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Acta Cryst. (2007). E63, m2231    [ doi:10.1107/S1600536807035829 ]

trans-Bis[2-(4-ethyl-4,5-dihydro-1,3-oxazol-2-yl)phenolato-[kappa]2N,O1]nickel(II)

Y. Zhang, T.-F. Liu and W.-G. Xu

Abstract top

In the title centrosymmetric compound, [Ni(C11H12NO2)2], the NiII ion is located on an inversion centre in a square-planar coordination geometry, with Ni-N distances of 1.8856 (11) Å and Ni-O distances of 1.8484 (10) Å. The crystal packing is stabilized by [pi]-[pi] stacking, the centroid-to-centroid distance being 3.748 (1) Å. A C-H...[pi] interaction is also observed in the crystal structure.

Comment top

The chemistry of oxazoline-based ligands continues to be an area of interest due to its ability to form kinetically inert chiral metal complexes of potential for asymmetric synthesis. In particular, oxazoline has been used as a chiral auxiliary in catalytic alkene cyclopropanation, in palladium-catalyzed allylic coupling, and in Diels-Alder reactions. Several metal complexes bearing 2-(2'-hydroxyphenyl)oxazolines have been reported in the literature (Cozzi et al., 1995; Braunstein et al., 2001; Kandasamy et al., 2004; Zhang et al., 2007).

We report here the crystal structure of the title compound, a Ni(II) complex with chiral ligand, 2-(4-ethyl-4,5-dihydrooxazol -2-yl)phenol, as coordination ligand.

The title compound, contains one centrosymmetric tetra-coordinated nickel(II) complex (Fig 1). The nickel atom is coordinated by two 2-(4-ethyl- 4,5-dihydrooxazol-2-yl)-phenol anions, with N atom and phenolyl O atom as coordination atoms. Pairs of equivalent ligands lie trans to each other in a slightly distorted square geometry about the nickel(II) atom. The distances of Ni–O are 1.8484 (10) Å, and the distances of Ni–N are 1.8856 (11) Å. The angle O1–Ni1–N1 is 92.22 (5) °, and the angle O1–Ni1–N1i is 87.78 (5) ° (symmetry code: (i) -x + 1, -y + 1, -z + 2).

The aryl and oxazoline least-squares planes are linked by π-π stacking interactions with Cg-Cgii distances 3.7475 (10) Å (symmetry code: (ii) 2 - x, 1 - y, 2 - z). The C—H···Cg (aryl ring) interactions are observed with H8Aiii···Cg = 2.77 Å (symmetry code: (iii) x, 1/2 - y, -1/2 + z) and H(8B)i···Cg = 2.920 Å (Spek, 2003).

Related literature top

For general background, see: Cozzi et al. (1995); Braunstein & Naud (2001); Kandasamy et al. (2004); Zhang et al. (2007). For synthesis, see: Serrano et al. (1995). For related literature, see: Spek (2003).

Experimental top

The racemic ligand, 2-(4-ethyl-4,5-dihydrooxazol-2-yl)phenol was prepared from 2-hydroxybenzonitrile and racemic 2-aminobutan-1-ol as literature reported (Serrano et al., 1995).

A solution of 2-(4-ethyl-4,5-dihydrooxazol-2-yl)phenol (30.56 mg, 0.16 mmol) in methanol (4 ml) was added to a stirred solution of Ni(NO3)2.6H2O (58.16 mg, 0.2 mmol) in methanol (2 ml). Crystals suitable for diffraction analysis were obtained after a few days.

Refinement top

H atoms were positioned geometrically (aromatic C—H = 0.93 Å, aliphatic C—H = 0.96–0.98 Å) and were included in the refinement in the riding model approximation, with Uiso(H) = 1.2Ueq(C) [1.5Ueq(C) for methyl H].

Computing details top

Data collection: SMART (Bruker, 2003); cell refinement: SAINT (Bruker, 2003); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL (Bruker, 1999); software used to prepare material for publication: SHELXTL.

