2,5-Bis(methoxy­meth­yl)-1,4-dioctyloxybenzene

The title mol­ecule, C₂₆H₄₆O₄, has symmetry. The non-H atoms of the oct­yloxy and methoxy­methyl chains are almost coplanar with the benzene ring. There are weak C—H...O hydrogen bonds and C—H...π-ring inter­actions in the structure. The mol­ecules are loosely packed in the structure. The unit-cell volume is 20% larger than is expected from the empirical rule pertinent to organic compounds, which states that the unit-cell volume (ų) is approximately equal to the number of non-H atoms in the unit cell multiplied by 18.

Key indicators

• Single-crystal X-ray study
• T = 293 K
• Mean [sigma](C-C) = 0.003 Å
• R factor = 0.074
• wR factor = 0.204
• Data-to-parameter ratio = 24.5

checkCIF/PLATON results

No syntax errors found



Alert level C
ABSTM02_ALERT_3_C  The ratio of expected to reported Tmax/Tmin(RR') is < 0.90
            Tmin and Tmax reported:      0.746     0.884
            Tmin(prime) and Tmax expected:      0.966     0.983
            RR(prime) =      0.858
            Please check that your absorption correction is appropriate.
PLAT026_ALERT_3_C Ratio Observed / Unique Reflections too Low ....         48 Perc.
PLAT061_ALERT_3_C Tmax/Tmin Range Test RR' too Large .............       0.86
PLAT062_ALERT_4_C Rescale T(min) & T(max) by .....................       1.11
PLAT230_ALERT_2_C Hirshfeld Test Diff for    O1     -   C3      ..       5.51 su
PLAT230_ALERT_2_C Hirshfeld Test Diff for    O2     -   C12     ..       5.68 su
PLAT250_ALERT_2_C Large U3/U1 Ratio for Average U(i,j) Tensor ....       2.31
PLAT764_ALERT_4_C Overcomplete CIF Bond List Detected (Rep/Expd) .       1.13 Ratio

Alert level G
ABSTM02_ALERT_3_G  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      1.112
            Tmax scaled      0.983 Tmin scaled      0.829
PLAT199_ALERT_1_G Check the Reported _cell_measurement_temperature        293 K
PLAT200_ALERT_1_G Check the Reported _diffrn_ambient_temperature .        293 K

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

   2 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   3 ALERT type 2 Indicator that the structure model may be wrong or deficient
   4 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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S1. Comment

The title molecule (Fig. 1) is situated on a crystallographic inversion centre. The non-hydrogen atoms of the octyloxy chains and methoxylmethyl chains are almost coplanar with the benzene ring. The structure is interesting for its loose packing. The unit cell volume of the title structure is by 1.20 larger than it is expected if the 18 ų rule of the volume per non-hydrogen atom in the structure is taken into account (Kempster & Lipson, 1972). Despite the loose packing there are no large voids in the structure (Spek, 2003).

Related literature

For related literature regarding the synthesis of the title compound, see: Wang & Wasielewski (1997). For related literature, see: Kempster & Lipson (1972); Spek (2003).

S2. Experimental

In accordance with preparative methods of similar compounds (Wang & Wasielewski, 1997), 6 ml of the solution of HBr in acetic acid (100 ml of the latter solution contained 31 g of HBr) was added at once to a suspension of 1,4-bis(octyloxy)benzene (5.9 g, 15.1 mmol) and paraformaldehyde (0.93 g, 31.0 mmol) in acetic acid (50 ml). This mixture was then heated to 60–70 °C under stirring for 2 h.

After cooling down to room temperature, the suspension was poured into 300 ml of water. The precipitate was filtered and dissolved in 30 ml of hot chloroform (temperature: 50–55 °C), then 50 ml of methanol was added under stirring. After cooling to room temperature, the white solid was filtered off and dried under vacuum.

The white solid was dissolved in petroleum ether that boils in the interval 60–90°C. The crystals suitable for X-ray structure determination were obtained by slow evaporation at room temperature.

¹HNMR and ¹³CNMR were determined with a Bruker Avance 400 MHz NMR spectrometer with tetramethylsilane as an internal standard.

