[N,N'-Bis(5-bromo­salicyl­idene)-o-phenylene­diaminato]copper(II)

In the title compound, {4,4'-di­bromo-2,2'-[o-phenyl­ene­bis­(nitrilo­methyl­idene)]­di­phen­ol­ato-O,N,N',O'}copper(II), [Cu(C₂₀H₁₂Br₂N₂O₂], the Cu^II ion shows a slightly distorted square-planar geometry with the N₂O₂ atoms of the Schiff base imine-phenol tetradentate ligand.

S1. Comment

Schiff-base complexes are one of the most important stereochemical models in transition metal coordination chemistry, with their easy preparation and structural variation (Garnovskii et al., 1993). Metal derivatives of Schiff bases have been extensively studied, and copper(II) and nickel(II) complexes play a major role in both synthetic and structural research. The geometry of the coordination sphere is usually planar in the case of Ni, but for Cu a tetrahedral distortion is often observed (Garnovskii et al., 1993). We have previously reported the crystal structures of several dimeric and monomeric Schiff-base complexes of Cu^II (Elmali et al., 1997; Elerman & Geselle, 1997; Elerman, Elmali & Özbey, 1998; Elerman, Elmali, Kabak & Svoboda, 1998). We report here the results of the reaction of copper(II) with the tetradentate ligand N,N'-bis(5-bromosalicylidene)-o-phenylenediamine, forming the title compound, (I). \scheme

Tetracoordinate Schiff-base metal complexes may form trans or cis planar or tetrahedral structures. A strictly planar or slightly distorted coordination is characteristic for transition metal complexes of copper(II) with a CuN₂O₂ coordination sphere (Garnovskii et al., 1993). In (I), the Cu atom is coordinated by two imine N atoms and two phenol O atoms from the imine-phenol ligand, in a slightly distorted square-planar coordination. The N1—Cu1—N2, N1—Cu1—O1, O1—Cu1—O2 and O2—Cu1—N2 bond angles are 84.6 (2), 94.1 (2), 87.4 (2) and 93.9 (2)°, respectively. The Cu—N distances [1.936 (4) and 1.946 (4) Å, respectively] are longer than the Cu—O distances [1.887 (4) and 1.882 (3) Å, respectively]. These distances agree with values in other square-planar coordinated copper(II) complexes (Akhtar & Drew, 1982; Labisbal et al., 1994). The planar molecules are stacked in columns along the b axis, with Cu···Cu separations of 3.399 (1) Å. However, this Cu···Cu dimeric interaction is considerably lower than the value of 3.613 (3) Å observed in N,N'-propylenebis[(2-hydroxy-1-naphthyl)methaniminato]copper(II) (Akhtar et al., 1982).

No unusual bond distances are observed in the salen derivative of (I); average distances and angles include C—C = 120.3 (3)?? [1.394?(?)], C—O = 1.294 (6), C—N = 1.420 (6) and C=N = 1.292?(7) Å, and phenyl C—C—C = 120.0?(3)°. These values are within the expected ranges for coordinated salen derivatives (Riley et al., 1986; Zamian et al., 1995; Schmidt et al., 1996).

S2. Experimental

Suitable crystals were obtained directly from the synthesis of compound (I). The preparation of the bis-N,N'-p-chloro?salicylideneamine-1,2-diaminobenzene followed the process described recently by Elerman, Elmali, Kabak & Svoboda (1998). Please clarify - the connection between this ref and the present work is not clear. Two solutions, bis-N,N'-p-chloro?salicylideneamine-1,2-diaminobenzene (0.5 mmol) in tetrahydrofuran (50 ml) and [Cu(O₂CCH₃)₂]·4H₂O in methanol (30 ml), were prepared and heated to boiling point. The mixture of the two solutions was then refluxed for 4 h. Crystals of (I) were obtained after 2 d.

S3. Refinement

H atoms bonded to C were refined using a riding model and H-atom displacement parameters were restricted to be 1.2U_eq of the parent atom.

Computing details

Data collection: CAD-4 Diffractometer Control Software (Enraf-Nonius, 1993); cell refinement: CAD-4 Diffractometer Control Software; data reduction: REDU4 (Stoe & Cie, 1991); program(s) used to solve structure: SHELXS86 (Sheldrick, 1990); program(s) used to refine structure: SHELXL93 (Sheldrick, 1993); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: SHELXL93.

Figures

Fig. 1. The molecular structure and atom-labelling scheme of (I). Displacement ellipsoids are plotted at the 50% probability level (ORTEP-3 for Windows; Farrugia, 1997).