Figures top
[Figure 1] Fig. 1. The molecular structure of the title compound. Displacement ellipsoids are drawn at the 30% probability level (symmetry code: -x + 1, -y + 1, -z + 2).
trans-Bis[2-(4-ethyl-4,5-dihydro-1,3-oxazol-2-yl)phenolato-\ κ2N,O1]nickel(II) top
Crystal data top
[Ni(C11H12NO2)2]F(000) = 460
Mr = 439.14Dx = 1.440 Mg m−3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybcCell parameters from 4600 reflections
a = 6.8507 (8) Åθ = 2.4–27.9°
b = 14.2231 (16) ŵ = 0.99 mm−1
c = 10.4333 (11) ÅT = 273 K
β = 94.978 (1)°Block, green
V = 1012.8 (2) Å30.46 × 0.37 × 0.26 mm
Z = 2
Data collection top
Bruker SMART CCD area-detector
diffractometer		2464 independent reflections
Radiation source: fine-focus sealed tube2117 reflections with I > 2σ(I)
graphiteRint = 0.015
Detector resolution: 0 pixels mm-1θmax = 28.2°, θmin = 2.4°
φ and ω scansh = −8→9
Absorption correction: multi-scan
(SADABS; Sheldrick, 1996)		k = −18→18
Tmin = 0.660, Tmax = 0.785l = −13→13
9124 measured 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)] = 0.027Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.078H-atom parameters constrained
S = 1.04 w = 1/[σ2(Fo2) + (0.0564P)2 + 0.2109P]
where P = (Fo2 + 2Fc2)/3
2464 reflections(Δ/σ)max < 0.001
134 parametersΔρmax = 0.28 e Å−3
0 restraintsΔρmin = −0.14 e Å−3
Crystal data top
[Ni(C11H12NO2)2]V = 1012.8 (2) Å3
Mr = 439.14Z = 2
Monoclinic, P21/cMo Kα radiation
a = 6.8507 (8) ŵ = 0.99 mm−1
b = 14.2231 (16) ÅT = 273 K
c = 10.4333 (11) Å0.46 × 0.37 × 0.26 mm
β = 94.978 (1)°
Data collection top
Bruker SMART CCD area-detector
diffractometer		2464 independent reflections
Absorption correction: multi-scan
(SADABS; Sheldrick, 1996)		2117 reflections with I > 2σ(I)
Tmin = 0.660, Tmax = 0.785Rint = 0.015
9124 measured reflectionsθmax = 28.2°
Refinement top
R[F2 > 2σ(F2)] = 0.027H-atom parameters constrained
wR(F2) = 0.078Δρmax = 0.28 e Å−3
S = 1.04Δρmin = −0.14 e Å−3
2464 reflectionsAbsolute structure: ?
134 parametersFlack parameter: ?
0 restraintsRogers parameter: ?
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
Ni10.50000.50001.00000.04033 (10)
N10.69407 (17)0.42879 (8)0.92667 (11)0.0416 (3)
O10.58717 (16)0.46227 (9)1.16463 (10)0.0539 (3)
C70.8531 (2)0.39736 (10)0.98742 (14)0.0421 (3)
O20.98132 (16)0.35575 (8)0.91413 (11)0.0537 (3)
C10.7605 (2)0.42966 (10)1.20546 (14)0.0448 (3)
C60.9035 (2)0.39973 (10)1.12425 (14)0.0427 (3)
