Bis[2,4-dibromo-6-(cyclo­propyl­imino­methyl)phenolato]nickel(II)

The title compound, [Ni(C₁₀H₈Br₂NO)₂], is a mononuclear nickel(II) complex. The Ni^II atom, located on an inversion centre, exhibits a square-planar coordination geometry. The metal atom is bonded to two phenolate O atoms and two imine N atoms from two Schiff base ligands.

Key indicators

• Single-crystal X-ray study
• T = 298 K
• Mean [sigma](C-C) = 0.006 Å
• R factor = 0.036
• wR factor = 0.084
• Data-to-parameter ratio = 17.8

checkCIF/PLATON results

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Alert level C
PLAT062_ALERT_4_C Rescale T(min) & T(max) by .....................       0.96
PLAT125_ALERT_4_C No _symmetry_space_group_name_Hall Given .......          ?

Alert level G
PLAT794_ALERT_5_G Check Predicted Bond Valency for Ni1         (2)       2.27

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   2 ALERT level C = Check and explain
   1 ALERT level G = General alerts; check

   0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   0 ALERT type 2 Indicator that the structure model may be wrong or deficient
   0 ALERT type 3 Indicator that the structure quality may be low
   2 ALERT type 4 Improvement, methodology, query or suggestion
   1 ALERT type 5 Informative message, check

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S1. Comment

Schiff base complexes have been of great interest for a long time (Chaturvedi, 1977; Archer & Wang, 1990; Costamagna et al., 1992; Yamada, 1999). These complexes play an important role in the development of coordination chemistry related to catalysis and enzymatic reactions, magnetism and molecular architectures. Recently, we have reported a few transition metal complexes (Wang & Li, 2007a,b; Li & Wang, 2007a). As an extension of the work on the structural investigation of these complexes, the title nickel(II) complex is reported here.

The title complex is a centrosymmetric mononuclear nickel(II) complex. The Ni^II atom, lying on the inversion centre, is four-coordinated and shows a square planar coordination geometry. It is bonded to two phenolate O and two imine N atoms from two Schiff base ligands. The Ni–O and Ni–N bond lengths are comparable to the corresponding values observed in other Schiff base nickel(II) complexes.

Related literature

For related literature on Schiff base complexes, see: Chaturvedi (1977); Archer & Wang (1990); Costamagna et al. (1992); Yamada (1999); Li & Wang (2007); Wang & Li (2007a,b).

S2. Experimental

3,5-Dibromosalicylaldehyde (0.2 mmol, 56.4 mg) and cyclopropylamine (0.2 mmol, 11.5 mg) were dissolved in a methanol solution (20 ml). The mixture was stirred at room temperature for 30 min, giving a clear yellow solution. To this solution was added a methanol solution (5 ml) of Ni(NO₃)₂·6H₂O (0.1 mmol, 29.1 mg) with stirring. The resulting mixture was stirred for a further 30 min at room temperature, giving a clear red solution. After allowing the solution to stand in air for a week, red block-shaped crystals were formed.

S3. Refinement

H atoms were placed in idealized positions and constrained to ride on their parent atoms, with C–H = 0.93–0.97 Å and U_iso(H) = 1.2U_eq(C).

Computing details

Data collection: SMART (Bruker, 1998); cell refinement: SAINT (Bruker, 1998); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997a); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997a); molecular graphics: SHELXTL (Sheldrick, 1997b); software used to prepare material for publication: SHELXTL.

Figures

Fig. 1. Molecular structure of (I) at 30% probability level.

