The chain structure of [Ni(C4H2O4)(C12H8N2)(H2O)]n with different types of fumarate bridging

Anna Uhrinová; Juraj Kuchár; Juraj Černák

doi:10.1107/S1600536811054614

. 2012 Jan 7;68(Pt 2):m92–m93. doi: 10.1107/S1600536811054614

The chain structure of [Ni(C₄H₂O₄)(C₁₂H₈N₂)(H₂O)]_n with different types of fumarate bridging

Anna Uhrinová ^a, Juraj Kuchár ^a,^*, Juraj Černák ^a

PMCID: PMC3274842 PMID: 22346891

Abstract

Using modified solvothermal conditions (longer cooling time), beside previously characterized dark-green crystals of [Ni(C₄H₂O₄)(C₁₂H₈N₂)] (main product), a few light-green crystals of the polymeric title compound, catena-poly[[aqua(1,10-phenanthroline-κ² N,N′)nickel(II)]-μ-fumarato-κ² O:O′-[aqua(1,10-phenanthroline-κ² N,N′)nickel(II)]-μ-fumarato-κ⁴ O,O′:O′′,O′′′], [Ni(C₄H₂O₄)(C₁₂H₈N₂)(H₂O)]_n were isolated. Its crystal structure is made up from zigzag chains, propagating in [001], in which the Ni²⁺ ions are linked alternatively by μ₂-fumarato and bis-chelating fumarato bridging ligands. The Ni²⁺ ion is coordinated in a deformed octahedral geometry by one chelating 1,10-phenanthroline ligand, one aqua ligand in a cis position with regard to both N-donor atoms and by two different fumarato ligands, each residing with its central C=C bond on an inversion centre, occupying the remaining coordination sites in a fac fashion. The chains thus formed are linked by O—H⋯O hydrogen bonds and π–π interactions between the aromatic rings of the phenanthroline ligands with a shortest ring centroid separation of 3.4787 (10) Å.

Related literature

For Ni²⁺ complexes containing both fum and phen ligands (fum = fumarato, phen = 1,10-phenanthroline), see: Černák et al. (2009 ▶) for [Ni(fum)(phen)] with a two-dimensional structure and Ma et al. (2003 ▶) for [Ni₂(phen)₄(fum)(H₂O)₂]fum·16H₂O with an ionic structure containing a dinuclear complex cation. For an Ni²⁺ complex, [Ni₂(fum)₂(py)₆]·2py (py = pyridine), exhibiting a one-dimensional structure with the same type of fumarato bridging ligands, see: Mori et al. (2004 ▶); Marsh et al. (2005 ▶).

Experimental

Crystal data

[Ni(C₄H₂O₄)(C₁₂H₈N₂)(H₂O)]
M _r = 370.99
Triclinic,
a = 7.8998 (4) Å
b = 9.8238 (5) Å
c = 11.3815 (8) Å
α = 68.677 (6)°
β = 70.141 (6)°
γ = 89.655 (5)°
V = 766.89 (8) Å³
Z = 2
Mo Kα radiation
μ = 1.29 mm⁻¹
T = 173 K
0.46 × 0.27 × 0.12 mm

Data collection

Oxford Diffraction Xcalibur Sapphire2 diffractometer
Absorption correction: analytical [Clark & Reid (1995 ▶) in CrysAlis PRO (Oxford Diffraction, 2009 ▶)] T _min = 0.658, T _max = 0.866
12619 measured reflections
3173 independent reflections
2972 reflections with I > 2σ(I)
R _int = 0.022

Refinement

R[F ² > 2σ(F ²)] = 0.022
wR(F ²) = 0.057
S = 1.04
3173 reflections
217 parameters
H-atom parameters constrained
Δρ_max = 0.33 e Å⁻³
Δρ_min = −0.25 e Å⁻³

Data collection: CrysAlis PRO (Oxford Diffraction, 2009 ▶); cell refinement: CrysAlis PRO; data reduction: CrysAlis PRO; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: DIAMOND (Crystal Impact, 2009 ▶); software used to prepare material for publication: SHELXL97.

Supplementary Material

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S1600536811054614/wm2574sup1.cif

e-68-00m92-sup1.cif^{(26.2KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536811054614/wm2574Isup2.hkl

e-68-00m92-Isup2.hkl^{(152.5KB, 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
O1—H1O1⋯O5	0.85	1.78	2.6085 (15)	163
O1—H2O1⋯O2ⁱ	0.85	1.93	2.7820 (15)	177

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Symmetry code: (i) Inline graphic .

