Acta Cryst. (2007). E63, m2308 [ doi:10.1107/S1600536807038226 ]
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N)bis(1,1,1,5,5,5-hexafluoropentane-2,4-dionato-2O,O')nickel(II)The title compound, [Ni(C5HF6O2)2(C2H3N)2], was obtained as an unintentional by-product in the reaction of Ni(hfac)2 (hfac is hexafluoroacetylacetonate) with pyrazine N,N'-dioxide in acetonitrile. The molecule is centrosymmetric and the ligands are trans to one another, with the NiII atom on a position with 2/m symmetry. The CF3 groups are in a symmetry-imposed eclipsed conformation. The acetonitrile methyl group is involved in weak non-classical C-H
O intermolecular hydrogen bonding to the propanedionate O atoms. This forms a chain synthon parallel to the b axis. The chains are further arranged into sheets parallel to the bc plane.
A solution of Ni(hfac)2 was added to a solution of 2 equivalents of pyrazine-dioxide in acetonitrile at room temperature. Slow evaporation of the resulting solution over five days resulted in a large crop of green parallelepiped shaped crystals (yield 73%).
The dionato H atoms were placed in geometrically idealized positions (C—H = 0.95 Å) and constrained to ride on their parent atom, with Uiso(H) = 1.2Ueq(C). Acetonitrile methyl H atoms were freely refined due to their involvement in H-bonding. The highest residual density peak and the deepest hole are located 1.00 and 0.82 Å, respectively, from atom F1.
Data collection: SMART (Bruker, 2003); cell refinement: SAINT-Plus (Bruker, 2006); data reduction: SAINT-Plus; program(s) used to solve structure: SHELXTL (Bruker, 2003); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: publCIF (Westrip, 2007).
![[Figure 1]](./ci2433fig1thm.gif)
| Fig. 1. The molecular structure of (I), showing 30% probability displacement ellipsoids. Only symmetry unique atoms are labelled. Hydrogen atoms are displayed as spheres of arbitrary radius. |
![[Figure 2]](./ci2433fig2thm.gif)
| Fig. 2. Diagram showing the hydrogen-bonding pattern (dashed lines) linking the molecules into an extended chain along the b axis. |
| [Ni(C5HF6O2)2(C2H3N)2] | F000 = 1096 |
| Mr = 554.93 | Dx = 1.806 Mg m−3 |
| Orthorhombic, Cmca | Mo Kα radiation λ = 0.71073 Å |
| Hall symbol: -C 2bc 2 | Cell parameters from 7181 reflections |
| a = 20.4841 (6) Å | θ = 2.9–30.0º |
| b = 7.1692 (2) Å | µ = 1.08 mm−1 |
| c = 13.9008 (4) Å | T = 90 (2) K |
| V = 2041.4 (1) Å3 | Parallelepiped, light green |
| Z = 4 | 0.21 × 0.20 × 0.10 mm |
| Bruker SMART APEX CCD area-detector diffractometer | 956 independent reflections |
| Radiation source: normal-focus sealed tube | 890 reflections with I > 2σ(I) |
| Monochromator: graphite | Rint = 0.025 |
| Detector resolution: 8.3 pixels mm-1 | θmax = 25.3º |
| T = 90(2) K | θmin = 2.0º |
| ω scans | h = −24→24 |
| Absorption correction: multi-scan (SADABS; Bruker, 2004) | k = −8→8 |
| Tmin = 0.805, Tmax = 0.900 | l = −16→16 |
| 14542 measured reflections |
| Refinement on F2 | Secondary atom site location: difference Fourier map |
| Least-squares matrix: full | Hydrogen site location: inferred from neighbouring sites |
| R[F2 > 2σ(F2)] = 0.026 | H atoms treated by a mixture of independent and constrained refinement |
