2,2′-[Ethane-1,2-diylbis(­oxy)]dibenz­alde­hyde

In the title compound, C₁₆H₁₄O₄, the benzene rings are inclined at a dihedral angle of 75.14 (9)°. The torsion angle of the bridging O—C—C—O group is −76.50 (11)°. In the crystal, mol­ecules are linked by C—H...O hydrogen bonds, forming C(6) chains along [100]. Furthermore, C—H...π inter­actions and π–π stacking inter­actions [centroid–centroid distances = 3.6957 (7) and 3.6735 (8) Å] contribute to the stability of the crystal packing.

Key indicators

• Single-crystal X-ray study
• T = 120 K
• Mean [sigma](C-C) = 0.002 Å
• R factor = 0.039
• wR factor = 0.101
• Data-to-parameter ratio = 16.3

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT906_ALERT_3_C Large K value in the Analysis of Variance ......      2.444
PLAT910_ALERT_3_C Missing # of FCF Reflections Below Th(Min) .....          2
PLAT911_ALERT_3_C Missing # FCF Refl Between THmin & STh/L=  0.600          5

Alert level G
PLAT005_ALERT_5_G No _iucr_refine_instructions_details  in the CIF          ? Do !
PLAT063_ALERT_4_G Crystal Size Likely too Large for Beam Size ....       0.62 mm
PLAT912_ALERT_4_G Missing # of FCF Reflections Above STh/L=  0.600          4

   0 ALERT level A = Most likely a serious problem - resolve or explain
   0 ALERT level B = A potentially serious problem, consider carefully
   3 ALERT level C = Check. Ensure it is not caused by an omission or oversight
   3 ALERT level G = General information/check it is not something unexpected

   0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   0 ALERT type 2 Indicator that the structure model may be wrong or deficient
   3 ALERT type 3 Indicator that the structure quality may be low
   2 ALERT type 4 Improvement, methodology, query or suggestion
   1 ALERT type 5 Informative message, check

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S1. Comment

The synthesis of bis functionalized compounds has attracted the interest of chemists in chemical industry. Such compounds are considered as significant precursores for building blocks of vital molecules in different studies such as supramolecular chemistry and nanoscience (Holland et al., 2007), bioactive bis heterocyclic compounds (Pedras et al., 2010; Mabkhot et al., 2012), and binucleating ligand designs (Gavrilova & Bosnich, 2004). In this concept the title compound has been synthesized among several derivatives of bis functionalized compounds as precursers for the synthesis of a series of macromolecular compounds.

The dihedral angle between the two benzene rings (C3–C8 and C10–C15) of the title compound (Fig. 1) is 75.14 (9)°. The torsion angle of the bridge O–C–C–O group is -76.50 (11)°. The C3–C4–C9–O3 and C10–C11–C16–O4 torsion angles of the two benzaldehyde groups are 175.10 (11) and -175.87 (13)°, respectively. Thus, they are almost coplanar with the rings to which they are attached. The bond lengths are normal (Allen et al., 1987).

In the crystal, molecules are connected by C–H···O hydrogen bonds, generating infinite chains with the graph-set motif C(6) (Table 1, Fig. 2; Bernstein et al., 1995) along the a axis. In addition, C–H···π interactions (Table 1) and π-π stacking interactions [Cg1···Cg1( - x, 2 - y, 1 - z) = 3.6957 (7) Å and Cg2···Cg2( 1 - x, 1 - y, 1 - z) = 3.6735 (8) Å; where Cg1 and Cg2 are the centroids of the C3–C8 and C10–C15 benzene rings, respectively] contribute to stabilize the crystal structure.

Related literature

For the synthesis and utlization of bis-funtionalized compounds, see: Holland et al. (2007); Pedras et al. (2010); Mabkhot et al. (2012); Gavrilova & Bosnich (2004). For bond-length data, see: Allen et al. (1987). For graph-set theory, see: Bernstein et al. (1995).

