{μ-2-[(3-Amino-2,2-dimethyl­prop­yl)imino­meth­yl]-6-meth­oxy­phenolato-1:2κ5 O 1,O 6:N,N′,O 1}{2-[(3-amino-2,2-dimethyl­prop­yl)imino­meth­yl]-6-meth­oxy­phenolato-1κ3 N,N′,O 1}-μ-azido-1:2κ2 N:N-azido-2κN-methanol-2κO-dinickel(II)

Akbar Ghaemi; Saeed Rayati; Kazem Fayyazi; Seik Weng Ng; Edward R T Tiekink

doi:10.1107/S1600536812029662

. 2012 Jul 4;68(Pt 8):m1027–m1028. doi: 10.1107/S1600536812029662

{μ-2-[(3-Amino-2,2-dimethylpropyl)iminomethyl]-6-methoxyphenolato-1:2κ⁵ O ¹,O ⁶:N,N′,O ¹}{2-[(3-amino-2,2-dimethylpropyl)iminomethyl]-6-methoxyphenolato-1κ³ N,N′,O ¹}-μ-azido-1:2κ² N:N-azido-2κN-methanol-2κO-dinickel(II)

Akbar Ghaemi ^a,^‡, Saeed Rayati ^b, Kazem Fayyazi ^a, Seik Weng Ng ^c,^d, Edward R T Tiekink ^c,^*

PMCID: PMC3414102 PMID: 22904709

Abstract

Two distinct coordination geometries are found in the binuclear title complex, [Ni₂(C₁₃H₁₉N₂O₂)₂(N₃)₂(CH₃OH)], as one Schiff base ligand is pentadentate, coordinating via the anticipated oxide O, imine N and amine N atoms (as for the second, tridentate, ligand) but the oxide O is bridging and coordination also occurs through the methoxy O atom. The Ni^II atoms are linked by a μ₂-oxide atom and one end of a μ₂-azide ligand, forming an Ni₂ON core. The coordination geometry for the Ni^II atom coordinated by the tridentate ligand is completed by the methoxy O atom derived from the pentadentate ligand, with the resulting N₃O₃ donor set defining a fac octahedron. The second Ni^II atom has its cis-octahedral N₄O₂ coordination geometry completed by the imine N and amine N atoms of the pentadentate Schiff base ligand, a terminally coordinated azide N and a methanol O atom. The arrangement is stabilized by an intramolecular hydrogen bond between the methanol H and the oxide O atom. Linear supramolecular chains along the a axis are formed in the crystal packing whereby two amine H atoms from different amine atoms hydrogen bond to the terminal N atom of the monodentate azide ligand.

Related literature

For background to azido derivatives of tridentate Schiff base Ni^II complexes, see: Ribas et al. (1999 ▶); Koner et al. (2009 ▶); Biswas et al. (2011 ▶). For a related structure, see: Ghaemi et al. (2012 ▶).

Experimental

Crystal data

[Ni₂(C₁₃H₁₉N₂O₂)₂(N₃)₂(CH₄O)]
M _r = 704.13
Monoclinic,
a = 8.0907 (2) Å
b = 18.5230 (4) Å
c = 21.1162 (4) Å
β = 96.674 (2)°
V = 3143.11 (12) Å³
Z = 4
Mo Kα radiation
μ = 1.25 mm⁻¹
T = 100 K
0.24 × 0.18 × 0.18 mm

Data collection

Agilent SuperNova Dual diffractometer with an Atlas detector
Absorption correction: multi-scan (CrysAlis PRO; Agilent, 2010 ▶) T _min = 0.753, T _max = 0.806
21789 measured reflections
7266 independent reflections
6115 reflections with I > 2σ(I)
R _int = 0.031

Refinement

R[F ² > 2σ(F ²)] = 0.031
wR(F ²) = 0.076
S = 1.01
7266 reflections
417 parameters
5 restraints
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.49 e Å⁻³
Δρ_min = −0.44 e Å⁻³

Data collection: CrysAlis PRO (Agilent, 2010 ▶); 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: ORTEP-3 for Windows (Farrugia, 1997 ▶) and DIAMOND (Brandenburg, 2006 ▶); software used to prepare material for publication: publCIF (Westrip, 2010 ▶).

Supplementary Material

Crystal structure: contains datablock(s) global, I. DOI: 10.1107/S1600536812029662/lh5496sup1.cif

e-68-m1027-sup1.cif^{(32.1KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536812029662/lh5496Isup2.hkl

e-68-m1027-Isup2.hkl^{(355.5KB, hkl)}

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

Table 1. Selected bond lengths (Å).

