Methyl 4-oxahepta-1,6-diene-2,6-di­carboxyl­ate

The crystal packing in the title compound, C₁₀H₁₄O₅, is determined by various weak C—H...O hydrogen bonds that result in parallel sheets of mol­ecules stacked along [010].

Key indicators

• Single-crystal X-ray study
• T = 153 K
• Mean [sigma](C-C) = 0.002 Å
• R factor = 0.039
• wR factor = 0.116
• Data-to-parameter ratio = 17.0

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry


 Alert Level B:



REFLT_03
         From the CIF: _diffrn_reflns_theta_max           28.29
         From the CIF: _reflns_number_total               2342
         TEST2: Reflns within _diffrn_reflns_theta_max
         Count of symmetry unique reflns         2689
         Completeness (_total/calc)             87.10%
          Alert B: < 90% complete (theta max?)

Author response: Some reflections missing due to rather weak diffraction at 2theta = 56.6\%. For 2theta = 55\% completeness is 93%, for 2theta = 50\% completeness is 98%.

General Notes



ABSTM_02  When printed, the submitted absorption T values will be replaced
          by the scaled T values. Since the ratio of scaled T's is
          identical to the ratio of reported T values, the scaling does
          not imply a change to the absorption corrections used in the
          study.
          Ratio of Tmax expected/reported      1.063
          Tmax scaled      0.989 Tmin scaled      0.945


 0 Alert Level A = Potentially serious problem

 1 Alert Level B = Potential problem

 0 Alert Level C = Please check

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S1. Comment

The title compound, (I), is interesting due to its high functionality. It can be used as a polymerizing agent not only on its own but also as a crosslinker. Although (I) has been well known for several years (Drewes et al., 1987), this is the first crystallographic determination.

The molecular structure of (I) shows non-crystallographic C_2v symmetry with atom O3 as its centre. The molecule is almost planar, with maximum deviations of −0.158 (1) Å for O4 and 0.120 (1) Å for O3 from the mean plane for all the atoms. The torsion angles C4—C3—C7—C8 and O2—C2—C9—O4 have values of 2.6 (1) and 9.4 (1)°, respectively. Bond lengths and angles are in good agreement with those reported for related structures, such as CIFYIZ10 or CUMYUE (Rohrer et al., 1984), and LIQHAU or LIQHIC (Steurer & Podlech, 1999). The crystal structure shows complex weak hydrogen-bonding patterns (Fig. 2). The C1—H1B···O4(x, y, z + 1) bridges of 2.44 Å (angle at H of 160°) lead to infinite chains of molecules along [001]. Additional C4—H4B···O2(x − 1, y, z) bridges of 2.53 Å (angle at H of 138°) in the [100] direction link these chains to sheets which are then stacked parallel along [010] with C5—H5B···O2(-x + 2, −y, −z + 2) and C10—H10B···O5(-x, −y + 1, −z + 1) contacts of 2.56 Å (angle at H of 152°) and 2.60 Å (angle at H of 142°), respectively. All these geometric parameters are normalized for C—H = 1.08 Å.

S2. Experimental

The compound was prepared according to a method already described in the literature (Drewes et al., 1987). After evaporation of the solvent fine plates of crystals were obtained and analysed via X-ray analysis. Furthermore NMR spectra were recorded on a Bruker AMX 300. ¹H NMR (300 MHz, CDCl₃, p.p.m.): δ = 3.77 (s, 6H, 2 × OCH₃), 4.55 (m, 4H, 2 × CH₂), 5.90 and 6.33 (m, 4H, 2 × ═CH₂); ¹³C NMR (75 MHz, CDCl₃): δ = 51.67 (q, 2 × OCH₃), 68.65 (t, 2 × CH₂), 125.89 (t, 2 × CH₂), 136.63 (s, 2 × ═C), 166.03 (s, 2 × C═O).

S3. Refinement

All H atoms were included in calculated positions, with C—H distances of 0.95 (for sp² H atoms), 0.99 (for sp³ H atoms) and 0.98 Å (for methyl sp³ H atoms). The H atoms were then included in the refinement riding on their parent atoms, with U_iso = 1.2U_eq (or 1.5U_eq for methyl H atoms).

Computing details

Data collection: SMART (Bruker, 1997); cell refinement: SMART; data reduction: SAINT (Bruker, 2000); program(s) used to solve structure: SHELXTL (Bruker, 1998); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL.

Figures

	Fig. 1. The molecular structure of the title compound. Displacement ellipsoids are drawn at the 50% probability level.
	Fig. 2. Packing diagram, viewed along [100]. Hydrogen bonding is indicated with dashed lines.

