metal-organic compounds
Bis(acetylacetonato-κ2O,O′)[copper(II)nickel(II)(0.31/0.69)]: a mixed-metal complex
aDepartment of Chemistry, Quaid-i-Azam University, Islamabad 45320, Pakistan, bDepartment of Chemistry, University of Malaya, 50603 Kuala Lumpur, Malaysia, and cThe School of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, England
*Correspondence e-mail: shahid_chme@yahoo.com
The title complex, [Cu0.31Ni0.69(C5H7O2)2], was isolated from the reaction of bis(N,N-dimethyaminoethanol)copper(II) with bis(acetylacetonato)nickel(II), which yielded crystals with mixed sites at the central metal position; the refined copper–nickel occupancy ratio is 0.31 (4):0.69 (4). Two acetylacetonate ligands, related by a centre of symmetry, are coordinated to the central metal atom in a square-planar configuration while the methyne C atoms of the acetylacetonate ligands, ca 3.02 Å away, are orthogonal to this plane at the metal site.
Related literature
For heterobimetallic complexes of copper and nickel, see: Hamid et al. (2006). For disorder in metal sites, see: Werndrup & Kessler (2001). For applications of mixed-metal ceramic oxides, see: Auciello & Ramesh(1996) and references therein. For mixed copper/nickel oxide catalysts, see: Kessler et al. (2001). For the synthesis of Cu(dmae)2 (dmae = N,N-dimethylaminoethanolato), see: Johnson et al. (2001). For the of Cu(acac)2 (acac = acetylacetonato), see: LeBrun et al. (1986). For the of Ni(acac)2·2H2O, see: Zhou et al. (2001). For the O—Cu/Ni—O chelate bite angle in related complexes, see: Aruffo et al. (1983).
Experimental
Crystal data
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Data collection: SMART (Bruker, 2007); cell SAINT (Bruker, 2007); data reduction: SAINT; program(s) used to solve structure: SIR2004 (Burla et al., 2005); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL.
Supporting information
https://doi.org/10.1107/S160053681002756X/su2192sup1.cif
contains datablocks I, global. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S160053681002756X/su2192Isup2.hkl
Bis(N,N-dimethylaminoethanolatoκ2 O, N) copper(II) (0.5 g, 2.1 mmol) and bis(acetylacetonato κ2 O, O') nickel(II) (0.54 g, 2.1 mmol) were reacted in 20 ml toluene as a solvent. After stirring for two hours, the solution was cannula filtered to remove unreacted reagents. Slow evaporation of the filtrate gave block-like blue crystals, suitable for single-crystal X-ray analysis, after two weeks.
The H-atoms were included in calculated positions, with C—H = 0.95(CH), 0.99(CH2) & 0.98(CH3) Å, with Uiso(H) = k × Ueq(C), where k = 1.5 for CH3 H-atoms and 1.2 for all other H-atoms.
The occupancy of the metal site was examined under three assumptions: All Ni gave R1(>4sig)= 0.0227, R1(all)= 0.0243; All Cu gave R1(>4sig)= 0.0236, R1(all)= 0.0252. Variable Ni:Cu ratio [which converged to 69 (4):31 (4)] gave R1(>4sig)= 0.0221, R1(all)= 0.0238. Elemental analysis of the Cu/Ni with a ICP-OES Fisons Horizon Spectrometer has: ratio Cu:Ni (31:69); Cu calulated 7.62%: found 7.86%; Ni calculated 15.68%: found 15.23%. The agreement is surprisingly good considering that Cu and Ni differ by only one electron.
Heterobimetallic complexes of copper and nickel have already been reported as precursors for chemical vapor deposition of ceramic material thin films (Hamid et al., 2006). Mixed metal ceramic oxides have multiple compositions and crystal structures, which results in a diversity of properties leading to a vast variety of potential applications (Auciello et al., 1996, and references therein). For example, a mixed copper/nickel oxide catalyst was deposited on a zeolite support and was shown to have extremely high activity towards methanol oxidation (Kessler et al., 2001).
