Poly[bis­­(μ₂-pyrimidine-κ²N:N′)bis­­(seleno­cyanato-κN)zinc]

The asymmetric unit of the title compound, [Zn(NCSe)₂(C₄H₄N₂)₂]_n, consists of one Zn²⁺ cation located on a special position with site symmetry 2/m, one seleno­cyanate anion on a mirror plane and one pyrimidine ligand on a twofold rotation axis. The zinc cation is coordinated by six N atoms of four pyrimidine ligands and two N-bonded seleno­cyanate anions in mutually trans orientations within a slightly distorted octa­hedral coordination environment. The Zn atoms are μ-1,3-bridged via the pyrimidine ligands into a polymeric layer extending parallel to (100).

Related literature

For isotypic structures with different divalent transition metals and thio­cyanate ligands, see: Bhosekar et al. (2010); Lloret et al. (1998, 1999); Wriedt et al. (2009); Wriedt & Näther (2010).

Experimental

Crystal data

• [Zn(NCSe)₂(C₄H₄N₂)₂]

• M_r = 435.51

• Orthorhombic, C m c a

• a = 9.4025 (9) Å

• b = 16.7146 (10) Å

• c = 8.7886 (5) Å

• V = 1381.21 (17) ų

• Z = 4

• Mo Kα radiation

• μ = 7.04 mm⁻¹

• T = 200 K

• 0.28 × 0.22 × 0.16 mm

Data collection

• Stoe IPDS-1 diffractometer

• Absorption correction: numerical (X-SHAPE and X-RED32; Stoe & Cie, 2008) T_min = 0.165, T_max = 0.321

• 4502 measured reflections

• 657 independent reflections

• 638 reflections with I > 2σ(I)

• R_int = 0.055

Refinement

• R[F² > 2σ(F²)] = 0.029

• wR(F²) = 0.073

• S = 1.15

• 657 reflections

• 51 parameters

• H-atom parameters constrained

• Δρ_max = 0.40 e Å⁻³

• Δρ_min = −0.81 e Å⁻³

Table 1
Selected geometric parameters (Å, °)

Zn1—N1	2.033 (3)
Zn1—N11	2.287 (2)

N1—C1—Se1	178.6 (3)

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: SHELXL97.

Supporting information

S1. Comment

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 of their thermal degradation products (Bhosekar et al., 2010; Wriedt et al., 2009; Wriedt & Näther, 2010)). Within this project we have reacted zinc(II) nitrate with potassium selenocyanate and pyrimidine in water, which leads to a single phase formation of the title compound, poly[bis(selenocyanato-κN)-bis(µ₂-pyrimidine-N,N')zinc].

The title compound is isotypic with its zinc, manganese(II), iron(II), cobalt(II) and nickel(II) thiocyanato coordination polymer analogues (Bhosekar et al., 2010; Lloret et al., 1998; Lloret et al., 1999; Wriedt et al., 2009; Wriedt & Näther, 2010). In the crystal structure the zinc atoms are surrounded by six N-atoms of four pyrimidine ligands and two N-bonded selenocyanato anions in mutually trans orientations in a slightly distorted octahedral geometry (Fig. 1). The pyrimidine ligands bridge the metal cations forming layers which extend along the ac plane (Fig. 2). These layers are stacked in the direction of the crystallographic b axis. The Zn—Zn intralayer separation amounts to 6.4352 (4) Å, whereas the shortest Zn—Zn interlayer separation is 9.4422 (5) Å.

Related literature

For isotypic structures with different divalent transition metals and thiocyanate ligands, see: Bhosekar et al. (2010); Lloret et al. (1998, 1999); Wriedt et al. (2009); Wriedt & Näther (2010).

S2. Experimental

The title compound was prepared by the reaction of 74.35 mg Zn(NO₃)₂ (0.25 mmol), 64.8 mg KSeCN (0.45 mmol) and 78.8 µL pyrimidine (0.50 mmol) in 1.00 ml water at RT in a closed 3 ml snap cap vial. After one week colourless needles of the title compound were obtained.

S3. Refinement

All H atoms were located in difference map but were positioned with idealized geometry and were refined isotropically with U_eq(H) = 1.2 U_eq(C) of the parent atom using a riding model with C—H = 0.95 Å.

Computing details

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: SHELXL97 (Sheldrick, 2008).

Figures

	Fig. 1. : Part of the crystal structure of the title compund, showing the coordination around Zn^2+, with labelling and displacement ellipsoids drawn at the 50% probability level. [Symmetry codes: i = -x, -y + 1, -z + 1; ii = -x, y, z; iii = x, -y + 1, -z + 1; iv = -x + 1/2, y, -z + 3/2.]
	Fig. 2. : Packing diagram of the title compound with view along the crystallographic b axis onto the polymeric layer (aqua = zinc; orange = selenium; blue = nitrogen; grey = carbon; light-grey = hydrogen).