C90.6929 (2)0.40152 (10)0.78937 (13)0.0435 (3)
H90.66950.45710.73460.052*
C20.8101 (3)0.42306 (12)1.33957 (15)0.0570 (4)
H20.71800.43991.39580.068*
C100.5365 (3)0.32755 (12)0.75391 (16)0.0576 (4)
H10A0.41220.34860.78160.069*
H10B0.57180.26940.79870.069*
C30.9921 (3)0.39224 (13)1.38856 (17)0.0628 (4)
H31.02070.38871.47720.075*
C51.0889 (2)0.36959 (11)1.17710 (17)0.0523 (4)
H51.18250.35161.12250.063*
C80.9026 (2)0.36654 (13)0.78168 (16)0.0543 (4)
H8A0.90340.30700.73650.065*
H8B0.97860.41180.73740.065*
C41.1339 (3)0.36634 (13)1.30740 (18)0.0619 (4)
H41.25750.34711.34130.074*
C110.5138 (3)0.30932 (16)0.60927 (18)0.0801 (6)
H11A0.63920.29390.58030.120*
H11B0.46330.36470.56540.120*
H11C0.42490.25790.59110.120*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Ni10.04070 (15)0.04505 (16)0.03585 (14)0.00470 (10)0.00680 (10)0.00219 (9)
N10.0441 (6)0.0435 (6)0.0378 (6)0.0015 (5)0.0066 (5)−0.0002 (5)
O10.0511 (6)0.0718 (7)0.0397 (5)0.0146 (5)0.0088 (4)0.0078 (5)
C70.0431 (7)0.0362 (7)0.0479 (7)−0.0004 (5)0.0081 (6)−0.0024 (5)
O20.0501 (6)0.0588 (7)0.0529 (6)0.0121 (5)0.0089 (5)−0.0072 (5)
C10.0492 (8)0.0422 (7)0.0426 (7)0.0006 (6)0.0023 (6)0.0046 (6)
C60.0452 (7)0.0365 (7)0.0460 (7)−0.0003 (5)0.0018 (6)0.0016 (5)
C90.0505 (8)0.0427 (7)0.0381 (7)−0.0017 (6)0.0086 (6)−0.0020 (5)
C20.0667 (10)0.0601 (10)0.0442 (8)0.0050 (8)0.0040 (7)0.0061 (7)
C100.0638 (10)0.0573 (9)0.0518 (9)−0.0153 (8)0.0061 (7)−0.0030 (7)
C30.0763 (12)0.0607 (10)0.0485 (9)0.0015 (8)−0.0120 (8)0.0070 (7)
C50.0472 (8)0.0469 (8)0.0618 (10)0.0034 (6)−0.0007 (7)−0.0008 (7)
C80.0557 (9)0.0571 (9)0.0512 (9)0.0039 (7)0.0118 (7)−0.0107 (7)
C40.0585 (10)0.0580 (10)0.0657 (11)0.0051 (8)−0.0145 (8)0.0044 (8)
C110.0972 (16)0.0866 (14)0.0549 (11)−0.0296 (12)−0.0031 (10)−0.0124 (10)
Geometric parameters (Å, °) top
Ni1—O1i1.8484 (10)C2—C31.377 (2)
Ni1—O11.8484 (10)C2—H20.9300
Ni1—N11.8856 (11)C10—C111.526 (2)
Ni1—N1i1.8856 (11)C10—H10A0.9700
N1—C71.2917 (18)C10—H10B0.9700
N1—C91.4834 (17)C3—C41.393 (3)
O1—C11.3113 (18)C3—H30.9300
C7—O21.3503 (16)C5—C41.369 (2)
C7—C61.440 (2)C5—H50.9300
O2—C81.447 (2)C8—H8A0.9700
C1—C21.414 (2)C8—H8B0.9700
C1—C61.415 (2)C4—H40.9300
C6—C51.407 (2)C11—H11A0.9600
C9—C101.524 (2)C11—H11B0.9600
C9—C81.529 (2)C11—H11C0.9600
C9—H90.9800
O1i—Ni1—O1180.0C1—C2—H2119.3
O1i—Ni1—N187.78 (5)C9—C10—C11111.49 (14)
O1—Ni1—N192.22 (5)C9—C10—H10A109.3
O1i—Ni1—N1i92.22 (5)C11—C10—H10A109.3
O1—Ni1—N1i87.78 (5)C9—C10—H10B109.3
