Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536807035829/xu2276sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S1600536807035829/xu2276Isup2.hkl |
CCDC reference: 657637
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.
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].
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).
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).
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.
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). |
[Ni(C11H12NO2)2] | F(000) = 460 |
Mr = 439.14 | Dx = 1.440 Mg m−3 |
Monoclinic, P21/c | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2ybc | Cell parameters from 4600 reflections |
a = 6.8507 (8) Å | θ = 2.4–27.9° |
b = 14.2231 (16) Å | µ = 0.99 mm−1 |
c = 10.4333 (11) Å | T = 273 K |
β = 94.978 (1)° | Block, green |
V = 1012.8 (2) Å3 | 0.46 × 0.37 × 0.26 mm |
Z = 2 |
Bruker SMART CCD area-detector diffractometer | 2464 independent reflections |
Radiation source: fine-focus sealed tube | 2117 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.015 |
Detector resolution: 0 pixels mm-1 | θmax = 28.2°, θmin = 2.4° |
φ and ω scans | h = −8→9 |
Absorption correction: multi-scan (SADABS; Sheldrick, 1996) | k = −18→18 |
Tmin = 0.660, Tmax = 0.785 | l = −13→13 |
9124 measured reflections |
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)] = 0.027 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.078 | H-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 parameters | Δρmax = 0.28 e Å−3 |
0 restraints | Δρmin = −0.14 e Å−3 |
[Ni(C11H12NO2)2] | V = 1012.8 (2) Å3 |
Mr = 439.14 | Z = 2 |
Monoclinic, P21/c | Mo Kα radiation |
a = 6.8507 (8) Å | µ = 0.99 mm−1 |
b = 14.2231 (16) Å | T = 273 K |
c = 10.4333 (11) Å | 0.46 × 0.37 × 0.26 mm |
β = 94.978 (1)° |
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 = 0.785 | Rint = 0.015 |
9124 measured reflections |
R[F2 > 2σ(F2)] = 0.027 | 0 restraints |
wR(F2) = 0.078 | H-atom parameters constrained |
S = 1.04 | Δρmax = 0.28 e Å−3 |
2464 reflections | Δρmin = −0.14 e Å−3 |
134 parameters |
x | y | z | Uiso*/Ueq | ||
Ni1 | 0.5000 | 0.5000 | 1.0000 | 0.04033 (10) | |
N1 | 0.69407 (17) | 0.42879 (8) | 0.92667 (11) | 0.0416 (3) | |
O1 | 0.58717 (16) | 0.46227 (9) | 1.16463 (10) | 0.0539 (3) | |
C7 | 0.8531 (2) | 0.39736 (10) | 0.98742 (14) | 0.0421 (3) | |
O2 | 0.98132 (16) | 0.35575 (8) | 0.91413 (11) | 0.0537 (3) | |
C1 | 0.7605 (2) | 0.42966 (10) | 1.20546 (14) | 0.0448 (3) | |
C6 | 0.9035 (2) | 0.39973 (10) | 1.12425 (14) | 0.0427 (3) | |
C9 | 0.6929 (2) | 0.40152 (10) | 0.78937 (13) | 0.0435 (3) | |
H9 | 0.6695 | 0.4571 | 0.7346 | 0.052* | |
C2 | 0.8101 (3) | 0.42306 (12) | 1.33957 (15) | 0.0570 (4) | |
H2 | 0.7180 | 0.4399 | 1.3958 | 0.068* | |
C10 | 0.5365 (3) | 0.32755 (12) | 0.75391 (16) | 0.0576 (4) | |
H10A | 0.4122 | 0.3486 | 0.7816 | 0.069* | |
H10B | 0.5718 | 0.2694 | 0.7987 | 0.069* | |
C3 | 0.9921 (3) | 0.39224 (13) | 1.38856 (17) | 0.0628 (4) | |
H3 | 1.0207 | 0.3887 | 1.4772 | 0.075* | |
C5 | 1.0889 (2) | 0.36959 (11) | 1.17710 (17) | 0.0523 (4) | |