Bis(2,4-dibromo-6-cyclopropyliminomethylphenolato)nickel(II)

Crystal data

[Ni(C10H8Br2NO)2]	F(000) = 668
Mr = 694.70	Dx = 2.217 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
a = 8.0170 (16) Å	Cell parameters from 1834 reflections
b = 9.2420 (18) Å	θ = 2.5–25.3°
c = 14.088 (3) Å	µ = 8.63 mm^−1
β = 94.62 (3)°	T = 298 K
V = 1040.4 (4) Å^3	Block, red
Z = 2	0.23 × 0.20 × 0.17 mm

Data collection

Bruker SMART CCD area-detector diffractometer	2362 independent reflections
Radiation source: fine-focus sealed tube	1801 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.041
ω scan	θmax = 27.5°, θmin = 2.6°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −10→10
Tmin = 0.152, Tmax = 0.241	k = −12→11
8738 measured reflections	l = −18→17

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.036	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.084	H-atom parameters constrained
S = 1.02	w = 1/[σ^2(Fo^2) + (0.0393P)^2] where P = (Fo^2 + 2Fc^2)/3
2362 reflections	(Δ/σ)max < 0.001
133 parameters	Δρmax = 0.51 e Å^−3
0 restraints	Δρmin = −0.56 e Å^−3

Special details

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > σ(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

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

	x	y	z	Uiso*/Ueq
Ni1	0.5000	0.0000	0.5000	0.02886 (18)
Br1	0.91324 (5)	−0.02357 (5)	0.26991 (3)	0.04253 (15)
Br2	1.30178 (6)	0.38800 (5)	0.48338 (3)	0.05101 (16)
O1	0.6838 (3)	0.0172 (3)	0.43016 (19)	0.0342 (6)
N1	0.6038 (4)	0.1142 (3)	0.6033 (2)	0.0283 (7)
C1	0.8438 (5)	0.1940 (4)	0.5221 (3)	0.0298 (8)
C2	0.8144 (5)	0.0988 (4)	0.4431 (3)	0.0292 (8)
C3	0.9399 (5)	0.0995 (4)	0.3777 (3)	0.0294 (8)
C4	1.0802 (5)	0.1830 (4)	0.3890 (3)	0.0327 (9)
H4	1.1601	0.1782	0.3448	0.039*
C5	1.1037 (5)	0.2754 (4)	0.4667 (3)	0.0335 (9)
C6	0.9869 (5)	0.2807 (4)	0.5324 (3)	0.0357 (9)
H6	1.0030	0.3426	0.5844	0.043*
C7	0.7349 (5)	0.1926 (4)	0.5975 (3)	0.0323 (9)
H7	0.7619	0.2553	0.6481	0.039*
C8	0.5247 (5)	0.1218 (4)	0.6926 (3)	0.0327 (9)
H8	0.4104	0.1602	0.6872	0.039*
C9	0.5548 (6)	0.0033 (5)	0.7635 (3)	0.0435 (11)
H9A	0.6342	−0.0716	0.7498	0.052*
H9B	0.4606	−0.0298	0.7968	0.052*
C10	0.6219 (5)	0.1516 (5)	0.7862 (3)	0.0431 (11)
H10A	0.7417	0.1664	0.7860	0.052*
H10B	0.5680	0.2082	0.8330	0.052*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Ni1	0.0286 (4)	0.0337 (4)	0.0244 (4)	−0.0010 (3)	0.0028 (3)	−0.0023 (3)
Br1	0.0411 (3)	0.0576 (3)	0.0295 (2)	0.0009 (2)	0.00693 (18)	−0.00779 (19)
Br2	0.0382 (3)	0.0608 (3)	0.0544 (3)	−0.0152 (2)	0.0063 (2)	0.0010 (2)
O1	0.0311 (15)	0.0441 (17)	0.0282 (15)	−0.0076 (13)	0.0066 (12)	−0.0065 (12)
N1	0.0308 (18)	0.0289 (17)	0.0258 (16)	−0.0011 (14)	0.0059 (13)	−0.0026 (13)
C1	0.031 (2)	0.029 (2)	0.030 (2)	0.0037 (17)	0.0048 (16)	0.0030 (16)
C2	0.031 (2)	0.033 (2)	0.0234 (19)	0.0064 (17)	0.0015 (15)	0.0053 (16)
C3	0.032 (2)	0.035 (2)	0.0219 (19)	0.0047 (17)	0.0021 (15)	−0.0017 (15)
C4	0.026 (2)	0.043 (2)	0.030 (2)	0.0045 (18)	0.0067 (16)	0.0054 (17)
C5	0.028 (2)	0.035 (2)	0.037 (2)	−0.0020 (17)	0.0028 (17)	0.0078 (18)
C6	0.039 (2)	0.038 (2)	0.030 (2)	−0.0029 (19)	0.0013 (17)	−0.0016 (17)
C7	0.037 (2)	0.034 (2)	0.0257 (19)	0.0017 (18)	0.0021 (16)	−0.0052 (16)
C8	0.035 (2)	0.039 (2)	0.025 (2)	−0.0066 (18)	0.0084 (17)	−0.0064 (16)
C9	0.048 (3)	0.050 (3)	0.033 (2)	0.002 (2)	0.012 (2)	−0.0020 (19)
C10	0.042 (3)	0.057 (3)	0.032 (2)	−0.011 (2)	0.0080 (19)	−0.009 (2)

