4,4,5,5-Tetra­methyl-2-(3,4,5-trimethoxy­phen­yl)imidazolidine-1-oxyl 3-oxide

Hai-Bo Wang; Lin-Lin Jing; Peng Gao; Xiao-Li Sun

doi:10.1107/S1600536809029274

. 2009 Aug 8;65(Pt 9):o2090. doi: 10.1107/S1600536809029274

4,4,5,5-Tetramethyl-2-(3,4,5-trimethoxyphenyl)imidazolidine-1-oxyl 3-oxide

Hai-Bo Wang ^a, Lin-Lin Jing ^a, Peng Gao ^a, Xiao-Li Sun ^a,^*

PMCID: PMC2969929 PMID: 21577507

Abstract

In the title nitronyl nitroxide radical compound, C₁₆C₂₃N₂O₅, the imidazole and benzene rings are twisted with respect to each other, making a dihedral angle of 26.2 (4)°. The imidazole ring adopts a half-chair conformation. Weak C—H⋯π interactions are also found.

Related literature

For the preparation of the title compound see: Ullman et al. (1974 ▶). For related structures, see: Feher et al. (2008 ▶); Gao et al. (2009 ▶); Qin et al. (2009 ▶); Cirujeda et al. (1995 ▶); Matsushita et al. (1997 ▶). For the coordination properties of the title compound and its use in the formation of molecule-based magnetic materials, see: Takui et al. (2009 ▶). For puckering parameters, see: Cremer & Pople (1975 ▶).

Experimental

Crystal data

C₁₆H₂₃N₂O₅
M _r = 323.36
Orthorhombic,
a = 20.623 (3) Å
b = 7.2168 (12) Å
c = 22.831 (4) Å
V = 3398.0 (10) Å³
Z = 8
Mo Kα radiation
μ = 0.09 mm⁻¹
T = 296 K
0.32 × 0.25 × 0.17 mm

Data collection

Bruker APEXII diffractometer
Absorption correction: none
15858 measured reflections
3027 independent reflections
1519 reflections with I > 2σ(I)
R _int = 0.062

Refinement

R[F ² > 2σ(F ²)] = 0.046
wR(F ²) = 0.119
S = 1.06
3027 reflections
216 parameters
H-atom parameters constrained
Δρ_max = 0.17 e Å⁻³
Δρ_min = −0.23 e Å⁻³

Data collection: APEX2 (Bruker, 2007 ▶); cell refinement: SAINT (Bruker, 2007 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEPIII (Burnett & Johnson, 1996 ▶) and ORTEP-3 for Windows (Farrugia, 1997 ▶); software used to prepare material for publication: SHELXTL (Sheldrick, 2008 ▶).

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536809029274/dn2472sup1.cif

e-65-o2090-sup1.cif^{(20.8KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809029274/dn2472Isup2.hkl

e-65-o2090-Isup2.hkl^{(148.6KB, hkl)}

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C14—H14A⋯Cg2ⁱ	0.96	2.80	3.644 (2)	147

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Symmetry code: (i) Inline graphic . Cg2 is the centroid of the phenyl ring.

Acknowledgments

We thank the Natural Science Foundation of China (grant No. 20802092) for financial support.

supplementary crystallographic information

Comment

The title radical compound was obtained from the oxidation of 4,4,5,5- tetramethyl-2-(3,4,5-trimethoxybenzenyl)-imidazolidine-1,3-diol, which was prepared by the condensation of 3,4,5-trimethoxybenzaldehyde with 2,3-Dimethyl-2,3-bis(hydroxyl-amino)butane. The title compound was used for coordination with many metal cations, such as Mn²⁺, Cu²⁺, and Ni²⁺, in order to form some molecule-based magnetic materials (Takui et al., 2009).

The molecular structure of the title compound is shown in Fig 1. Examination of bond length within the five membered rings shows an average structure as observed with related compounds (Cirujeda et al., 1995; Feher et al., 2008; Gao et al., 2009; Matsushita et al., 1997; Qin et al., 2009).

The imidazole and the phenyl rings are twisted with respect to each other making a dihedral angle of 26.2 (4)°. The imidazole ring has an half-chair conformation with puckering parameters O(2)=. 0.0275 (2)Å and φ= 233.0 (5)°(Cremer & Pople, 1975). The crystal structure is stabilized by weak C—H···π (Table 1, Cg2 is the centroid of the phenyl ring) and van der Waals interactions.

Experimental

The compound 4,4,5,5-tetramethyl-2-(3,4,5-trimethoxybenzenyl)-imidazolidine -1-oxyl-3-oxide was prepared according to the method reported by Ullman et al. (1974). 2,3-Dimethyl-2,3-bis(hydroxylamino) butane (1.48 g, 10.0 mmol) and 3,4,5-trimethoxybenzaldehyde (1.96 g, 10.0 mmol) were dissolved in a methanol-water mixture (2:1), which was stirred for 5 h at reflux temperature, then cooled to room temperature and filtered. The white powder was washed by methanol. This product was dried under vaccum, then, it was suspended in dichloromethane (50.0 ml) and the water solution (30.0 ml) of NaIO₄(1.7 g) was added and stirred at ice bath for 20 min. The reaction mixture was extracted by dichloromethane (30.0 ml) for twice and the organic layer was combined and dried over Na₂SO₄. Then the solvent was removed to give a dark blue residue which was purified by a flash column chromatography (eluent, ether and petroleum ether, the ratio of volume is 2 to 1) to yield the title compound (I) as a dark blue powder. Single crystals of compound (I) were obtained from the mixed solution of n-heptane and dichloromethane (the ratio of volume is 1 to 1).