H5 | 1.1825 | 0.3516 | 1.1225 | 0.063* | |
C8 | 0.9026 (2) | 0.36654 (13) | 0.78168 (16) | 0.0543 (4) | |
H8A | 0.9034 | 0.3070 | 0.7365 | 0.065* | |
H8B | 0.9786 | 0.4118 | 0.7374 | 0.065* | |
C4 | 1.1339 (3) | 0.36634 (13) | 1.30740 (18) | 0.0619 (4) | |
H4 | 1.2575 | 0.3471 | 1.3413 | 0.074* | |
C11 | 0.5138 (3) | 0.30932 (16) | 0.60927 (18) | 0.0801 (6) | |
H11A | 0.6392 | 0.2939 | 0.5803 | 0.120* | |
H11B | 0.4633 | 0.3647 | 0.5654 | 0.120* | |
H11C | 0.4249 | 0.2579 | 0.5911 | 0.120* |
U11 | U22 | U33 | U12 | U13 | U23 | |
Ni1 | 0.04070 (15) | 0.04505 (16) | 0.03585 (14) | 0.00470 (10) | 0.00680 (10) | 0.00219 (9) |
N1 | 0.0441 (6) | 0.0435 (6) | 0.0378 (6) | 0.0015 (5) | 0.0066 (5) | −0.0002 (5) |
O1 | 0.0511 (6) | 0.0718 (7) | 0.0397 (5) | 0.0146 (5) | 0.0088 (4) | 0.0078 (5) |
C7 | 0.0431 (7) | 0.0362 (7) | 0.0479 (7) | −0.0004 (5) | 0.0081 (6) | −0.0024 (5) |
O2 | 0.0501 (6) | 0.0588 (7) | 0.0529 (6) | 0.0121 (5) | 0.0089 (5) | −0.0072 (5) |
C1 | 0.0492 (8) | 0.0422 (7) | 0.0426 (7) | 0.0006 (6) | 0.0023 (6) | 0.0046 (6) |
C6 | 0.0452 (7) | 0.0365 (7) | 0.0460 (7) | −0.0003 (5) | 0.0018 (6) | 0.0016 (5) |
C9 | 0.0505 (8) | 0.0427 (7) | 0.0381 (7) | −0.0017 (6) | 0.0086 (6) | −0.0020 (5) |
C2 | 0.0667 (10) | 0.0601 (10) | 0.0442 (8) | 0.0050 (8) | 0.0040 (7) | 0.0061 (7) |
C10 | 0.0638 (10) | 0.0573 (9) | 0.0518 (9) | −0.0153 (8) | 0.0061 (7) | −0.0030 (7) |
C3 | 0.0763 (12) | 0.0607 (10) | 0.0485 (9) | 0.0015 (8) | −0.0120 (8) | 0.0070 (7) |
C5 | 0.0472 (8) | 0.0469 (8) | 0.0618 (10) | 0.0034 (6) | −0.0007 (7) | −0.0008 (7) |
C8 | 0.0557 (9) | 0.0571 (9) | 0.0512 (9) | 0.0039 (7) | 0.0118 (7) | −0.0107 (7) |
C4 | 0.0585 (10) | 0.0580 (10) | 0.0657 (11) | 0.0051 (8) | −0.0145 (8) | 0.0044 (8) |
C11 | 0.0972 (16) | 0.0866 (14) | 0.0549 (11) | −0.0296 (12) | −0.0031 (10) | −0.0124 (10) |
Ni1—O1i | 1.8484 (10) | C2—C3 | 1.377 (2) |
Ni1—O1 | 1.8484 (10) | C2—H2 | 0.9300 |
Ni1—N1 | 1.8856 (11) | C10—C11 | 1.526 (2) |
Ni1—N1i | 1.8856 (11) | C10—H10A | 0.9700 |
N1—C7 | 1.2917 (18) | C10—H10B | 0.9700 |
N1—C9 | 1.4834 (17) | C3—C4 | 1.393 (3) |
O1—C1 | 1.3113 (18) | C3—H3 | 0.9300 |
C7—O2 | 1.3503 (16) | C5—C4 | 1.369 (2) |
C7—C6 | 1.440 (2) | C5—H5 | 0.9300 |
O2—C8 | 1.447 (2) | C8—H8A | 0.9700 |
C1—C2 | 1.414 (2) | C8—H8B | 0.9700 |
C1—C6 | 1.415 (2) | C4—H4 | 0.9300 |
C6—C5 | 1.407 (2) | C11—H11A | 0.9600 |
C9—C10 | 1.524 (2) | C11—H11B | 0.9600 |
C9—C8 | 1.529 (2) | C11—H11C | 0.9600 |
C9—H9 | 0.9800 | ||
O1i—Ni1—O1 | 180.0 | C1—C2—H2 | 119.3 |
O1i—Ni1—N1 | 87.78 (5) | C9—C10—C11 | 111.49 (14) |
O1—Ni1—N1 | 92.22 (5) | C9—C10—H10A | 109.3 |
O1i—Ni1—N1i | 92.22 (5) | C11—C10—H10A | 109.3 |
O1—Ni1—N1i | 87.78 (5) | C9—C10—H10B | 109.3 |
N1—Ni1—N1i | 180.000 (1) | C11—C10—H10B | 109.3 |
C7—N1—C9 | 108.48 (12) | H10A—C10—H10B | 108.0 |
C7—N1—Ni1 | 125.53 (10) | C2—C3—C4 | 121.02 (16) |
C9—N1—Ni1 | 125.97 (9) | C2—C3—H3 | 119.5 |
C1—O1—Ni1 | 127.96 (9) | C4—C3—H3 | 119.5 |
N1—C7—O2 | 115.87 (13) | C4—C5—C6 | 121.17 (16) |
N1—C7—C6 | 126.71 (13) | C4—C5—H5 | 119.4 |
O2—C7—C6 | 117.39 (13) | C6—C5—H5 | 119.4 |
