Tetra­aqua­bis­(2-{[5-(pyridin-4-yl)-1,3,4-oxadiazol-2-yl]sulfan­yl}acetato)­iron(II)

Hai-Rong Wang; Guo-Ting Li

doi:10.1107/S1600536811038918

. 2011 Sep 30;67(Pt 10):m1457. doi: 10.1107/S1600536811038918

Tetraaquabis(2-{[5-(pyridin-4-yl)-1,3,4-oxadiazol-2-yl]sulfanyl}acetato)iron(II)

Hai-Rong Wang ^a,^*, Guo-Ting Li ^a

PMCID: PMC3201331 PMID: 22058719

Abstract

In the title compound, [Fe(C₉H₆N₃O₃S)₂(H₂O)₄] or [Fe(POA)₂(H₂O)₄], the Fe^II atom is located on an inversion center and is ligated by four O atoms of coordinated water molecules in the equatorial plane while two POA ligands acting as monodentate ligands occupy the axial positions through their pyridyl N atoms, completing a slightly distorted octahedral coordination geometry. A three-dimensional supramolecular network is formed by multiple O—H⋯O hydrogen-bonding interactions between the coordinated water donors and the uncoordinated carboxyl acceptors.

Related literature

For the synthesis of 5-(4-pyridyl)-1,3,4-oxadiazole-2-thione, see: Young & Wood (1955 ▶). For metal-assisted transformation of N-benzoyldithiocarbazate to 5-phenyl-1,3,4-oxadiazole-2-thiol (pot) in the presence of ethylenediamine, and its first-row transition-metal complexes, see: Tripathi et al. (2007 ▶). For Zn^II and Cd^II metal-organic polymers with the versatile building block 5-(4-pyridyl)-1,3,4-oxadiazole-2-thiol, see: Du et al. (2006 ▶).

Experimental

Crystal data

[Fe(C₉H₆N₃O₃S)₂(H₂O)₄]
M _r = 600.37
Monoclinic,
a = 14.365 (3) Å
b = 10.709 (2) Å
c = 7.5709 (15) Å
β = 91.45 (3)°
V = 1164.2 (4) Å³
Z = 2
Mo Kα radiation
μ = 0.90 mm⁻¹
T = 293 K
0.20 × 0.20 × 0.20 mm

Data collection

Siemens SMART CCD diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 1996 ▶) T _min = 0.949, T _max = 1.000
12366 measured reflections
2285 independent reflections
2179 reflections with I > 2σ(I)
R _int = 0.034

Refinement

R[F ² > 2σ(F ²)] = 0.036
wR(F ²) = 0.078
S = 1.13
2285 reflections
185 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.33 e Å⁻³
Δρ_min = −0.25 e Å⁻³

Data collection: SMART (Siemens, 1996 ▶); cell refinement: SAINT (Siemens, 1994 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: SHELXTL (Sheldrick, 2008 ▶); software used to prepare material for publication: SHELXL97.

Supplementary Material

Crystal structure: contains datablock(s) I. DOI: 10.1107/S1600536811038918/si2366sup1.cif

e-67-m1457-sup1.cif^{(17.5KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536811038918/si2366Isup2.hkl

e-67-m1457-Isup2.hkl^{(112.3KB, hkl)}

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

Table 1. Selected bond lengths (Å).

Fe1—O1	2.0605 (17)
Fe1—O2	2.1340 (18)
Fe1—N1	2.2359 (18)

Open in a new tab

Table 2. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O1—H1A⋯O5ⁱ	0.83 (3)	1.87 (3)	2.691 (3)	170 (3)
O1—H1B⋯O5ⁱⁱ	0.83 (3)	1.82 (4)	2.649 (2)	174 (3)
O2—H2A⋯O4ⁱⁱ	0.82 (3)	2.07 (3)	2.896 (3)	177 (3)
O2—H2B⋯O4ⁱⁱⁱ	0.84 (4)	1.98 (4)	2.817 (3)	175 (3)

Open in a new tab

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

Acknowledgments

This work was supported by the Natural Science Foundation of China.

