Diethyl 4,4′-(ethane-1,2-diyldi­oxy)dibenzoate

Abstract

The title compound, C₂₀H₂₂O₆, was obtained by the reaction of ethyl 4-hy­droxy­benzoate with 1,2-dichloro­ethane in dimethyl­formamide. The mol­ecule lies around the crystallographic inversion center at (0,0,0), with the asymmetric unit consisting of one half of the mol­ecule. The two ethyl groups are in trans positions. The ethyl, carboxyl, aryl and O—CH₂ groups are coplanar with an r.m.s. deviation of 0.0208 (9) Å. The whole mol­ecule is planar with an r.m.s. deviation of 0.0238 (9) Å for the 19 atoms used in the calculation and 0.0071 (9) Å for the two aryl groups in the mol­ecule. A weak inter­molecular C—H⋯O hydrogen bond and a C—H⋯π inter­action help to consolidate the three-dimensional network.

Related literature

For the synthesis and structures of diesters, see Hou & Kan (2007 ▶); Tashiro et al. (1990 ▶); Zhang et al. (2007 ▶). For the properties and applications of diesters, see: Chen & Liu (2002 ▶). For the synthesis of the title compound, see: Ma & Liu (2002 ▶); Ma & Cao (2011 ▶). For standard bond lengths, see: Allen et al. (1987 ▶).

Experimental

Crystal data

• C₂₀H₂₂O₆

• M _r = 358.38

• Monoclinic,

• a = 4.8504 (10) Å

• b = 15.847 (3) Å

• c = 12.0159 (19) Å

• β = 104.250 (8)°

• V = 895.2 (3) ų

• Z = 2

• Mo Kα radiation

• μ = 0.10 mm⁻¹

• T = 298 K

• 0.49 × 0.35 × 0.22 mm

Data collection

• Bruker SMART CCD area-detector diffractometer

• Absorption correction: multi-scan (SADABS; Sheldrick, 1996 ▶) T _min = 0.960, T _max = 0.979

• 8592 measured reflections

• 1980 independent reflections

• 1713 reflections with I > 2σ(I)

• R _int = 0.032

Refinement

• R[F ² > 2σ(F ²)] = 0.039

• wR(F ²) = 0.130

• S = 1.02

• 1980 reflections

• 119 parameters

• H-atom parameters constrained

• Δρ_max = 0.34 e Å⁻³

• Δρ_min = −0.34 e Å⁻³

Data collection: SMART (Bruker, 2001 ▶); cell refinement: SAINT (Bruker, 2002 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: SHELXTL (Sheldrick, 2008 ▶); software used to prepare material for publication: SHELXTL.

Supplementary Material

Supplementary material file. DOI: 10.1107/S1600536811021258/ez2245Isup3.cml

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

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

Cg is the centroid of the C4–C9 ring.

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C6—H6A⋯O2i	0.93	2.47	3.2784 (16)	146
C10—H10B⋯Cgii	0.97	2.65	3.741 (2)	143

Symmetry codes: (i) ; (ii) .

supplementary crystallographic information

Comment

There has been, in recent years, a considerable interest in the study of esters (Hou & Kan, 2007; Tashiro et al., 1990; Zhang et al., 2007), since these compounds are commodity chemicals used as intermediates in the manufacture of acids and to produce many important industrial products. Hence, our current work aims to prepare esters to produce acids and investigate their coordination behaviors with metal ions and study their applications in many fields (Chen & Liu, 2002). Herein, we report a new diester which was obtained by reaction of ethyl 4-hydroxybenzoate with 1,2-dichloroethane in DMF and its structure was confirmed by elemental analysis, IR, NMR spectra and X-ray crystal analysis.

