4,4′-Dibromo-2,2′-{ethane-1,2-diylbis[(methyl­imino)­methyl­ene]}diphenol

Augusto Rivera; Jicli José Rojas; Jaime Ríos-Motta; Michal Dušek; Karla Fejfarová

doi:10.1107/S1600536811017193

. 2011 May 14;67(Pt 6):o1391. doi: 10.1107/S1600536811017193

4,4′-Dibromo-2,2′-{ethane-1,2-diylbis[(methylimino)methylene]}diphenol

Augusto Rivera ^a,^*, Jicli José Rojas ^a, Jaime Ríos-Motta ^a, Michal Dušek ^b, Karla Fejfarová ^b

PMCID: PMC3120315 PMID: 21754779

Abstract

The asymmetric unit of the title compound, C₁₈H₂₂Br₂N₂O₂, contains one half-molecule that is related to the other half by a center of inversion located at the mid-point of the central C—C bond. The hydroxy (phenolic) groups are linked to the N atoms by O—H⋯N hydrogen bonds, which generate S(6) rings.

Related literature

For the synthesis, see: Rivera et al. (2010 ▶). For the uses of tetrahydrosalens in coordination chemistry, see: Atwood (1997 ▶). For a related structure, see: Nazarenko et al. (2000 ▶). For reference bond lenghts, see: Allen et al. (1987 ▶).

Experimental

Crystal data

C₁₈H₂₂Br₂N₂O₂
M _r = 458.2
Orthorhombic,
a = 15.9282 (3) Å
b = 6.1123 (2) Å
c = 18.3315 (4) Å
V = 1784.72 (8) Å³
Z = 4
Cu Kα radiation
μ = 5.87 mm⁻¹
T = 120 K
0.36 × 0.06 × 0.05 mm

Data collection

Oxford Diffraction Xcalibur diffractometer with an Atlas (Gemini ultra Cu) detector
Absorption correction: multi-scan (CrysAlis PRO; Oxford Diffraction, 2009 ▶) T _min = 0.611, T _max = 1
24526 measured reflections
1591 independent reflections
1482 reflections with I > 3σ(I)
R _int = 0.028

Refinement

R[F ² > 2σ(F ²)] = 0.021
wR(F ²) = 0.075
S = 1.52
1591 reflections
112 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.20 e Å⁻³
Δρ_min = −0.32 e Å⁻³

Data collection: CrysAlis PRO (Oxford Diffraction, 2009 ▶); cell refinement: CrysAlis PRO; data reduction: CrysAlis PRO; program(s) used to solve structure: SIR2002 (Burla et al., 2003 ▶); program(s) used to refine structure: JANA2006 (Petříček et al., 2006 ▶); molecular graphics: DIAMOND (Brandenburg & Putz, 2005 ▶); software used to prepare material for publication: JANA2006.

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536811017193/hb5874sup1.cif

e-67-o1391-sup1.cif^{(15KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536811017193/hb5874Isup2.hkl

e-67-o1391-Isup2.hkl^{(77.1KB, 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
O4—H4o⋯N2	0.81 (2)	1.86 (2)	2.6051 (19)	154 (2)

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Acknowledgments

We acknowledge the Dirección de Investigaciones Sede Bogotá (DIB) of the Universidad Nacional de Colombia for financial support and the Institutional research plan No. AVOZ10100521 of the Institute of Physics and the Praemium Academiae project of the Academy of Sciences of the Czech Republic.

supplementary crystallographic information

Comment

Recently, we reported the synthesis of a new class of ligands by a ring-opening reduction of bis-1,3-benzoxazines with sodium borohydride (Rivera et al., 2010), and the products of these reactions are referred to as N,N'-disubstituted tetrahydro-salens (Atwood, 1997). Here we report the crystal structure of title compound (I). The C(sp³)—X bond distances and angles in (I) are within normal ranges (Allen et al., 1987) and comparable with a related structure (Nazarenko, et al., 2000). The C—N bonds in the N—CH₂CH₂—N segment are anti to each other, with a torsion angle of 180°. The observed conformation is stabilized by the short intramolecular hydrogen bonds O—H··· N (Table 1), and these interactions generate S(6) ring motifs.

Experimental

Sodium borohydride (3.0 mmol, 0.11 g) was added to a solution of 3,3'-ethylene-bis-(3,4-dihydro-6-bromo-2H-1,3-benzoxazine) (1 mmol) in ethanol (15 ml), and the mixture was stirred magnetically for 30 min at room temperature. After completion of the reaction, the mixture was poured into ice-cold water, neutralized with ammonium chloride (12 ml), and extracted with CHCl₃ (3 times 10 cm³). The combined extracts were dried over anhydrous Na₂SO₄ and evaporated. The solid obtained was purified by recrystallization from ethanol to yield colourless needles of (I).