supplementary materials


hg5154 scheme

Acta Cryst. (2012). E68, o217    [ doi:10.1107/S1600536811054018 ]

Methyl 2-{[2-(4,4,5,5-tetramethyl-1,3-dioxyl-4,5-dihydroimidazol-2-yl)phenyl]oxy}acetate

H.-B. Wang, L.-L. Jing and X.-L. Sun

Abstract top

In the title compound, C16H21N2O5, the benzene ring is nearly perpendicular to the imidazole ring, making a torsion angle of 88.6 (8)°·The crystal structure is stabilized by non-classical C-H...O and C-H...[pi] interactions, which build up a three-dimensional network.

Comment top

Nitronyl nitroxides, stable organic radicals, synthesized more than 30 years ago (Osiecki et al., 1968), have received considerable attention recently because of their capability of magnetism, anticancer, antiradiation and antioxidation in biological chemistry and magnetic material fields (Soule et al. 2007).

The dihedral angle for imidazole and the phenyl rings is 88.6 (8)°. The dihedral angle is bigger than other nitronyl nitroxide reported on literature (Jing et al. 2011). In the title compound, the nitronyl nitroxide ring is almost in one plane, but the nitronyl nitroxide unit often displays a twisted or half-chair conformation for other related compounds (Wang et al.2009; Jing et al. 2011).

The crystal structure is stabilized by non-classical C—H···O and C—H···π (Table 1, Cg2 is the centroid of the phenyl ring) hydrogen bonds.

Related literature top

For the chemical and physical properties of nitronyl nitroxides, see: Osiecki & Ullman (1968). For their biological activity, see: Soule et al. (2007). For related structures, see: Wang et al. (2009); Jing et al. (2011).

Experimental top

A mixture of 250 mg (1.0 mmol) of 2-(2'-Hydroxyl)phenyl-4,4,5,5-tetramethylimidazoline-3-oxide-1-oxyl, 0.30 ml of methyl bromoacetate and 100 mg of sodium methylate in 5 ml of anhydrous tetrahydrofuran was stirred at 60°C for 5 h and TLC (CHCl3/CH3OH, 20:1)indicated the complete disapperance of the raw material. Then the solvent was removed to give a dark blue residue which was purified by a flash column chromatography (eluent, chloroform and methanol, the ratio ofvolume is 20 to 1) to yield the title compound as a dark red powder. Single crystals of compound were obtained from the mixed solution of n-hexaneand dichloromethane (the ratio of volume is 1 to 1).

Refinement top

H atoms were positioned geometrically and were allowed to ride on the C atoms to which they are bonded, with C—H = 0.93–0.97 Å and Uiso(H) = 1.2Ueq(Caromatic) or Uiso(H) = 1.5Ueq(Cmethyl).

Computing details top

Data collection: APEX2 (Bruker, 2007); cell refinement: SAINT (Bruker, 2007); data reduction: SAINT (Bruker, 2007); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2009).

Figures top
[Figure 1] Fig. 1. Molecular structure of the title compound with atom numbering scheme. Displacement ellipsoids are drawn at the 30% probability level. H atoms are presented as a small spheres of arbitrary radius.
Methyl 2-{[2-(4,4,5,5-tetramethyl-1,3-dioxyl- 4,5-dihydroimidazol-2-yl)phenyl]oxy}acetate top
Crystal data top
C16H21N2O5F(000) = 684
Mr = 321.35Dx = 1.286 Mg m3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybcCell parameters from 1441 reflections
a = 11.421 (6) Åθ = 2.7–20.5°
b = 7.381 (4) ŵ = 0.10 mm1
c = 19.700 (11) ÅT = 296 K
β = 91.832 (6)°Block, red
V = 1659.8 (16) Å30.23 × 0.21 × 0.14 mm
Z = 4
Data collection top
Bruker APEXII CCD
diffractometer
3082 independent reflections
Radiation source: fine-focus sealed tube1717 reflections with I > 2σ(I)
graphiteRint = 0.049
φ and ω scansθmax = 25.5°, θmin = 2.1°
Absorption correction: multi-scan
(SADABS; Bruker, 2007)
h = 1313
Tmin = 0.978, Tmax = 0.987k = 88
11481 measured reflectionsl = 2321
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)] = 0.060Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.219H-atom parameters constrained
S = 0.95 w = 1/[σ2(Fo2) + (0.140P)2]
where P = (Fo2 + 2Fc2)/3
3082 reflections(Δ/σ)max < 0.001
213 parametersΔρmax = 0.42 e Å3
30 restraintsΔρmin = 0.42 e Å3
Crystal data top
C16H21N2O5V = 1659.8 (16) Å3
Mr = 321.35Z = 4
Monoclinic, P21/cMo Kα radiation
a = 11.421 (6) ŵ = 0.10 mm1
b = 7.381 (4) ÅT = 296 K
c = 19.700 (11) Å0.23 × 0.21 × 0.14 mm
β = 91.832 (6)°
Data collection top
Bruker APEXII CCD
diffractometer
3082 independent reflections
Absorption correction: multi-scan
(SADABS; Bruker, 2007)
1717 reflections with I > 2σ(I)
Tmin = 0.978, Tmax = 0.987Rint = 0.049
11481 measured reflectionsθmax = 25.5°
Refinement top
R[F2 > 2σ(F2)] = 0.060H-atom parameters constrained
wR(F2) = 0.219Δρmax = 0.42 e Å3
S = 0.95Δρmin = 0.42 e Å3
3082 reflectionsAbsolute structure: ?
213 parametersFlack parameter: ?
30 restraintsRogers parameter: ?
Special details top