The structure consists of a neutral molecular unit (Fig. 1).The molecule lies on a crystallographic inversion center at (0, 0, 0), thus leading to one half of the molecule being present per asymmetric unit. All bond lengths and angles are within normal ranges (Allen et al., 1987). The ethyl, aryl, carboxyl and the O—CH₂ groups of one half molecule are coplanar to form one plane with an r.m.s. deviation of 0.0208 (9) Å. By symmetry, the whole molecule is coplanar with an r.m.s deviation of 0.0238 (9) Å for 19 atoms being used for calculation and 0.0071 (9) Å for the two aryl groups at the molecule. Because of the symmetry of the inversion center, the two ethyl groups at the molecule are in a trans position. One weak hydrogen bond between one hydrogen atom and the oxygen atom of a neighboring molecule is present in the structure: H6A on C6 and O2ⁱⁱ [symmetry code: (ii) x, -y+1/2, z-1/2] (Table 1). The molecules display intermolecular C—H···π interactions between a –CH₂-(C10) and a neighboring aryl group [H..Cg 2.647 Å, Cg is the centroid of the six membered ring of C4ⁱⁱⁱ-C9ⁱⁱⁱ, symmetry code: (iii) x+1, y, z].

Experimental

The title compound was obtained by the reaction of ethyl 4-hydroxybenzoate with 1,2-dichloroethane in N,N'-dimethylformamide (DMF) according to a reported procedure (Ma & Liu, 2002; Ma & Cao, 2011). In a 100 cm³ flask fitted with a funnel, ethyl 4-hydroxybenzoate (8.3 g, 50 mM) and potassium carbonate were mixed in 50 cm³ of DMF. To this solution was added dropwise a stoichiometric quantity of 1,2-dichloroethane (2.5 g, 25 mM) dissolved in 20 cm³ of DMF for a period of an hour with stirring. The mixture was then stirred for 24 h at 353 K. The solution was concentrated under reduced pressure and the white solid formed by adding a large quantity of water (200 cm³) was filtered off and recrystallized from ethanol and decolored with activated carbon. A colorless solid was obtained (yield 30 %, m.p: 388–390 K). Slow evaporation of a solution of the title compound in ethanol and dichloromethane (1:1) led to the formation of colorless crystals, which were suitable for X-ray characterization. Anal. Calcd. for [C₂₀H₂₂O₆] (%): C, 67.03; H, 6.19; found: C, 66.75; H, 6.46; IR(KBr), (cm^-1): 1711, (C=O), 1605, 1509, 1477 (C=C of aryl), 1280, 1252, 1165, 1105 (CH₂—O—CH₂), 1045, 1027, 870-715, (Ar—H). ¹H NMR (CDCl₃): 7.97 (d, 4H, J = 8.8 Hz, aryl, c), 6.94 (d, 4H, J = 8.8 Hz, aryl, d), 4.34 (d, 4H, OCH₂CH₂, f), 4.31 (d, 4H, COOCH₂, g), 1.35 (t, 6H, –CH₃, h). ¹³C NMR: 166.4 (–COO, a), 162.4 (aryl, b), 131.8 (aryl, c), 123.7 (aryl, e), 114.4 (aryl, d), 66.6 (CH₂CH₂, f), 60.9 (CH₂CH₂, g), 14.6 (–CH₃, h). (see Figure 3 for the NMR atom number assignment).

Refinement

All H atoms were positioned geometrically and refined using a riding model with C—H = 0.93 - 0.97 Å and with U_iso(H) = 1.2 times U_eq(C).

Figures

Fig. 1.

The molecular structure of the title compound with the atom numbering scheme. Displacement ellipsoids are drawn at the 50% probability level. H atoms are presented as small spheres of arbitrary radius. [Symmetry code: (i) -x, -y, -z]

Fig. 2.

A view of the crystal packing along the a axis. The thin dashed lines are used to show the hydrogen bonds. The thick dashed line is used to show the intermolecular CH-π interactions of –CH2-(C6) and the neighboring aryl groups, from their H atoms to the centroids of the rings of the aryl groups.

Fig. 3.

An additional scheme with the numbering scheme used for the NMR spectra.

Crystal data

C20H22O6	F(000) = 380
Mr = 358.38	Dx = 1.330 Mg m−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 8592 reflections
a = 4.8504 (10) Å	θ = 2.2–27.2°
b = 15.847 (3) Å	µ = 0.10 mm−1
c = 12.0159 (19) Å	T = 298 K
β = 104.250 (8)°	Prism, colorless
V = 895.2 (3) Å3	0.49 × 0.35 × 0.22 mm
Z = 2

Data collection

Bruker SMART CCD area-detector diffractometer	1980 independent reflections
Radiation source: fine-focus sealed tube	1713 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.032
Detector resolution: 0 pixels mm-1	θmax = 27.2°, θmin = 2.2°
φ and ω scans	h = −6→5
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	k = −20→20
Tmin = 0.960, Tmax = 0.979	l = −15→14
8592 measured reflections

