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

Rivera, A.; Rojas, J.J.; Ríos-Motta, J.; Dušek, M.; Fejfarová, K.

doi:10.1107/S1600536811017193

organic compounds

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Volume 67| Part 6| June 2011| Page o1391

doi:10.1107/S1600536811017193

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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 and Karla Fejfarová ^b

^aDepartamento de Química, Universidad Nacional de Colombia, Colombia, and ^bInstitute of Physics ASCR, v.i.i., Na Slovance 2, 182 21 Praha 8, Czech Republic
^*Correspondence e-mail: ariverau@unal.edu.co

(Received 6 May 2011; accepted 6 May 2011; online 14 May 2011)

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, P b c a
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 $[Oxford Diffraction (2009). CrysAlis PRO. Oxford Diffraction Ltd, Yarnton, England.]$ ) 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[F² > 2σ(F²)] = 0.021
wR(F²) = 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

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)

Data collection: CrysAlis PRO (Oxford Diffraction, 2009 $[Oxford Diffraction (2009). CrysAlis PRO. Oxford Diffraction Ltd, Yarnton, England.]$ ); 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.

Supporting information

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

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

checkCIF report

Comment top

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.

Related literature top

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 top

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).

Computing details top

Data collection: CrysAlis PRO (Oxford Diffraction, 2009); cell refinement: CrysAlis PRO (Oxford Diffraction, 2009); data reduction: CrysAlis PRO (Oxford Diffraction, 2009); 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 (Petříček et al., 2006).

Figures top

	Fig. 1. The molecule of the title compound. Displacement ellipsoids are drawn at 50% probability level. Atoms with suffix i are generated by the symmetry operation (1–x, –y, 2–z).
	Fig. 2. The packing for (I).

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

Crystal data top

C₁₈H₂₂Br₂N₂O₂	F(000) = 920
M_r = 458.2	D_x = 1.705 Mg m⁻³
Orthorhombic, Pbca	Cu Kα radiation, λ = 1.5418 Å
Hall symbol: -P 2ac 2ab	Cell parameters from 16599 reflections
a = 15.9282 (3) Å	θ = 2.8–66.9°
b = 6.1123 (2) Å	µ = 5.87 mm⁻¹
c = 18.3315 (4) Å	T = 120 K
V = 1784.72 (8) Å³	Needle, colourless
Z = 4	0.36 × 0.06 × 0.05 mm

Data collection top

Oxford Diffraction Xcalibur diffractometer with an Atlas (Gemini ultra Cu) detector	1591 independent reflections
Radiation source: Enhance Ultra (Cu) X-ray Source	1482 reflections with I > 3σ(I)
Mirror monochromator	R_int = 0.028
Detector resolution: 10.3784 pixels mm^-1	θ_max = 67.1°, θ_min = 4.8°
Rotation method data acquisition using ω scans	h = −18→18
Absorption correction: multi-scan (CrysAlis PRO; Oxford Diffraction, 2009)	k = −7→7
T_min = 0.611, T_max = 1	l = −21→21
24526 measured reflections

Refinement top

Refinement on F²	41 constraints
R[F² > 2σ(F²)] = 0.021	H atoms treated by a mixture of independent and constrained refinement
wR(F²) = 0.075	Weighting scheme based on measured s.u.'s w = 1/[σ²(I) + 0.0016I²]
S = 1.52	(Δ/σ)_max = 0.008
1591 reflections	Δρ_max = 0.20 e Å⁻³
112 parameters	Δρ_min = −0.32 e Å⁻³
0 restraints

Crystal data top

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

Data collection top

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

Refinement top

R[F² > 2σ(F²)] = 0.021	0 restraints
wR(F²) = 0.075	H atoms treated by a mixture of independent and constrained refinement
S = 1.52	Δρ_max = 0.20 e Å⁻³
1591 reflections	Δρ_min = −0.32 e Å⁻³
112 parameters

Special details top

Experimental. CrysAlisPro, Oxford Diffraction (2009), Empirical absorption correction using spherical harmonics, implemented in SCALE3 ABSPACK scaling algorithm.

