Poly[[μ2-aqua-tetraaquadi-μ3-malonato-nickel(II)strontium(II)] dihydrate]

Ming-Lin Guo; Long Liu; Cong-Cong Lu

doi:10.1107/S1600536810049779

. 2010 Dec 4;67(Pt 1):m19–m20. doi: 10.1107/S1600536810049779

Poly[[μ₂-aqua-tetraaquadi-μ₃-malonato-nickel(II)strontium(II)] dihydrate]

Ming-Lin Guo ^a,^*, Long Liu ^a, Cong-Cong Lu ^a

PMCID: PMC3050271 PMID: 21522545

Abstract

The unit-cell parameters for the title mixed-metal coordination polymer, {[NiSr(C₃H₂O₄)₂(H₂O)₅]·2H₂O}_n, which is isostructural with its Co-containing analogue, were reported previously [Gil de Muro et al. (1999 ▶). Eur. J. Inorg. Chem. pp. 935–943]; the full crystal structure including a description of the hydrogen bonding is reported here. The Sr²⁺ ion is bonded to five O atoms from three different malonate dianions and four water molecules, displaying a distorted tricapped trigonal–prismatic coordination geometry. Two malonate dianions, two water molecules and one Ni²⁺ ion build up a dianionic [Ni(C₃H₂O₄)₂(H₂O)₂]²⁻ unit incorporating a slightly distorted NiO₆ octahedron, which coordinates to three nearby Sr²⁺ ions. This arrangement creates a metal-organic framework having a 20-membered ring with four Ni and six Sr atoms lying in the bc plane. The coordinated and uncoordinated water molecules are responsible for the formation of two D5 hydrogen-bonded water chains within the 20-membered ring and they are linked into an R4 water cluster via two bifurcated O—H⋯(O,O) links.

Related literature

For the cobalt-containing analogue of the title compound and the previous unit-cell determination, see: Gil de Muro et al. (1999 ▶). For a related structure, see: Gil de Muro et al. (2000 ▶). For hydrogen-bonded water clusters, see: Infantes & Motherwell (2002 ▶). For graph-set notation, see: Bernstein et al. (1995 ▶).

Experimental

Crystal data

[NiSr(C₃H₂O₄)₂(H₂O)₅]·2H₂O
M _r = 476.53
Monoclinic,
a = 6.7745 (14) Å
b = 14.220 (3) Å
c = 15.629 (3) Å
β = 101.10 (3)°
V = 1477.4 (5) Å³
Z = 4
Mo Kα radiation
μ = 4.97 mm⁻¹
T = 294 K
0.12 × 0.06 × 0.04 mm

Data collection

Rigaku Saturn CCD area-detector diffractometer
Absorption correction: multi-scan (CrystalClear; Rigaku/MSC, 2005 ▶) T _min = 0.548, T _max = 0.712
9983 measured reflections
2609 independent reflections
2235 reflections with I > 2σ(I)
R _int = 0.045

Refinement

R[F ² > 2σ(F ²)] = 0.035
wR(F ²) = 0.098
S = 1.05
2609 reflections
208 parameters
H-atom parameters constrained
Δρ_max = 0.78 e Å⁻³
Δρ_min = −0.59 e Å⁻³

Data collection: CrystalClear (Rigaku/MSC, 2005 ▶); cell refinement: CrystalClear; data reduction: CrystalClear; 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: SHELXTL.

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536810049779/hb5748sup1.cif

e-67-00m19-sup1.cif^{(26.3KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810049779/hb5748Isup2.hkl

e-67-00m19-Isup2.hkl^{(128.1KB, hkl)}

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

Table 1. Selected bond lengths (Å).