S2. Experimental

A solution of 1.22 g m (0.01 mol) salicyldehyde in hot ethanolic KOH (prepared by dissolving 560 mg (0.01 mol) KOH in 100 ml of absolute ethanol) was stirred until a clear solution was obtained, which was then evaporated under vacuum. The residue was dissolved in DMF (25 ml) and 940 mg (0.005 mol) of dibromoethane was added. The reaction mixture was refluxed for 5 minutes, during which KBr was separated out. The solvent was then removed in vacuo and the remaining solid was washed with water and crystallized from ethanol to give high quality crystals (Mp. 393 K) suitable for X-ray analysis in an good yield (84%).

S3. Refinement

All H atoms were found in a difference map, but placed geometrically with C—H = 0.95 Å (aromatic H) and 0.99 Å (methylene H) and were refined using a riding model with U_iso(H) = 1.2U_eq(C).

Computing details

Data collection: CrystalClear-SM Expert (Rigaku, 2012); cell refinement: CrystalClear-SM Expert (Rigaku, 2012); data reduction: CrystalClear-SM Expert (Rigaku, 2012); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012); software used to prepare material for publication: WinGX (Farrugia, 2012) and PLATON (Spek, 2009).

Figures

	Fig. 1. View of the molecular structure of the title compound with the atom numbering scheme. Displacement ellipsoids for non-H atoms are drawn at the 50% probability level.
	Fig. 2. Partial packing diagram of the title compound showing hydrogen bonds as dashed lines. H atoms not involved in hydrogen bonds have been omitted for clarity.

2,2'-[Ethane-1,2-diylbis(oxy)]dibenzaldehyde

Crystal data

C16H14O4	Z = 2
Mr = 270.27	F(000) = 284
Triclinic, P1	Dx = 1.381 Mg m^−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71075 Å
a = 7.7571 (1) Å	Cell parameters from 4015 reflections
b = 8.3277 (1) Å	θ = 1.9–27.5°
c = 11.2965 (1) Å	µ = 0.10 mm^−1
α = 82.283 (7)°	T = 120 K
β = 75.839 (7)°	Block, colourless
γ = 66.823 (6)°	0.62 × 0.44 × 0.22 mm
V = 649.87 (4) Å^3

Data collection

Rigaku R-AXIS conversion diffractometer	2969 independent reflections
Radiation source: Sealed Tube	2862 reflections with I > 2σ(I)
Graphite Monochromator monochromator	Rint = 0.031
Detector resolution: 10.0000 pixels mm^-1	θmax = 27.5°, θmin = 2.9°
profile data from ω–scans	h = −10→8
Absorption correction: multi-scan (CrystalClear-SM Expert; Rigaku, 2012)	k = −10→10
Tmin = 0.878, Tmax = 1.000	l = −14→14
9715 measured reflections

Refinement

Refinement on F^2	Hydrogen site location: inferred from neighbouring sites
Least-squares matrix: full	H-atom parameters constrained
R[F^2 > 2σ(F^2)] = 0.039	W = 1/[Σ^2(FO^2) + (0.0397P)^2 + 0.2051P] WHERE P = (FO^2 + 2FC^2)/3
wR(F^2) = 0.101	(Δ/σ)max < 0.001
S = 1.07	Δρmax = 0.34 e Å^−3
2969 reflections	Δρmin = −0.19 e Å^−3
182 parameters	Extinction correction: SHELXL97 (Sheldrick, 2008), FC^*=KFC[1+0.001XFC^2Λ^3/SIN(2Θ)]^-1/4
0 restraints	Extinction coefficient: 0.039 (4)

Special details

Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All su's are estimated from the variances of the (full) variance-covariance matrix. The cell e.s.d.'s are taken into account in the estimation of distances, angles and torsion angles