Acknowledgments

Financial support by the Slovak Ministry of Education (VEGA project No. 1/0089/09) is gratefully acknowledged.

supplementary crystallographic information

Comment

Within our broader study on low-dimensional compounds of Ni(II) in the aqueous-alcoholic system Ni(II)-fum-phen (fum = fumarato, phen = 1,10-phenanthroline) using solvothermal conditions, we have isolated the title compound [Ni(fum)(H₂O)(phen)] (I) in the form of few light-green crystals accompanying the major dark-green crystalline product [Ni(fum)(phen)] (II) (Černák et al., 2009). Such dark-green crystals were only formed if the reaction mixture was cooled from 373 K down to room temperature during 8 h. When the cooling time was elongated to 20 h, some light-green crystals of (I) likewise appeared.

The crystal structure of (I) is built up of zigzag chains exhibiting the backbone composition [–Ni–fum–Ni–fum–]_n propagating parallel to the [001] direction. Within the chain the Ni²⁺ ions are linked alternatively by µ₂-fumarato and bis-chelating fumarato bridging ligands (Fig. 1, Fig. 2). The same type of chains is observed in [Ni₂(fum)₂(py)₆]^.2py (Mori et al., 2004; Marsh et al., 2005). On the other hand, the dark-green [Ni(fum)(phen)] exhibits a two-dimensional crystal structure built up of dimers of crystallographically non-equivalent Ni²⁺ ions linked by two different types of bridging fumarato ligands (Černák et al., 2009).

The Ni²⁺ central atom in (I) is octahedrally coordinated in a deformed NiN₂O₃O donor set by one chelating phen ligand, one aqua ligand placed in cis-position with regard to both donor nitrogen atoms of the phen ligand, and three coordination sites are occupied by oxygen atoms originating from two chemically different fum ligands, one coordinating through one O-donor atom, and the second one coordinating in a chelating fashion (Fig. 2). The presence of an additional aqua ligand in the coordination sphere of the Ni(II) atom lowers the number of free coordination sites available for polymerization from four in (II) to three in (I). Consequently, a crystal structure with lower dimensionality is realised.

The mean value of the Ni–N bond lengths (2.07 (2) Å) is close to that observed in [Ni₂(phen)₄(fum)(H₂O)₂]fum^.16H₂O (2.096 (1) Å) (Ma et al., 2003). In (I) two crystallographically independent fum^2- ligands in the asymmetric unit reside on an inversion centre. The chelating fum ligand coordinates in an unsymmetrical fashion and the corresponding Ni—O bonds are longer with respect to the Ni—O bond of the monodentately coordinating fum ligand (Table 2). A similar situation as to the Ni–O bond lengths was observed in [Ni₂(fum)₂(py)₆]^.2py (Mori et al., 2004). The Ni—O bond length of the aqua ligand exhibits an usual value (Ma et al., 2003).

Both hydrogen atoms of the aqua ligand are involved in rather strong hydrogen bonds of the O—H···O type (Fig. 3, Table 3). The H1O1 atom forms an intermolecular hydrogen bond with the not coordinating O5 atom from the carboxylate group. On the other hand, the H2O1 atom participates in an intermolecular hydrogen bond with the O2 atom (symmetry code 2 - x, 1 - y, -z) linking neighbouring chains; due to symmetry operators (centre of symmetry) the chains are linked with a pair of such hydrogen bond forming a ring arrangement R₂²(8).

Moreover, the chains interact also through π—π interactions between the aromatic rings of the phen ligands (Fig. 3). The distances between the centres of gravity, Cgi of the aromatic rings, are: 3.7942 (11) Å for Cg1—Cg1^iv (Cg1 is the centre of gravity of the aromatic ring formed by atoms N1, C10, C9, C3, C2, C1) and 3.4787 (10) Å for Cg2···Cg2^v (Cg2 is the centre of gravity of the aromatic ring formed by atoms N2, C8, C7, C6, C11, C12). Similar π—π interactions were also observed in the structure of the dark-green [Ni(fum)(phen)] (Černák et al., 2009).

Experimental

A Parr reaction vessel (total volume 20 cm³) was filled with 6 cm³ of aqueous-ethanolic solution (1:1) containing 238 mg (1 mmol) of NiCl₂^.6H₂O, 116 mg (1 mmol) of fumaric acid and 396 mg (2 mmol) of 1,10-phenantroline. Finally, 112 mg (2 mmol) of solid KOH was added. The closed reaction vessel was heated by uniform heating rate to 373 K during one hour and then was left at this temperature for 80 h. The reaction vessel was then uniformly cooled to room temperature during 20 h. The product consisted of dark-green crystals of [Ni(fum)(phen)] (main product) and few light-green crystals of [Ni(fum)(H₂O)(phen)]. The mixture of crystals was separated from the mother liquor by filtration and dried at laboratory temperature. The light-green crystals were picked up and used for X-ray study.