catena-Poly[bis­[cis-dipyrimidine-trans-dithio­cyanato­iron(II)]-di-μ-pyrimidine-[trans-dithio­cyanato­iron(II)]-di-μ-pyrimidine]

Mario Wriedt; Sina Sellmer; Inke Jess; Christian Näther

doi:10.1107/S1600536809005509

. 2009 Feb 21;65(Pt 3):m296–m297. doi: 10.1107/S1600536809005509

catena-Poly[bis[cis-dipyrimidine-trans-dithiocyanatoiron(II)]-di-μ-pyrimidine-[trans-dithiocyanatoiron(II)]-di-μ-pyrimidine]

Mario Wriedt ^a, Sina Sellmer ^a, Inke Jess ^a, Christian Näther ^a,^*

PMCID: PMC2968508 PMID: 21582078

Abstract

In the crystal structure of the title compound, [Fe₃(NCS)₆(C₄H₄N₂)₈]_n, each iron(II) cation is coordinated by four N-bonded pyrimidine ligands and two N-bonded thiocyanate anions in a distorted octahedral environment. The asymmetric unit consists of one iron cation located on a crystallographic center of inversion, as well as one iron cation, three thiocyanate anions and four pyrimidine ligands occupying general positions. The structure consists of square secondary building units (SBUs) with an Fe atom at each corner, which are μ-N ¹:N ³-bridged by the pyrimidine ligands. The SBUs are linked into infinite chains running in the c-axis direction via common opposite corners.

Related literature

For related pyrimidine structures, see: Lloret et al. (1998 ▶); Näther et al. (2007 ▶); Näther & Jess (2004 ▶). For general background, see: Näther & Greve (2003 ▶); Näther, Wriedt & Jess (2003 ▶); Wriedt et al. (2008 ▶, 2009 ▶).

Experimental

Crystal data

[Fe₃(NCS)₆(C₄H₄N₂)₈]
M _r = 1156.77
Monoclinic,
a = 18.256 (1) Å
b = 16.2855 (9) Å
c = 8.2765 (4) Å
β = 100.042 (7)°
V = 2423.0 (2) Å³
Z = 2
Mo Kα radiation
μ = 1.20 mm⁻¹
T = 170 K
0.12 × 0.10 × 0.07 mm

Data collection

Stoe IPDS-1 diffractometer
Absorption correction: numerical (X-SHAPE and X-RED32; Stoe, 2008 ▶) T _min = 0.859, T _max = 0.912
20463 measured reflections
4615 independent reflections
3795 reflections with I > 2σ(I)
R _int = 0.064

Refinement

R[F ² > 2σ(F ²)] = 0.051
wR(F ²) = 0.124
S = 1.13
4615 reflections
314 parameters
H-atom parameters constrained
Δρ_max = 0.95 e Å⁻³
Δρ_min = −0.41 e Å⁻³

Data collection: X-AREA (Stoe, 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 ▶); software used to prepare material for publication: XCIF in SHELXTL.

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536809005509/im2102sup1.cif

e-65-0m296-sup1.cif^{(20.7KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809005509/im2102Isup2.hkl

e-65-0m296-Isup2.hkl^{(226.1KB, hkl)}

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

Table 1. Selected bond lengths (Å).

Fe1—N41	2.075 (3)
Fe1—N51	2.089 (3)
Fe1—N1	2.252 (3)
Fe1—N31	2.254 (3)
Fe1—N21	2.262 (3)
Fe1—N11	2.304 (3)
Fe2—N61	2.075 (3)
Fe2—N61ⁱ	2.075 (3)
Fe2—N2	2.252 (3)
Fe2—N2ⁱ	2.252 (3)
Fe2—N32ⁱⁱ	2.291 (3)
Fe2—N32ⁱⁱⁱ	2.291 (3)

Open in a new tab

Symmetry codes: (i) Inline graphic ; (ii) ; (iii) .

Acknowledgments

MW thanks the Stiftung Stipendien-Fonds des Verbandes der Chemischen Industrie and the Studienstiftung des deutschen Volkes" for a PhD scholarship. Moreover, we gratefully acknowledge financial support by the State of Schleswig-Holstein and we thank Professor Dr. Wolfgang Bensch for the opportunity to use his experimental facility.

supplementary crystallographic information

Comment

In our ongoing investigation on the syntheses, structures and properties of new coordination polymers based on paramagnetic metal pseudohalides and N-donor ligands, we have demonstrated that new ligand deficient coordination polymers with interesting magnetic interactions can be conveniently prepared by thermal decomposition of suitable ligand rich precursor compounds (Näther & Greve, 2003 and Wriedt et al., 2009). In further investigations we have reacted iron(II) sulfate heptahydrate and potassium thiocyanate with pyrimidine leading to the formation of single crystals of the title compound.

The 3:8 title compound [(Fe(SCN)₂)₃(µ-pyrimidine)₈(pyrimidine)₂]_n structurally (Fig. 1) represents a chain-like coordination polymer consisting of square SBU's with shared opposite corners as the characteristic motif. Each square SBU contains four iron(II) cations in its corners that are µ-1,3-(N,N') bridged by pyrimidine ligands. The commonly used corner iron cations are located on crystallographic centers of inversion and are each octahedrally coordinated by four bridging pyrimidine ligands and two symmetry related terminal N-bonded thiocyanate anions. The iron cations in general positions are each octahedrally coordinated by two bridging pyrimidine ligands as well as two terminal N-bonded pyrimidine ligands and two terminal N-bonded thiocyanate anions (Fig 2). The Fe—NCS distances amount to 2.075 (3) and 2.089 (3) Å and the Fe—N_pyrimidine distances range from 2.252 (3) to 2.304 (3) Å. The angles around the iron cations range from 86.9 (1) to 180.0°. The shortest intra- and interchain Fe···Fe distances measure to 6.2508 (6) and 8.7620 (8)Å, respectively.

Experimental

FeSO₄.7H₂O and pyrimidine were obtained from Alfa Aesar, KSCN was obtained from Fluka. 0.25 mmol (69.5 mg) FeSO₄ × 7 H₂O, 0.5 mmol (48.6 mg) KSCN and 9 mmol (720.8 mg) pyrimidine were transfered into a test-tube. In a solvent-free reaction at room temperature without stirring red block-shaped single crystals of the title compound were obtained after 2 weeks.