Refinement. Refinement on F² for ALL reflections except those flagged by the user for potential systematic errors. Weighted R-factors wR and all goodnesses of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The observed criterion of F² > σ(F²) is used only for calculating -R-factor-obs 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	0.02681 (11)	0.67683 (11)	0.39979 (7)	0.0234 (2)
O2	0.09562 (12)	0.63138 (10)	0.13897 (7)	0.0229 (2)
O3	0.42624 (12)	0.70766 (12)	0.54585 (8)	0.0310 (3)
O4	0.29048 (14)	0.91784 (11)	−0.12808 (8)	0.0335 (3)
C1	−0.10587 (16)	0.66169 (14)	0.33728 (10)	0.0222 (3)
C2	0.00997 (16)	0.53887 (14)	0.23588 (10)	0.0221 (3)
C3	−0.04430 (16)	0.76808 (13)	0.50371 (9)	0.0198 (3)
C4	0.09320 (16)	0.78082 (14)	0.55953 (10)	0.0203 (3)
C5	0.03276 (17)	0.87486 (14)	0.66511 (10)	0.0238 (3)
C6	−0.16055 (18)	0.95186 (15)	0.71668 (10)	0.0264 (3)
C7	−0.29501 (17)	0.93499 (15)	0.66234 (10)	0.0254 (3)
C8	−0.23910 (16)	0.84489 (14)	0.55568 (10)	0.0225 (3)
C9	0.29937 (16)	0.69362 (15)	0.50767 (10)	0.0235 (3)
C10	0.20867 (15)	0.54157 (14)	0.03822 (10)	0.0201 (3)
C11	0.28537 (16)	0.63720 (14)	−0.05755 (10)	0.0205 (3)
C12	0.40808 (16)	0.55234 (15)	−0.16216 (10)	0.0237 (3)
C13	0.45243 (17)	0.37632 (16)	−0.17322 (11)	0.0267 (3)
C14	0.37194 (17)	0.28415 (15)	−0.07953 (11)	0.0255 (3)
C15	0.25049 (17)	0.36520 (15)	0.02579 (10)	0.0228 (3)
C16	0.23854 (17)	0.82470 (15)	−0.04713 (11)	0.0252 (3)
H1A	−0.18070	0.77750	0.30370	0.0270*
H1B	−0.19620	0.61520	0.39420	0.0270*
H2A	0.11090	0.43660	0.26590	0.0270*
H2B	−0.07370	0.49650	0.20600	0.0270*
H5	0.12500	0.88620	0.70190	0.0290*
H6	−0.20120	1.01580	0.78860	0.0320*
H7	−0.42750	0.98600	0.69880	0.0300*
H8	−0.33240	0.83580	0.51880	0.0270*
