Bis[4-bromo-2-(ethyl­imino­meth­yl)phenolato-κ² N,O]nickel(II)

Abstract

In the title complex, [Ni(C₉H₉BrNO)₂], the Ni^II ion lies on an inversion centre and is coordinated in a slightly distorted square-planar geometry by two N atoms and two O atoms from two symmetry-related bidentate 4-bromo-2-(ethyl­imino­meth­yl)phenolate ligands. The complex forms a one-dimensional chain in the crystal structure through short C—H⋯Br contacts (H⋯Br = 3.009 Å).

Related literature

For background to Schiff base compounds, see: Gupta & Sutar (2008 ▶); Zhang et al. (2008 ▶, 2009 ▶); Zhang & Feng (2010 ▶); Ge et al. (2011 ▶). For Schiff base coordination models, see: Nakagima et al. (1989 ▶); Zhang et al. (2007 ▶).

Experimental

Crystal data

• [Ni(C₉H₉BrNO)₂]

• M _r = 512.83

• Monoclinic,

• a = 13.456 (6) Å

• b = 4.803 (2) Å

• c = 14.743 (6) Å

• β = 102.157 (8)°

• V = 931.4 (7) ų

• Z = 2

• Mo Kα radiation

• μ = 5.35 mm⁻¹

• T = 293 K

• 0.15 × 0.12 × 0.11 mm

Data collection

• Bruker SMART CCD area-detector diffractometer

• Absorption correction: multi-scan (SADABS; Bruker, 2004 ▶) T _min = 0.465, T _max = 0.558

• 4567 measured reflections

• 1651 independent reflections

• 995 reflections with I > 2σ(I)

• R _int = 0.164

Refinement

• R[F ² > 2σ(F ²)] = 0.057

• wR(F ²) = 0.142

• S = 1.03

• 1651 reflections

• 116 parameters

• H-atom parameters constrained

• Δρ_max = 0.79 e Å⁻³

• Δρ_min = −0.52 e Å⁻³

Data collection: SMART (Bruker, 2004 ▶); cell refinement: SAINT (Bruker, 2004 ▶); 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: SHELXL97.

Supplementary Material

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

supplementary crystallographic information

Comment

Schiff base complexes have been studied for many years (Gupta & Sutar, 2008; Zhang et al., 2008, 2009; Zhang & Feng, 2010; Ge et al., 2011) and produced increasing interest because of their anticancer, antiviral, catalytic and fluorescent properties. Most model studies of metal complexes of Schiff base ligands containing salicylaldehyde and amino acids have focused on the binding mode of these ligands (Nakagima et al., 1989; Zhang et al., 2007). The crystal structures of the complexes obtained demonstrate that the Schiff base ligands act in a bidentate, tridentate, tetradentate or pentadentate mode, coordinating through the phenolate O, imine N and carboxylate O atoms. Our research group is interested in bidentate Schiff bases derived from 5-bromo-2-hydroxy-benzaldehyde and ethylamine.

In the title complex, the Ni^II ion lies on a centre of inversion and is coordinated by two O and two N atoms from two bidentate 5-bromo-N-ethylsalicylaldimino ligands, forming a slightly distorted square-planar geometry (Fig. 1). The compound further form a one-dimensional crystal structure (Fig. 2) through C—H···Br contacts (C9···Br1ⁱ = 3.871 (1) Å, H9···Br1 = 3.009 Å, symmetry code: (i) -x, -y, 1 - z).

Experimental

To a solution of 5-bromo-2-hydroxy-benzaldehyde (0.181 g, 1.0 mmol), ethylamine (0.044 g, 1 mmol), and sodium hydroxide (0.040 g, 1 mmol) in 20 ml absolute methanol was added slowly a solution of nickel nitrate hexahydrate (0.145 g, 0.5 mmol) in methanol. The mixture was stirred for 3 h at room temperature to give a green solution, which was filtered and the filtrate was left to stand at room temperature. Green block crystals suitable for X-ray diffraction were obtained by slow evaporation. yield: 84.6% (based on Ni). Elemental analysis, calculated: C 42.12, H 3.57, N 5.48%; Found: C 42.15, H 3.54, N 5.46%.