supplementary crystallographic information

Comment

Recently, pyridyl-containing 1,3,4-oxadiazole-2-thione have been systematically explored as promising bridging ligands in coordination chemistry. Metal- assisted transformation of N-benzoyldithiocarbazate to 5-phenyl-1,3,4-oxadiazole-2-thiol (pot) in the presence of ethylenediamine, and its first row transition metal complexes were discussed by N. K. Singh and coworkers [Tripathi et al., (2007)]. A report describing Zn^II and Cd^II metal-organic polymers with a versatile building block 5-(4-pyridyl) -1,3,4-oxadiazole-2-thiol was presented by Du et al., (2006). We purposedly engrafted the carboxylic group into the 5-(pyridin-4-yl)-1,3,4-oxadiazol-2-ylthio backbone and synthesized the multifunctional ligands 2-(5-(pyridin-4-yl)-1,3,4-oxadiazol-2-ylthio)acetic acid (HPOA). Herein we report that the reaction of FeSO₄.7H₂O and sodium(I) salt of HPOA leads to a new complex [Fe(POA)₂(H₂O)₄] (Fig.1).

The title compound is a mononuclear complex in which every Fe^II ion located at the inversion center i reproduces the whole molecule through the asymmetry unit consisting of one-half Fe^II, one deprotonated POA and two water molecules. In (1) the iron(II) center is ligated by four O from water molecules in the equatorial plane, and two POA anions acting as monodentate ligands and occupy the axial positions through their pyridyl nitrogen atoms coordinating to Fe^II, which is in an axial-elongated octahedral coordination sphere with the bond distances of Fe—O and Fe—N ranging from 2.0605 (17) to 2.2359 (18) Å (Table 1).

In (1) the uncoordinated carboxyl groups as typical hydrogen-bonding acceptors are authentically interesting in the construction of an intricate three-dimensional supramolecular network. Clearly, further aggregation of the monomers (1) is directed by the multiple hydrogen-bonding between the coordinated water donors and the uncoordinated carboxyl acceptors. Fig. 2 shows the complicated hydrogen-bonding system among monomers (1): each coordination water molecule in one monomer forms two O—H···O hydrogen bonds (Table 2) with carboxyl groups to bridge two monomers, while every carboxyl group of POA in the monomer acts as a three-connected hydrogen-bonding acceptor and adopts two different hydrogen-bonding models (bridging and chelating modes) to links with three monomers. Consequently, every monomer acts as a novel six-connected supramolecular synthon to connect with six adjacent monomers. In this way monomers (1) are arrayed to create a three-dimensional supramolecular architecture as shown in Fig. 3.

Experimental

5-(4-pyridyl)-1,3,4-oxadiazole-2-thione was synthesized according to the reported method (Young & Wood, 1955). The sodium(I) salt of the ligand 2-(5-(pyridin-4-yl)-1,3,4-oxadiazol-2-ylthio)acetic acid (HPOA) was synthesized as the following process. To a solution of sodium hydroxide (1.60 g, 40 mmol) and 95% alcohol (50 ml) was added 5-pyridyl-2-mercapto-1,3,4-oxadiazole (3.58 g, 20 mmol) and the resulting mixture was refluxed for half an hour. And then a solution of chloroactic acid (1.89 g, 20 mmol) and 95% alcohol (70 ml) was dropwise added to the mixture with continuous refluxing for 3 h. Pale yellow precipitate was filtered. After recrystallized from alcohol/water (2:1), the obtained pure product was 2.76 g. Yield: 51%. Selected IR (cm^-1, KBr pellet): 3489(w), 1598(s), 1464(m), 1402(s), 1220(m), 1190(m), 1084(m), 909(m), 835(m), 704(w), 519(m).

The title compound (1), was prepared according to the following process. A mixture of NaPOA (51.8 mg, 0.2 mmol), FeSO₄.7H₂O (27.8 mg, 0.1 mmol) and deionized water (20 ml) was stirred for 30 minutes and then filtered. The filtrate was allowed to evaporate at room temperature for three days, and yellow crystals were obtain in 36% yield. Selected IR (cm^-1, KBr pellet): 3416(m), 3194(m), 1618(s), 1545(s), 1495(w), 1450(s), 1423(w), 1379(s), 1226(m), 1198(m), 1087(w), 1063(w), 1003(w), 871(w), 840(w), 799(w), 743(w), 707(s), 586(w), 522(w).