Refinement. The refinement was carried out against all reflections. The conventional R-factor is always based on F. The goodness of fit as well as the weighted R-factor are based on F and F² for refinement carried out on F and F², respectively. The threshold expression is used only for calculating R-factors etc. and it is not relevant to the choice of reflections for refinement.

The program used for refinement, Jana2006, uses the weighting scheme based on the experimental expectations, see _refine_ls_weighting_details, that does not force S to be one. Therefore the values of S are usually larger than the ones from the SHELX program.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
Br1	0.640851 (13)	0.05571 (4)	0.580303 (11)	0.03125 (11)
O4	0.61560 (9)	0.4268 (2)	0.88393 (7)	0.0270 (4)
N2	0.58909 (9)	0.0319 (2)	0.93218 (8)	0.0195 (4)
C1	0.59115 (9)	0.1285 (3)	0.80150 (9)	0.0202 (4)
C2	0.62193 (10)	0.3384 (3)	0.81629 (9)	0.0214 (5)
C3	0.66038 (12)	0.4593 (3)	0.76131 (11)	0.0242 (5)
C4	0.66647 (10)	0.3757 (3)	0.69103 (9)	0.0251 (5)
C5	0.63443 (9)	0.1714 (3)	0.67664 (10)	0.0227 (5)
C6	0.59736 (10)	0.0460 (3)	0.73124 (10)	0.0217 (5)
C7	0.54916 (10)	−0.0057 (3)	0.86063 (9)	0.0216 (4)
C8	0.53980 (10)	−0.0646 (3)	0.99219 (9)	0.0218 (5)
C9	0.67487 (11)	−0.0584 (3)	0.93342 (10)	0.0241 (5)
H3	0.682855	0.601479	0.77203	0.0291*
H4	0.692687	0.459508	0.65304	0.0301*
H6	0.576136	−0.09726	0.720273	0.026*
H7a	0.490778	0.032417	0.863354	0.0259*
H7b	0.552676	−0.158184	0.848428	0.0259*
H8a	0.573654	−0.070797	1.035465	0.0262*
H8b	0.525375	−0.212723	0.980158	0.0262*
H9a	0.701148	−0.023134	0.97905	0.0289*
H9b	0.672436	−0.214496	0.927867	0.0289*
H9c	0.706892	0.003417	0.894138	0.0289*
H4o	0.6031 (15)	0.326 (4)	0.9104 (12)	0.0323*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Br1	0.03214 (19)	0.0431 (2)	0.01850 (19)	0.00457 (7)	−0.00120 (6)	−0.00091 (7)
O4	0.0343 (7)	0.0206 (6)	0.0260 (7)	−0.0033 (5)	0.0042 (5)	−0.0036 (5)
N2	0.0153 (7)	0.0236 (8)	0.0195 (7)	−0.0017 (5)	0.0009 (5)	0.0002 (5)
C1	0.0144 (7)	0.0228 (8)	0.0235 (8)	0.0010 (6)	−0.0004 (6)	0.0020 (7)
C2	0.0172 (7)	0.0228 (8)	0.0243 (8)	0.0015 (6)	−0.0011 (6)	0.0006 (7)
C3	0.0210 (8)	0.0226 (9)	0.0291 (10)	−0.0022 (6)	−0.0008 (7)	0.0037 (6)
C4	0.0180 (8)	0.0298 (9)	0.0276 (9)	−0.0002 (7)	−0.0002 (6)	0.0075 (7)
C5	0.0181 (8)	0.0314 (10)	0.0185 (8)	0.0044 (6)	−0.0013 (5)	0.0004 (7)
C6	0.0190 (8)	0.0228 (9)	0.0232 (9)	0.0018 (6)	−0.0032 (6)	0.0008 (6)
C7	0.0194 (8)	0.0244 (8)	0.0210 (8)	−0.0042 (7)	−0.0012 (6)	0.0005 (7)
C8	0.0189 (8)	0.0251 (9)	0.0214 (8)	−0.0012 (6)	0.0012 (6)	0.0036 (6)
C9	0.0163 (9)	0.0289 (10)	0.0271 (8)	0.0019 (6)	0.0000 (7)	0.0004 (6)