¹H NMR (CDCl₃, 400 MHz) δ (p.p.m.) 6.91 (s, 2 H), 4.48 (s, 4 H), 3.93 (m, 4 H), 3.42 (s, 6 H), 1.76 (m, 4 H), 1.45 (m, 4 H), 1.32 (m, 18 H), 0.89 (t, 6 H); ¹³C NMR (CDCl₃, 400 MHz) δ (p.p.m.) 150.0, 126.1, 111.9, 76.57, 68.73, 68.46, 57.86, 31.35, 28.98, 28.86, 28.78, 25.66, 13.60.

S3. Refinement

All the H atoms could be found in the difference Fourier maps. Nevertheless, they were placed into the idealized positions and refined in a riding atom approximation with following constraints: C_methyl - H_methyl = 0.96; C_methylene - H_methylene = 0.97; C_aryl - H_aryl = 0.93 Å. U_isoH = 1.2U_eqC except for methyls where U_isoH = 1.5U_eqC.

Computing details

Data collection: XSCANS (Bruker, 1996); cell refinement: XSCANS; data reduction: SHELXTL (Bruker, 1997); program(s) used to solve structure: SIR97 (Altomare et al., 1999); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL; software used to prepare material for publication: WinGX (Farrugia, 1999).

Figures

	Fig. 1. The molecular structure of title compound showing 50% probability displacement ellipsoids.
	Fig. 2. The packing diagram of the title structure.

2,5-Bis(methoxymethyl)-1,4-dioctyloxybenzene

Crystal data

C26H46O4	Z = 1
Mr = 422.63	F(000) = 234
Triclinic, P1	Dx = 1.081 Mg m^−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 6.6253 (9) Å	Cell parameters from 61 reflections
b = 8.8218 (9) Å	θ = 4.9–15.1°
c = 11.7625 (15) Å	µ = 0.07 mm^−1
α = 106.662 (8)°	T = 293 K
β = 95.398 (10)°	Prism, colourless
γ = 96.066 (9)°	0.48 × 0.38 × 0.25 mm
V = 649.32 (14) Å^3

Data collection

Bruker P4 diffractometer	1622 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.044
Graphite monochromator	θmax = 29.0°, θmin = 3.1°
ω scans	h = −8→1
Absorption correction: ψ scan (XSCANS; Bruker, 1996)	k = −11→11
Tmin = 0.746, Tmax = 0.884	l = −16→16
4198 measured reflections	3 standard reflections every 97 reflections
3375 independent reflections	intensity decay: 1.2%

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)] = 0.074	Hydrogen site location: difference Fourier map
wR(F^2) = 0.204	H-atom parameters constrained
S = 1.05	w = 1/[σ^2(Fo^2) + (0.0902P)^2] where P = (Fo^2 + 2Fc^2)/3
3375 reflections	(Δ/σ)max < 0.001
138 parameters	Δρmax = 0.20 e Å^−3
0 restraints	Δρmin = −0.21 e Å^−3
84 constraints