Methyl 4-oxahept-1,6-diene-2,6-dicarboxylate

Crystal data

C10H14O5	Z = 2
Mr = 214.21	F(000) = 228
Triclinic, P1	Dx = 1.315 Mg m^−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 6.8104 (13) Å	Cell parameters from 1575 reflections
b = 7.1777 (14) Å	θ = 3.1–28.2°
c = 12.458 (3) Å	µ = 0.11 mm^−1
α = 74.713 (3)°	T = 153 K
β = 78.365 (4)°	Plate, colorless
γ = 67.939 (3)°	0.50 × 0.50 × 0.10 mm
V = 540.84 (18) Å^3

Data collection

SMART APEX CCD area-detector diffractometer	2342 independent reflections
Radiation source: sealed tube	1880 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.035
ϕ and ω scans	θmax = 28.3°, θmin = 1.7°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −7→8
Tmin = 0.889, Tmax = 0.931	k = −9→9
3269 measured reflections	l = −14→15

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: difference Fourier map
wR(F^2) = 0.116	H-atom parameters constrained
S = 1.05	w = 1/[σ^2(Fo^2) + (0.0687P)^2] where P = (Fo^2 + 2Fc^2)/3
2342 reflections	(Δ/σ)max = 0.001
138 parameters	Δρmax = 0.18 e Å^−3
0 restraints	Δρmin = −0.24 e Å^−3

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
O1	0.71444 (12)	0.17269 (14)	1.29153 (6)	0.0327 (2)
O2	0.95015 (11)	0.15845 (13)	1.13605 (6)	0.0348 (2)
O3	0.47136 (11)	0.27161 (12)	0.94051 (6)	0.0276 (2)
O4	0.57704 (13)	0.22754 (15)	0.60466 (7)	0.0445 (3)
O5	0.22465 (12)	0.32825 (13)	0.59753 (7)	0.0354 (2)
C1	0.88874 (19)	0.1302 (2)	1.35511 (10)	0.0390 (3)
H1A	0.9927	−0.0067	1.3506	0.059*
H1B	0.8329	0.1353	1.4336	0.059*
H1C	0.9582	0.2334	1.3241	0.059*
C2	0.76908 (17)	0.18184 (16)	1.18083 (9)	0.0244 (3)
C3	0.58714 (16)	0.22190 (15)	1.11852 (9)	0.0227 (2)
C4	0.38952 (17)	0.24803 (17)	1.16838 (9)	0.0280 (3)
H4A	0.3597	0.2415	1.2469	0.034*
H4B	0.2781	0.2733	1.1255	0.034*
C5	0.65277 (16)	0.22592 (18)	0.99564 (9)	0.0266 (3)
H5A	0.7211	0.3313	0.9628	0.032*
H5B	0.7579	0.0908	0.9849	0.032*
C6	0.53389 (17)	0.26234 (17)	0.82555 (9)	0.0252 (3)
H6A	0.6425	0.1266	0.8188	0.030*
H6B	0.5978	0.3694	0.7876	0.030*
C7	0.34295 (17)	0.29528 (16)	0.77066 (9)	0.0250 (3)
C8	0.14597 (18)	0.32978 (19)	0.82317 (10)	0.0333 (3)
H8A	0.0328	0.3454	0.7840	0.040*
H8B	0.1185	0.3388	0.8998	0.040*
C9	0.39622 (18)	0.27957 (17)	0.65022 (9)	0.0278 (3)
C10	0.2706 (2)	0.3134 (2)	0.48025 (10)	0.0431 (3)
H10A	0.3513	0.4036	0.4392	0.065*
H10B	0.1365	0.3556	0.4482	0.065*
H10C	0.3551	0.1712	0.4743	0.065*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.0230 (4)	0.0513 (5)	0.0235 (4)	−0.0126 (4)	−0.0027 (3)	−0.0073 (4)
O2	0.0202 (4)	0.0519 (6)	0.0331 (5)	−0.0114 (4)	0.0006 (3)	−0.0142 (4)
O3	0.0201 (4)	0.0392 (5)	0.0229 (4)	−0.0081 (3)	−0.0021 (3)	−0.0088 (3)
O4	0.0266 (5)	0.0721 (7)	0.0307 (5)	−0.0109 (4)	0.0016 (4)	−0.0163 (4)
O5	0.0283 (5)	0.0479 (5)	0.0285 (5)	−0.0060 (4)	−0.0076 (3)	−0.0122 (4)
C1	0.0295 (7)	0.0600 (9)	0.0279 (6)	−0.0133 (6)	−0.0080 (5)	−0.0090 (6)
C2	0.0214 (6)	0.0251 (6)	0.0260 (6)	−0.0074 (4)	0.0003 (4)	−0.0072 (4)
C3	0.0204 (6)	0.0217 (5)	0.0254 (6)	−0.0065 (4)	−0.0017 (4)	−0.0052 (4)
C4	0.0226 (6)	0.0332 (6)	0.0277 (6)	−0.0100 (5)	−0.0016 (4)	−0.0060 (5)
C5	0.0177 (5)	0.0332 (6)	0.0268 (6)	−0.0066 (4)	−0.0012 (4)	−0.0070 (5)
C6	0.0211 (6)	0.0296 (6)	0.0242 (6)	−0.0081 (4)	0.0012 (4)	−0.0080 (4)
C7	0.0233 (6)	0.0235 (5)	0.0262 (6)	−0.0058 (4)	−0.0033 (4)	−0.0045 (4)
C8	0.0249 (6)	0.0415 (7)	0.0309 (6)	−0.0078 (5)	−0.0032 (5)	−0.0087 (5)
C9	0.0250 (6)	0.0295 (6)	0.0268 (6)	−0.0073 (5)	−0.0036 (5)	−0.0053 (5)
C10	0.0413 (8)	0.0589 (9)	0.0290 (7)	−0.0104 (6)	−0.0101 (5)	−0.0140 (6)

