A new polymorph of 4,4'-(ethyl­enedi­oxy)dibenzaldehyde

The crystal structure of a new crystalline form of 4,4'-(ethyl­enedi­oxy)dibenzaldehyde, C₁₆H₁₄O₄, has been determined in the space group Cc using low-temperature X-ray diffraction data. The two phenyl rings have a dihedral angle of 76.03 (6)°, in contrast to their near-coplanarity in the previously reported polymorph.

Key indicators

• Single-crystal X-ray study
• T = 100 K
• Mean [sigma](C-C) = 0.003 Å
• R factor = 0.039
• wR factor = 0.107
• Data-to-parameter ratio = 8.5

checkCIF/PLATON results

No syntax errors found



Alert level B
PLAT111_ALERT_2_B ADDSYM Detects (Pseudo) Centre of Symmetry .....         90 PerFi

Alert level C
PLAT062_ALERT_4_C Rescale T(min) & T(max) by .....................       0.97

Alert level G
REFLT03_ALERT_4_G Please check that the estimate of the number of Friedel pairs is
            correct. If it is not, please give the correct count in the
            _publ_section_exptl_refinement section of the submitted CIF.
           From the CIF: _diffrn_reflns_theta_max           28.01
           From the CIF: _reflns_number_total               1547
           Count of symmetry unique reflns         1554
           Completeness (_total/calc)             99.55%
           TEST3: Check Friedels for noncentro structure
           Estimate of Friedel pairs measured         0
           Fraction of Friedel pairs measured     0.000
           Are heavy atom types Z>Si present         no

   0 ALERT level A = In general: serious problem
   1 ALERT level B = Potentially serious problem
   1 ALERT level C = Check and explain
   1 ALERT level G = General alerts; check

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

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Computing details

Data collection: SMART (Bruker, 2001); cell refinement: SAINT (Bruker, 2001); data reduction: SAINT (Bruker, 2001); program(s) used to solve structure: SHELXTL (Sheldrick, 2001); program(s) used to refine structure: SHELXTL; molecular graphics: ORTEP-3 (Version 1.08; Farugia, 1997); software used to prepare material for publication: SHELXTL.

4,4'-(ethylenedioxy)dibenzaldehyde

Crystal data

C16H14O4	F(000) = 568
Mr = 270.27	Dx = 1.400 Mg m^−3
Monoclinic, Cc	Melting point: 385 K
Hall symbol: C -2yc	Mo Kα radiation, λ = 0.71073 Å
a = 16.024 (3) Å	Cell parameters from 4018 reflections
b = 11.300 (2) Å	θ = 2.3–28.0°
c = 7.8015 (16) Å	µ = 0.10 mm^−1
β = 114.79 (3)°	T = 100 K
V = 1282.5 (5) Å^3	Prism, colourless
Z = 4	0.45 × 0.30 × 0.27 mm

Data collection

Bruker SMART APEX CCD area-detector diffractometer	1547 independent reflections
Radiation source: sealed X-ray tube, Bruker SMART APEX	1542 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.017
1700 ω scan frames, 0.3°, 10 sec	θmax = 28.0°, θmin = 2.3°
Absorption correction: multi-scan (SADABS; Sheldrick, 2004)	h = −21→17
Tmin = 0.907, Tmax = 1.000	k = −14→12
5563 measured reflections	l = −10→10

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.039	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.107	H-atom parameters constrained
S = 1.04	w = 1/[σ^2(Fo^2) + (0.0727P)^2 + 0.5376P] where P = (Fo^2 + 2Fc^2)/3
1547 reflections	(Δ/σ)max < 0.001
181 parameters	Δρmax = 0.34 e Å^−3
2 restraints	Δρmin = −0.22 e Å^−3

Special details

Experimental. Refinement of F² against unique set of 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.

