supplementary materials


gg2104 scheme

Acta Cryst. (2012). E68, m1373    [ doi:10.1107/S1600536812042420 ]

Bis[4-(4-bromophenylimino-[kappa]N)pent-2-en-2-olato-[kappa]O]copper(II)

P. S. E. Bungu, M. Schutte and G. Steyl

Abstract top

In the title compound, [Cu(C11H11BrNO)2], the CuII atom is in a distorted square-planar geometry, with the two bidentate ketimine ligands positioned in a trans geometry. Two intermolecular C-H...O hydrogen bond interactions are present which link the molecules in a zigzag manner along the a axis. The molecules pack in layers along the diagonal of the bc plane.

Comment top

Beta-diketimine ligands are a versatile class of molecules that display an impressive range of diverse applications in coordination chemistry (Bourget-Merle et al. 2002). The success of these ligands (Stender et al. 2001) is presumably due to the scope for suitable tuning of the steric and electronic properties and due to its easy synthetic accessibility to coordinate to early transition metals (Hsu et al. 2004). Here we report the crystal structure of the Cu(II) complex containing a ketiminate ligand, [OC(Me)CHC(Me)NH (Ar)] where Ar = 4-bromophenyl. Structural analysis shows that the title compound crystallized as black cuboidal crystals in the monoclinic space group, P21/c, with one molecule in the asymmetric unit and with approximately non-crystallographic C2 symmetry. The complex shows a four coordinate environment around the copper atom where two ketimine ligands act as bidentate N,O-chelators and lie in the trans conformation to create two six-membered chelate rings (Cu—O—C—C—C—N). Similar structures are reported in literature and the bond distances and angles of this structure compare well to those in literature (Bryndin et al. 2008, Hsu et al. 2007, John et al.2007).

In this structure, the dihedral angles of the two coordinate planes, O1—Cu1—N2 and O2—Cu1—N1, are 24.1 (2)° and 21.1 (2)° respectively. Also, the Cu—O and Cu—N bond distances are all marginally unequal, hence suggesting distorted square-planer geometry around the Cu(II) center. In Figure 1, the Cu1—O1 and Cu1—O2 bond lengths are 1.911 (2) Å and 1.909 (2) Å while the Cu1—N1 and Cu1—N2 bond lengths were 1.958 (2) Å and 1.948 (2) Å respectively. The presence of the 4-bromophenyl group has caused a slight decrease in the Cu—N bond distances when compared to the respective analogues of copper ketimine complexes by Bryndin et al. 2008 (Cu—N = 1.960 (2) Å and 1.965 (2) Å) and Hsu et al. 2007 (Cu—N = 1.974 (1) Å and 1.974 (1) Å). Owing to the presence of the distortion, the four N—Cu—O bond angles are marginally different from the ideal value of a square planer geometry of 90° and are reported as 94.70 (8)° (N1—Cu1—O1) and 94.80 (8)° (N2—Cu1—O2). The diagonal angles, N1—Cu1—N2 and O1—Cu1—O2, are reported as 148.20 (9)° and 145.59 (8)° which also differ substantially from the ideal angle of 180° and are comparable to results reported by Bryndin et al. 2008 and Hsu et al. 2007.These differences were made apparent when comparing the results to the structures by John et al. 2007, where phenoxy-ketimine ligands were used as bidentate ligands for both Cu(II) and Ni(II), in which almost a perfect square planar geometry was obeserved. The stabilization is dominated by two intermolecular C—H···O hydrogen bonds (C115—H115···O1) 2.47 Å and C215—H215···O1 = 2.54 Å) (Table 2). ππ stacking is observed between neighbouring molecules with a centroid-to-hydrogen bond distance of 3.7236 (9) Å. Five pi-interactions (centroid-to-hydrogen) are observed with a distance varying between 3.527 (1) Å and 3.746 (1) Å. The hydrogen and pi-interactions as well as the pi–pi stacking is illustrated in Figure 2. The molecules pack in alternating layers along the c axis possibly due to the hydrogen- and π interactions.

Related literature top

For similar structures, see: Bourget-Merle et al. (2002); Bryndin et al. (2008) Hsu et al. (2004, 2007) John et al. (2007); Stender et al. (2001).