Geometric parameters (Å, º)

O1—C2	1.3447 (13)	C1—H1A	0.9800
O1—C1	1.4524 (13)	C1—H1B	0.9800
O2—C2	1.2151 (13)	C1—H1C	0.9800
O3—C6	1.4212 (13)	C4—H4A	0.9500
O3—C5	1.4230 (13)	C4—H4B	0.9500
O4—C9	1.2093 (14)	C5—H5A	0.9900
O5—C9	1.3416 (13)	C5—H5B	0.9900
O5—C10	1.4549 (14)	C6—H6A	0.9900
C2—C3	1.4911 (14)	C6—H6B	0.9900
C3—C4	1.3293 (15)	C8—H8A	0.9500
C3—C5	1.5016 (15)	C8—H8B	0.9500
C6—C7	1.5023 (15)	C10—H10A	0.9800
C7—C8	1.3308 (16)	C10—H10B	0.9800
C7—C9	1.4949 (15)	C10—H10C	0.9800
C2—O1—C1	115.15 (9)	C3—C4—H4A	120.0
C6—O3—C5	110.40 (8)	C3—C4—H4B	120.0
C9—O5—C10	115.18 (9)	H4A—C4—H4B	120.0
O2—C2—O1	123.04 (10)	O3—C5—H5A	109.7
O2—C2—C3	123.25 (10)	C3—C5—H5A	109.7
O1—C2—C3	113.71 (9)	O3—C5—H5B	109.7
C4—C3—C2	122.70 (10)	C3—C5—H5B	109.7
C4—C3—C5	124.47 (10)	H5A—C5—H5B	108.2
C2—C3—C5	112.82 (9)	O3—C6—H6A	109.7
O3—C5—C3	110.04 (8)	C7—C6—H6A	109.7
O3—C6—C7	109.70 (8)	O3—C6—H6B	109.7
C8—C7—C9	122.51 (10)	C7—C6—H6B	109.7
C8—C7—C6	124.25 (10)	H6A—C6—H6B	108.2
C9—C7—C6	113.22 (9)	C7—C8—H8A	120.0
O4—C9—O5	123.20 (10)	C7—C8—H8B	120.0
O4—C9—C7	123.12 (10)	H8A—C8—H8B	120.0
O5—C9—C7	113.68 (9)	O5—C10—H10A	109.5
O1—C1—H1A	109.5	O5—C10—H10B	109.5
O1—C1—H1B	109.5	H10A—C10—H10B	109.5
H1A—C1—H1B	109.5	O5—C10—H10C	109.5
O1—C1—H1C	109.5	H10A—C10—H10C	109.5
H1A—C1—H1C	109.5	H10B—C10—H10C	109.5
H1B—C1—H1C	109.5
C1—O1—C2—O2	−0.65 (16)	C5—O3—C6—C7	175.78 (8)
C1—O1—C2—C3	178.96 (9)	O3—C6—C7—C8	0.63 (15)
O2—C2—C3—C4	−179.73 (11)	O3—C6—C7—C9	−177.70 (8)
O1—C2—C3—C4	0.66 (15)	C10—O5—C9—O4	0.25 (17)
O2—C2—C3—C5	1.14 (15)	C10—O5—C9—C7	−179.64 (9)
O1—C2—C3—C5	−178.47 (8)	C8—C7—C9—O4	−172.14 (12)
C6—O3—C5—C3	−176.15 (8)	C6—C7—C9—O4	6.22 (16)
C4—C3—C5—O3	2.85 (15)	C8—C7—C9—O5	7.74 (16)
C2—C3—C5—O3	−178.03 (8)	C6—C7—C9—O5	−173.89 (9)