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
C10.2619 (4)1.4589 (6)0.1296 (2)0.0838 (13)
H1A0.22191.35110.14470.126*
H1B0.29991.51380.16730.126*
H1C0.20651.54240.11170.126*
C20.3169 (3)1.2963 (5)0.03053 (17)0.0527 (9)
C30.4199 (3)1.2593 (4)0.01652 (17)0.0524 (9)
H3A0.48691.22220.00920.063*
H3B0.44091.36780.04190.063*
C40.4695 (3)1.0655 (4)0.10896 (18)0.0509 (9)
C50.5846 (3)1.1206 (5)0.1134 (2)0.0616 (10)
H50.61301.20360.08250.074*
C60.6575 (3)1.0515 (5)0.1642 (2)0.0705 (11)
H60.73531.08870.16700.085*
C70.6184 (3)0.9304 (5)0.2103 (2)0.0749 (12)
H70.66840.88650.24460.090*
C80.5027 (3)0.8732 (5)0.2053 (2)0.0667 (11)
H80.47530.78930.23620.080*
C90.4280 (3)0.9395 (4)0.15493 (18)0.0505 (9)
C100.3067 (3)0.8761 (4)0.14568 (16)0.0461 (8)
C110.1010 (3)0.8621 (4)0.14948 (16)0.0476 (8)
C120.1454 (3)0.7110 (4)0.10154 (17)0.0505 (9)
C130.0269 (4)1.0061 (6)0.1154 (2)0.0898 (14)
H13A0.00681.09630.14820.135*
H13B0.04340.95230.09650.135*
H13C0.06991.06160.07980.135*
C140.0445 (5)0.7921 (6)0.2134 (2)0.1018 (17)
H14A0.09160.69660.23300.153*
H14B0.03240.74650.20200.153*
H14C0.03850.88910.24560.153*
C150.1063 (6)0.7353 (9)0.0277 (2)0.124 (2)
H15A0.12670.85470.01290.186*
H15B0.02300.71950.02330.186*
H15C0.14450.64700.00030.186*
C160.1231 (4)0.5185 (5)0.1239 (3)0.0999 (17)
H16A0.16440.43630.09540.150*
H16B0.04070.49340.12030.150*
H16C0.15010.50350.17020.150*
N10.2724 (2)0.7420 (4)0.10481 (18)0.0709 (10)
N20.2136 (2)0.9510 (4)0.17210 (14)0.0554 (8)
O10.3482 (2)1.4130 (3)0.07761 (13)0.0671 (8)
O20.2212 (2)1.2324 (4)0.02691 (14)0.0769 (9)
O30.38813 (19)1.1206 (3)0.06102 (13)0.0623 (7)
O40.3397 (3)0.6491 (5)0.0681 (2)0.1186 (12)
O50.2140 (2)1.0877 (5)0.21176 (16)0.1025 (12)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
C10.102 (3)0.079 (3)0.069 (3)0.011 (2)0.021 (2)0.010 (2)
C20.053 (2)0.052 (2)0.053 (2)0.0063 (16)0.0076 (16)0.0013 (17)
C30.0467 (18)0.049 (2)0.061 (2)0.0090 (15)0.0073 (16)0.0017 (17)
C40.0395 (17)0.053 (2)0.060 (2)0.0063 (15)0.0010 (16)0.0017 (17)
C50.046 (2)0.058 (2)0.080 (3)0.0111 (16)0.0016 (18)0.002 (2)
C60.046 (2)0.063 (3)0.101 (3)0.0059 (18)0.011 (2)0.003 (2)
C70.062 (2)0.062 (2)0.100 (3)0.0017 (19)0.022 (2)0.007 (2)
C80.067 (2)0.058 (2)0.075 (3)0.0052 (18)0.008 (2)0.013 (2)
C90.0442 (17)0.049 (2)0.058 (2)0.0058 (15)0.0019 (16)0.0013 (17)
C100.0486 (18)0.0436 (19)0.0463 (19)0.0044 (15)0.0057 (15)0.0049 (16)