H9	0.33550	0.62190	0.44020	0.0280*
H12	0.46170	0.61600	−0.22640	0.0280*
H13	0.53720	0.31880	−0.24420	0.0320*
H14	0.40060	0.16380	−0.08780	0.0310*
H15	0.19620	0.30080	0.08900	0.0270*
H16	0.16270	0.87630	0.02780	0.0300*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.0200 (4)	0.0302 (4)	0.0205 (4)	−0.0089 (3)	−0.0034 (3)	−0.0061 (3)
O2	0.0284 (4)	0.0212 (4)	0.0187 (4)	−0.0107 (3)	−0.0016 (3)	−0.0015 (3)
O3	0.0251 (5)	0.0358 (5)	0.0361 (5)	−0.0147 (4)	−0.0104 (4)	0.0025 (4)
O4	0.0444 (6)	0.0263 (4)	0.0336 (5)	−0.0190 (4)	−0.0086 (4)	0.0051 (4)
C1	0.0208 (5)	0.0257 (5)	0.0218 (5)	−0.0099 (4)	−0.0053 (4)	−0.0010 (4)
C2	0.0255 (6)	0.0231 (5)	0.0197 (5)	−0.0118 (4)	−0.0047 (4)	0.0009 (4)
C3	0.0227 (5)	0.0180 (5)	0.0180 (5)	−0.0084 (4)	−0.0031 (4)	0.0013 (4)
C4	0.0231 (5)	0.0192 (5)	0.0193 (5)	−0.0100 (4)	−0.0044 (4)	0.0035 (4)
C5	0.0310 (6)	0.0215 (5)	0.0222 (5)	−0.0123 (5)	−0.0090 (4)	0.0026 (4)
C6	0.0341 (6)	0.0218 (5)	0.0203 (5)	−0.0087 (5)	−0.0028 (5)	−0.0026 (4)
C7	0.0240 (6)	0.0220 (5)	0.0244 (5)	−0.0059 (4)	0.0002 (4)	−0.0003 (4)
C8	0.0215 (5)	0.0230 (5)	0.0228 (5)	−0.0090 (4)	−0.0043 (4)	0.0006 (4)
C9	0.0240 (6)	0.0250 (5)	0.0219 (5)	−0.0107 (4)	−0.0056 (4)	0.0035 (4)
C10	0.0199 (5)	0.0228 (5)	0.0190 (5)	−0.0077 (4)	−0.0068 (4)	−0.0013 (4)
C11	0.0210 (5)	0.0220 (5)	0.0210 (5)	−0.0093 (4)	−0.0077 (4)	0.0009 (4)
C12	0.0245 (6)	0.0262 (6)	0.0212 (5)	−0.0103 (4)	−0.0055 (4)	0.0005 (4)
C13	0.0284 (6)	0.0272 (6)	0.0217 (5)	−0.0079 (5)	−0.0029 (4)	−0.0045 (4)
C14	0.0299 (6)	0.0206 (5)	0.0264 (6)	−0.0082 (4)	−0.0079 (5)	−0.0030 (4)
C15	0.0264 (6)	0.0224 (5)	0.0219 (5)	−0.0111 (4)	−0.0071 (4)	0.0015 (4)
C16	0.0296 (6)	0.0234 (5)	0.0246 (5)	−0.0106 (5)	−0.0087 (5)	−0.0001 (4)