| wR(F2) = 0.069 | w = 1/[σ2(Fo2) + (0.0363P)2 + 3.0631P] where P = (Fo2 + 2Fc2)/3 |
| S = 1.08 | (Δ/σ)max = 0.001 |
| 956 reflections | Δρmax = 0.50 e Å−3 |
| 89 parameters | Δρmin = −0.24 e Å−3 |
| Primary atom site location: structure-invariant direct methods | Extinction correction: none |
| [Ni(C5HF6O2)2(C2H3N)2] | V = 2041.4 (1) Å3 |
| Mr = 554.93 | Z = 4 |
| Orthorhombic, Cmca | Mo Kα |
| a = 20.4841 (6) Å | µ = 1.08 mm−1 |
| b = 7.1692 (2) Å | T = 90 (2) K |
| c = 13.9008 (4) Å | 0.21 × 0.20 × 0.10 mm |
| Bruker SMART APEX CCD area-detector diffractometer | 956 independent reflections |
| Absorption correction: multi-scan (SADABS; Bruker, 2004) | 890 reflections with I > 2σ(I) |
| Tmin = 0.805, Tmax = 0.900 | Rint = 0.025 |
| 14542 measured reflections |
| R[F2 > 2σ(F2)] = 0.026 | 89 parameters |
| wR(F2) = 0.069 | H atoms treated by a mixture of independent and constrained refinement |
| S = 1.08 | Δρmax = 0.50 e Å−3 |
| 956 reflections | Δρmin = −0.24 e Å−3 |
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 | ||
| Ni1 | 0.5000 | 0.0000 | 0.5000 | 0.01765 (16) | |
| C1 | 0.37064 (9) | 0.1065 (2) | 0.43182 (13) | 0.0243 (4) | |
| C2 | 0.33788 (13) | 0.0000 | 0.5000 | 0.0294 (6) | |
| H2 | 0.2915 | 0.0000 | 0.5000 | 0.035* | |
| C3 | 0.33054 (10) | 0.2315 (3) | 0.36471 (15) | 0.0344 (5) | |
| C4 | 0.5000 | 0.3617 (4) | 0.63509 (18) | 0.0225 (5) | |
| C5 | 0.5000 | 0.5185 (4) | 0.7013 (2) | 0.0268 (6) | |
| H5A | 0.5364 (12) | 0.514 (4) | 0.741 (2) | 0.061 (8)* | |
| H5B | 0.5000 | 0.628 (6) | 0.665 (3) | 0.058 (12)* | |
| F1 | 0.26677 (6) | 0.1999 (2) | 0.36833 (12) | 0.0604 (5) | |
| F2 | 0.33928 (7) | 0.41007 (19) | 0.38887 (11) | 0.0531 (4) | |
| F3 | 0.35020 (7) | 0.2156 (2) | 0.27393 (9) | 0.0495 (4) | |
| N1 | 0.5000 | 0.2359 (3) | 0.58532 (15) | 0.0242 (5) | |
| O1 | 0.43089 (6) | 0.12008 (17) | 0.41713 (9) | 0.0226 (3) |
| U11 | U22 | U33 | U12 | U13 | U23 | |
| Ni1 | 0.0161 (3) | 0.0194 (3) | 0.0174 (2) | 0.000 | 0.000 | 0.00028 (17) |
| C1 | 0.0214 (9) | 0.0249 (9) | 0.0266 (10) | 0.0009 (7) | −0.0029 (7) | −0.0029 (8) |
| C2 | 0.0176 (13) | 0.0353 (15) | 0.0353 (15) | 0.000 | 0.000 | 0.0019 (12) |
| C3 | 0.0235 (10) | 0.0442 (13) | 0.0354 (11) | 0.0042 (9) | −0.0041 (8) | 0.0075 (10) |
| C4 | 0.0246 (13) | 0.0231 (13) | 0.0198 (12) | 0.000 | 0.000 | 0.0051 (11) |
| C5 | 0.0385 (17) | 0.0209 (13) | 0.0209 (14) | 0.000 | 0.000 | −0.0011 (11) |
| F1 | 0.0231 (7) | 0.0842 (11) | 0.0738 (10) | 0.0021 (7) | −0.0135 (7) | 0.0323 (9) |
| F2 | 0.0610 (9) | 0.0372 (8) | 0.0610 (9) | 0.0183 (7) | −0.0115 (7) | 0.0081 (7) |
| F3 | 0.0478 (8) | 0.0700 (9) | 0.0307 (7) | 0.0158 (7) | −0.0109 (6) | 0.0065 (6) |
| N1 | 0.0275 (12) | 0.0235 (12) | 0.0215 (11) | 0.000 | 0.000 | 0.0008 (10) |
| O1 | 0.0204 (6) | 0.0257 (7) | 0.0218 (6) | 0.0012 (5) | −0.0020 (5) | 0.0022 (5) |
| Ni1—O1i | 2.0180 (12) | C2—C1i | 1.390 (2) |
| Ni1—O1 | 2.0180 (12) | C2—H2 | 0.95 |
| Ni1—O1ii | 2.0180 (12) | C3—F1 | 1.327 (2) |
| Ni1—O1iii | 2.0180 (12) | C3—F3 | 1.329 (2) |
| Ni1—N1 | 2.066 (2) | C3—F2 | 1.335 (3) |
| Ni1—N1ii | 2.066 (2) | C4—N1 | 1.137 (3) |
| C1—O1 | 1.255 (2) | C4—C5 | 1.453 (4) |
| C1—C2 | 1.390 (2) | C5—H5A | 0.93 (3) |
| C1—C3 | 1.532 (3) | C5—H5B | 0.93 (4) |