The title complex was synthesized by the reaction of Cu (dmae)2 (dmae = N,N-dimethylaminoethanolato) (Johnson et al., 2001) with Ni(acac)2.2H2O (acac = acetylacetonato) in toluene. In contrast to the formation of the oligomeric bimetallic complex (Hamid et al., 2006), the title compound crystallized out with the central position partially occupied by Cu and partially by Ni, with a refined Cu:Ni occupancy ratio of 0.31 (4):0.69 (4). A similar type of disorder in the metal site was observed previously in Ni(Ni0.25Cu0.75)2(µ3-OH)(µ-OAc)2(η1-OAc)2(µ,η2–ORN)2 (η2-RNOH)][RN–OH=(CH3)2N(CH2)(CHOH)CH3)] (Werndrup et al., 2001), where the two metal sites were occupied by 75% Cu and 25% Ni. The distribution of two metals at the central position in the title complex is random which means some of the molecules would have each of the two Cu and Ni atoms, or in other words if we consider it to be systematic, in every molecule the position will be occupied by exactly 0.31 Cu and 0.69 Ni atoms.
The molecular structure of the title complex is shown in Figure 1. The geometry of the title complex is square planer, similar to that of Cu(acac)2 (LeBrun et al., 1986) where two ligands coordinate to the metal atom in the same plane, while in the nickel(II) complex, Ni(acac)2 (Zhou et al., 2001), which crystallized with two coordinated water molecules, the metal has an octahedral coordination sphere. The metal to oxygen (O1, O2) bond distances [1.9196 (10) and 1.9225 (10) Å] are slightly longer than those in Cu(acac)2 [1.914 (4), 1.914 (4)Å] but shorter than the average value found in Ni(acac)2 [2.0147Å]. The O—Cu/Ni—O chelate bite angle is 93.72 (4)° which is comparable to that found in Cu(acac)2 [93.2 (2)°] and other complexes of this type (Aruffo et al., 1983). The chelate bite angles are of course larger than those in the octahedral nickel(II) complex mentioned above [91.65 (8)°, 89.99 (8)°].
For heterobimetallic complexes of copper and nickel, see: Hamid et al. (2006). For disorder in metal sites, see: Werndrup et al. (2001). For applications of mixed-metal ceramic oxides, see: Auciello et al. (1996) and references therein. For mixed copper/nickel oxide catalysts, see: Kessler et al. (2001). For the synthesis of Cu(dmae)2, see: Johnson et al. (2001). For the
of Cu(acac)2 (acac = acetylacetonato), see: LeBrun et al. (1986). For the of Ni(acac)2.2H2O, see: Zhou et al. (2001). For the O—Cu/Ni—O chelate bite angle in related complexes, see: Aruffo et al. (1983).Data collection: SMART (Bruker, 2007); cell
SAINT (Bruker, 2007); data reduction: SAINT (Bruker, 2007); program(s) used to solve structure: SIR2004 (Burla et al., 2005); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).Fig. 1. View of the molecular structure of the title molecule with displacement ellipsoids drawn at the 50% probability level. |