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 unique set of 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
O1	0.57553 (10)	0.61655 (14)	0.4986 (2)	0.0199 (3)
O2	1.00723 (12)	0.59686 (15)	1.0323 (3)	0.0289 (4)
O3	0.41579 (11)	0.61540 (14)	0.1430 (2)	0.0212 (3)
O4	0.02783 (13)	0.72937 (15)	−0.5308 (2)	0.0281 (4)
C1	0.66725 (14)	0.6242 (2)	0.6154 (3)	0.0174 (4)
C2	0.69131 (15)	0.7177 (2)	0.7439 (3)	0.0196 (4)
H2	0.6460	0.7717	0.7445	0.024*
C3	0.78259 (15)	0.7305 (2)	0.8709 (3)	0.0205 (4)
H3	0.7998	0.7946	0.9579	0.025*
C4	0.84986 (15)	0.65037 (19)	0.8729 (3)	0.0183 (4)
C5	0.82417 (15)	0.5578 (2)	0.7416 (3)	0.0201 (4)
H5	0.8693	0.5032	0.7416	0.024*
C6	0.73362 (15)	0.5449 (2)	0.6116 (3)	0.0196 (4)
H6	0.7168	0.4829	0.5210	0.023*
C7	0.94565 (16)	0.6642 (2)	1.0132 (3)	0.0226 (5)
H7	0.9599	0.7310	1.0944	0.027*
C8	0.54651 (15)	0.51773 (19)	0.3720 (3)	0.0207 (4)
H8A	0.5679	0.4429	0.4430	0.025*
H8B	0.5726	0.5235	0.2777	0.025*
C9	0.44283 (16)	0.51972 (19)	0.2747 (3)	0.0203 (4)
H9A	0.4196	0.4439	0.2080	0.024*
H9B	0.4170	0.5307	0.3687	0.024*
C10	0.32553 (14)	0.62357 (19)	0.0213 (3)	0.0182 (4)
C11	0.30470 (16)	0.7128 (2)	−0.1164 (3)	0.0209 (5)
H11	0.3518	0.7632	−0.1179	0.025*
C12	0.21533 (15)	0.72623 (19)	−0.2490 (3)	0.0204 (5)
H12	0.2013	0.7857	−0.3431	0.024*
C13	0.14526 (15)	0.65375 (19)	−0.2468 (3)	0.0193 (4)
C14	0.16614 (15)	0.5665 (2)	−0.1089 (3)	0.0209 (4)
H14	0.1185	0.5175	−0.1064	0.025*
C15	0.25634 (15)	0.5501 (2)	0.0258 (3)	0.0196 (4)
H15	0.2704	0.4900	0.1188	0.023*
C16	0.05003 (15)	0.6685 (2)	−0.3900 (3)	0.0218 (4)
H16	0.0028	0.6276	−0.3709	0.026*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.0155 (7)	0.0218 (8)	0.0190 (7)	0.0001 (6)	0.0039 (6)	−0.0026 (6)
O2	0.0186 (7)	0.0277 (8)	0.0348 (9)	0.0022 (7)	0.0057 (6)	0.0007 (7)
O3	0.0185 (7)	0.0233 (8)	0.0185 (7)	−0.0031 (6)	0.0043 (6)	0.0029 (6)
O4	0.0216 (7)	0.0336 (9)	0.0246 (8)	0.0071 (7)	0.0052 (6)	0.0039 (7)
C1	0.0155 (10)	0.0210 (10)	0.0151 (9)	−0.0005 (7)	0.0059 (8)	0.0017 (7)
C2	0.0181 (10)	0.0181 (10)	0.0228 (10)	0.0015 (8)	0.0087 (8)	−0.0013 (8)
C3	0.0188 (10)	0.0196 (10)	0.0211 (10)	−0.0034 (8)	0.0064 (8)	−0.0027 (8)
C4	0.0193 (10)	0.0166 (10)	0.0186 (10)	0.0001 (8)	0.0074 (8)	0.0014 (7)
C5	0.0190 (11)	0.0204 (11)	0.0220 (10)	0.0019 (8)	0.0097 (9)	0.0008 (8)
C6	0.0221 (11)	0.0179 (10)	0.0192 (10)	−0.0001 (8)	0.0091 (9)	−0.0018 (7)
C7	0.0197 (11)	0.0243 (11)	0.0217 (10)	−0.0042 (8)	0.0066 (9)	−0.0016 (8)
C8	0.0192 (10)	0.0230 (10)	0.0172 (9)	0.0006 (9)	0.0050 (8)	−0.0025 (8)
C9	0.0211 (10)	0.0199 (10)	0.0165 (9)	−0.0022 (8)	0.0043 (8)	0.0008 (8)
C10	0.0189 (10)	0.0189 (10)	0.0150 (9)	0.0000 (7)	0.0055 (8)	−0.0020 (7)
C11	0.0205 (11)	0.0212 (11)	0.0219 (10)	−0.0023 (8)	0.0098 (9)	0.0009 (8)
C12	0.0238 (12)	0.0169 (9)	0.0219 (11)	0.0017 (8)	0.0110 (9)	0.0021 (8)
C13	0.0172 (10)	0.0207 (11)	0.0200 (10)	0.0022 (8)	0.0078 (8)	−0.0029 (8)
C14	0.0190 (10)	0.0228 (11)	0.0217 (10)	−0.0028 (8)	0.0095 (8)	−0.0030 (8)
C15	0.0189 (10)	0.0215 (10)	0.0179 (9)	−0.0015 (8)	0.0072 (8)	0.0002 (7)
C16	0.0180 (11)	0.0208 (11)	0.0247 (10)	0.0002 (8)	0.0069 (9)	−0.0038 (8)

Geometric parameters (Å, º)