Geometric parameters (Å, º)

O1—C1	1.4337 (16)	C12—C13	1.3834 (17)
O1—C3	1.3611 (13)	C13—C14	1.3910 (18)
O2—C2	1.4332 (14)	C14—C15	1.3876 (17)
O2—C10	1.3593 (13)	C1—H1A	0.9900
O3—C9	1.2166 (17)	C1—H1B	0.9900
O4—C16	1.2147 (15)	C2—H2A	0.9900
C1—C2	1.5011 (15)	C2—H2B	0.9900
C3—C4	1.4081 (18)	C5—H5	0.9500
C3—C8	1.3940 (18)	C6—H6	0.9500
C4—C5	1.3942 (15)	C7—H7	0.9500
C4—C9	1.4731 (18)	C8—H8	0.9500
C5—C6	1.3839 (19)	C9—H9	0.9500
C6—C7	1.392 (2)	C12—H12	0.9500
C7—C8	1.3906 (16)	C13—H13	0.9500
C10—C11	1.4090 (16)	C14—H14	0.9500
C10—C15	1.3929 (16)	C15—H15	0.9500
C11—C12	1.3951 (16)	C16—H16	0.9500
C11—C16	1.4717 (16)
C1—O1—C3	118.45 (10)	C2—C1—H1A	110.00
C2—O2—C10	117.35 (8)	C2—C1—H1B	110.00
O1—C1—C2	107.09 (10)	H1A—C1—H1B	109.00
O2—C2—C1	108.23 (9)	O2—C2—H2A	110.00
O1—C3—C4	115.69 (11)	O2—C2—H2B	110.00
O1—C3—C8	124.17 (11)	C1—C2—H2A	110.00
C4—C3—C8	120.14 (10)	C1—C2—H2B	110.00
C3—C4—C5	119.49 (11)	H2A—C2—H2B	108.00
C3—C4—C9	120.26 (10)	C4—C5—H5	120.00
C5—C4—C9	120.24 (12)	C6—C5—H5	120.00
C4—C5—C6	120.50 (12)	C5—C6—H6	120.00
C5—C6—C7	119.52 (11)	C7—C6—H6	120.00
C6—C7—C8	121.24 (12)	C6—C7—H7	119.00
C3—C8—C7	119.08 (12)	C8—C7—H7	119.00
O3—C9—C4	124.12 (11)	C3—C8—H8	120.00
O2—C10—C11	116.23 (9)	C7—C8—H8	120.00
O2—C10—C15	123.99 (10)	O3—C9—H9	118.00
C11—C10—C15	119.79 (10)	C4—C9—H9	118.00
C10—C11—C12	119.48 (10)	C11—C12—H12	120.00
C10—C11—C16	120.45 (10)	C13—C12—H12	120.00
C12—C11—C16	120.07 (11)	C12—C13—H13	120.00
C11—C12—C13	120.59 (11)	C14—C13—H13	120.00
C12—C13—C14	119.48 (11)	C13—C14—H14	119.00
C13—C14—C15	121.06 (11)	C15—C14—H14	119.00
C10—C15—C14	119.57 (11)	C10—C15—H15	120.00
O4—C16—C11	124.30 (11)	C14—C15—H15	120.00
O1—C1—H1A	110.00	O4—C16—H16	118.00
O1—C1—H1B	110.00	C11—C16—H16	118.00
C3—O1—C1—C2	−173.57 (9)	C4—C5—C6—C7	−0.04 (16)
C1—O1—C3—C8	1.68 (15)	C5—C6—C7—C8	−1.24 (17)
C1—O1—C3—C4	−178.90 (9)	C6—C7—C8—C3	0.98 (17)
C10—O2—C2—C1	179.42 (10)	O2—C10—C11—C12	177.80 (11)
C2—O2—C10—C15	−2.20 (18)	O2—C10—C11—C16	−1.51 (18)
C2—O2—C10—C11	177.73 (11)	C15—C10—C11—C12	−2.27 (19)
O1—C1—C2—O2	−76.50 (11)	C15—C10—C11—C16	178.42 (12)
O1—C3—C4—C9	−1.99 (15)	O2—C10—C15—C14	−178.22 (12)
C8—C3—C4—C5	−1.78 (16)	C11—C10—C15—C14	1.9 (2)
O1—C3—C8—C7	179.93 (9)	C10—C11—C12—C13	1.0 (2)
C4—C3—C8—C7	0.54 (16)	C16—C11—C12—C13	−179.70 (13)
C8—C3—C4—C9	177.46 (10)	C10—C11—C16—O4	−175.87 (13)
O1—C3—C4—C5	178.78 (10)	C12—C11—C16—O4	4.8 (2)
C3—C4—C9—O3	175.10 (11)	C11—C12—C13—C14	0.7 (2)
C5—C4—C9—O3	−5.67 (18)	C12—C13—C14—C15	−1.1 (2)
C3—C4—C5—C6	1.53 (16)	C13—C14—C15—C10	−0.2 (2)
C9—C4—C5—C6	−177.71 (10)

Hydrogen-bond geometry (Å, º)

Cg1 and Cg2 are the centroids of the C3–C8 and C10–C15 benzene rings, respectively.

D—H···A	D—H	H···A	D···A	D—H···A
C8—H8···O3^i	0.95	2.44	3.2508 (17)	144
C9—H9···O1	0.95	2.40	2.7412 (16)	101
C16—H16···O2	0.95	2.42	2.7561 (15)	101
C2—H2A···Cg1^ii	0.99	2.68	3.4220 (12)	132
C2—H2B···Cg2^iii	0.99	2.70	3.5964 (14)	151

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