catena-Poly[[cobalt(II)-μ-aqua-di-μ-butano­ato-κ2 O:O′;κ2 O:O] 0.7-hydrate]

A I Fischer; V V Gurzhiy; A N Belyaev

doi:10.1107/S1600536811019271

. 2011 May 28;67(Pt 6):m807–m808. doi: 10.1107/S1600536811019271

catena-Poly[[cobalt(II)-μ-aqua-di-μ-butanoato-κ² O:O′;κ² O:O] 0.7-hydrate]

A I Fischer ^a,^*, V V Gurzhiy ^b,^‡, A N Belyaev ^a

PMCID: PMC3120566 PMID: 21754682

Abstract

In the title coordination polymer, {[Co(C₃H₇COO)₂(H₂O)]·0.7H₂O}_n, the Co²⁺ cation is coordinated by four bridging butanoate anions and two bridging water molecules in a severely distorted octahedral geometry. The Co²⁺ cations are linked by means of bridging ligands into polymeric chains along [010]. These chains are further connected to each other through hydrogen bonds involving partially occupied disordered water molecules; thus, sheets parallel to (001) are formed. One of the positions of disordered water O atom lies on a twofold axis. Two atoms of the aliphatic chain of one of the butanoate anions are disordered over two positions each.

Related literature

For properties and applications of cobalt carboxylates, see: Eremenko et al. (2009 ▶); Gates (1992 ▶); Parshall & Ittel (1992 ▶); Partenheimer (1995 ▶). For related structures, see: Jiao et al. (2000 ▶); Fischer et al. (2010 ▶).

Experimental

Crystal data

[Co(C₄H₇O₂)₂(H₂O)]·0.7H₂O
M _r = 263.75
Monoclinic,
a = 14.8377 (13) Å
b = 6.2597 (7) Å
c = 25.743 (3) Å
β = 104.900 (3)°
V = 2310.6 (4) Å³
Z = 8
Mo Kα radiation
μ = 1.49 mm⁻¹
T = 210 K
0.10 × 0.08 × 0.03 mm

Data collection

Bruker APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2007 ▶) T _min = 0.301, T _max = 0.351
12584 measured reflections
2731 independent reflections
1752 reflections with I > 2σ(I)
R _int = 0.096

Refinement

R[F ² > 2σ(F ²)] = 0.042
wR(F ²) = 0.096
S = 0.82
2731 reflections
156 parameters
2 restraints
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.62 e Å⁻³
Δρ_min = −0.58 e Å⁻³

Data collection: APEX2 (Bruker, 2009 ▶); cell refinement: SAINT (Bruker, 2009 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: DIAMOND (Brandenburg, 2008 ▶); software used to prepare material for publication: publCIF (Westrip, 2010 ▶).

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536811019271/ya2137sup1.cif

e-67-0m807-sup1.cif^{(17.4KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536811019271/ya2137Isup2.hkl

e-67-0m807-Isup2.hkl^{(131.4KB, hkl)}

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

Table 1. Selected bond lengths (Å).

Co1—O3	2.027 (2)
Co1—O5	2.049 (2)
Co1—O4	2.074 (2)
Co1—O4ⁱ	2.105 (2)
Co1—O2	2.163 (2)
Co1—O2ⁱⁱ	2.217 (2)

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

supplementary crystallographic information

Comment

Cobalt carboxylates are of great importance because of their application in homogeneous oxidation catalysis (Gates, 1992; Parshall & Ittel, 1992; Partenheimer, 1995), and their interesting magnetic properties (Eremenko et al., 2009). Recently, we have reported on the crystal structure of the polymeric cobalt(II) propionate dihydrate, which was prepared by the reaction of cobalt(II) carbonate hydrate with aqueous propionic acid (Fischer et al., 2010). We found that the use of butyric acid instead of propionic acid leads to an analogous product, {[Co(C₃H₇COO)₂(H₂O)].0.7H₂O}_n (I). This salt, named as cobalt(II) butyrate 1.7-hydrate, is interesting for us as a starting reagent for the preparation of the mixed-valence cobalt carboxylates.

The crystal structure of the title compound contains one independent Co²⁺ cation coordinated by four O atoms of four bridging butyrates and two O atoms of bridging water molecules in a severely distorted octahedral coordination (Fig. 1). The cis-angles about the Co atom range from 80.77 (9) to 106.47 (9)°, the Co—O bond lengths are in the range of 2.027 (2) – 2.217 (2) Å; this data correlates with the angles and the distances in cobalt(II) acetate dihydrate with similar structure (Jiao et al., 2000) as well as isostructural cobalt(II) propionate dihydrate (Fischer et al., 2010). The structure of the title compound features infinite chains with composition _∞[Co(C₃H₇COO)_4/2(H₂O)_2/2] running along [010]. The Co···Co minimum distance in the chain is equal to 3.1436 (7) Å. The bridging butyrate groups adopt two coordination modes, monodentate and syn-syn bidentate. The bidentate group has C—O bonds of practically equal length, 1.253 (4) and 1.254 (4) Å, whereas monodentate group has different C—O bond lengths, 1.231 (4) and 1.293 (4) Å. The chains are connected to each other through O—H···O hydrogen bonds involving partially occupied disordered water molecules; as a result, the sheets parallel to the (001) plane are produced (Fig. 2). The O61 atom of disordered solvate water molecule occupies a special position on the twofold axis.

Experimental

To a solution of butyric acid (8.8 g, 100 mmol) in water (50 ml), an excess of fresh cobalt(II) carbonate hydrate, CoCO₃.xH₂O (x=0.35–1.00), (8.0 g, approximately 60 mmol) was added. The reaction mixture was periodically stirred in ultrasonic bath at room temperature until the liberation of carbon dioxide ceased. The unreacted CoCO₃.xH₂O was removed by filtration, and the filtrate was allowed to stand at room temperature for slow evaporation. After a few days, red single crystals of the title compound suitable for X-ray diffraction study precipitated. Yield 82%.