Tetra­kis(μ3-2-{[1,1-bis­(hydroxy­meth­yl)-2-oxidoeth­yl]imino­meth­yl}-6-methoxy­phenol­ato)tetra­nickel(II) tetra­hydrate

Yujing Guo; Lianzhi Li; Yan Liu; Jianfang Dong; Daqi Wang

doi:10.1107/S1600536808009872

. 2008 Apr 16;64(Pt 5):m675–m676. doi: 10.1107/S1600536808009872

Tetrakis(μ₃-2-{[1,1-bis(hydroxymethyl)-2-oxidoethyl]iminomethyl}-6-methoxyphenolato)tetranickel(II) tetrahydrate

Yujing Guo ^a, Lianzhi Li ^a,^*, Yan Liu ^a, Jianfang Dong ^a, Daqi Wang ^a

PMCID: PMC2961190 PMID: 21202214

Abstract

The title complex, [Ni₄(C₁₂H₁₅NO₄)₄]·4H₂O, has crystallographic fourfold inversion symmetry, with each Ni^II ion coordinated in a slightly distorted square-pyramidal coordination environment and forming an Ni₄O₄ cubane-like core. In the crystal structure, intermolecular O—H⋯O hydrogen bonds connect complex and water molecules to form a three-dimensional network. The O atom of one of the unique hydroxymethyl groups is disordered over two sites, with the ratio of occupancies being approximately 0.79:0.21.

Related literature

For related literature, see: Dong, Li, Xu & Wang (2007 ▶); Dong, Li, Xu, Cui & Wang (2007 ▶); Koikawa et al. (2005 ▶); Mishtu et al. (2002 ▶); Nihei et al. (2003 ▶).

Experimental

Crystal data

[Ni₄(C₁₂H₁₅NO₄)₄]·4H₂O
M _r = 1319.90
Tetragonal,
a = 18.754 (2) Å
c = 15.4395 (15) Å
V = 5430.3 (10) Å³
Z = 4
Mo Kα radiation
μ = 1.45 mm⁻¹
T = 298 (2) K
0.30 × 0.29 × 0.28 mm

Data collection

Bruker SMART CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 1996 ▶) T _min = 0.670, T _max = 0.686
11110 measured reflections
2399 independent reflections
1840 reflections with I > 2σ(I)
R _int = 0.034

Refinement

R[F ² > 2σ(F ²)] = 0.066
wR(F ²) = 0.194
S = 1.08
2399 reflections
186 parameters
H-atom parameters constrained
Δρ_max = 1.23 e Å⁻³
Δρ_min = −0.70 e Å⁻³

Data collection: SMART (Siemens, 1996 ▶); cell refinement: SAINT (Siemens, 1996 ▶); 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: SHELXTL.

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536808009872/lh2612sup1.cif

e-64-0m675-sup1.cif^{(18.9KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808009872/lh2612Isup2.hkl

e-64-0m675-Isup2.hkl^{(117.4KB, hkl)}

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

Table 1. Selected geometric parameters (Å, °).

Ni1—O1	1.912 (4)
Ni1—O3	1.941 (4)
Ni1—N1	1.949 (6)
Ni1—O3ⁱ	1.970 (4)
Ni1—O3ⁱⁱ	2.565 (5)

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O1—Ni1—O3	172.2 (2)
O1—Ni1—N1	94.3 (2)
O3—Ni1—N1	84.1 (2)
O1—Ni1—O3ⁱ	94.57 (19)
O3—Ni1—O3ⁱ	88.47 (19)
N1—Ni1—O3ⁱ	166.1 (2)
O1—Ni1—O3ⁱⁱ	94.23 (17)
O3—Ni1—O3ⁱⁱ	79.80 (17)
N1—Ni1—O3ⁱⁱ	117.2 (2)
O3ⁱ—Ni1—O3ⁱⁱ	72.63 (17)

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

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

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O5—H5⋯N1	0.82	2.58	2.988 (9)	112
O4—H4⋯O6ⁱⁱⁱ	0.82	1.94	2.714 (8)	157
O4′—H4′⋯O6ⁱⁱⁱ	0.82	1.96	2.68 (3)	148
O6—H6A⋯O1^iv	0.85	1.95	2.803 (7)	180
O6—H6B⋯O4^v	0.85	2.04	2.892 (9)	180

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

Acknowledgments

The authors thank the Natural Science Foundation of Shandong Province (grant No. Y2004B02) for a research grant.

supplementary crystallographic information

Comment

The chemistry of transition metal ion complexes of hydroxy (aryl-OH and alkyl-OH) rich molecules containing imine/amine group is important in the biomimetic studies of metalloproteins (Mishtu et al., 2002). Polynuclear metal complexes with tridentate ligand containing hydroxyl groups as terminal coordinating atoms have been reported and have attracted much attention (Nihei et al., 2003).

A few structurally characterized multinuclear complexes containing Schiff base ligands has been reported( e.g. Dong, Li, Xu & Wang (2007); Dong, Li, Xu, Cui & Wang (2007); Nihei et al., 2003). Herein, we report the synthesis and crystal structure of a novel tetranickel(II) complex with a tridentate Schiff base ligand derived from the condensation of o-vanillin and trihydroxymethylaminomethane.

The title compound contains a tetranuclear cubane core based on an approximately cubic array of alternating nickel and oxygen atoms (Fig.1). Each Ni^II ion is in a distorted square-pyramidal coordination environment with one nitrogen and two oxygen atoms from one Schiff base ligand and two oxygen atoms from the symmetry related units of the cubane core. The Ni atom deviates from the basal plane (formed by O1, N1, O3 and O3ⁱ, symmetry code (i) y - 7/4, -x + 3/4, -z + 7/4) by 0.1299 (33) Å, with a significantly longer Ni—O_apical bond distance (Table 1). In the molecular structure, the Ni—Ni distances (3.472 (4) Å, 3.182 (3) Å) are longer than some reported values (Koikawa et al., 2005). In addition, there are four H₂O solvent molecules, which are involved in intermolecular O-H···O hydrogen bonds (Fig. 2, Table 2) which stabilize the crystal atructure along with van der Waals forces.

Experimental

Trihydroxymethylaminomethane(1 mmol, 121.14 mg) was dissolved in hot methanol (10 ml) and added successively to a methanol solution(3 ml) of o-vanillin (1 mmol, 152.15 mg). The mixture was then stirred at 323 K for 2 h. Subsequently, an aqueous solution(2 ml) of nickel chlorate hexahydrate(1 mmol, 237.66 mg) was added dropwise and stirred for another 5 h. The solution was held at room temperature for ten days, whereupon green blocky crystals suitable for X-ray diffraction were obtained.