C110.0458 (17)0.0477 (19)0.0496 (19)0.0064 (14)0.0043 (14)0.0001 (16)
C120.0446 (17)0.054 (2)0.053 (2)0.0072 (15)0.0036 (15)0.0041 (17)
C130.084 (3)0.071 (3)0.112 (3)0.021 (2)0.037 (3)0.017 (3)
C140.135 (4)0.087 (3)0.087 (3)0.029 (3)0.064 (3)0.011 (3)
C150.146 (5)0.161 (5)0.065 (3)0.050 (4)0.009 (3)0.027 (3)
C160.094 (3)0.054 (3)0.155 (5)0.019 (2)0.056 (3)0.017 (3)
N10.0510 (16)0.0576 (18)0.106 (2)0.0131 (14)0.0310 (16)0.0363 (17)
N20.0490 (16)0.0664 (19)0.0506 (17)0.0029 (14)0.0012 (13)0.0165 (15)
O10.0691 (16)0.0705 (17)0.0612 (16)0.0152 (13)0.0052 (13)0.0127 (13)
O20.0480 (15)0.094 (2)0.089 (2)0.0201 (14)0.0036 (13)0.0184 (16)
O30.0472 (13)0.0689 (17)0.0704 (16)0.0189 (11)0.0041 (11)0.0219 (13)
O40.0707 (18)0.099 (2)0.189 (3)0.0214 (15)0.0467 (19)0.074 (2)
O50.076 (2)0.124 (3)0.107 (2)0.0052 (17)0.0016 (17)0.075 (2)
Geometric parameters (Å, °) top
C1—O11.439 (5)C10—N11.328 (4)
C1—H1A0.9600C11—N21.498 (4)
C1—H1B0.9600C11—C131.503 (5)
C1—H1C0.9600C11—C141.524 (5)
C2—O21.194 (4)C11—C121.557 (4)
C2—O11.324 (4)C12—N11.468 (4)
C2—C31.500 (5)C12—C161.512 (5)
C3—O31.403 (4)C12—C151.518 (6)
C3—H3A0.9700C13—H13A0.9600
C3—H3B0.9700C13—H13B0.9600
C4—O31.365 (4)C13—H13C0.9600
C4—C51.376 (4)C14—H14A0.9600
C4—C91.392 (5)C14—H14B0.9600
C5—C61.378 (5)C14—H14C0.9600
C5—H50.9300C15—H15A0.9600
C6—C71.360 (5)C15—H15B0.9600
C6—H60.9300C15—H15C0.9600
C7—C81.388 (5)C16—H16A0.9600
C7—H70.9300C16—H16B0.9600
C8—C91.377 (5)C16—H16C0.9600
C8—H80.9300N1—O41.272 (4)
C9—C101.468 (4)N2—O51.276 (4)
C10—N21.320 (4)
O1—C1—H1A109.5C13—C11—C12115.2 (3)
O1—C1—H1B109.5C14—C11—C12114.4 (3)
H1A—C1—H1B109.5N1—C12—C16108.0 (3)
O1—C1—H1C109.5N1—C12—C15106.5 (3)
H1A—C1—H1C109.5C16—C12—C15110.1 (4)
H1B—C1—H1C109.5N1—C12—C11101.7 (2)
O2—C2—O1124.6 (3)C16—C12—C11115.8 (3)
O2—C2—C3126.3 (3)C15—C12—C11113.9 (3)
O1—C2—C3109.1 (3)C11—C13—H13A109.5
O3—C3—C2107.8 (3)C11—C13—H13B109.5
O3—C3—H3A110.2H13A—C13—H13B109.5
C2—C3—H3A110.2C11—C13—H13C109.5
O3—C3—H3B110.2H13A—C13—H13C109.5
C2—C3—H3B110.2H13B—C13—H13C109.5
H3A—C3—H3B108.5C11—C14—H14A109.5
O3—C4—C5125.7 (3)C11—C14—H14B109.5
O3—C4—C9114.3 (3)H14A—C14—H14B109.5
C5—C4—C9120.0 (3)C11—C14—H14C109.5
C4—C5—C6119.4 (4)H14A—C14—H14C109.5
C4—C5—H5120.3H14B—C14—H14C109.5
C6—C5—H5120.3C12—C15—H15A109.5
C7—C6—C5121.6 (3)C12—C15—H15B109.5
C7—C6—H6119.2H15A—C15—H15B109.5
C5—C6—H6119.2C12—C15—H15C109.5
C6—C7—C8119.0 (4)H15A—C15—H15C109.5
C6—C7—H7120.5H15B—C15—H15C109.5
C8—C7—H7120.5C12—C16—H16A109.5