[Cu0.31Ni0.69(C5H7O2)2] | F(000) = 269 |
Mr = 258.40 | Dx = 1.602 Mg m−3 |
Monoclinic, P21/n | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2yn | Cell parameters from 2222 reflections |
a = 10.265 (1) Å | θ = 2.6–28.2° |
b = 4.6300 (5) Å | µ = 1.87 mm−1 |
c = 11.2830 (11) Å | T = 100 K |
β = 92.431 (2)° | Block, blue |
V = 535.76 (9) Å3 | 0.45 × 0.45 × 0.20 mm |
Z = 2 |
Bruker SMART CCD area-detector diffractometer | 1242 independent reflections |
Radiation source: fine-focus sealed tube | 1159 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.013 |
phi and ω scans | θmax = 28.2°, θmin = 2.6° |
Absorption correction: multi-scan (SADABS; Sheldrick, 2008) | h = −9→13 |
Tmin = 0.487, Tmax = 0.706 | k = −6→5 |
3086 measured reflections | l = −13→14 |
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)] = 0.022 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.059 | H-atom parameters constrained |
S = 1.07 | w = 1/[σ2(Fo2) + (0.0305P)2 + 0.3448P] where P = (Fo2 + 2Fc2)/3 |
1242 reflections | (Δ/σ)max < 0.001 |
73 parameters | Δρmax = 0.37 e Å−3 |
0 restraints | Δρmin = −0.35 e Å−3 |
[Cu0.31Ni0.69(C5H7O2)2] | V = 535.76 (9) Å3 |
Mr = 258.40 | Z = 2 |
Monoclinic, P21/n | Mo Kα radiation |
a = 10.265 (1) Å | µ = 1.87 mm−1 |
b = 4.6300 (5) Å | T = 100 K |
c = 11.2830 (11) Å | 0.45 × 0.45 × 0.20 mm |
β = 92.431 (2)° |
Bruker SMART CCD area-detector diffractometer | 1242 independent reflections |
Absorption correction: multi-scan (SADABS; Sheldrick, 2008) | 1159 reflections with I > 2σ(I) |
Tmin = 0.487, Tmax = 0.706 | Rint = 0.013 |
3086 measured reflections |
R[F2 > 2σ(F2)] = 0.022 | 0 restraints |
wR(F2) = 0.059 | H-atom parameters constrained |
S = 1.07 | Δρmax = 0.37 e Å−3 |
1242 reflections | Δρmin = −0.35 e Å−3 |
73 parameters |
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. |
x | y | z | Uiso*/Ueq | Occ. (<1) | |
C1 | 0.81881 (15) | 0.5644 (4) | 0.55275 (14) | 0.0207 (3) | |
H1A | 0.8798 | 0.4228 | 0.5220 | 0.031* | |
H1B | 0.8547 | 0.6431 | 0.6279 | 0.031* | |
H1C | 0.8056 | 0.7213 | 0.4952 | 0.031* | |
C2 | 0.69044 (14) | 0.4199 (3) | 0.57303 (13) | 0.0167 (3) | |
C3 | 0.61101 (16) | 0.5306 (3) | 0.65990 (14) | 0.0184 (3) | |
H3 | 0.6416 | 0.6941 | 0.7037 | 0.022* | |
C4 | 0.48909 (14) | 0.4159 (3) | 0.68655 (13) | 0.0170 (3) | |
C5 | 0.41401 (16) | 0.5520 (4) | 0.78376 (14) | 0.0219 (3) | |
H5A | 0.3603 | 0.7100 | 0.7508 | 0.033* | |
H5B | 0.4751 | 0.6279 | 0.8452 | 0.033* | |
H5C | 0.3578 | 0.4065 | 0.8186 | 0.033* | |
Ni1 | 0.5000 | 0.0000 | 0.5000 | 0.01368 (10) | 0.69 (4) |
Cu1 | 0.5000 | 0.0000 | 0.5000 | 0.01368 (10) | 0.31 (4) |
O1 | 0.66241 (10) | 0.2061 (2) | 0.50564 (9) | 0.0185 (2) | |
O2 | 0.43456 (10) | 0.2013 (2) | 0.63411 (9) | 0.0182 (2) |
U11 | U22 | U33 | U12 | U13 | U23 | |
C1 | 0.0171 (7) | 0.0222 (7) | 0.0229 (7) | −0.0021 (6) | 0.0022 (6) | −0.0017 (6) |