Sr1—O11	2.556 (2)
Sr1—O12	2.574 (3)
Sr1—O2ⁱ	2.581 (3)
Sr1—O6ⁱⁱ	2.598 (3)
Sr1—O13	2.618 (3)
Sr1—O2	2.660 (3)
Sr1—O13ⁱⁱⁱ	2.688 (2)
Sr1—O1	2.751 (3)
Sr1—O5ⁱⁱ	2.816 (3)
Ni1—O4	2.020 (3)
Ni1—O7	2.024 (3)
Ni1—O5	2.026 (2)
Ni1—O1	2.032 (3)
Ni1—O9	2.038 (3)
Ni1—O10	2.064 (3)

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

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

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O15—H15A⋯O14^iv	0.84	2.26	2.997 (5)	148
O15—H15A⋯O14	0.84	2.33	2.867 (5)	123
O15—H15B⋯O3^v	0.85	2.29	2.881 (7)	127
O14—H14B⋯O8^vi	0.86	2.21	3.072 (5)	176
O14—H14A⋯O10ⁱⁱ	0.86	2.14	2.936 (4)	152
O13—H13B⋯O11ⁱ	0.85	1.93	2.728 (4)	155
O13—H13A⋯O7ⁱⁱⁱ	0.85	2.01	2.836 (4)	163
O12—H12B⋯O7	0.85	2.42	3.080 (4)	135
O12—H12B⋯O9	0.85	2.36	3.094 (5)	144
O12—H12A⋯O3^vii	0.85	1.94	2.772 (4)	166
O11—H11B⋯O8^vi	0.85	1.83	2.681 (4)	176
O11—H11A⋯O4ⁱⁱ	0.85	1.89	2.727 (4)	172
O10—H10B⋯O6^viii	0.85	1.91	2.728 (4)	162
O10—H10A⋯O3^ix	0.85	1.86	2.714 (4)	178
O9—H9B⋯O15	0.85	1.84	2.663 (5)	162
O9—H9A⋯O8^vi	0.84	1.81	2.652 (4)	173

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Symmetry codes: (i) Inline graphic ; (ii) ; (iii) ; (iv) ; (v) ; (vi) ; (vii) ; (viii) ; (ix) .

Acknowledgments

We thank Tianjin Polytechnic University for financial support.

supplementary crystallographic information

Comment

Here we report the structure of the title compound, (I), [SrNi(mal)₂(H₂O)₅].2H₂O (mal = malonate dianion). Although isotypic complex [SrCo(mal)₂(H₂O)₅].2H₂O (Gil de Muro et al., 1999) had been reported, the difficulty in locating the water hydrogen atoms prevents from description of hydrogen bonding for the structure. Herein, we report the structure of the title heterobimetallic malonate complex, (I), with dianionic [Ni(C₃H₂O₄)₂(H₂O)₂]^2- structure,

The asymmetric unit in the structure of (I) comprises one Sr atom, one [Ni(C₃H₂O₄)₂(H₂O)₂]^2- dianion, three coordinated water and two solvent water molecules, and is shown in Fig. 1 in a symmetry-expanded view which displays the full coordination of the Ni and Sr atom. Selected geometric parameters are given in Table 1. The Ni atom has a slightly enlongated axial distortion octahedral coordination. The Ni1 atom deviates by 0.0251 (4)Å from the least-squares plane defined by four O atoms subtended by the two ligands at its metal atom. The O—Ni—O angles are close to 90°, the mean Ni1—O bond distance are 2.026 (2) Å. These are somewhat shorter than those (2.051 (3) Å) in [CaNi(mal)₂(H₂O)₂].2H₂O (Gil de Muro et al., 2000), while the Ni—O_water bonds except for Ni1—O9(2.038 (3) Å) are in good agreement with those (2.066 (4) Å) observed for above-mentioned compounds. The variability of the coordination modes of malonate ligands, monodentate, bidentate chelating, chelated six-membered and bridging bonding modes, are all present. As can be seen in Table 1, the O—C—O angles for carboxylate groups of two malonates range from 120.9 (3) to 123.9 (4)°, all of the C—O bond distances are in the range 1.246 (4)–1.265 (4)Å except the shortest O7—C6 being 1.233 (4)Å and the longest O1—C1 being 1.272 (4) Å. These indicate that all of carboxylate groups of malonates are somewhat delocalized.