| O1i—Ni1—O1 | 90.90 (7) | C2—C1—C3 | 118.54 (18) |
| O1i—Ni1—O1ii | 89.10 (7) | C1—C2—C1i | 122.3 (3) |
| O1—Ni1—O1ii | 180.0 | C1—C2—H2 | 118.9 |
| O1i—Ni1—O1iii | 180.00 (5) | C1i—C2—H2 | 118.9 |
| O1—Ni1—O1iii | 89.10 (7) | F1—C3—F3 | 108.63 (18) |
| O1ii—Ni1—O1iii | 90.90 (7) | F1—C3—F2 | 106.62 (18) |
| O1i—Ni1—N1 | 91.23 (6) | F3—C3—F2 | 106.28 (18) |
| O1—Ni1—N1 | 88.77 (6) | F1—C3—C1 | 113.87 (18) |
| O1ii—Ni1—N1 | 91.23 (6) | F3—C3—C1 | 111.43 (17) |
| O1iii—Ni1—N1 | 88.77 (6) | F2—C3—C1 | 109.62 (17) |
| O1i—Ni1—N1ii | 88.77 (6) | N1—C4—C5 | 178.2 (3) |
| O1—Ni1—N1ii | 91.23 (6) | C4—C5—H5A | 110.5 (18) |
| O1ii—Ni1—N1ii | 88.77 (6) | C4—C5—H5B | 108 (2) |
| O1iii—Ni1—N1ii | 91.23 (6) | H5A—C5—H5B | 110 (2) |
| N1—Ni1—N1ii | 180.0 | C4—N1—Ni1 | 177.6 (2) |
| O1—C1—C2 | 128.94 (18) | C1—O1—Ni1 | 124.34 (12) |
| O1—C1—C3 | 112.50 (16) |
| Symmetry codes: (i) x, −y, −z+1; (ii) −x+1, −y, −z+1; (iii) −x+1, y, z. |
| D—H···A | D—H | H···A | D···A | D—H···A |
| C5—H5B···O1iv | 0.93 (4) | 2.56 (4) | 3.381 (3) | 146.5 (6) |
| C5—H5B···O1v | 0.93 (4) | 2.56 (4) | 3.381 (3) | 146.5 (6) |
| Symmetry codes: (iv) −x+1, −y+1, −z+1; (v) x, −y+1, −z+1. |
| D—H···A | D—H | H···A | D···A | D—H···A |
| C5—H5B···O1i | 0.93 (4) | 2.56 (4) | 3.381 (3) | 146.5 (6) |
| C5—H5B···O1ii | 0.93 (4) | 2.56 (4) | 3.381 (3) | 146.5 (6) |
| Symmetry codes: (i) −x+1, −y+1, −z+1; (ii) x, −y+1, −z+1. |
The Bruker–Siemens SMART APEX diffraction facility was established at the University of Idaho with the assistance of the NSF–EPSCoR program and the M. J. Murdock Charitable Trust, Vancouver, WA, USA.
Baird, I. R., Rettig, S. J., James, B. R. & Skov, K. A. (1999). Can. J. Chem. 77, 1821–1833.
Bruker (2003). SMART (Version 5.632) and SHELXTL (Version 6.14). Bruker AXS Inc., Madison, Wisconsin, USA.
Bruker (2004). SADABS. Version 2004/1. Bruker AXS Inc., Madison, Wisconsin, USA.
Bruker (2006). SAINT-Plus. Version 7.23a. Bruker AXS Inc., Madison, Wisconsin, USA.
Chen, Z. N., Appelt, R. & Vahrenkamp, H. (2000). Inorg. Chim. Acta, 309, 65–71.
Westrip, S. P. (2007). publCIF. In preparation.
The title compound, (I), is centrosymmetric with a trans orientation of the ligands, and is shown in Fig. 1. Although the ligand disposition around Ni1 is not perfectly perpendicular (see Table 1), the mean plane through the C and O atoms of both hexafluoroacetylacetonate (hfac) ligands and the Ni1 atom is perpendicular to the plane through the acetonitrile-Ni plane. The CF3 groups of the hfac ligands are in a symmetry imposed eclipsed conformation.
trans-[Cp(PPh3)2RuCN]2Ni(hfac)2 is the only known structurally related species with a similar trans Ni(hfac)2(cyano)2 core (Chen et al., 2000). Although the substituents on the cyano group distort the geometry, the central hfac-Ni core is also perpendicular to the N—Ni—N vector as seen in (I). A related ruthenium analogue, cis-Ru(hfac)2(MeCN)2 (Baird et al., 1999) is a cis-isomer.
There is weak bifurcated intermolecular hydrogen bonding between the acetonitrile methyl group and the propanedionato oxygen (Fig. 2, Table 2), linking the molecules into a chain synthon parallel to the b-axis. The chains are further arranged into sheets parallel to the bc plane.