C9—C8—C7120.6 (4)C12—C16—H16B109.5
C9—C8—H8119.7H16A—C16—H16B109.5
C7—C8—H8119.7C12—C16—H16C109.5
C8—C9—C4119.4 (3)H16A—C16—H16C109.5
C8—C9—C10122.4 (3)H16B—C16—H16C109.5
C4—C9—C10118.1 (3)O4—N1—C10125.1 (3)
N2—C10—N1109.0 (3)O4—N1—C12120.3 (3)
N2—C10—C9125.9 (3)C10—N1—C12114.5 (3)
N1—C10—C9124.9 (3)O5—N2—C10125.8 (3)
N2—C11—C13106.8 (3)O5—N2—C11121.0 (3)
N2—C11—C14106.5 (3)C10—N2—C11113.2 (3)
C13—C11—C14111.2 (3)C2—O1—C1117.2 (3)
N2—C11—C12101.6 (2)C4—O3—C3117.7 (2)
O2—C2—C3—O36.6 (5)N2—C10—N1—O4175.5 (4)
O1—C2—C3—O3173.5 (3)C9—C10—N1—O40.3 (6)
O3—C4—C5—C6179.1 (3)N2—C10—N1—C121.5 (4)
C9—C4—C5—C60.8 (5)C9—C10—N1—C12176.7 (3)
C4—C5—C6—C70.2 (6)C16—C12—N1—O461.9 (5)
C5—C6—C7—C81.0 (6)C15—C12—N1—O456.3 (5)
C6—C7—C8—C90.7 (6)C11—C12—N1—O4175.8 (4)
C7—C8—C9—C40.3 (6)C16—C12—N1—C10121.0 (4)
C7—C8—C9—C10176.9 (3)C15—C12—N1—C10120.8 (4)
O3—C4—C9—C8179.5 (3)C11—C12—N1—C101.4 (4)
C5—C4—C9—C81.1 (5)N1—C10—N2—O5177.4 (3)
O3—C4—C9—C102.2 (5)C9—C10—N2—O52.3 (6)
C5—C4—C9—C10176.2 (3)N1—C10—N2—C111.0 (4)
C8—C9—C10—N293.2 (5)C9—C10—N2—C11176.1 (3)
C4—C9—C10—N289.6 (4)C13—C11—N2—O557.3 (4)
C8—C9—C10—N192.4 (5)C14—C11—N2—O561.6 (4)
C4—C9—C10—N184.8 (4)C12—C11—N2—O5178.3 (3)
N2—C11—C12—N10.7 (3)C13—C11—N2—C10121.2 (3)
C13—C11—C12—N1114.3 (3)C14—C11—N2—C10119.9 (3)
C14—C11—C12—N1115.0 (4)C12—C11—N2—C100.1 (3)
N2—C11—C12—C16116.1 (3)O2—C2—O1—C13.0 (5)
C13—C11—C12—C16128.9 (4)C3—C2—O1—C1177.1 (3)
C14—C11—C12—C161.7 (5)C5—C4—O3—C37.2 (5)
N2—C11—C12—C15114.8 (4)C9—C4—O3—C3174.5 (3)
C13—C11—C12—C150.2 (5)C2—C3—O3—C4179.6 (3)
C14—C11—C12—C15130.9 (4)
Hydrogen-bond geometry (Å, °) top
Cg2 is the centroid of the phenyl ring.
D—H···AD—HH···AD···AD—H···A
C3—H3A···O4i0.972.513.327 (5)141
C3—H3B···O4ii0.972.443.195 (5)134
C8—H8···Cg2iii0.932.993.896 (5)164
Symmetry codes: (i) −x+1, −y+2, −z; (ii) x, y+1, z; (iii) −x+1, y−1/2, −z+1/2.
Table 1
Hydrogen-bond geometry (Å, °)
top
Cg2 is the centroid of the phenyl ring.
D—H···AD—HH···AD···AD—H···A
C3—H3A···O4i0.972.513.327 (5)141
C3—H3B···O4ii0.972.443.195 (5)134
C8—H8···Cg2iii0.932.993.896 (5)164
Symmetry codes: (i) −x+1, −y+2, −z; (ii) x, y+1, z; (iii) −x+1, y−1/2, −z+1/2.
Acknowledgements top

We thank the Natural Science Foundation of China (grant No. 81001398) for financial support and Yongliang Shao (Lanzhou University) for the X-ray measurements.

references
References top

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