C2 | 0.0168 (7) | 0.0163 (7) | 0.0170 (7) | 0.0004 (6) | −0.0016 (5) | 0.0029 (5) |
C3 | 0.0196 (7) | 0.0186 (7) | 0.0172 (7) | −0.0019 (6) | 0.0008 (5) | −0.0023 (5) |
C4 | 0.0192 (7) | 0.0167 (7) | 0.0151 (7) | 0.0016 (6) | 0.0008 (5) | 0.0013 (5) |
C5 | 0.0228 (8) | 0.0230 (8) | 0.0204 (7) | −0.0013 (6) | 0.0058 (6) | −0.0039 (6) |
Ni1 | 0.01363 (14) | 0.01262 (15) | 0.01500 (15) | −0.00132 (9) | 0.00309 (9) | −0.00194 (9) |
Cu1 | 0.01363 (14) | 0.01262 (15) | 0.01500 (15) | −0.00132 (9) | 0.00309 (9) | −0.00194 (9) |
O1 | 0.0179 (5) | 0.0171 (5) | 0.0207 (5) | −0.0008 (4) | 0.0029 (4) | −0.0019 (4) |
O2 | 0.0188 (5) | 0.0165 (5) | 0.0195 (5) | −0.0015 (4) | 0.0037 (4) | −0.0015 (4) |
C1—C2 | 1.504 (2) | C4—C5 | 1.505 (2) |
C1—H1A | 0.9800 | C5—H5A | 0.9800 |
C1—H1B | 0.9800 | C5—H5B | 0.9800 |
C1—H1C | 0.9800 | C5—H5C | 0.9800 |
C2—O1 | 1.2737 (18) | Ni1—O1i | 1.9196 (10) |
C2—C3 | 1.399 (2) | Ni1—O1 | 1.9196 (10) |
C3—C4 | 1.404 (2) | Ni1—O2i | 1.9225 (10) |
C3—H3 | 0.9500 | Ni1—O2 | 1.9226 (10) |
C4—O2 | 1.2737 (18) | ||
C2—C1—H1A | 109.5 | C4—C5—H5A | 109.5 |
C2—C1—H1B | 109.5 | C4—C5—H5B | 109.5 |
H1A—C1—H1B | 109.5 | H5A—C5—H5B | 109.5 |
C2—C1—H1C | 109.5 | C4—C5—H5C | 109.5 |
H1A—C1—H1C | 109.5 | H5A—C5—H5C | 109.5 |
H1B—C1—H1C | 109.5 | H5B—C5—H5C | 109.5 |
O1—C2—C3 | 125.43 (14) | O1i—Ni1—O1 | 179.999 (1) |
O1—C2—C1 | 115.60 (13) | O1i—Ni1—O2i | 93.72 (4) |
C3—C2—C1 | 118.95 (14) | O1—Ni1—O2i | 86.28 (4) |
C2—C3—C4 | 124.25 (14) | O1i—Ni1—O2 | 86.28 (4) |
C2—C3—H3 | 117.9 | O1—Ni1—O2 | 93.72 (4) |
C4—C3—H3 | 117.9 | O2i—Ni1—O2 | 180.0 |
O2—C4—C3 | 125.02 (14) | C2—O1—Ni1 | 125.45 (10) |
O2—C4—C5 | 115.87 (13) | C4—O2—Ni1 | 125.62 (9) |
C3—C4—C5 | 119.10 (14) | ||
O1—C2—C3—C4 | 1.3 (3) | O2i—Ni1—O1—C2 | 172.90 (12) |
C1—C2—C3—C4 | 179.64 (14) | O2—Ni1—O1—C2 | −7.10 (12) |
C2—C3—C4—O2 | −1.3 (2) | C3—C4—O2—Ni1 | −4.3 (2) |
C2—C3—C4—C5 | 178.91 (15) | C5—C4—O2—Ni1 | 175.47 (10) |
C3—C2—O1—Ni1 | 4.2 (2) | O1i—Ni1—O2—C4 | −172.85 (12) |
C1—C2—O1—Ni1 | −174.11 (10) | O1—Ni1—O2—C4 | 7.15 (12) |
O1i—Ni1—O1—C2 | 170 (6) | O2i—Ni1—O2—C4 | 98 (29) |
Symmetry code: (i) −x+1, −y, −z+1. |
Experimental details
Crystal data | |
Chemical formula | [Cu0.31Ni0.69(C5H7O2)2] |
Mr | 258.40 |
Crystal system, space group | Monoclinic, P21/n |
Temperature (K) | 100 |
a, b, c (Å) | 10.265 (1), 4.6300 (5), 11.2830 (11) |
β (°) | 92.431 (2) |
V (Å3) | 535.76 (9) |
Z | 2 |
Radiation type | Mo Kα |
µ (mm−1) | 1.87 |
Crystal size (mm) | 0.45 × 0.45 × 0.20 |
Data collection | |
Diffractometer | Bruker SMART CCD area-detector |
Absorption correction | Multi-scan (SADABS; Sheldrick, 2008) |
Tmin, Tmax | 0.487, 0.706 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 3086, 1242, 1159 |
Rint | 0.013 |
(sin θ/λ)max (Å−1) | 0.665 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.022, 0.059, 1.07 |
No. of reflections | 1242 |