Experimental top

Copper nitrate Cu(NO3)2 (100 mg, 0.044 mmol) was dissolved in MeOH and refluxed with 2 equivalent of C11H11BrONH (237 mg, 0.94 mmol) for 2 h. The product was filtered at ambient temperature and dried in air. Black crystals were grown overnight from chloroform/ether (1:1, 10 ml) mixture. (yield: 169 mg, 0.29 mmol and 67%).

Refinement top

All aromatic and methine H atoms were positioned geometrically and allowed to ride on their parent atoms, with Uiso(H) = 1.2Ueq(C) of the parent atom with the C—H distance of 0.95 Å. The methyl H atoms were placed in geometrically idealized positions and contrained to ride the parent atom with Uiso(H)= 1.5Ueq(C) and at a distance of) 0.98 Å.

Computing details top

Data collection: APEX2 (Bruker, 2008); cell refinement: SAINT-Plus (Bruker, 2008); data reduction: SAINT-Plus (Bruker, 2008); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg & Putz, 2005); software used to prepare material for publication: WinGX (Farrugia, 1999).

Figures top
[Figure 1] Fig. 1. Representation of the title compound, showing the numbering scheme and displacement ellipsoids (50% probability).
[Figure 2] Fig. 2. Observed hydrogen interactions (green dashed line), π-π stacking (yellow dashed lines) and π-interactions(red dashed lines) in the crystal structure (hydrogen atoms omitted for clarity).
Bis[4-(4-bromophenylimino-κN)pent-2-en-2-olato-κO]copper(II) top
Crystal data top
[Cu(C11H11BrNO)2]F(000) = 1132
Mr = 569.77Dx = 1.702 Mg m3
Dm = 1.702 Mg m3
Dm measured by not measured
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybcCell parameters from 4022 reflections
a = 12.493 (3) Åθ = 2.6–28.3°
b = 11.559 (4) ŵ = 4.60 mm1
c = 15.415 (4) ÅT = 100 K
β = 92.306 (14)°Cuboid, black
V = 2224.2 (11) Å30.64 × 0.25 × 0.15 mm
Z = 4
Data collection top
Bruker APEXII CCD
diffractometer
4291 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.034
φ and ω scansθmax = 28.4°, θmin = 3.5°
Absorption correction: multi-scan
(SADABS; Bruker, 2008)
h = 1616
Tmin = 0.262, Tmax = 0.502k = 1515
13700 measured reflectionsl = 2020
5558 independent reflections
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.034Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.082H-atom parameters constrained
S = 1.00 w = 1/[σ2(Fo2) + (0.0411P)2]
where P = (Fo2 + 2Fc2)/3
5558 reflections(Δ/σ)max = 0.001
266 parametersΔρmax = 0.65 e Å3
0 restraintsΔρmin = 0.89 e Å3
Crystal data top
[Cu(C11H11BrNO)2]V = 2224.2 (11) Å3
Mr = 569.77Z = 4
Monoclinic, P21/cMo Kα radiation
a = 12.493 (3) ŵ = 4.60 mm1
b = 11.559 (4) ÅT = 100 K
c = 15.415 (4) Å0.64 × 0.25 × 0.15 mm
β = 92.306 (14)°
Data collection top
Bruker APEXII CCD
diffractometer
5558 independent reflections
Absorption correction: multi-scan
(SADABS; Bruker, 2008)
4291 reflections with I > 2σ(I)
Tmin = 0.262, Tmax = 0.502Rint = 0.034
13700 measured reflectionsθmax = 28.4°
Refinement top
R[F2 > 2σ(F2)] = 0.034H-atom parameters constrained
wR(F2) = 0.082Δρmax = 0.65 e Å3
S = 1.00Δρmin = 0.89 e Å3
5558 reflectionsAbsolute structure: ?
266 parametersFlack parameter: ?
0 restraintsRogers parameter: ?
Special details top

Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'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 > 2σ(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 (Å2) top
xyzUiso*/Ueq
C110.8322 (2)0.8020 (3)0.36239 (16)0.0212 (6)
H11A0.90550.8130.38590.032*
H11B0.80110.87720.34620.032*
H11C0.83310.75220.3110.032*
C120.76552 (18)0.7460 (2)0.43032 (15)0.0149 (5)
C130.66749 (18)0.7913 (2)0.44918 (15)0.0175 (5)
H130.64610.85930.41850.021*
C140.59432 (18)0.7476 (2)0.50978 (16)0.0167 (5)
C150.48851 (19)0.8093 (3)0.51301 (18)0.0243 (6)
H15A0.43660.77270.47230.036*
H15B0.49780.89060.49690.036*
H15C0.46220.80480.5720.036*
C210.6951 (2)0.2875 (3)0.71567 (18)0.0256 (6)
H21A0.62280.31330.72870.038*
H21B0.73180.2590.76890.038*
H21C0.69050.22520.67250.038*
C220.7570 (2)0.3872 (2)0.68015 (17)0.0179 (5)
C230.8587 (2)0.4111 (2)0.71350 (17)0.0202 (6)
H230.88470.36430.76040.024*
C240.92856 (19)0.4990 (2)0.68462 (16)0.0177 (5)
C251.0380 (2)0.5049 (3)0.73005 (18)0.0294 (7)
H25A1.08980.4630.69590.044*
H25B1.03490.46970.78770.044*
H25C1.06010.5860.7360.044*
C1110.54017 (18)0.6141 (2)0.61825 (15)0.0129 (5)
C1120.56717 (19)0.6087 (2)0.70644 (16)0.0174 (5)
H1120.63160.64370.72830.021*
C1130.50063 (19)0.5526 (2)0.76277 (16)0.0177 (5)
H1130.51910.54860.82310.021*
C1140.40750 (18)0.5026 (2)0.73001 (15)0.0150 (5)
C1150.37692 (18)0.5094 (2)0.64311 (15)0.0151 (5)
H1150.31130.47640.6220.018*
C1160.44426 (18)0.5657 (2)0.58699 (15)0.0149 (5)
H1160.42460.5710.52690.018*
C2110.97726 (17)0.6546 (2)0.59351 (14)0.0127 (5)
C2120.95377 (18)0.7715 (2)0.59664 (15)0.0150 (5)
H2120.8890.79590.62130.018*
C2131.02240 (18)0.8536 (2)0.56474 (15)0.0157 (5)
H2131.00560.93370.56720.019*
C2141.11628 (18)0.8159 (2)0.52909 (15)0.0168 (5)
C2151.14142 (19)0.6996 (2)0.52416 (16)0.0187 (6)
H2151.20620.67560.49940.022*
C2161.07162 (18)0.6190 (2)0.55558 (16)0.0159 (5)
H2161.08770.53890.55150.019*
N10.61776 (14)0.65887 (19)0.56113 (12)0.0133 (4)
N20.90082 (15)0.57349 (18)0.62280 (13)0.0130 (4)
O10.80748 (12)0.65429 (16)0.46501 (10)0.0152 (4)
O20.70804 (13)0.44317 (15)0.61821 (11)0.0166 (4)
Cu10.75794 (2)0.58295 (3)0.567779 (18)0.01230 (8)
Br10.32073 (2)0.41819 (2)0.806750 (16)0.02103 (8)
Br21.21072 (2)0.92786 (3)0.48364 (2)0.03221 (9)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
C110.0233 (13)0.0226 (16)0.0175 (12)0.0046 (11)0.0012 (10)0.0066 (11)
C120.0180 (11)0.0132 (13)0.0130 (11)0.0037 (10)0.0052 (9)0.0005 (10)
C130.0199 (12)0.0158 (14)0.0164 (12)0.0007 (10)0.0039 (10)0.0069 (11)
C140.0161 (11)0.0154 (14)0.0183 (12)0.0011 (10)0.0050 (9)0.0016 (11)