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	0.3812 (2)	0.14518 (16)	0.61889 (13)	0.0605 (5)
O2	0.0976 (3)	0.33836 (18)	0.38263 (15)	0.0781 (6)
C1	0.0952 (3)	−0.0715 (2)	0.57603 (17)	0.0481 (6)
H1A	0.1603	−0.1192	0.6275	0.058*
C2	0.0963 (3)	0.1405 (2)	0.48497 (17)	0.0457 (5)
C3	0.1910 (3)	0.0668 (2)	0.56160 (18)	0.0468 (5)
C4	0.4938 (3)	0.0743 (2)	0.69460 (19)	0.0504 (6)
H4A	0.5184	−0.0312	0.6493	0.061*
H4B	0.4179	0.0642	0.7593	0.061*
C5	0.6946 (3)	0.1825 (2)	0.74413 (18)	0.0519 (6)
H5A	0.6666	0.2895	0.7830	0.062*
H5B	0.7705	0.1874	0.6784	0.062*
C6	0.8262 (3)	0.1272 (2)	0.83323 (19)	0.0515 (5)
H6A	0.7490	0.1190	0.8978	0.062*
H6B	0.8585	0.0217	0.7937	0.062*
C7	1.0233 (3)	0.2394 (2)	0.88503 (19)	0.0543 (6)
H7A	0.9905	0.3455	0.9223	0.065*
H7B	1.1014	0.2455	0.8204	0.065*
C8	1.1552 (3)	0.1891 (3)	0.97676 (19)	0.0573 (6)
H8A	1.1896	0.0838	0.9389	0.069*
H8B	1.0758	0.1810	1.0405	0.069*
C9	1.3533 (3)	0.3028 (3)	1.0317 (2)	0.0592 (6)
H9A	1.4318	0.3123	0.9679	0.071*
H9B	1.3189	0.4078	1.0707	0.071*
C10	1.4858 (3)	0.2508 (3)	1.1217 (2)	0.0662 (7)
H10A	1.4068	0.2397	1.1849	0.079*
H10C	1.5225	0.1467	1.0824	0.079*
C11	1.6788 (4)	0.3651 (3)	1.1768 (3)	0.0897 (9)
H11A	1.7535	0.3271	1.2346	0.135*
H11B	1.6441	0.4687	1.2156	0.135*
H11C	1.7618	0.3723	1.1154	0.135*
C12	0.2062 (3)	0.2960 (2)	0.47022 (18)	0.0476 (5)
H12A	0.2199	0.3812	0.5452	0.057*
H12B	0.3424	0.2800	0.4497	0.057*
C13	0.1897 (4)	0.4850 (3)	0.3717 (2)	0.0841 (9)
H13A	0.1130	0.5101	0.3077	0.126*
H13B	0.3276	0.4759	0.3548	0.126*
H13C	0.1909	0.5683	0.4452	0.126*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.0485 (9)	0.0573 (9)	0.0761 (10)	−0.0090 (7)	−0.0201 (8)	0.0353 (8)
O2	0.0733 (11)	0.0697 (10)	0.0955 (12)	−0.0189 (9)	−0.0216 (10)	0.0518 (9)
C1	0.0416 (12)	0.0495 (11)	0.0541 (12)	−0.0006 (9)	−0.0102 (10)	0.0243 (10)
C2	0.0409 (11)	0.0458 (11)	0.0502 (12)	−0.0006 (9)	−0.0039 (10)	0.0195 (9)
C3	0.0346 (11)	0.0486 (11)	0.0532 (12)	−0.0057 (9)	−0.0096 (9)	0.0177 (9)
C4	0.0410 (12)	0.0537 (12)	0.0577 (13)	−0.0012 (9)	−0.0099 (10)	0.0263 (10)
C5	0.0434 (12)	0.0516 (12)	0.0588 (13)	−0.0041 (10)	−0.0082 (10)	0.0220 (10)
C6	0.0423 (12)	0.0560 (12)	0.0553 (12)	−0.0022 (10)	−0.0083 (10)	0.0233 (10)
C7	0.0460 (13)	0.0540 (12)	0.0604 (13)	−0.0052 (10)	−0.0083 (11)	0.0222 (10)
C8	0.0444 (12)	0.0618 (13)	0.0635 (14)	−0.0050 (11)	−0.0105 (11)	0.0251 (11)
C9	0.0470 (13)	0.0623 (14)	0.0631 (14)	−0.0064 (11)	−0.0122 (11)	0.0216 (11)
C10	0.0531 (14)	0.0697 (15)	0.0700 (15)	−0.0027 (12)	−0.0175 (12)	0.0237 (12)
C11	0.0639 (17)	0.101 (2)	0.0935 (19)	−0.0119 (15)	−0.0290 (15)	0.0328 (16)
C12	0.0333 (11)	0.0479 (11)	0.0563 (12)	−0.0026 (9)	−0.0104 (9)	0.0153 (9)
C13	0.0745 (19)	0.0752 (17)	0.114 (2)	−0.0097 (14)	−0.0009 (17)	0.0585 (16)

Geometric parameters (Å, º)