[N,N'-Bis(5-bromosalicylidene)-o-phenylenediamine]copper(II)

Crystal data

[Cu(C20H12Br2N2O2)]	F(000) = 1044
Mr = 535.70	Dx = 2.039 Mg m^−3
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71093 Å
a = 12.114 (1) Å	Cell parameters from 25 reflections
b = 8.095 (2) Å	θ = 2.3–10.3°
c = 18.538 (6) Å	µ = 5.85 mm^−1
β = 106.30 (1)°	T = 299 K
V = 1744.8 (7) Å^3	Prism, brown
Z = 4	0.30 × 0.13 × 0.05 mm

Data collection

Enraf-Nonius CAD-4 diffractometer	1973 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.045
Graphite monochromator	θmax = 26.0°, θmin = 1.8°
θ/2θ scans	h = −14→9
Absorption correction: empirical (using intensity measurements) via ψ scans (north et al., 1968) ?	k = −9→0
Tmin = 0.421, Tmax = 0.752	l = −22→22
6199 measured reflections	3 standard reflections every 120 min
3399 independent reflections	intensity decay: −3.1%

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.040	H atoms treated by a mixture of independent and constrained refinement
wR(F^2) = 0.115	Calculated w = 1/[σ^2(Fo^2) + (0.0621P)^2] where P = (Fo^2 + 2Fc^2)/3
S = 1.02	(Δ/σ)max < 0.001
3399 reflections	Δρmax = 0.81 e Å^−3
245 parameters	Δρmin = −1.08 e Å^−3
0 restraints	Extinction correction: SHELXL93 (Sheldrick, 1993), Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.0001 (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 on F² for ALL reflections except for 0 with very negative F² or flagged by the user for potential systematic errors. Weighted R-factors wR and all goodnesses of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The observed criterion of F² > σ(F²) is used only for calculating _R_factor_obs 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.

The structure was solved by direct-phase determination. The parameters of the complete structure could be refined by full-matrix least-squares methods including anisotropic displacement parameters for non-H atoms.