Ni1—O2	2.0155 (14)
Ni1—O3	2.2589 (13)
Ni1—O4	2.0201 (13)
Ni1—N1	2.0166 (16)
Ni1—N2	2.0621 (17)
Ni1—N5	2.0862 (16)
Ni2—O4	2.0451 (13)
Ni2—O5	2.1364 (14)
Ni2—N3	2.0478 (16)
Ni2—N5	2.1505 (16)
Ni2—N4	2.0797 (16)
Ni2—N8	2.0715 (17)

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

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O5—H5⋯O2	0.83 (1)	1.80 (1)	2.604 (2)	161 (3)
N2—H22⋯N10ⁱ	0.88 (1)	2.32 (2)	3.121 (2)	153 (2)
N4—H42⋯N10ⁱ	0.87 (1)	2.19 (1)	3.040 (2)	165 (2)

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Symmetry code: (i) Inline graphic .

Acknowledgments

The authors gratefully acknowledge practical support of this study by the Islamic Azad University, Saveh Branch, and thank the Ministry of Higher Education (Malaysia) for funding structural studies through the High-Impact Research scheme (UM.C/HIR/MOHE/SC/3).

supplementary crystallographic information

Comment

The design and magnetism of polynuclear complexes containing paramagnetic centres connected through pseudo-halide bridges have attracted significant recent interest owing to their importance in understanding the basics of magnetic interactions and magneto-structural correlations with relevance to condensed matter physics, materials chemistry and coordination chemistry. Amongst these materials investigated, and relevant to the present report describing the crystal structure determination of the title complex (I), are azido derivatives of tridentate Schiff base Ni^II structures (Ribas et al., 1999; Koner et al., 2009; Biswas et al., 2011). Recently, we described the structure of a centrosymmetric Cu^II complex which featured asymmetrically bridging azido ligands and a tridentate mode of coordination of the Schiff base ligand (Ghaemi et al., 2012). Herein, a related binuclear Ni^II complex (I) is described.

In the binuclear complex (I), Fig. 1, the Ni^II atoms are bridged by a µ₂-oxido atom and one end of a µ₂-azido ligand to generate a Ni₂ON core. The coordination geometry for the Ni1 atom is completed by a methoxy-O atom derived from the same ligand that provides the µ₂-oxido bridge and the oxido-O, imine-O and amine-N donor atoms derived from a tridentate uninegative Schiff base ligand. The coordination geometry about the Ni2 atom is completed by the imine-N and amine-N atoms of the original Schiff base ligand, indicating that this is pentadentate, a terminally coordinate azido-N and a methanol-O atom. The N₃O₃ donor set for the Ni1 atom defines a fac-octahedron, whereas the N₄O₂ donor set for the Ni2 atom defines a cis-octahedron. Table 1 collects the Ni—L bond lengths and shows that the µ₂-oxido bridge is symmetric but some asymmetry is present in the µ₂-azido bridge. The longest Ni—O bond lengths for each Ni atom involves methoxy-O (Ni1) and methanol-O (Ni2). As expected, the Ni—N(terminal azide) bond is shorter than the Ni—N bridging distances. The Ni—N(imine) bond lengths are the shorter of the Ni—N bond lengths for the two environments.

Hydrogen bonding occurs in the structure, Table 1. The methanol-H forms an intramolecular hydrogen bond to the oxido-O2 atom to close six-membered {···HONiONiO} and {···HONiNNiO} synthons, Fig. 2. Two of the amine-H atoms form hydrogen bonds to the terminal-N10 atom of the monodentate azido ligand to form eight-membered {···HNNiONiNH···N} and {···HNNiNNiNH···N} synthons, Fig. 2, and a linear supramolecular chain along the a axis, Fig. 3.

Experimental

To prepare this complex, a methanolic solution (40 ml) of 2,2'-dimethylpropylenediamine (1 mmol, 0.102 g) was first mixed with 2-hydroxy-3-methoxybenzaldehyde (2 mmol, 0.304 g) under stirring to prepare the desired Schiff-base in situ. Stirring was continued for 30 min. Then, Cu(NO₃)₂.3H₂O (0.120 g, 0.5 mmol) and Ni(NO₃)2.6H₂O (0.145 g, 0.5 mmol) dissolved in methanol (20 ml) was added to the solution and the resulting mixture was stirred for about 10 min. Finally, an aqueous solution of NaN₃ (2 ml, 8 mmol, 0.52 g) was added drop-wise to the resulting mixture with continuous stirring, and the solution was filtered. Dark-green crystals were formed within few days from the filtered solution. Analysis confirmed the formation of a di-nickel(II) complex rather than the anticipated hetero-metallic complex, as confirmed by X-ray crystallography. Anal. Calc. for C₂₇H₄₂N₁₀Ni₂O₅: C, 46.06; H, 6.01; N, 19.89. Found: C, 45.93; H, 5.85; N, 19.76%. IR (KBr) [cm^-1]: ν_as(N₃) 2047, 2068 vs, ν(C═N) 1620 s, ν(C═C) 1540 s, ν(C—O) 1224 m, ν(O—H) 3340 b. Yield: 56%, M.pt: 544–548 K.