Geometric parameters (Å, º)

Ni1—O1	1.844 (3)	C4—C5	1.389 (5)
Ni1—O1^i	1.844 (3)	C4—H4	0.9300
Ni1—N1^i	1.931 (3)	C5—C6	1.370 (5)
Ni1—N1	1.931 (3)	C6—H6	0.9300
Br1—C3	1.896 (4)	C7—H7	0.9300
Br2—C5	1.898 (4)	C8—C9	1.489 (6)
O1—C2	1.291 (4)	C8—C10	1.502 (5)
N1—C7	1.284 (5)	C8—H8	0.9800
N1—C8	1.456 (5)	C9—C10	1.498 (6)
C1—C6	1.398 (5)	C9—H9A	0.9700
C1—C2	1.423 (5)	C9—H9B	0.9700
C1—C7	1.429 (5)	C10—H10A	0.9700
C2—C3	1.418 (5)	C10—H10B	0.9700
C3—C4	1.363 (5)
O1—Ni1—O1^i	180.0	C5—C6—C1	120.6 (4)
O1—Ni1—N1^i	87.67 (12)	C5—C6—H6	119.7
O1^i—Ni1—N1^i	92.33 (12)	C1—C6—H6	119.7
O1—Ni1—N1	92.33 (12)	N1—C7—C1	127.2 (3)
O1^i—Ni1—N1	87.67 (12)	N1—C7—H7	116.4
N1^i—Ni1—N1	180.0	C1—C7—H7	116.4
C2—O1—Ni1	130.5 (2)	N1—C8—C9	119.1 (3)
C7—N1—C8	116.3 (3)	N1—C8—C10	122.4 (3)
C7—N1—Ni1	124.5 (3)	C9—C8—C10	60.1 (3)
C8—N1—Ni1	119.1 (2)	N1—C8—H8	114.8
C6—C1—C2	121.3 (4)	C9—C8—H8	114.8
C6—C1—C7	118.2 (4)	C10—C8—H8	114.8
C2—C1—C7	120.2 (3)	C8—C9—C10	60.4 (3)
O1—C2—C3	121.4 (3)	C8—C9—H9A	117.7
O1—C2—C1	123.6 (3)	C10—C9—H9A	117.7
C3—C2—C1	115.1 (3)	C8—C9—H9B	117.7
C4—C3—C2	123.3 (3)	C10—C9—H9B	117.7
C4—C3—Br1	118.2 (3)	H9A—C9—H9B	114.9
C2—C3—Br1	118.5 (3)	C9—C10—C8	59.5 (3)
C3—C4—C5	119.9 (3)	C9—C10—H10A	117.8
C3—C4—H4	120.1	C8—C10—H10A	117.8
C5—C4—H4	120.1	C9—C10—H10B	117.8
C6—C5—C4	119.9 (4)	C8—C10—H10B	117.8
C6—C5—Br2	120.5 (3)	H10A—C10—H10B	115.0
C4—C5—Br2	119.6 (3)

Symmetry code: (i) −x+1, −y, −z+1.