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

	x	y	z	Uiso*/Ueq
C1	0.7592 (5)	0.5058 (7)	0.0268 (3)	0.0373 (13)
C2	0.8578 (5)	0.5846 (7)	0.0729 (3)	0.0422 (14)
H2	0.8742 (5)	0.5731 (7)	0.1248 (3)	0.051*
C3	0.9302 (5)	0.6768 (7)	0.0446 (3)	0.0460 (15)
H3	0.9950 (5)	0.7253 (7)	0.0768 (3)	0.055*
C4	0.9065 (5)	0.6978 (7)	−0.0326 (3)	0.0392 (13)
C5	0.8127 (5)	0.6259 (7)	−0.0801 (3)	0.0377 (13)
H5	0.7985 (5)	0.6397 (7)	−0.1317 (3)	0.045*
C6	0.7367 (4)	0.5307 (6)	−0.0519 (3)	0.0311 (12)
C7	0.6382 (4)	0.4638 (6)	−0.1063 (3)	0.0339 (12)
H7	0.6304 (4)	0.4864 (6)	−0.1567 (3)	0.041*
C8	0.4641 (4)	0.3107 (6)	−0.1476 (3)	0.0321 (12)
C9	0.4449 (5)	0.3338 (7)	−0.2248 (3)	0.0403 (13)
H9	0.4959 (5)	0.3972 (7)	−0.2424 (3)	0.048*
C10	0.3511 (5)	0.2632 (8)	−0.2748 (3)	0.0432 (15)
H10	0.3385 (5)	0.2810 (8)	−0.3261 (3)	0.052*
C11	0.2758 (5)	0.1672 (8)	−0.2503 (3)	0.046 (2)
H11	0.2128 (5)	0.1194 (8)	−0.2847 (3)	0.055*
C12	0.2945 (4)	0.1416 (7)	−0.1733 (3)	0.0397 (14)
H12	0.2434 (4)	0.0766 (7)	−0.1565 (3)	0.048*
C13	0.3882 (4)	0.2119 (6)	−0.1216 (3)	0.0327 (12)
C14	0.3562 (4)	0.1027 (6)	−0.0105 (3)	0.0323 (12)
H14	0.2912 (4)	0.0518 (6)	−0.0415 (3)	0.039*
C15	0.3794 (4)	0.0761 (6)	0.0686 (3)	0.0297 (12)
C16	0.3004 (4)	−0.0206 (7)	0.0933 (3)	0.0346 (12)
H16	0.2375 (4)	−0.0668 (7)	0.0583 (3)	0.042*
C17	0.3151 (4)	−0.0473 (7)	0.1680 (3)	0.0351 (12)
C18	0.4091 (4)	0.0204 (7)	0.2207 (3)	0.0372 (13)
H18	0.4200 (4)	−0.0006 (7)	0.2715 (3)	0.045*
C19	0.4848 (5)	0.1165 (7)	0.1986 (3)	0.0387 (13)
H19	0.5456 (5)	0.1635 (7)	0.2350 (3)	0.046*
C20	0.4747 (4)	0.1483 (7)	0.1222 (3)	0.0341 (12)
N1	0.5592 (4)	0.3742 (5)	−0.0906 (2)	0.0325 (10)
N2	0.4171 (3)	0.1905 (5)	−0.0427 (2)	0.0303 (10)
O1	0.6948 (3)	0.4196 (5)	0.0575 (2)	0.0451 (10)
O2	0.5531 (3)	0.2365 (5)	0.1052 (2)	0.0416 (10)
Br1	1.00562 (6)	0.82823 (9)	−0.07253 (4)	0.0585 (2)
Br2	0.21163 (5)	−0.18366 (9)	0.20131 (3)	0.0539 (2)
Cu1	0.55747 (5)	0.30701 (8)	0.00928 (3)	0.0317 (2)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C1	0.037 (3)	0.040 (3)	0.032 (3)	0.001 (3)	0.004 (2)	0.000 (2)
C2	0.036 (3)	0.058 (4)	0.025 (3)	−0.006 (3)	−0.004 (2)	−0.004 (3)
C3	0.041 (3)	0.051 (4)	0.038 (3)	−0.007 (3)	−0.002 (3)	−0.003 (3)
C4	0.037 (3)	0.036 (3)	0.045 (3)	−0.003 (3)	0.013 (3)	−0.003 (3)
C5	0.044 (3)	0.040 (3)	0.027 (3)	0.002 (3)	0.008 (2)	−0.005 (2)
C6	0.030 (3)	0.034 (3)	0.026 (2)	0.000 (2)	0.002 (2)	0.001 (2)
C7	0.041 (3)	0.036 (3)	0.022 (2)	0.004 (3)	0.004 (2)	0.001 (2)
C8	0.027 (3)	0.037 (3)	0.026 (2)	0.005 (3)	−0.002 (2)	−0.006 (2)
C9	0.043 (3)	0.048 (4)	0.025 (2)	−0.001 (3)	0.001 (2)	0.002 (3)
C10	0.039 (3)	0.065 (4)	0.023 (2)	0.004 (3)	0.003 (2)	0.000 (3)
C11	0.038 (3)	0.061 (4)	0.029 (3)	0.002 (3)	−0.006 (2)	−0.006 (3)
C12	0.030 (3)	0.057 (4)	0.025 (3)	0.001 (3)	−0.005 (2)	−0.001 (3)
C13	0.033 (3)	0.036 (3)	0.025 (2)	0.005 (3)	0.002 (2)	−0.001 (2)
C14	0.026 (3)	0.039 (3)	0.026 (2)	0.001 (2)	−0.001 (2)	−0.002 (2)
C15	0.027 (3)	0.036 (3)	0.023 (2)	0.007 (2)	0.001 (2)	0.003 (2)
C16	0.029 (3)	0.041 (3)	0.028 (3)	0.003 (3)	−0.002 (2)	0.000 (2)
C17	0.033 (3)	0.041 (3)	0.031 (3)	0.001 (3)	0.008 (2)	0.003 (3)
C18	0.038 (3)	0.048 (4)	0.022 (2)	0.004 (3)	0.002 (2)	−0.001 (2)
C19	0.035 (3)	0.049 (3)	0.028 (3)	0.000 (3)	0.002 (2)	0.000 (3)
C20	0.030 (3)	0.042 (3)	0.027 (2)	0.003 (3)	0.002 (2)	0.000 (2)
N1	0.036 (3)	0.033 (2)	0.022 (2)	0.005 (2)	−0.002 (2)	0.001 (2)
N2	0.027 (2)	0.037 (3)	0.021 (2)	0.001 (2)	−0.004 (2)	0.002 (2)
O1	0.042 (2)	0.060 (3)	0.024 (2)	−0.019 (2)	−0.004 (2)	0.003 (2)
O2	0.041 (2)	0.057 (3)	0.020 (2)	−0.010 (2)	−0.004 (2)	0.004 (2)
Br1	0.0532 (4)	0.0687 (5)	0.0571 (4)	−0.0174 (4)	0.0214 (3)	−0.0037 (4)
Br2	0.0545 (4)	0.0694 (5)	0.0359 (3)	−0.0194 (4)	0.0096 (3)	0.0030 (3)
Cu1	0.0321 (4)	0.0376 (4)	0.0199 (3)	−0.0003 (3)	−0.0020 (2)	0.0006 (3)

