1,2-Bis(4-amino­phen­oxy)ethane

Abstract

The mol­ecule of the title compound, C₁₄H₁₆N₂O₂, is located on a crystallographic twofold rotation axis. The central O—C—C—O bridge adopts a gauche conformation. One of the amine H atoms is disordered over two equally occupied positions. The crystal structure is stabilized by N—H⋯O and N—H⋯N hydrogen bonds.

Related literature

For related literature, see: Barikani & Mehdipour-Ataei (2000 ▶); Eastmond & Paprotny (1999 ▶); Hsio et al. (1997 ▶); Liaw & Liaw (2001 ▶); Yang & Chen (1993 ▶); Hergenrother et al. (2002 ▶).

Experimental

Crystal data

• C₁₄H₁₆N₂O₂

• M _r = 244.29

• Orthorhombic,

• a = 14.2157 (9) Å

• b = 10.4608 (8) Å

• c = 8.1817 (5) Å

• V = 1216.68 (14) ų

• Z = 4

• Mo Kα radiation

• μ = 0.09 mm⁻¹

• T = 173 (2) K

• 0.37 × 0.35 × 0.23 mm

Data collection

• Stoe IPDSII two-circle diffractometer

• Absorption correction: none

• 15103 measured reflections

• 1700 independent reflections

• 1549 reflections with I > 2σ(I)

• R _int = 0.049

Refinement

• R[F ² > 2σ(F ²)] = 0.048

• wR(F ²) = 0.119

• S = 1.20

• 1700 reflections

• 95 parameters

• H atoms treated by a mixture of independent and constrained refinement

• Δρ_max = 0.29 e Å⁻³

• Δρ_min = −0.19 e Å⁻³

Data collection: X-AREA (Stoe & Cie, 2001 ▶); cell refinement: X-AREA; data reduction: X-AREA; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: XP in SHELXTL-Plus (Sheldrick, 2008 ▶); software used to prepare material for publication: PLATON (Spek, 2003 ▶).

Supplementary Material

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
N1—H1A⋯O1i	0.93 (2)	2.53 (2)	3.4082 (18)	158.6 (18)
N1—H1B⋯N1ii	0.94 (4)	2.48 (4)	3.360 (3)	157 (4)
N1—H1C⋯N1iii	0.96 (5)	2.61 (5)	3.468 (3)	148 (3)

Symmetry codes: (i) ; (ii) ; (iii) .

supplementary crystallographic information

Comment

Aromatic polyimides are well accepted as high performance and heat resistant materials (Hergenrother et al., 2000). They exhibit a favorable balance of physical and chemical properties, show excellent thermal, mechanical and electrical properties and are thus widely used in microelectronics and aerospace engineering (Eastmond & Paprotny, 1999). However, the technological and industrial application of rigid polyimides are limited by processing difficulties due to their high melting or glass transition temperatures and their lack of solubility in most organic solvents (Hsio et al., 1997). Strong interactions between polyimide chains and their rigid structures are the main reason for these behaviors. To overcome such a drawback, different methods have been introduced to modifiy their structures. Many efforts have been made in designing and synthesizing new dianhydrides (Eastmond & Paprotny, 1999) and diamines (Yang & Chen, 1993), and therefore producing a great variety of more soluble and processable polyimides for various purposes and applications. Incorporation of flexible units such as –NHCO–, –O–, (Barikani & Mehdipour-Ataei, 2000), –CO– and –SO2- is one of the most important approaches to overcome these processing problems (Liaw & Liaw, 2001). The title compound is such a new starting material for the synthesis of high performance polyimides.

Molecules of the title compound, C₁₄H₁₆N₂O₄, are located on a crystallographic twofold rotation axis. The central O—C—C—O bridge adopts a gauche conformation. One of the amino H atoms is disordered over two equally occupied positions. As a result of that, neighbouring molecules are connected by alternating hydrogen bonds, either N1-H1B···N1ⁱⁱ or N1-H1C···N1ⁱⁱⁱ, because H1B and H1C and their symmetry equivalents would be too close to each other and would be mutually exclusive (symmetry codes: see Table 1). In addition, the crystal structure is stabilized by N—H···O hydrogen bonds (Table 1).