C7—O2—C8 | 106.70 (11) | O2—C8—C9 | 104.97 (11) |
O1—C1—C2 | 118.56 (14) | O2—C8—H8A | 110.8 |
O1—C1—C6 | 124.49 (13) | C9—C8—H8A | 110.8 |
C2—C1—C6 | 116.96 (14) | O2—C8—H8B | 110.8 |
C5—C6—C1 | 120.34 (14) | C9—C8—H8B | 110.8 |
C5—C6—C7 | 120.79 (14) | H8A—C8—H8B | 108.8 |
C1—C6—C7 | 118.82 (13) | C5—C4—C3 | 119.07 (16) |
N1—C9—C10 | 111.07 (12) | C5—C4—H4 | 120.5 |
N1—C9—C8 | 102.09 (12) | C3—C4—H4 | 120.5 |
C10—C9—C8 | 113.99 (14) | C10—C11—H11A | 109.5 |
N1—C9—H9 | 109.8 | C10—C11—H11B | 109.5 |
C10—C9—H9 | 109.8 | H11A—C11—H11B | 109.5 |
C8—C9—H9 | 109.8 | C10—C11—H11C | 109.5 |
C3—C2—C1 | 121.36 (16) | H11A—C11—H11C | 109.5 |
C3—C2—H2 | 119.3 | H11B—C11—H11C | 109.5 |
O1i—Ni1—N1—C7 | 161.17 (13) | O2—C7—C6—C5 | 7.2 (2) |
O1—Ni1—N1—C7 | −18.83 (13) | N1—C7—C6—C1 | 7.4 (2) |
O1i—Ni1—N1—C9 | −17.12 (11) | O2—C7—C6—C1 | −170.52 (13) |
O1—Ni1—N1—C9 | 162.88 (11) | C7—N1—C9—C10 | 110.60 (15) |
N1—Ni1—O1—C1 | 21.57 (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—O2 | 4.75 (17) | Ni1—N1—C9—C8 | 167.25 (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—C3 | 2.4 (2) |
Ni1—N1—C7—C6 | 8.3 (2) | N1—C9—C10—C11 | 171.80 (15) |
N1—C7—O2—C8 | 4.60 (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—C2 | 167.16 (12) | C1—C6—C5—C4 | 1.6 (2) |
Ni1—O1—C1—C6 | −13.2 (2) | C7—C6—C5—C4 | −176.08 (15) |
O1—C1—C6—C5 | 177.19 (15) | C7—O2—C8—C9 | −11.42 (16) |
C2—C1—C6—C5 | −3.1 (2) | N1—C9—C8—O2 | 13.45 (15) |
O1—C1—C6—C7 | −5.1 (2) | C10—C9—C8—O2 | −106.41 (14) |
C2—C1—C6—C7 | 174.57 (14) | C6—C5—C4—C3 | 0.9 (3) |
N1—C7—C6—C5 | −174.93 (14) | C2—C3—C4—C5 | −1.6 (3) |
Symmetry code: (i) −x+1, −y+1, −z+2. |
D—H···A | D—H | H···A | D···A | D—H···A |
C8—H8B···Cgii | 0.97 | 2.77 | 3.552 (2) | 138 |
C8—H8A···Cgiii | 0.97 | 2.92 | 3.769 (2) | 147 |
Symmetry codes: (ii) −x+2, −y+1, −z+2; (iii) x, −y+1/2, z−1/2. |
Experimental details
Crystal data | |
Chemical formula | [Ni(C11H12NO2)2] |
Mr | 439.14 |
Crystal system, space group | Monoclinic, P21/c |
Temperature (K) | 273 |
a, b, c (Å) | 6.8507 (8), 14.2231 (16), 10.4333 (11) |
β (°) | 94.978 (1) |
V (Å3) | 1012.8 (2) |
Z | 2 |
Radiation type | Mo Kα |
µ (mm−1) | 0.99 |
Crystal size (mm) | 0.46 × 0.37 × 0.26 |
Data collection | |
Diffractometer | Bruker SMART CCD area-detector |
Absorption correction | Multi-scan (SADABS; Sheldrick, 1996) |
Tmin, Tmax | 0.660, 0.785 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 9124, 2464, 2117 |
Rint | 0.015 |
(sin θ/λ)max (Å−1) | 0.665 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.027, 0.078, 1.04 |
No. of reflections | 2464 |
No. of parameters | 134 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.28, −0.14 |
Computer programs: SMART (Bruker, 2003), SAINT (Bruker, 2003), SAINT, SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), SHELXTL (Bruker, 1999), SHELXTL.
D—H···A | D—H | H···A | D···A | D—H···A |
C8—H8B···Cgi | 0.97 | 2.77 | 3.552 (2) | 138 |
C8—H8A···Cgii | 0.97 | 2.92 | 3.769 (2) | 147 |
Symmetry codes: (i) −x+2, −y+1, −z+2; (ii) x, −y+1/2, z−1/2. |
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).