Geometric parameters (Å, º)

C1—O1	1.291 (6)	C11—H11	0.93
C1—C2	1.411 (7)	C12—C13	1.385 (7)
C1—C6	1.423 (7)	C12—H12	0.93
C2—C3	1.364 (8)	C13—N2	1.416 (6)
C2—H2	0.93	C14—N2	1.286 (6)
C3—C4	1.388 (8)	C14—C15	1.430 (6)
C3—H3	0.93	C14—H14	0.93
C4—C5	1.358 (8)	C15—C16	1.409 (7)
C4—Br1	1.898 (5)	C15—C20	1.421 (7)
C5—C6	1.409 (7)	C16—C17	1.362 (7)
C5—H5	0.93	C16—H16	0.93
C6—C7	1.434 (7)	C17—C18	1.388 (7)
C7—N1	1.298 (6)	C17—Br2	1.899 (5)
C7—H7	0.93	C18—C19	1.351 (7)
C8—C9	1.396 (7)	C18—H18	0.93
C8—C13	1.401 (7)	C19—C20	1.410 (7)
C8—N1	1.423 (6)	C19—H19	0.93
C9—C10	1.374 (8)	C20—O2	1.296 (6)
C9—H9	0.93	N1—Cu1	1.936 (4)
C10—C11	1.369 (8)	N2—Cu1	1.946 (4)
C10—H10	0.93	O1—Cu1	1.887 (4)
C11—C12	1.398 (7)	O2—Cu1	1.882 (3)
O1—C1—C2	119.4 (5)	C12—C13—N2	125.5 (5)
O1—C1—C6	124.2 (5)	C8—C13—N2	115.4 (4)
C2—C1—C6	116.3 (5)	N2—C14—C15	125.9 (5)
C3—C2—C1	122.7 (5)	N2—C14—H14	117.1 (3)
C3—C2—H2	118.7 (3)	C15—C14—H14	117.1 (3)
C1—C2—H2	118.7 (3)	C16—C15—C20	119.6 (4)
C2—C3—C4	119.7 (5)	C16—C15—C14	117.5 (4)
C2—C3—H3	120.2 (3)	C20—C15—C14	122.8 (5)
C4—C3—H3	120.2 (3)	C17—C16—C15	120.8 (5)
C5—C4—C3	120.6 (5)	C17—C16—H16	119.6 (3)
C5—C4—Br1	119.4 (4)	C15—C16—H16	119.6 (3)
C3—C4—Br1	120.0 (4)	C16—C17—C18	120.0 (5)
C4—C5—C6	120.6 (5)	C16—C17—Br2	120.9 (4)
C4—C5—H5	119.7 (3)	C18—C17—Br2	119.1 (4)
C6—C5—H5	119.7 (3)	C19—C18—C17	120.4 (5)
C5—C6—C1	120.0 (5)	C19—C18—H18	119.8 (3)
C5—C6—C7	116.5 (4)	C17—C18—H18	119.8 (3)
C1—C6—C7	123.4 (5)	C18—C19—C20	122.3 (5)
N1—C7—C6	125.0 (4)	C18—C19—H19	118.8 (3)
N1—C7—H7	117.5 (3)	C20—C19—H19	118.8 (3)
C6—C7—H7	117.5 (3)	O2—C20—C19	118.8 (5)
C9—C8—C13	119.5 (4)	O2—C20—C15	124.3 (4)
C9—C8—N1	125.4 (5)	C19—C20—C15	116.8 (5)
C13—C8—N1	115.1 (4)	C7—N1—C8	122.0 (4)
C10—C9—C8	120.3 (5)	C7—N1—Cu1	125.4 (3)
C10—C9—H9	119.8 (3)	C8—N1—Cu1	112.6 (3)
C8—C9—H9	119.8 (3)	C14—N2—C13	122.6 (4)
C11—C10—C9	120.9 (5)	C14—N2—Cu1	125.0 (3)
C11—C10—H10	119.5 (3)	C13—N2—Cu1	112.4 (3)
C9—C10—H10	119.5 (3)	C1—O1—Cu1	127.9 (3)
C10—C11—C12	119.4 (5)	C20—O2—Cu1	127.9 (3)