Experimental

A two neck 250 ml round bottom flask was charged with 1 g of 1,2-di(p-nitrophenyloxy) ethylene (3.28 mmoles), 10 ml of hydrazine monohydrate, 80 ml of ethanol and 0.06 g of 5% palladium on carbon (Pd/C).The mixture was heated to reflux for 16 h and then filtered to remove Pd/C and the crude solid was recrystallized from ethanol to yield 92.2% of the diamine, m.p. 352K.

Refinement

All H atoms could be located by difference Fourier synthesis but were ultimately placed in calculated positions using a riding model with C—H(aromatic) = 0.95 Å or C—H(methylene) = 0.99 Å with fixed individual displacement parameters [U_iso(H) = 1.2 U_eq(C). The amino H atoms were freely refined. One of the amino H atoms is disordered over two equally occupied positions.

Figures

Fig. 1.

The structure of the title compound showing the atomic numbering scheme. Displacement ellipsoids are drawn at the 50% probability level and only one of the two alternative types of N-H hydrogen atoms is shown. Symmetry code for generating equivalent atoms: (A) -x+2, y, -z+3/2.

Crystal data

C14H16N2O2	Dx = 1.334 Mg m−3
Mr = 244.29	Melting point: 179 K
Orthorhombic, Pbcn	Mo Kα radiation λ = 0.71073 Å
Hall symbol: -P 2n 2ab	Cell parameters from 14232 reflections
a = 14.2157 (9) Å	θ = 3.5–29.7º
b = 10.4608 (8) Å	µ = 0.09 mm−1
c = 8.1817 (5) Å	T = 173 (2) K
V = 1216.68 (14) Å3	Block, dark red
Z = 4	0.37 × 0.35 × 0.23 mm
F000 = 520

Data collection

Stoe IPDSII two-circle diffractometer	1549 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.049
Monochromator: graphite	θmax = 29.6º
T = 173(2) K	θmin = 3.5º
ω scans	h = −19→19
Absorption correction: none	k = −14→11
15103 measured reflections	l = −11→11
1700 independent reflections

Refinement

Refinement on F2	Hydrogen site location: inferred from neighbouring sites
Least-squares matrix: full	H atoms treated by a mixture of independent and constrained refinement
R[F2 > 2σ(F2)] = 0.048	w = 1/[σ2(Fo2) + (0.0299P)2 + 0.7945P] where P = (Fo2 + 2Fc2)/3
wR(F2) = 0.119	(Δ/σ)max < 0.001
S = 1.20	Δρmax = 0.29 e Å−3
1700 reflections	Δρmin = −0.19 e Å−3
95 parameters	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.024 (2)
Secondary atom site location: difference Fourier map

Special details

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 (Ų)

	x	y	z	Uiso*/Ueq	Occ. (<1)
O1	0.91391 (6)	0.60429 (10)	0.65677 (12)	0.0243 (3)
N1	0.52550 (9)	0.65323 (15)	0.5428 (2)	0.0332 (3)
H1A	0.5093 (15)	0.718 (2)	0.470 (3)	0.048 (6)*
H1B	0.496 (3)	0.573 (4)	0.537 (5)	0.042 (11)*	0.50
H1C	0.486 (3)	0.650 (4)	0.638 (6)	0.048 (12)*	0.50
C1	0.81695 (9)	0.61092 (12)	0.63296 (15)	0.0198 (3)
C2	0.78489 (9)	0.71034 (13)	0.53437 (17)	0.0232 (3)
H2	0.8285	0.7684	0.4872	0.028*
C3	0.68899 (10)	0.72479 (13)	0.50483 (17)	0.0239 (3)
H3	0.6678	0.7931	0.4377	0.029*
C4	0.62345 (9)	0.64020 (13)	0.57255 (17)	0.0234 (3)
C5	0.65662 (10)	0.54140 (14)	0.67195 (19)	0.0268 (3)
H5	0.6131	0.4835	0.7196	0.032*
C6	0.75275 (10)	0.52624 (13)	0.70255 (17)	0.0240 (3)
H6	0.7742	0.4586	0.7704	0.029*
C7	0.94691 (9)	0.49765 (13)	0.75075 (18)	0.0244 (3)
H7A	0.9230	0.4169	0.7033	0.029*
H7B	0.9237	0.5043	0.8645	0.029*

Atomic displacement parameters (Ų)