C150.0200 (13)0.0201 (16)0.0324 (15)0.0052 (11)0.0024 (11)0.0068 (13)
C210.0281 (14)0.0198 (16)0.0287 (15)0.0056 (12)0.0016 (12)0.0103 (13)
C220.0205 (12)0.0140 (14)0.0195 (13)0.0000 (10)0.0036 (10)0.0017 (11)
C230.0240 (13)0.0172 (14)0.0190 (13)0.0008 (11)0.0038 (10)0.0098 (11)
C240.0189 (12)0.0185 (15)0.0156 (12)0.0012 (11)0.0008 (9)0.0026 (11)
C250.0215 (13)0.037 (2)0.0291 (15)0.0055 (13)0.0112 (11)0.0184 (14)
C1110.0132 (11)0.0131 (13)0.0123 (11)0.0010 (9)0.0011 (9)0.0007 (10)
C1120.0162 (12)0.0184 (14)0.0171 (12)0.0017 (10)0.0040 (9)0.0022 (11)
C1130.0192 (12)0.0214 (15)0.0121 (12)0.0018 (11)0.0024 (9)0.0025 (11)
C1140.0136 (11)0.0154 (14)0.0164 (12)0.0025 (10)0.0047 (9)0.0021 (10)
C1150.0120 (10)0.0166 (14)0.0166 (12)0.0004 (10)0.0010 (9)0.0038 (11)
C1160.0142 (11)0.0167 (14)0.0136 (11)0.0012 (10)0.0014 (9)0.0026 (10)
C2110.0107 (10)0.0167 (14)0.0103 (11)0.0009 (10)0.0032 (8)0.0000 (10)
C2120.0139 (11)0.0170 (14)0.0140 (11)0.0015 (10)0.0010 (9)0.0030 (10)
C2130.0176 (11)0.0121 (13)0.0172 (12)0.0015 (10)0.0013 (9)0.0012 (10)
C2140.0134 (11)0.0190 (14)0.0182 (12)0.0029 (10)0.0011 (9)0.0039 (11)
C2150.0144 (11)0.0210 (15)0.0210 (13)0.0015 (10)0.0049 (10)0.0030 (11)
C2160.0167 (12)0.0120 (13)0.0188 (12)0.0023 (10)0.0006 (10)0.0009 (10)
N10.0118 (9)0.0144 (11)0.0133 (10)0.0015 (8)0.0032 (7)0.0014 (9)
N20.0117 (9)0.0126 (11)0.0147 (10)0.0002 (8)0.0004 (7)0.0017 (9)
O10.0176 (8)0.0154 (10)0.0123 (8)0.0008 (7)0.0018 (6)0.0021 (7)
O20.0172 (8)0.0118 (10)0.0210 (9)0.0019 (7)0.0013 (7)0.0044 (7)
Cu10.01157 (14)0.01196 (17)0.01323 (15)0.00026 (11)0.00136 (11)0.00234 (12)
Br10.02047 (14)0.02328 (16)0.01966 (14)0.00309 (11)0.00480 (10)0.00181 (11)
Br20.02029 (14)0.02105 (17)0.0562 (2)0.00094 (12)0.01245 (13)0.01269 (15)
Geometric parameters (Å, º) top
C11—C121.509 (3)C111—C1161.391 (3)
C11—H11A0.98C111—N11.432 (3)
C11—H11B0.98C112—C1131.387 (4)
C11—H11C0.98C112—H1120.95
C12—O11.289 (3)C113—C1141.376 (3)
C12—C131.374 (3)C113—H1130.95
C13—C141.426 (3)C114—C1151.380 (3)
C13—H130.95C114—Br11.905 (2)
C14—N11.321 (3)C115—C1161.392 (3)
C14—C151.505 (3)C115—H1150.95
C15—H15A0.98C116—H1160.95
C15—H15B0.98C211—C2121.385 (4)
C15—H15C0.98C211—C2161.398 (3)
C21—C221.503 (4)C211—N21.424 (3)
C21—H21A0.98C212—C2131.382 (3)
C21—H21B0.98C212—H2120.95
C21—H21C0.98C213—C2141.385 (3)
C22—O21.287 (3)C213—H2130.95
C22—C231.380 (3)C214—C2151.383 (4)
C23—C241.422 (4)C214—Br21.904 (3)
C23—H230.95C215—C2161.377 (4)
C24—N21.320 (3)C215—H2150.95
C24—C251.512 (3)C216—H2160.95
C25—H25A0.98N1—Cu11.958 (2)
C25—H25B0.98N2—Cu11.948 (2)
C25—H25C0.98O1—Cu11.9110 (17)
C111—C1121.389 (3)O2—Cu11.9085 (19)