No. of parameters | 73 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.37, −0.35 |
Computer programs: SMART (Bruker, 2007), SAINT (Bruker, 2007), SIR2004 (Burla et al., 2005), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).
Acknowledgements
We thank the Higher Education Commission of Pakistan for funding.
References
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Heterobimetallic complexes of copper and nickel have already been reported as precursors for chemical vapor deposition of ceramic material thin films (Hamid et al., 2006). Mixed metal ceramic oxides have multiple compositions and crystal structures, which results in a diversity of properties leading to a vast variety of potential applications (Auciello et al., 1996, and references therein). For example, a mixed copper/nickel oxide catalyst was deposited on a zeolite support and was shown to have extremely high activity towards methanol oxidation (Kessler et al., 2001).
The title complex was synthesized by the reaction of Cu (dmae)2 (dmae = N,N-dimethylaminoethanolato) (Johnson et al., 2001) with Ni(acac)2.2H2O (acac = acetylacetonato) in toluene. In contrast to the formation of the oligomeric bimetallic complex (Hamid et al., 2006), the title compound crystallized out with the central position partially occupied by Cu and partially by Ni, with a refined Cu:Ni occupancy ratio of 0.31 (4):0.69 (4). A similar type of disorder in the metal site was observed previously in Ni(Ni0.25Cu0.75)2(µ3-OH)(µ-OAc)2(η1-OAc)2(µ,η2–ORN)2 (η2-RNOH)][RN–OH=(CH3)2N(CH2)(CHOH)CH3)] (Werndrup et al., 2001), where the two metal sites were occupied by 75% Cu and 25% Ni. The distribution of two metals at the central position in the title complex is random which means some of the molecules would have each of the two Cu and Ni atoms, or in other words if we consider it to be systematic, in every molecule the position will be occupied by exactly 0.31 Cu and 0.69 Ni atoms.
The molecular structure of the title complex is shown in Figure 1. The geometry of the title complex is square planer, similar to that of Cu(acac)2 (LeBrun et al., 1986) where two ligands coordinate to the metal atom in the same plane, while in the nickel(II) complex, Ni(acac)2 (Zhou et al., 2001), which crystallized with two coordinated water molecules, the metal has an octahedral coordination sphere. The metal to oxygen (O1, O2) bond distances [1.9196 (10) and 1.9225 (10) Å] are slightly longer than those in Cu(acac)2 [1.914 (4), 1.914 (4)Å] but shorter than the average value found in Ni(acac)2 [2.0147Å]. The O—Cu/Ni—O chelate bite angle is 93.72 (4)° which is comparable to that found in Cu(acac)2 [93.2 (2)°] and other complexes of this type (Aruffo et al., 1983). The chelate bite angles are of course larger than those in the octahedral nickel(II) complex mentioned above [91.65 (8)°, 89.99 (8)°].