Refinement

H atoms were positioned geometrically and refined with a riding model, with distances 0.96 (CH₃), 0.97 (CH₂) or 0.93 Å (aromatic CH), and with U_iso(H) = 1.2 U_eq(carrier C) or U_iso(H) = 1.5 U_eq(CH₃).

Figures

Fig. 1.

The molecular structure of the title complex, showing 30% probability displacement ellipsoids. H atoms were omitted.

Fig. 2.

Packing drawing of the title compound.

Crystal data

[Ni(C9H9BrNO)2]	F(000) = 508
Mr = 512.83	Dx = 1.829 Mg m−3
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yn	Cell parameters from 1651 reflections
a = 13.456 (6) Å	θ = 2.3–25.1°
b = 4.803 (2) Å	µ = 5.35 mm−1
c = 14.743 (6) Å	T = 293 K
β = 102.157 (8)°	Block, green
V = 931.4 (7) Å3	0.15 × 0.12 × 0.11 mm
Z = 2

Data collection

Bruker SMART CCD area-detector diffractometer	1651 independent reflections
Radiation source: fine-focus sealed tube	995 reflections with I > 2σ(I)
graphite	Rint = 0.164
φ and ω scans	θmax = 25.1°, θmin = 2.3°
Absorption correction: multi-scan (SADABS; Bruker, 2004)	h = −15→16
Tmin = 0.465, Tmax = 0.558	k = −5→5
4567 measured reflections	l = −17→14

Refinement

Refinement on F2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.057	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.142	H-atom parameters constrained
S = 1.03	w = 1/[σ2(Fo2) + (0.0386P)2] where P = (Fo2 + 2Fc2)/3
1651 reflections	(Δ/σ)max < 0.001
116 parameters	Δρmax = 0.79 e Å−3
0 restraints	Δρmin = −0.52 e Å−3
0 constraints

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
Br1	0.14681 (6)	0.5969 (2)	0.56509 (5)	0.0835 (4)
C1	0.0224 (5)	0.9743 (16)	0.8127 (5)	0.0595 (18)
C2	−0.0114 (6)	1.0740 (16)	0.7195 (5)	0.069 (2)
H2	−0.0590	1.2170	0.7075	0.083*
C3	0.0255 (5)	0.9609 (18)	0.6489 (4)	0.067 (2)
H3	0.0025	1.0257	0.5887	0.080*
C4	0.0964 (5)	0.7519 (18)	0.6657 (4)	0.065 (2)
C5	0.1313 (5)	0.6526 (17)	0.7529 (4)	0.064 (2)
H5	0.1806	0.5139	0.7635	0.077*
C6	0.0921 (5)	0.7616 (15)	0.8278 (4)	0.0556 (17)
C7	0.1305 (5)	0.6525 (16)	0.9196 (5)	0.0638 (19)
H7	0.1794	0.5130	0.9257	0.077*
C8	0.1627 (6)	0.5937 (18)	1.0814 (5)	0.080 (3)
H8A	0.1164	0.5395	1.1206	0.096*
H8B	0.1951	0.4265	1.0646	0.096*
C9	0.2412 (6)	0.783 (2)	1.1336 (6)	0.100 (3)
H9A	0.2914	0.8198	1.0976	0.150*
H9B	0.2730	0.6973	1.1913	0.150*
H9C	0.2100	0.9548	1.1459	0.150*
N1	0.1026 (4)	0.7322 (12)	0.9936 (3)	0.0560 (15)
Ni1	0.0000	1.0000	1.0000	0.0544 (4)
O1	−0.0152 (4)	1.0925 (11)	0.8785 (3)	0.0712 (15)

Atomic displacement parameters (Ų)