N1—Ni1—N1i180.000 (1)C11—C10—H10B109.3
C7—N1—C9108.48 (12)H10A—C10—H10B108.0
C7—N1—Ni1125.53 (10)C2—C3—C4121.02 (16)
C9—N1—Ni1125.97 (9)C2—C3—H3119.5
C1—O1—Ni1127.96 (9)C4—C3—H3119.5
N1—C7—O2115.87 (13)C4—C5—C6121.17 (16)
N1—C7—C6126.71 (13)C4—C5—H5119.4
O2—C7—C6117.39 (13)C6—C5—H5119.4
C7—O2—C8106.70 (11)O2—C8—C9104.97 (11)
O1—C1—C2118.56 (14)O2—C8—H8A110.8
O1—C1—C6124.49 (13)C9—C8—H8A110.8
C2—C1—C6116.96 (14)O2—C8—H8B110.8
C5—C6—C1120.34 (14)C9—C8—H8B110.8
C5—C6—C7120.79 (14)H8A—C8—H8B108.8
C1—C6—C7118.82 (13)C5—C4—C3119.07 (16)
N1—C9—C10111.07 (12)C5—C4—H4120.5
N1—C9—C8102.09 (12)C3—C4—H4120.5
C10—C9—C8113.99 (14)C10—C11—H11A109.5
N1—C9—H9109.8C10—C11—H11B109.5
C10—C9—H9109.8H11A—C11—H11B109.5
C8—C9—H9109.8C10—C11—H11C109.5
C3—C2—C1121.36 (16)H11A—C11—H11C109.5
C3—C2—H2119.3H11B—C11—H11C109.5
O1i—Ni1—N1—C7161.17 (13)O2—C7—C6—C57.2 (2)
O1—Ni1—N1—C7−18.83 (13)N1—C7—C6—C17.4 (2)
O1i—Ni1—N1—C9−17.12 (11)O2—C7—C6—C1−170.52 (13)
O1—Ni1—N1—C9162.88 (11)C7—N1—C9—C10110.60 (15)
N1—Ni1—O1—C121.57 (14)Ni1—N1—C9—C10−70.87 (15)
N1i—Ni1—O1—C1−158.43 (14)C7—N1—C9—C8−11.28 (15)
C9—N1—C7—O24.75 (17)Ni1—N1—C9—C8167.25 (10)
Ni1—N1—C7—O2−173.78 (9)O1—C1—C2—C3−177.90 (16)
C9—N1—C7—C6−173.18 (13)C6—C1—C2—C32.4 (2)
Ni1—N1—C7—C68.3 (2)N1—C9—C10—C11171.80 (15)
N1—C7—O2—C84.60 (17)C8—C9—C10—C11−73.5 (2)
C6—C7—O2—C8−177.26 (13)C1—C2—C3—C4−0.1 (3)
Ni1—O1—C1—C2167.16 (12)C1—C6—C5—C41.6 (2)
Ni1—O1—C1—C6−13.2 (2)C7—C6—C5—C4−176.08 (15)
O1—C1—C6—C5177.19 (15)C7—O2—C8—C9−11.42 (16)
C2—C1—C6—C5−3.1 (2)N1—C9—C8—O213.45 (15)
O1—C1—C6—C7−5.1 (2)C10—C9—C8—O2−106.41 (14)
C2—C1—C6—C7174.57 (14)C6—C5—C4—C30.9 (3)
N1—C7—C6—C5−174.93 (14)C2—C3—C4—C5−1.6 (3)
Symmetry codes: (i) −x+1, −y+1, −z+2.
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
C8—H8B···Cgii0.972.773.552 (2)138
C8—H8A···Cgiii0.972.923.769 (2)147
Symmetry codes: (ii) −x+2, −y+1, −z+2; (iii) x, −y+1/2, z−1/2.
Table 1
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
C8—H8B···Cgi0.972.773.552 (2)138
C8—H8A···Cgii0.972.923.769 (2)147
Symmetry codes: (i) −x+2, −y+1, −z+2; (ii) x, −y+1/2, z−1/2.
Acknowledgements top

The authors acknowledge support from the Natural Science Foundation Council of China (NSFC) (grant No. 20401003) and the Excellent Young Scholars Research Fund of the Beijing Institute of Technology (grant No. 000Y07–26).

references
References top

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