Bis(dimethyl­malonato-κ2 O,O′)bis­[4-(4-pyridylamino-κN 4)pyridinium]nickel(II) hexa­hydrate

Gregory A Farnum; Robert L LaDuca

doi:10.1107/S160053680803835X

. 2008 Nov 22;64(Pt 12):m1603. doi: 10.1107/S160053680803835X

Bis(dimethylmalonato-κ² O,O′)bis[4-(4-pyridylamino-κN ⁴)pyridinium]nickel(II) hexahydrate

Gregory A Farnum ^a, Robert L LaDuca ^a,^*

PMCID: PMC2960085 PMID: 21581200

Abstract

In the title compound, [Ni(C₅H₆O₄)₂(C₁₀H₁₀N₃)₂]·6H₂O, divalent nickel ions situated on the crystallographic twofold axis are octahedrally coordinated by four O atoms from two dimethylmalonate ligands in a 1,3-chelating mode and two N atoms from two protonated monodentate 4,4′-dipyridylamine molecules. The molecules link into chains via N—H⋯O hydrogen bonding mediated by protonated pyridyl groups. The chains form layer patterns via π–π stacking [centroid–centroid distance = 3.777 (2) Å] . Water molecule hexamers are generated from the unligated water molecules (three per asymmetric unit) by inversion centers at Wyckoff position d. These clusters are situated between the pseudolayers, providing hydrogen-bonding pathways that build up the three-dimensional structure.

Related literature

For 4,4′-dipyridylamine (dpa) coordination polymers, see: Martin et al. (2007 ▶). For cobalt and nickel malonate dpa coordination polymers, see: Montney et al. (2008 ▶).

Experimental

Crystal data

[Ni(C₅H₆O₄)₂(C₁₀H₁₀N₃)₂]·6H₂O
M _r = 771.42
Monoclinic,
a = 18.428 (4) Å
b = 8.0473 (16) Å
c = 23.731 (5) Å
β = 97.96 (3)°
V = 3485.4 (12) Å³
Z = 4
Mo Kα radiation
μ = 0.63 mm⁻¹
T = 173 (2) K
0.30 × 0.30 × 0.10 mm

Data collection

Bruker SMART 1K diffractometer
Absorption correction: multi-scan (TWINABS; Sheldrick, 2007 ▶) T _min = 0.833, T _max = 0.939
49338 measured reflections
3998 independent reflections
3222 reflections with I > 2σ(I)
R _int = 0.079

Refinement

R[F ² > 2σ(F ²)] = 0.054
wR(F ²) = 0.163
S = 1.09
3998 reflections
246 parameters
10 restraints
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.84 e Å⁻³
Δρ_min = −0.61 e Å⁻³

Data collection: SMART (Bruker, 2006 ▶); cell refinement: SAINT-Plus (Bruker, 2006 ▶); data reduction: SAINT-Plus and CELL-NOW (Sheldrick, 2003 ▶); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: Crystal Maker (Palmer, 2007 ▶); software used to prepare material for publication: SHELXL97.

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S160053680803835X/pk2132sup1.cif

e-64-m1603-sup1.cif^{(21.9KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S160053680803835X/pk2132Isup2.hkl

e-64-m1603-Isup2.hkl^{(196.1KB, hkl)}

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

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O1W—H1WA⋯O3Wⁱ	0.85	1.96	2.811 (4)	180
O1W—H1WB⋯O2W	0.840 (18)	2.05 (2)	2.870 (3)	166 (4)
O2W—H2WA⋯O3	0.840 (18)	1.904 (19)	2.741 (3)	174 (4)
O2W—H2WB⋯O4ⁱⁱ	0.844 (18)	1.95 (2)	2.751 (3)	158 (4)
O3W—H3WA⋯O1W	0.85	1.90	2.754 (4)	179
O3W—H3WB⋯O3ⁱⁱⁱ	0.85	1.94	2.793 (3)	179
N2—H2N⋯O2W^iv	0.866 (18)	2.16 (2)	2.985 (3)	158 (3)
N3—H3N⋯O2^v	0.82 (4)	1.86 (4)	2.683 (3)	176 (4)

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

Acknowledgments

The authors gratefully acknowledge the donors of the American Chemical Society Petroleum Research Fund and Michigan State University for funding this work.

supplementary crystallographic information

Comment

The dipodal tethering ligand 4,4'-dipyridylamine (dpa) has proven beneficial for the construction of coordination polymer solids with novel topologies (Martin et al., 2007). Isostructural cobalt and nickel malonate dpa coordination polymers possess a three-dimensional 4⁴6⁶ sqp (square pyramidal) topology (Montney et al., 2008). In an attempt to probe the effect of alkyl group substitution on coordination polymer structure by using dimethylmalonate, green crystals of the title compound were obtained.

The asymmetric unit of the title compound contains a nickel atom on a crystallographic two-fold axis, one dimethylmalonate dianion, one protonated Hdpa⁺ ligand and three water molecules of crystallization. Operation of the two-fold axis generates a neutral molecular complex, {[Ni(dimethylmalonate)₂(Hdpa)₂].6H₂O}, in which the nickel atom is octahedrally coordinated (Fig. 1). The dimethylmalonate ligands bind in a 1,3-chelating fashion, each bridging two cis coordination sites. The Hdpa ligands are disposed in a cis fashion relative to each other.

Neighboring [Ni(dimethylmalonate)₂(Hdpa)₂ molecules are connected into supramolecular chain patterns, parallel to the c crystal direction, through hydrogen bonding between the protonated pyridyl termini of the Hdpa ligands and unligated dimethylmalonate oxygen atoms. These chains interact viaπ–π stacking between protonated pyridyl rings to form supramolecular layers oriented parallel to the bc crystal planes (Fig. 2). The supramolecular layers interact with each other by hydrogen bonding patterns between the dpa central amine groups or dimethylmalonate carboxylate groups and water molecules of crystallization to form the three-dimensional structure of the title compound (Fig. 3). The unligated water molecules themselves form a hydrogen bonded hexameric cluster centered on a cyclic tetrameric unit, as seen in Fig. 1. The centroids of the clusters rest on crystallographic inversion centers (Wyckoff position d).

Experimental

All chemicals were obtained commercially. Nickel perchlorate hexahydrate (135 mg, 0.37 mmol) and dimethylmalonic acid (49 mg, 0.74 mmol) were dissolved in 3 ml water in a glass vial. A 1 ml aliquot of a 1:1 water–ethanol was carefully layered onto the aqueous solution, followed by 3 ml of an ethanolic solution of dpa (127 mg, 0.74 mmol). Green blocks of the title compound formed after 1 week.