O1—C3	1.382 (2)	C7—H7A	0.9700
O1—C4	1.426 (2)	C7—H7B	0.9700
O2—C12	1.363 (2)	C8—C9	1.528 (3)
O2—C13	1.416 (2)	C8—H8A	0.9700
C1—C3	1.377 (3)	C8—H8B	0.9700
C1—C2^i	1.382 (2)	C9—C10	1.514 (3)
C1—H1A	0.9300	C9—H9A	0.9700
C2—C3	1.394 (3)	C9—H9B	0.9700
C2—C12	1.547 (3)	C10—C11	1.506 (3)
C3—C2	1.394 (3)	C10—H10A	0.9700
C4—C5	1.512 (2)	C10—H10C	0.9700
C4—H4A	0.9700	C11—H11A	0.9600
C4—H4B	0.9700	C11—H11B	0.9600
C5—C6	1.519 (3)	C11—H11C	0.9600
C5—H5A	0.9700	C12—C2	1.547 (3)
C5—H5B	0.9700	C12—H12A	0.9700
C6—C7	1.513 (2)	C12—H12B	0.9700
C6—H6A	0.9700	C13—H13A	0.9600
C6—H6B	0.9700	C13—H13B	0.9600
C7—C8	1.518 (3)	C13—H13C	0.9600
C3—O1—C4	118.11 (15)	C7—C8—H8A	108.7
C12—O2—C13	111.18 (17)	C9—C8—H8A	108.7
C3—C1—C2^i	120.90 (18)	C7—C8—H8B	108.7
C3—C1—H1A	119.6	C9—C8—H8B	108.7
C2^i—C1—H1A	119.6	H8A—C8—H8B	107.6
C1^i—C2—C3	118.55 (17)	C10—C9—C8	114.05 (19)
C1^i—C2—C12	121.69 (17)	C10—C9—H9A	108.7
C3—C2—C12	119.77 (17)	C8—C9—H9A	108.7
C1—C3—O1	125.25 (18)	C10—C9—H9B	108.7
C1—C3—C2	120.56 (17)	C8—C9—H9B	108.7
O1—C3—C2	114.19 (17)	H9A—C9—H9B	107.6
O1—C4—C5	107.17 (16)	C11—C10—C9	113.6 (2)
O1—C4—H4A	110.3	C11—C10—H10A	108.8
C5—C4—H4A	110.3	C9—C10—H10A	108.8
O1—C4—H4B	110.3	C11—C10—H10C	108.8
C5—C4—H4B	110.3	C9—C10—H10C	108.8
H4A—C4—H4B	108.5	H10A—C10—H10C	107.7
C4—C5—C6	113.12 (17)	C10—C11—H11A	109.5
C4—C5—H5A	109.0	C10—C11—H11B	109.5
C6—C5—H5A	109.0	H11A—C11—H11B	109.5
C4—C5—H5B	109.0	C10—C11—H11C	109.5
C6—C5—H5B	109.0	H11A—C11—H11C	109.5
H5A—C5—H5B	107.8	H11B—C11—H11C	109.5
C7—C6—C5	112.50 (17)	O2—C12—C2	110.14 (15)
C7—C6—H6A	109.1	O2—C12—H12A	109.6
C5—C6—H6A	109.1	C2—C12—H12A	109.6
C7—C6—H6B	109.1	O2—C12—H12B	109.6
C5—C6—H6B	109.1	C2—C12—H12B	109.6
H6A—C6—H6B	107.8	H12A—C12—H12B	108.1
C6—C7—C8	113.56 (17)	O2—C13—H13A	109.5
C6—C7—H7A	108.9	O2—C13—H13B	109.5
C8—C7—H7A	108.9	H13A—C13—H13B	109.5
C6—C7—H7B	108.9	O2—C13—H13C	109.5
C8—C7—H7B	108.9	H13A—C13—H13C	109.5
H7A—C7—H7B	107.7	H13B—C13—H13C	109.5
C7—C8—C9	114.26 (18)

Symmetry code: (i) −x, −y, −z+1.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C1—H1A···O2^i	0.93	2.41	2.747 (3)	101
C5—H5B···Cg1^ii	0.97	2.93	3.750 (2)	143
C5—H5B···Cg1^iii	0.97	2.93	3.750 (2)	143

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