Geometric parameters (Å, º) top

Br1—C5	1.9051 (18)	C4—H4	0.96
O4—H4o	0.81 (2)	C5—C6	1.392 (2)
N2—C7	1.476 (2)	C6—H6	0.96
N2—C8	1.475 (2)	C7—H7a	0.96
N2—C9	1.474 (2)	C7—H7b	0.96
C1—C2	1.400 (2)	C8—C8ⁱ	1.521 (2)
C1—C6	1.387 (2)	C8—H8a	0.96
C1—C7	1.515 (2)	C8—H8b	0.96
C2—C3	1.392 (3)	C9—H9a	0.96
C3—C4	1.389 (3)	C9—H9b	0.96
C3—H3	0.96	C9—H9c	0.96
C4—C5	1.375 (3)

C7—N2—C8	111.79 (13)	N2—C7—C1	111.17 (13)
C7—N2—C9	110.78 (13)	N2—C7—H7a	109.4713
C8—N2—C9	109.40 (13)	N2—C7—H7b	109.4711
C2—C1—C6	119.21 (15)	C1—C7—H7a	109.4712
C2—C1—C7	120.83 (14)	C1—C7—H7b	109.4709
C6—C1—C7	119.93 (15)	H7a—C7—H7b	107.7191
C1—C2—C3	120.04 (16)	N2—C8—C8ⁱ	112.14 (13)
C2—C3—C4	120.46 (16)	N2—C8—H8a	109.4713
C2—C3—H3	119.771	N2—C8—H8b	109.4716
C4—C3—H3	119.7725	C8ⁱ—C8—H8a	109.4716
C3—C4—C5	119.09 (16)	C8ⁱ—C8—H8b	109.4707
C3—C4—H4	120.4567	H8a—C8—H8b	106.6664
C5—C4—H4	120.4562	N2—C9—H9a	109.4705
Br1—C5—C4	119.68 (13)	N2—C9—H9b	109.471
Br1—C5—C6	119.00 (14)	N2—C9—H9c	109.4718
C4—C5—C6	121.31 (16)	H9a—C9—H9b	109.4713
C1—C6—C5	119.85 (16)	H9a—C9—H9c	109.4714
C1—C6—H6	120.0729	H9b—C9—H9c	109.4713
C5—C6—H6	120.073

N2—C8—C8ⁱ—N2ⁱ	180

Symmetry code: (i) −x+1, −y, −z+2.

Hydrogen-bond geometry (Å, º) top

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)

Experimental details

Crystal data
Chemical formula	C₁₈H₂₂Br₂N₂O₂
M_r	458.2
Crystal system, space group	Orthorhombic, Pbca
Temperature (K)	120
a, b, c (Å)	15.9282 (3), 6.1123 (2), 18.3315 (4)
V (Å³)	1784.72 (8)
Z	4
Radiation type	Cu Kα
µ (mm⁻¹)	5.87
Crystal size (mm)	0.36 × 0.06 × 0.05

Data collection
Diffractometer	Oxford Diffraction Xcalibur diffractometer with an Atlas (Gemini ultra Cu) detector
Absorption correction	Multi-scan (CrysAlis PRO; Oxford Diffraction, 2009)
T_min, T_max	0.611, 1
No. of measured, independent and observed [I > 3σ(I)] reflections	24526, 1591, 1482
R_int	0.028
(sin θ/λ)_max (Å⁻¹)	0.597

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.021, 0.075, 1.52
No. of reflections	1591
No. of parameters	112
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.20, −0.32

Computer programs: CrysAlis PRO (Oxford Diffraction, 2009), SIR2002 (Burla et al., 2003), JANA2006 (Petříček et al., 2006), DIAMOND (Brandenburg & Putz, 2005).

Hydrogen-bond geometry (Å, º) top

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)

Acknowledgements

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.

References

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Petříček, V., Dušek, M. & Palatinus, L. (2006). JANA2006. Institute of Physics, Praha, Czech Republic. Google Scholar
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