The coordination polyhedron around the Sr atom is a nine-coordinate distorted tricapped trigonal prism defined by five O atoms from three carboxylate groups and four O atoms from coordinated water molecules. Two of the three carboxylate groups coordinate with the Sr atom in a chelate fashion, whereas the other one is in a bridging mode and serve as bridges between two Sr atoms. Atoms O1, O2, O13 and O13ⁱⁱⁱ (see Fig. 1 for symmetry codes) are coplanar within deviations of less than 0.128 (2)Å and form one uncapped rectangular face. Atoms O2, O13, O5ⁱⁱ and O11 are coplanar, with no deviations of more than 0.150 (2) Å, and form the second rectangular face, with O6ⁱⁱ and O2ⁱ as the capping atoms. Atoms O1, O11, O5ⁱⁱ and O13ⁱⁱⁱ are in the same plane with displacements of less than 0.142 (3) Å, forming the third rectangular face capped by atom O12. The angle between the planes defined by the triangles O1/O2/O11 and O5ⁱⁱ/O13/O13ⁱⁱⁱ is 2.67 (14)°. The average Sr1—O distance are 2.649 (2) Å, slightly shorter than those in [SrCo(mal)₂(H₂O)₅].2H₂O (Gil de Muro et al., 1999). The strontium polyhedra are linked to a dimer via bridge atoms O2 and O2ⁱ as a common edge. The dianionic [Ni(mal)₂(H₂O)₂]^2- act as building blocks to coordinating to three Sr atoms (Fig. 1) via atoms O5, O6, O1 and O2. As the result, each group of four atoms Ni, and six Sr build up a decanuclear 20-membered ring at bc plane direction. These are further joined into a two-dimensional layer (Fig. 2). The Sr dimers are further linked between them along the a direction via other common edge, O13—O13ⁱⁱⁱ, due to the presence of an inversion center at the middle point of these edges, forming a zigzag SrO₇ chain. And as chains of edge-sharing Sr polyhedra propagate in the direction of the a axis and strontium polyhedra chains are linked between them by corner-sharing NiO₆ distorted octahedra, thus, three-dimensional metal-organic framework is completed.

Solvent water molecules are embed in such decanuclear 20-membered rings composed of four [Ni(mal)₂(H₂O)₂]^2- connecting the Sr dimers. Hydrogen-bonding interactions between them are responsible for the conformation of a R4 water cluster with overhanging water molecules (Infantes & Motherwell, 2002). The detailed structure of the water cluster is shown in Figure 2. First, the solvent water molecules are linked into a D5 water chain of O12, O9, O15, O14 and O10ⁱⁱ. Atom H15A as a bifurcated hydrogen one, the four solvent water molecules are further connected via H15A and symmetry-expanded hydrogen bonds and produce this R4 water cluster. As can be seen from Table 2 and Figure 2, within the water cluster, water molecules O14 displays tetrahedral geometry with double hydrogen-bond donors and acceptors. The O···O distances are in range of 2.663 (5)–3.094 (5) Å with an average of 2.89 (1) Å.

The dianionic [Ni(mal)₂(H₂O)₂]^2- act as both hydrogen-bonded donors and acceptors and engage in distinct hydrogen-bonding interactions (Fig. 3 and Table 2). Except for their conformation of R₂²(12) ring between two adjacent dianions, at least there are the following hydrogen-bonded graph sets (Bernstein, et al., 1995): (1) the non-coordinated O8 atom is involved in forming strong hydrogen bond O11—H11B···O8^vii and responsible for the conformation of two 8-membered hydrogen bonded ring R₃³(8) and R₃²(8); (2) hydrogen bond O12—H12B···O9 engage in the formation of a S(6) ring and a three-center hydrogen bond R₁²(4) via atom O7. (3) H atoms of water molecule O9 act as proton donors, coordinate to O15 and O8^vii as acceptors, and further via water molecule O14, build up an 8-membered ring R₄³(8) motif; (4) hydrogen bond O10—H10B···O6^ix participate in the conformation of an 8-membered hydrogen bonded ring R₂²(8) and a S(8) hydrogen bonded ring motif via two Sr atoms and one Ni atom. In addition, around the Sr dimers there is a S(6) ring hydrogen-bonded graph set via O13—H13B···O11ⁱ hydrogen bonds. These play an important role in manipulation of the three-dimensional metal-organic framework with pore.

Experimental

The title complex was prepared under continuous stirring with successive addition of CH₂(COONa)₂.H₂O (0.33 g, 2 mmol), NiCl₂.6H₂O (0.24 g, 1 mmol), and Sr(NO₃)₂ (0.21 g, 1 mmol) to distilled water (10 ml) at room temperature. After filtration, slow evaporation over a period of two days at room temperature provided pale green prisms of (I).