C10—C11—H11	120.3 (3)	O2—Cu1—O1	87.4 (2)
C12—C11—H11	120.3 (3)	O2—Cu1—N1	178.4 (2)
C13—C12—C11	120.8 (5)	O1—Cu1—N1	94.1 (2)
C13—C12—H12	119.6 (3)	O2—Cu1—N2	93.9 (2)
C11—C12—H12	119.6 (3)	O1—Cu1—N2	178.5 (2)
C12—C13—C8	119.1 (4)	N1—Cu1—N2	84.6 (2)
O1—C1—C2—C3	179.6 (5)	C14—C15—C20—O2	−4.1 (8)
C6—C1—C2—C3	−1.5 (8)	C16—C15—C20—C19	0.5 (7)
C1—C2—C3—C4	1.0 (9)	C14—C15—C20—C19	177.7 (5)
C2—C3—C4—C5	−0.7 (9)	C6—C7—N1—C8	−179.5 (5)
C2—C3—C4—Br1	179.2 (4)	C6—C7—N1—Cu1	−1.2 (8)
C3—C4—C5—C6	1.0 (9)	C9—C8—N1—C7	0.8 (8)
Br1—C4—C5—C6	−179.0 (4)	C13—C8—N1—C7	178.0 (5)
C4—C5—C6—C1	−1.5 (8)	C9—C8—N1—Cu1	−177.6 (4)
C4—C5—C6—C7	178.2 (5)	C13—C8—N1—Cu1	−0.4 (5)
O1—C1—C6—C5	−179.5 (5)	C15—C14—N2—C13	−179.6 (5)
C2—C1—C6—C5	1.7 (8)	C15—C14—N2—Cu1	0.7 (8)
O1—C1—C6—C7	0.8 (9)	C12—C13—N2—C14	−0.9 (8)
C2—C1—C6—C7	−178.0 (5)	C8—C13—N2—C14	−179.7 (5)
C5—C6—C7—N1	−179.7 (5)	C12—C13—N2—Cu1	178.8 (4)
C1—C6—C7—N1	0.0 (8)	C8—C13—N2—Cu1	0.0 (6)
C13—C8—C9—C10	1.4 (8)	C2—C1—O1—Cu1	178.4 (4)
N1—C8—C9—C10	178.5 (5)	C6—C1—O1—Cu1	−0.3 (8)
C8—C9—C10—C11	−1.1 (9)	C19—C20—O2—Cu1	−176.5 (4)
C9—C10—C11—C12	0.4 (9)	C15—C20—O2—Cu1	5.3 (8)
C10—C11—C12—C13	−0.2 (9)	C20—O2—Cu1—O1	177.6 (5)
C11—C12—C13—C8	0.5 (8)	C20—O2—Cu1—N1	−25 (7)
C11—C12—C13—N2	−178.2 (5)	C20—O2—Cu1—N2	−3.1 (5)
C9—C8—C13—C12	−1.2 (8)	C1—O1—Cu1—O2	178.8 (5)
N1—C8—C13—C12	−178.5 (5)	C1—O1—Cu1—N1	−0.6 (5)
C9—C8—C13—N2	177.7 (5)	C1—O1—Cu1—N2	25 (7)
N1—C8—C13—N2	0.3 (6)	C7—N1—Cu1—O2	−156 (6)
N2—C14—C15—C16	178.2 (5)	C8—N1—Cu1—O2	22 (7)
N2—C14—C15—C20	0.9 (8)	C7—N1—Cu1—O1	1.3 (5)
C20—C15—C16—C17	−0.8 (8)	C8—N1—Cu1—O1	179.7 (3)
C14—C15—C16—C17	−178.2 (5)	C7—N1—Cu1—N2	−178.1 (5)
C15—C16—C17—C18	−0.3 (8)	C8—N1—Cu1—N2	0.4 (3)
C15—C16—C17—Br2	−177.9 (4)	C14—N2—Cu1—O2	0.1 (4)
C16—C17—C18—C19	1.8 (8)	C13—N2—Cu1—O2	−179.6 (3)
Br2—C17—C18—C19	179.4 (4)	C14—N2—Cu1—O1	154 (7)
C17—C18—C19—C20	−2.1 (8)	C13—N2—Cu1—O1	−25 (7)
C18—C19—C20—O2	−177.3 (5)	C14—N2—Cu1—N1	179.5 (4)
C18—C19—C20—C15	1.0 (8)	C13—N2—Cu1—N1	−0.2 (3)
C16—C15—C20—O2	178.7 (5)