C12—C11—H11A109.5C113—C112—H112119.8
C12—C11—H11B109.5C111—C112—H112119.8
H11A—C11—H11B109.5C114—C113—C112119.1 (2)
C12—C11—H11C109.5C114—C113—H113120.5
H11A—C11—H11C109.5C112—C113—H113120.5
H11B—C11—H11C109.5C113—C114—C115121.9 (2)
O1—C12—C13125.2 (2)C113—C114—Br1118.74 (18)
O1—C12—C11114.5 (2)C115—C114—Br1119.31 (18)
C13—C12—C11120.3 (2)C114—C115—C116118.6 (2)
C12—C13—C14127.2 (2)C114—C115—H115120.7
C12—C13—H13116.4C116—C115—H115120.7
C14—C13—H13116.4C111—C116—C115120.4 (2)
N1—C14—C13122.4 (2)C111—C116—H116119.8
N1—C14—C15121.5 (2)C115—C116—H116119.8
C13—C14—C15116.2 (2)C212—C211—C216119.0 (2)
C14—C15—H15A109.5C212—C211—N2119.1 (2)
C14—C15—H15B109.5C216—C211—N2121.8 (2)
H15A—C15—H15B109.5C213—C212—C211121.5 (2)
C14—C15—H15C109.5C213—C212—H212119.3
H15A—C15—H15C109.5C211—C212—H212119.3
H15B—C15—H15C109.5C212—C213—C214118.2 (2)
C22—C21—H21A109.5C212—C213—H213120.9
C22—C21—H21B109.5C214—C213—H213120.9
H21A—C21—H21B109.5C215—C214—C213121.7 (2)
C22—C21—H21C109.5C215—C214—Br2119.67 (18)
H21A—C21—H21C109.5C213—C214—Br2118.7 (2)
H21B—C21—H21C109.5C216—C215—C214119.3 (2)
O2—C22—C23125.3 (2)C216—C215—H215120.3
O2—C22—C21114.8 (2)C214—C215—H215120.3
C23—C22—C21119.8 (2)C215—C216—C211120.3 (3)
C22—C23—C24126.5 (2)C215—C216—H216119.8
C22—C23—H23116.8C211—C216—H216119.8
C24—C23—H23116.8C14—N1—C111120.6 (2)
N2—C24—C23123.0 (2)C14—N1—Cu1123.75 (16)
N2—C24—C25120.7 (2)C111—N1—Cu1115.60 (16)
C23—C24—C25116.2 (2)C24—N2—C211119.9 (2)
C24—C25—H25A109.5C24—N2—Cu1124.07 (16)
C24—C25—H25B109.5C211—N2—Cu1116.06 (15)
H25A—C25—H25B109.5C12—O1—Cu1123.98 (15)
C24—C25—H25C109.5C22—O2—Cu1125.06 (16)
H25A—C25—H25C109.5O2—Cu1—O1145.59 (8)
H25B—C25—H25C109.5O2—Cu1—N294.80 (8)
C112—C111—C116119.5 (2)O1—Cu1—N293.64 (8)
C112—C111—N1118.3 (2)O2—Cu1—N195.43 (8)
C116—C111—N1121.8 (2)O1—Cu1—N194.70 (8)
C113—C112—C111120.4 (2)N2—Cu1—N1148.20 (9)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C115—H115···O1i0.952.473.370 (3)157
C215—H215···O2ii0.952.543.378 (3)147
Symmetry codes: (i) x+1, y+1, z+1; (ii) x+2, y+1, z+1.
Selected bond lengths (Å) top
N1—Cu11.958 (2)O1—Cu11.9110 (17)
N2—Cu11.948 (2)O2—Cu11.9085 (19)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C115—H115···O1i0.952.473.370 (3)157.1
C215—H215···O2ii0.952.543.378 (3)146.5
Symmetry codes: (i) x+1, y+1, z+1; (ii) x+2, y+1, z+1.
Acknowledgements top

We would like to thank the crystallographer for the data collection, and the University of the Free State, the Chemistry Department, the NRF, Sasol Ltd and Inkaba YeAfrica for funding.

references
References top

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