Bis[2-(benzyl­amino)­pyridine-κN 1]bis­(2-formyl­phenolato-κ2 O,O′)nickel(II)

Kouassi Ayikoé; Ray J Butcher; Yilma Gultneh

doi:10.1107/S1600536811001425

. 2011 Jan 15;67(Pt 2):m207–m208. doi: 10.1107/S1600536811001425

Bis[2-(benzylamino)pyridine-κN ¹]bis(2-formylphenolato-κ² O,O′)nickel(II)

Kouassi Ayikoé ^a, Ray J Butcher ^a,^*, Yilma Gultneh ^a

PMCID: PMC3051610 PMID: 21522871

Abstract

In the title complex, [Ni(C₇H₅O₂)₂(C₁₂H₁₂N₂)₂], the Ni^II atom lies on a center of inversion and is coordinated in an octahedral geometry by two 2-(benzylamino)pyridine (2-BAP) and two 2-formylphenolate ligands with the O-atom donors in the equatorial plane and the pyridine N atoms in axial positions. There are hydrogen-bonding interactions between the secondary amine H atom and the phenolate O atom, as well as C—H⋯O interactions, which result in the dihedral angle between the aromatic phenyl ring of the 2-formylphenolate moiety and the pyridine ring being 80.23 (4)°. In the packing, there are both C—H⋯π interactions, which link the molecules into chains along the b axis, and offset π–π interactions involving both the pyridine and phenyl rings of the 2-BAP ligands [centroid–centroid distances = 4.0100 (8) Å for the pyridine rings and 3.6601 (8) and 4.8561 (8) Å for the phenyl rings].

Related literature

For the structures of similar octahedral nickel complexes, see: Assey et al. (2010a ▶,b ▶); Butcher et al. (2009 ▶); Gultneh et al. (2008 ▶). For bond-length data, Allen et al. (1987 ▶).

Experimental

Crystal data

[Ni(C₇H₅O₂)₂(C₁₂H₁₂N₂)₂]
M _r = 669.40
Triclinic,
a = 8.1747 (5) Å
b = 9.3365 (5) Å
c = 10.9183 (6) Å
α = 73.926 (5)°
β = 84.766 (5)°
γ = 77.247 (5)°
V = 780.58 (8) Å³
Z = 1
Mo Kα radiation
μ = 0.67 mm⁻¹
T = 110 K
0.47 × 0.41 × 0.35 mm

Data collection

Oxford Diffraction Xcalibur diffractometer with a Ruby detector
Absorption correction: multi-scan (CrysAlis PRO; Oxford Diffraction, 2009 ▶) T _min = 0.932, T _max = 1.000
9822 measured reflections
5136 independent reflections
4216 reflections with I > 2σ(I)
R _int = 0.025

Refinement

R[F ² > 2σ(F ²)] = 0.034
wR(F ²) = 0.086
S = 1.05
5136 reflections
218 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.46 e Å⁻³
Δρ_min = −0.27 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: SHELXTL (Sheldrick, 2008 ▶); software used to prepare material for publication: SHELXTL.

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536811001425/zl2338sup1.cif

e-67-0m207-sup1.cif^{(21.2KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536811001425/zl2338Isup2.hkl

e-67-0m207-Isup2.hkl^{(251.5KB, hkl)}

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

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

Cg4 is the centroid of the C1A–C6A ring.

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N2B—H2BN⋯O1A	0.775 (17)	2.147 (18)	2.8550 (14)	152.0 (17)
C1B—H1BA⋯O1Aⁱ	0.95	2.42	2.9216 (14)	113
C3B—H3BA⋯Cg4ⁱⁱ	0.95	2.44	3.3674 (14)	166
C11B—H11A⋯Cg4ⁱⁱⁱ	0.95	2.91	3.7535 (17)	148

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

Acknowledgments

RJB wishes to acknowledge the NSF-MRI program (grant No. CHE-0619278) for funds to purchase the diffractometer. KA thanks the National Science Foundations’ AGEP Fellowship for support.

supplementary crystallographic information

Comment

As part of our continuing studies (Gultneh et al. 2008; Assey et al., 2010a, 2010b; Butcher et al., 2009) of nickel(II) complexes with relevance to the nickel containing metalloenzymes, we wish to report the structure of the mixed ligand complex, C₃₈H₃₄N₄NiO₄, where the Ni lies on a center of inversion and contains two 2-benzylaminopyridine (2-BAP) and two salicylaldehyde molecules where the O donors form an equatorial plane with pyridine N's in axial positions, thus the Ni is in an octahedral coordination environment.

The Ni—O and Ni—N bond distances (see Table 1) are within the normal ranges observed in other Ni complexes containing similar ligands (Allen et al., 1987). There are hydrogen bonding interactions between the secondary amine H and phenolic O as well as C—H···O interactions which result in the dihedral angle between the aromatic phenyl ring of the salicylaldehyde moiety and the pyridine ring being 80.23 (4)°. The dihedral angle between the NiO₄ plane and salicylaldehyde plane is 10.31 (5)°. In the packing there are both intermolecular C-H···π interactions (see Table 1) involving the salicylaldehyde anion which link the molecules into a chain in the b direction. In addition there are offsetting π–π interactions involving both the pyridine and phenyl rings of the 2-BAP moiety (see Figure 3). For the pyridine rings, Cg–Cg distance 4.0100 (8), perpendicular distance 3.3506 (5), slippage 2.203 Symmetry 1-x, 1-y, 1-z; for the phenyl rings (a) Cg-Cg -distance 3.6601 (8), perpendicular distance 3.4408 (5), slippage 1.248 Symmetry -x, 1-y, 2-z; (b) Cg–Cg distance 4.8561 (8), perpendicular distance 3.0743 (5), slippage 3.759 Symmetry 1-x, 1-y, 2-z.

Experimental

Salicylaldehyde (0.23 g, 1.9 mmol) and 0.370 g of 2-benzylaminopyridine (2.0 mmol) were separately dissolved in 20 ml and 30 ml of methanol respectively before mixing and stirring under reflux followed by addition of 0.36 g (1.5 mmol) of NiCl₂.6H₂O in MeOH (20 ml). 2-Benzylaminopyridine, a secondary amine, has shown a chelating ability to nickel salts (nitrate and perchlorate) even in the presence of an aryl aldehyde (Butcher et al., 2009). The solution of the salt and the two ligands was stirred overnight at room temperature. The mixture was evaporated under reduced pressure and a dark-green semi-solid was obtained. A small amount of the complex was then dissolved in 5 ml of DMF, filtered and layered with diethyl ether. Light green X-ray quality crystals were obtained after slow diffusion of the diethyl ether into DMF (yield 68%, m.p. 410 - 412 K). IR Data: 3330 cm^-1ν(N—H) benzylamine nitrogen-hydrogen stretching; 3078 cm^-1 and 3018 cm^-1ν(C—H) aldehyde C—H stretching; 2851 cm^-1 and 2770 cm^-1 benzyl ν(C—H); 1615 cm^-1ν(C=O) aldehyde carbonyl stretching; 1533 cm^-1 and 1516 cm^-1ν(N—C) and ν(N—H) bendings respectively; 1471 cm^-1, 1445 cm^-1 v(Ar C—H) bendings; 757 cm^-1ν (out of plane aromatic bend). UV-vis data (in cm^-1 with ε_max [M^-1.cm^-1] in brackets): 32154 (1847), 25510 (1306), 15476 (13), and 9174 (7). Room temperature magnetic moment was 3.01 BM.