O1—C1	1.369 (2)	C8—C9	1.510 (3)
O1—C8	1.433 (3)	C8—H8A	0.9900
O2—C7	1.205 (3)	C8—H8B	0.9900
O3—C10	1.360 (3)	C9—H9A	0.9900
O3—C9	1.428 (3)	C9—H9B	0.9900
O4—C16	1.216 (3)	C10—C15	1.397 (3)
C1—C2	1.395 (3)	C10—C11	1.407 (3)
C1—C6	1.401 (3)	C11—C12	1.379 (3)
C2—C3	1.388 (3)	C11—H11	0.9500
C2—H2	0.9500	C12—C13	1.396 (3)
C3—C4	1.403 (3)	C12—H12	0.9500
C3—H3	0.9500	C13—C14	1.393 (3)
C4—C5	1.400 (3)	C13—C16	1.475 (3)
C4—C7	1.473 (3)	C14—C15	1.398 (3)
C5—C6	1.386 (3)	C14—H14	0.9500
C5—H5	0.9500	C15—H15	0.9500
C6—H6	0.9500	C16—H16	0.9500
C7—H7	0.9500
C1—O1—C8	117.11 (17)	H8A—C8—H8B	108.5
C10—O3—C9	117.82 (16)	O3—C9—C8	108.13 (18)
O1—C1—C2	114.99 (19)	O3—C9—H9A	110.1
O1—C1—C6	123.91 (19)	C8—C9—H9A	110.1
C2—C1—C6	121.1 (2)	O3—C9—H9B	110.1
C3—C2—C1	118.9 (2)	C8—C9—H9B	110.1
C3—C2—H2	120.6	H9A—C9—H9B	108.4
C1—C2—H2	120.6	O3—C10—C15	124.39 (19)
C2—C3—C4	121.0 (2)	O3—C10—C11	115.08 (18)
C2—C3—H3	119.5	C15—C10—C11	120.5 (2)
C4—C3—H3	119.5	C12—C11—C10	119.4 (2)
C5—C4—C3	119.1 (2)	C12—C11—H11	120.3
C5—C4—C7	121.19 (19)	C10—C11—H11	120.3
C3—C4—C7	119.8 (2)	C11—C12—C13	120.9 (2)
C6—C5—C4	120.7 (2)	C11—C12—H12	119.5
C6—C5—H5	119.7	C13—C12—H12	119.5
C4—C5—H5	119.7	C12—C13—C14	119.4 (2)
C5—C6—C1	119.2 (2)	C12—C13—C16	120.5 (2)
C5—C6—H6	120.4	C14—C13—C16	120.1 (2)
C1—C6—H6	120.4	C13—C14—C15	120.8 (2)
O2—C7—C4	124.7 (2)	C13—C14—H14	119.6
O2—C7—H7	117.6	C15—C14—H14	119.6
C4—C7—H7	117.6	C10—C15—C14	118.9 (2)
O1—C8—C9	107.80 (18)	C10—C15—H15	120.5
O1—C8—H8A	110.1	C14—C15—H15	120.5
C9—C8—H8A	110.1	O4—C16—C13	124.5 (2)
O1—C8—H8B	110.1	O4—C16—H16	117.8
C9—C8—H8B	110.1	C13—C16—H16	117.8
C8—O1—C1—C2	−176.24 (18)	O1—C8—C9—O3	72.20 (18)
C8—O1—C1—C6	3.1 (3)	C9—O3—C10—C15	5.1 (3)
O1—C1—C2—C3	178.49 (19)	C9—O3—C10—C11	−174.22 (18)
C6—C1—C2—C3	−0.8 (3)	O3—C10—C11—C12	178.52 (19)
C1—C2—C3—C4	−0.8 (3)	C15—C10—C11—C12	−0.8 (3)
C2—C3—C4—C5	1.3 (3)	C10—C11—C12—C13	0.9 (3)
C2—C3—C4—C7	−178.1 (2)	C11—C12—C13—C14	−0.2 (3)
C3—C4—C5—C6	−0.2 (3)	C11—C12—C13—C16	−179.64 (19)
C7—C4—C5—C6	179.27 (19)	C12—C13—C14—C15	−0.6 (3)
C4—C5—C6—C1	−1.4 (3)	C16—C13—C14—C15	178.89 (19)
O1—C1—C6—C5	−177.32 (19)	O3—C10—C15—C14	−179.19 (18)
C2—C1—C6—C5	1.9 (3)	C11—C10—C15—C14	0.1 (3)
C5—C4—C7—O2	−3.3 (3)	C13—C14—C15—C10	0.6 (3)
C3—C4—C7—O2	176.2 (2)	C12—C13—C16—O4	11.0 (3)
C1—O1—C8—C9	173.54 (16)	C14—C13—C16—O4	−168.5 (2)
C10—O3—C9—C8	171.20 (17)