Di-μ-azido-κ4 N:N-bis­({2-[(3-amino-2,2-dimethyl­prop­yl)imino­meth­yl]-6-meth­oxy­phenolato-1κ3 N,N′,O 1}copper(II))

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

doi:10.1107/S1600536812028954

. 2012 Jun 30;68(Pt 7):m993–m994. doi: 10.1107/S1600536812028954

Di-μ-azido-κ⁴ N:N-bis({2-[(3-amino-2,2-dimethylpropyl)iminomethyl]-6-methoxyphenolato-1κ³ N,N′,O ¹}copper(II))

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

PMCID: PMC3393238 PMID: 22807806

Abstract

The complete molecule of the title complex, [Cu₂(C₁₃H₁₉N₂O₂)₂(N₃)₂], is generated by the application of a centre of inversion. The central Cu₂N₂ core is a rhombus as the μ₂-azide ligands bridge in an asymmetric fashion. Each Cu^II atom is also coordinated by a monoanionic tridentate Schiff base ligand via the anticipated oxide O, imine N and amine N atoms. The resulting N₄O coordination geometry is based on a square pyramid. No specific intermolecular interactions are noted in the crystal packing, but the amine H atoms form intramolecular N—H⋯O(oxide)/N(azide) hydrogen bonds.

Related literature

For background to azido derivatives of tridentate Schiff base copper(II) structures, see: Adhikary & Koner (2010 ▶). For a related structure, see: Ghaemi et al. (2012 ▶). For additional structural analysis, see: Addison et al. (1984 ▶).

Experimental

Crystal data

[Cu₂(C₁₃H₁₉N₂O₂)₂(N₃)₂]
M _r = 681.76
Monoclinic,
a = 9.1733 (5) Å
b = 12.2369 (5) Å
c = 13.0988 (6) Å
β = 98.203 (5)°
V = 1455.33 (12) Å³
Z = 2
Mo Kα radiation
μ = 1.51 mm⁻¹
T = 100 K
0.20 × 0.15 × 0.10 mm

Data collection

Agilent SuperNova Dual diffractometer with an Atlas detector
Absorption correction: multi-scan (CrysAlis PRO; Agilent, 2010 ▶) T _min = 0.674, T _max = 1.000
5747 measured reflections
3314 independent reflections
2628 reflections with I > 2σ(I)
R _int = 0.034

Refinement

R[F ² > 2σ(F ²)] = 0.039
wR(F ²) = 0.105
S = 1.06
3314 reflections
198 parameters
2 restraints
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.54 e Å⁻³
Δρ_min = −0.52 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/S1600536812028954/sj5249sup1.cif

e-68-0m993-sup1.cif^{(19.4KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536812028954/sj5249Isup2.hkl

e-68-0m993-Isup2.hkl^{(159.3KB, hkl)}

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

Table 1. Selected bond lengths (Å).

Cu—O2	1.9047 (18)
Cu—N1	1.960 (2)
Cu—N2	2.001 (2)
Cu—N3	2.023 (2)
Cu—N3ⁱ	2.641 (2)

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Symmetry code: (i) Inline graphic .

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

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N2—H1N⋯O2ⁱ	0.87 (1)	2.35 (2)	2.956 (3)	127 (2)
N2—H2N⋯N3	0.88 (1)	2.36 (3)	2.752 (3)	107 (3)

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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

Azido-bridged copper(II) complexes continue to attract attention in relation to investigations of small molecule activation of copper-containing proteins and for new magnetic materials (Adhikary & Koner, 2010). Recently, the crystal structure of a related Ni^II complex was described in which the Schiff base ligand was shown to coordinate in two distinct modes, i.e. a tridentate mode towards one Ni^II atom and in a pentadentate mode, bridging two Ni^II atoms (Ghaemi et al., 2012).

In the centrosymmetric binuclear complex (I), Fig. 1, the Cu^II atoms are bridged by one end of each of two µ₂-azido ligands to generate an Ni₂N₂ core with the shape of a rhombus as the bridge is asymmetric, Table 1. The coordination geometry for the Cu^II atom is completed by the oxido-O, imine-O and amino-N donor atoms derived from a tridentate uninegative Schiff base ligand. The N₄O donor set defines a coordination geometry close to square pyramidal. This is quantified by the value of τ = 0.12 which compares to the τ values of 0.0 and 1.0 for ideal square pyramidal and trigonal bipyramidal geometries, respectively (Addison et al., 1984). The configuration is stabilized by an intramolecular N—H···O(oxido) and N—H···N(azido) hydrogen bonds, Table 2. Globally, molecules stack in columns aligned along the a axis, Fig. 2, without specific intermolecular interactions between them.

Experimental

A mixture of 2,2-dimethylpropylenediamine (0.234 g, 2.3 mmol) was added to a clear solution of Cu(NO₃)₂.3H₂O (0.50 g, 2.07 mmol) dissolved in methanol (25 ml), which immediately produced an intense-blue solution. The solution was then heated to boiling and a methanolic solution of 2-hydroxy-3-methoxybenzaldehyde (0.273 g, 1.8 mmol) was added drop-wise over 2 h under refluxing conditions. Reflux was continued for another 45 min. Then an excess sodium azide (0.5 g, 7.7 mmol) dissolved in water (2 ml) was added. The precipitate was filtered and dissolved in methanol. Brown crystals were formed within a few days from the methanolic solution. Anal. Calc. for C₂₆H₃₈Cu₂N₁₀O₄: C, 45.81; H, 5.62; N, 20.55. Found: C, 45.77; H, 5.57; N, 20.66%. IR (KBr) [ν, cm^-1]: ν_as(N₃) 2035 versus, ν(C═N) 1621 s, ν(C═C) 1540 s, ν(C—O) 1224 m. M.pt: 476–478. Yield: 60%.