	U11	U22	U33	U12	U13	U23
O1	0.0192 (4)	0.0272 (5)	0.0264 (5)	−0.0010 (4)	−0.0026 (4)	0.0063 (4)
N1	0.0205 (6)	0.0377 (7)	0.0413 (8)	0.0012 (5)	−0.0023 (5)	0.0043 (6)
C1	0.0202 (6)	0.0214 (6)	0.0178 (5)	−0.0003 (5)	−0.0017 (4)	−0.0017 (5)
C2	0.0231 (6)	0.0230 (6)	0.0235 (6)	−0.0010 (5)	0.0019 (5)	0.0039 (5)
C3	0.0246 (6)	0.0239 (6)	0.0233 (6)	0.0036 (5)	−0.0001 (5)	0.0028 (5)
C4	0.0205 (6)	0.0254 (6)	0.0244 (6)	0.0005 (5)	−0.0010 (5)	−0.0028 (5)
C5	0.0228 (6)	0.0267 (6)	0.0310 (7)	−0.0048 (5)	−0.0004 (5)	0.0043 (6)
C6	0.0247 (6)	0.0223 (6)	0.0250 (6)	−0.0023 (5)	−0.0033 (5)	0.0050 (5)
C7	0.0237 (6)	0.0233 (6)	0.0261 (6)	−0.0007 (5)	−0.0050 (5)	0.0024 (5)

Geometric parameters (Å, °)

O1—C1	1.3938 (15)	C3—C4	1.3992 (19)
O1—C7	1.4338 (16)	C3—H3	0.9500
N1—C4	1.4202 (18)	C4—C5	1.397 (2)
N1—H1A	0.93 (2)	C5—C6	1.3983 (19)
N1—H1B	0.94 (4)	C5—H5	0.9500
N1—H1C	0.96 (5)	C6—H6	0.9500
C1—C2	1.3928 (18)	C7—C7i	1.510 (2)
C1—C6	1.3935 (18)	C7—H7A	0.9900
C2—C3	1.3927 (18)	C7—H7B	0.9900
C2—H2	0.9500
C1—O1—C7	115.93 (10)	C5—C4—C3	118.27 (12)
C4—N1—H1A	115.0 (14)	C5—C4—N1	120.12 (13)
C4—N1—H1B	112 (3)	C3—C4—N1	121.61 (13)
H1A—N1—H1B	120 (3)	C4—C5—C6	121.20 (12)
C4—N1—H1C	115 (3)	C4—C5—H5	119.4
H1A—N1—H1C	114 (3)	C6—C5—H5	119.4
H1B—N1—H1C	75 (3)	C1—C6—C5	119.65 (12)
C2—C1—C6	119.80 (12)	C1—C6—H6	120.2
C2—C1—O1	116.21 (11)	C5—C6—H6	120.2
C6—C1—O1	123.98 (12)	O1—C7—C7i	108.83 (10)
C3—C2—C1	120.12 (12)	O1—C7—H7A	109.9
C3—C2—H2	119.9	C7i—C7—H7A	109.9
C1—C2—H2	119.9	O1—C7—H7B	109.9
C2—C3—C4	120.96 (12)	C7i—C7—H7B	109.9
C2—C3—H3	119.5	H7A—C7—H7B	108.3
C4—C3—H3	119.5
C7—O1—C1—C2	−176.63 (12)	C3—C4—C5—C6	−0.5 (2)
C7—O1—C1—C6	4.11 (19)	N1—C4—C5—C6	179.72 (14)
C6—C1—C2—C3	−0.3 (2)	C2—C1—C6—C5	0.4 (2)
O1—C1—C2—C3	−179.57 (12)	O1—C1—C6—C5	179.62 (13)
C1—C2—C3—C4	−0.2 (2)	C4—C5—C6—C1	0.0 (2)
C2—C3—C4—C5	0.6 (2)	C1—O1—C7—C7i	174.05 (12)
C2—C3—C4—N1	−179.62 (14)

Symmetry codes: (i) −x+2, y, −z+3/2.

Hydrogen-bond geometry (Å, °)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1A···O1ii	0.93 (2)	2.53 (2)	3.4082 (18)	158.6 (18)
N1—H1B···N1iii	0.94 (4)	2.48 (4)	3.360 (3)	157 (4)
N1—H1C···N1iv	0.96 (5)	2.61 (5)	3.468 (3)	148 (3)

Symmetry codes: (ii) x−1/2, −y+3/2, −z+1; (iii) −x+1, −y+1, −z+1; (iv) −x+1, y, −z+3/2.