Poly[bis(µ₂-pyrimidine-κ²N:N')bis(selenocyanato- κN)zinc]

Crystal data

[Zn(NCSe)2(C4H4N2)2]	Z = 4
Mr = 435.51	F(000) = 832
Orthorhombic, Cmca	Dx = 2.094 Mg m^−3
Hall symbol: -C 2bc 2	Mo Kα radiation, λ = 0.71073 Å
a = 9.4025 (9) Å	µ = 7.04 mm^−1
b = 16.7146 (10) Å	T = 200 K
c = 8.7886 (5) Å	Needle, colourless
V = 1381.21 (17) Å^3	0.28 × 0.22 × 0.16 mm

Data collection

Stoe IPDS-1 diffractometer	657 independent reflections
Radiation source: fine-focus sealed tube	638 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.055
ϕ scans	θmax = 25.5°, θmin = 3.4°
Absorption correction: numerical (X-SHAPE and X-RED32; Stoe & Cie, 2008)	h = −11→11
Tmin = 0.165, Tmax = 0.321	k = −19→17
4502 measured reflections	l = −9→10

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)] = 0.029	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.073	H-atom parameters constrained
S = 1.15	w = 1/[σ^2(Fo^2) + (0.0424P)^2 + 2.801P] where P = (Fo^2 + 2Fc^2)/3
657 reflections	(Δ/σ)max = 0.001
51 parameters	Δρmax = 0.40 e Å^−3
0 restraints	Δρmin = −0.81 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
Zn1	0.0000	0.5000	0.5000	0.0172 (2)
N1	0.0000	0.40527 (19)	0.6452 (4)	0.0220 (7)
C1	0.0000	0.3787 (2)	0.7666 (4)	0.0164 (7)
Se1	0.0000	0.34051 (3)	0.95337 (5)	0.0329 (2)
N11	0.1681 (2)	0.56159 (13)	0.6471 (2)	0.0191 (5)
C11	0.2500	0.5254 (2)	0.7500	0.0190 (7)
H11	0.2500	0.4685	0.7500	0.023*
C12	0.1740 (3)	0.64196 (17)	0.6445 (3)	0.0216 (6)
H12	0.1240	0.6699	0.5671	0.026*
C13	0.2500	0.6849 (2)	0.7500	0.0227 (8)
H13	0.2500	0.7417	0.7500	0.027*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Zn1	0.0157 (3)	0.0225 (4)	0.0133 (4)	0.000	0.000	0.0033 (2)
N1	0.0240 (16)	0.0238 (17)	0.0182 (16)	0.000	0.000	0.0017 (13)
C1	0.0123 (15)	0.0190 (17)	0.0178 (18)	0.000	0.000	−0.0030 (14)
Se1	0.0494 (4)	0.0337 (3)	0.0156 (3)	0.000	0.000	0.00690 (16)
N11	0.0147 (11)	0.0240 (12)	0.0186 (11)	−0.0001 (8)	−0.0012 (9)	0.0001 (8)
C11	0.0113 (15)	0.0247 (19)	0.0210 (18)	0.000	−0.0013 (14)	0.000
C12	0.0186 (13)	0.0262 (14)	0.0198 (13)	0.0001 (11)	−0.0012 (11)	0.0026 (10)
C13	0.0192 (19)	0.0212 (19)	0.028 (2)	0.000	−0.0011 (16)	0.000

Geometric parameters (Å, º)

Zn1—N1^i	2.033 (3)	N11—C11	1.333 (3)
Zn1—N1	2.033 (3)	N11—C12	1.345 (4)
Zn1—N11	2.287 (2)	C11—N11^iv	1.333 (3)
Zn1—N11^i	2.287 (2)	C11—H11	0.9500
Zn1—N11^ii	2.287 (2)	C12—C13	1.373 (3)
Zn1—N11^iii	2.287 (2)	C12—H12	0.9500
N1—C1	1.156 (5)	C13—C12^iv	1.373 (3)
C1—Se1	1.761 (4)	C13—H13	0.9500
N1^i—Zn1—N1	180.00 (11)	C1—N1—Zn1	151.5 (3)
N1^i—Zn1—N11	90.23 (9)	N1—C1—Se1	178.6 (3)
N1—Zn1—N11	89.77 (9)	C11—N11—C12	116.2 (2)
N1^i—Zn1—N11^i	89.77 (9)	C11—N11—Zn1	125.3 (2)
N1—Zn1—N11^i	90.23 (9)	C12—N11—Zn1	117.95 (17)
N11—Zn1—N11^i	180.0	N11^iv—C11—N11	126.0 (4)
N1^i—Zn1—N11^ii	90.23 (9)	N11^iv—C11—H11	117.0
N1—Zn1—N11^ii	89.77 (9)	N11—C11—H11	117.0
N11—Zn1—N11^ii	87.46 (11)	N11—C12—C13	122.2 (3)
N11^i—Zn1—N11^ii	92.54 (11)	N11—C12—H12	118.9
N1^i—Zn1—N11^iii	89.77 (9)	C13—C12—H12	118.9
N1—Zn1—N11^iii	90.23 (9)	C12—C13—C12^iv	117.0 (4)
N11—Zn1—N11^iii	92.54 (11)	C12—C13—H13	121.5
N11^i—Zn1—N11^iii	87.45 (11)	C12^iv—C13—H13	121.5
N11^ii—Zn1—N11^iii	180.0

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