Refinement

Refinement on F2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.039	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.130	H-atom parameters constrained
S = 1.02	w = 1/[σ2(Fo2) + (0.0876P)2 + 0.1852P] where P = (Fo2 + 2Fc2)/3
1980 reflections	(Δ/σ)max < 0.001
119 parameters	Δρmax = 0.34 e Å−3
0 restraints	Δρmin = −0.34 e Å−3

Special details

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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 > 2sigma(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
O1	−1.19587 (17)	0.35479 (5)	−0.09590 (7)	0.0219 (2)
O2	−0.9567 (2)	0.37413 (6)	0.08774 (8)	0.0313 (3)
O3	−0.30202 (17)	0.06258 (5)	−0.06554 (7)	0.0209 (2)
C1	−1.5949 (3)	0.43801 (8)	−0.19241 (11)	0.0302 (3)
H1A	−1.7199	0.4833	−0.1843	0.045*
H1B	−1.7026	0.3869	−0.2106	0.045*
H1C	−1.5046	0.4510	−0.2530	0.045*
C2	−1.3723 (3)	0.42675 (7)	−0.08179 (11)	0.0234 (3)
H2A	−1.2566	0.4772	−0.0643	0.028*
H2B	−1.4617	0.4164	−0.0192	0.028*
C3	−0.9916 (2)	0.33543 (7)	−0.00155 (10)	0.0199 (3)
C4	−0.8119 (2)	0.26316 (7)	−0.01966 (10)	0.0188 (3)
C5	−0.8593 (2)	0.21922 (7)	−0.12413 (10)	0.0199 (3)
H5A	−1.0097	0.2346	−0.1851	0.024*
C6	−0.6832 (2)	0.15314 (7)	−0.13669 (10)	0.0196 (3)
H6A	−0.7145	0.1243	−0.2060	0.024*
C7	−0.4580 (2)	0.12990 (7)	−0.04481 (10)	0.0174 (3)
C8	−0.4063 (2)	0.17353 (7)	0.05940 (10)	0.0197 (3)
H8A	−0.2549	0.1584	0.1201	0.024*
C9	−0.5851 (2)	0.23998 (7)	0.07089 (10)	0.0197 (3)
H9A	−0.5526	0.2693	0.1400	0.024*
C10	−0.0671 (2)	0.03624 (7)	0.02485 (9)	0.0182 (3)
H10A	−0.1317	0.0179	0.0912	0.022*
H10B	0.0678	0.0820	0.0478	0.022*

Atomic displacement parameters (Ų)

	U11	U22	U33	U12	U13	U23
O1	0.0219 (4)	0.0201 (4)	0.0220 (4)	0.0073 (3)	0.0025 (3)	−0.0001 (3)
O2	0.0341 (5)	0.0299 (5)	0.0257 (5)	0.0111 (4)	−0.0005 (4)	−0.0075 (4)
O3	0.0185 (4)	0.0204 (4)	0.0212 (4)	0.0056 (3)	0.0002 (3)	−0.0036 (3)
C1	0.0313 (7)	0.0299 (7)	0.0275 (7)	0.0108 (5)	0.0034 (5)	0.0042 (5)
C2	0.0235 (6)	0.0183 (5)	0.0281 (6)	0.0065 (4)	0.0058 (5)	−0.0008 (4)
C3	0.0199 (6)	0.0182 (5)	0.0209 (6)	0.0009 (4)	0.0040 (4)	0.0011 (4)
C4	0.0188 (6)	0.0169 (5)	0.0210 (6)	0.0006 (4)	0.0053 (4)	0.0014 (4)
C5	0.0198 (6)	0.0192 (5)	0.0194 (6)	0.0013 (4)	0.0025 (4)	0.0023 (4)
C6	0.0217 (6)	0.0190 (5)	0.0176 (5)	−0.0001 (4)	0.0036 (4)	−0.0007 (4)
C7	0.0163 (5)	0.0154 (5)	0.0210 (6)	0.0002 (4)	0.0053 (4)	0.0007 (4)
C8	0.0176 (5)	0.0200 (5)	0.0200 (6)	0.0009 (4)	0.0019 (4)	0.0004 (4)
C9	0.0208 (6)	0.0186 (5)	0.0191 (6)	−0.0001 (4)	0.0039 (4)	−0.0022 (4)
C10	0.0158 (5)	0.0176 (5)	0.0200 (5)	0.0017 (4)	0.0021 (4)	−0.0008 (4)