	U11	U22	U33	U12	U13	U23
Br1	0.0908 (6)	0.1153 (9)	0.0524 (5)	−0.0021 (5)	0.0331 (4)	−0.0090 (4)
C1	0.069 (4)	0.064 (5)	0.049 (4)	−0.013 (4)	0.021 (3)	0.003 (3)
C2	0.086 (5)	0.078 (6)	0.046 (4)	0.012 (4)	0.017 (4)	0.013 (4)
C3	0.075 (5)	0.090 (6)	0.038 (4)	−0.002 (5)	0.017 (3)	0.011 (4)
C4	0.070 (4)	0.089 (6)	0.043 (4)	−0.017 (4)	0.026 (3)	−0.005 (4)
C5	0.067 (5)	0.081 (6)	0.050 (4)	0.011 (4)	0.022 (3)	−0.001 (4)
C6	0.060 (4)	0.061 (5)	0.049 (4)	0.001 (4)	0.019 (3)	0.001 (3)
C7	0.075 (5)	0.060 (5)	0.062 (5)	0.012 (4)	0.026 (4)	0.008 (4)
C8	0.110 (6)	0.078 (6)	0.059 (5)	0.040 (5)	0.033 (5)	0.024 (4)
C9	0.087 (6)	0.141 (9)	0.066 (5)	0.012 (6)	0.001 (5)	0.029 (6)
N1	0.071 (4)	0.061 (4)	0.038 (3)	0.000 (3)	0.018 (3)	0.004 (3)
Ni1	0.0691 (8)	0.0562 (8)	0.0417 (7)	0.0038 (6)	0.0205 (5)	0.0068 (6)
O1	0.093 (4)	0.083 (4)	0.044 (3)	0.027 (3)	0.030 (2)	0.013 (2)

Geometric parameters (Å, °)

Br1—C4	1.907 (7)	C7—H7	0.9300
C1—O1	1.314 (9)	C8—C9	1.481 (12)
C1—C6	1.373 (10)	C8—N1	1.527 (8)
C1—C2	1.435 (10)	C8—H8A	0.9700
C2—C3	1.358 (10)	C8—H8B	0.9700
C2—H2	0.9300	C9—H9A	0.9600
C3—C4	1.371 (10)	C9—H9B	0.9600
C3—H3	0.9300	C9—H9C	0.9600
C4—C5	1.359 (9)	N1—Ni1	1.904 (6)
C5—C6	1.420 (9)	Ni1—O1i	1.815 (4)
C5—H5	0.9300	Ni1—O1	1.815 (4)
C6—C7	1.442 (9)	Ni1—N1i	1.904 (6)
C7—N1	1.284 (8)
O1—C1—C6	124.0 (6)	C9—C8—H8A	109.3
O1—C1—C2	117.9 (7)	N1—C8—H8A	109.3
C6—C1—C2	118.1 (7)	C9—C8—H8B	109.3
C3—C2—C1	120.5 (7)	N1—C8—H8B	109.3
C3—C2—H2	119.8	H8A—C8—H8B	108.0
C1—C2—H2	119.8	C8—C9—H9A	109.5
C2—C3—C4	120.5 (6)	C8—C9—H9B	109.5
C2—C3—H3	119.8	H9A—C9—H9B	109.5
C4—C3—H3	119.8	C8—C9—H9C	109.5
C5—C4—C3	121.1 (7)	H9A—C9—H9C	109.5
C5—C4—Br1	119.4 (6)	H9B—C9—H9C	109.5
C3—C4—Br1	119.6 (5)	C7—N1—C8	113.2 (6)
C4—C5—C6	119.7 (7)	C7—N1—Ni1	126.0 (5)
C4—C5—H5	120.2	C8—N1—Ni1	120.8 (4)
C6—C5—H5	120.2	O1i—Ni1—O1	180.000 (2)
C1—C6—C5	120.1 (6)	O1i—Ni1—N1i	92.8 (2)
C1—C6—C7	121.3 (6)	O1—Ni1—N1i	87.2 (2)
C5—C6—C7	118.5 (6)	O1i—Ni1—N1	87.2 (2)
N1—C7—C6	125.3 (7)	O1—Ni1—N1	92.8 (2)
N1—C7—H7	117.3	N1i—Ni1—N1	180.0 (3)
C6—C7—H7	117.3	C1—O1—Ni1	129.9 (5)
C9—C8—N1	111.4 (7)

Symmetry codes: (i) −x, −y+2, −z+2.