—N2	180.0	C4—C5—O1	118.0 (3)
N1—Cd1—S1^ii	87.83 (8)	C5—C6—C7	119.8 (3)
N1^i—Cd1—S1^ii	92.17 (8)	C5—C6—H6A	119.9
N2^i—Cd1—S1^ii	84.24 (7)	C7—C6—H6A	120.3
N2—Cd1—S1^ii	95.76 (7)	C2—C7—C6	120.4 (3)
N1—Cd1—S1^iii	92.17 (8)	C2—C7—H7A	119.8
N1^i—Cd1—S1^iii	87.83 (8)	C6—C7—H7A	119.8
N2^i—Cd1—S1^iii	95.76 (7)	C1—N1—Cd1	161.7 (3)
N2—Cd1—S1^iii	84.24 (7)	C2—N2—Cd1	119.76 (19)
S1^ii—Cd1—S1^iii	180.0	C2—N2—H2B	112.4
N1—C1—S1	177.6 (3)	Cd1—N2—H2B	99.9
C7—C2—C3	119.3 (3)	C2—N2—H2A	106.3
C7—C2—N2	120.2 (3)	Cd1—N2—H2A	106.3
C3—C2—N2	120.5 (3)	H2B—N2—H2A	112.2
C4—C3—C2	120.7 (3)	C5^iv—O1—C5	115.4 (3)
C4—C3—H3A	119.7	C1—S1—Cd1^v	106.59 (11)
C2—C3—H3A	119.6

Symmetry codes: (i) −x, −y, −z+1; (ii) −x+1/2, −y−1/2, −z+1; (iii) x−1/2, y+1/2, z; (iv) −x+1, y, −z+3/2; (v) x+1/2, y−1/2, z.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N2—H2B···S1^iii	0.90	2.91	3.438 (3)	119
N2—H2A···S1^vi	0.90	2.55	3.431 (3)	167

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