Geometric parameters (Å, °)

O1—C3	1.3446 (14)	C4—C5	1.4040 (16)
O1—C2	1.4604 (13)	C5—C6	1.3829 (15)
O2—C3	1.2109 (15)	C5—H5A	0.9300
O3—C7	1.3659 (13)	C6—C7	1.3977 (16)
O3—C10	1.4294 (13)	C6—H6A	0.9300
C1—C2	1.5027 (18)	C7—C8	1.3978 (16)
C1—H1A	0.9600	C8—C9	1.3925 (16)
C1—H1B	0.9600	C8—H8A	0.9300
C1—H1C	0.9600	C9—H9A	0.9300
C2—H2A	0.9700	C10—C10i	1.513 (2)
C2—H2B	0.9700	C10—H10A	0.9700
C3—C4	1.4874 (15)	C10—H10B	0.9700
C4—C9	1.3928 (16)
C3—O1—C2	114.29 (9)	C6—C5—H5A	119.9
C7—O3—C10	117.60 (8)	C4—C5—H5A	119.9
C2—C1—H1A	109.5	C5—C6—C7	119.79 (10)
C2—C1—H1B	109.5	C5—C6—H6A	120.1
H1A—C1—H1B	109.5	C7—C6—H6A	120.1
C2—C1—H1C	109.5	O3—C7—C6	114.96 (10)
H1A—C1—H1C	109.5	O3—C7—C8	124.36 (10)
H1B—C1—H1C	109.5	C6—C7—C8	120.68 (10)
O1—C2—C1	107.71 (10)	C9—C8—C7	118.94 (11)
O1—C2—H2A	110.2	C9—C8—H8A	120.5
C1—C2—H2A	110.2	C7—C8—H8A	120.5
O1—C2—H2B	110.2	C8—C9—C4	120.89 (10)
C1—C2—H2B	110.2	C8—C9—H9A	119.6
H2A—C2—H2B	108.5	C4—C9—H9A	119.6
O2—C3—O1	123.03 (10)	O3—C10—C10i	105.17 (11)
O2—C3—C4	124.07 (11)	O3—C10—H10A	110.7
O1—C3—C4	112.89 (10)	C10i—C10—H10A	110.7
C9—C4—C5	119.45 (10)	O3—C10—H10B	110.7
C9—C4—C3	117.87 (10)	C10i—C10—H10B	110.7
C5—C4—C3	122.68 (11)	H10A—C10—H10B	108.8
C6—C5—C4	120.23 (11)
C3—O1—C2—C1	−177.91 (10)	C10—O3—C7—C6	179.46 (9)
C2—O1—C3—O2	0.12 (16)	C10—O3—C7—C8	−1.26 (16)
C2—O1—C3—C4	−178.70 (9)	C5—C6—C7—O3	178.44 (9)
O2—C3—C4—C9	−1.66 (17)	C5—C6—C7—C8	−0.88 (16)
O1—C3—C4—C9	177.15 (9)	O3—C7—C8—C9	−178.42 (10)
O2—C3—C4—C5	179.57 (11)	C6—C7—C8—C9	0.83 (16)
O1—C3—C4—C5	−1.62 (16)	C7—C8—C9—C4	−0.16 (16)
C9—C4—C5—C6	0.41 (16)	C5—C4—C9—C8	−0.45 (16)
C3—C4—C5—C6	179.16 (10)	C3—C4—C9—C8	−179.26 (10)
C4—C5—C6—C7	0.25 (16)	C7—O3—C10—C10i	−178.04 (10)

Symmetry codes: (i) −x, −y, −z.

Hydrogen-bond geometry (Å, °)

Cg is the centroid of the C4–C9 ring.

D—H···A	D—H	H···A	D···A	D—H···A
C6—H6A···O2ii	0.93	2.47	3.2784 (16)	146.
C10—H10B···Cgiii	0.97	2.65	3.741 (2)	143

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