1,4-Bis[(2,6-dimethoxy-phen-yl)ethyn-yl]benzene.

The title compound, C(26)H(22)O(4), is a derivative of 1,4-bis-(phenyl-ethyn-yl)benzene substituted by four meth-oxy groups at the terminal benzene rings. The asymmetric unit consists of two half-molecules; one centrosymmetric molecule is planar but the other is non-planar, with dihedral angles of 67.7 (1)° between the central benzene ring and the terminal benzene rings. In the crystal structure, mol-ecules form a zigzag mol-ecular network due to π-π [the inter-planar and centroid-centroid distances between the benzene rings are 3.50 (1) and 3.57 (1) Å, respectively] and C-H⋯π inter-actions (2.75 Å). Introduction of the four meth-oxy groups results in the supra-molecular architecture.

Related literature

The synthetic research of ethynylated aromatic compounds has attracted considerable attention because of inter­est in their mol­ecular structures (Bunz et al., 1999 ▶; Kawase et al., 2003 ▶), optical properties (Beeby et al., 2002 ▶; Bunz, 2000 ▶) and mol­ecular electronics (Tour, 2000 ▶). 1,4-Bis(phenyl­ethyn­yl)benzene is used as a building block in applications such as liquid-crystalline materials (Dai et al., 1999 ▶) and electron-conducting mol­ecular wires (Moore et al., 2006 ▶). For related mol­ecular structures, including a 1,4-bis­(phenyl­ethyn­yl)benzene system, see: Watt et al. (2004 ▶); Li et al. (1998 ▶); Filatov & Petrukhina (2005 ▶).

Experimental

Crystal data

C26H22O4

M = 398.44

Monoclinic,

a = 12.391 (4) Å

b = 10.313 (3) Å

c = 16.611 (5) Å

β = 95.323 (4)°

V = 2113.5 (11) Å3

Z = 4

Mo Kα radiation

μ = 0.08 mm−1

T = 173 (1) K

0.47 × 0.35 × 0.10 mm

Data collection

Rigaku/MSC Mercury CCD diffractometer

Absorption correction: none

16248 measured reflections

4775 independent reflections

4206 reflections with I > 2σ(I)

R int = 0.028

Refinement

R[F 2 > 2σ(F 2)] = 0.055

wR(F 2) = 0.120

S = 1.12

4775 reflections

271 parameters

H-atom parameters constrained

Δρmax = 0.20 e Å−3

Δρmin = −0.16 e Å−3

Data collection: CrystalClear (Rigaku/MSC, 2001 ▶); cell refinement: CrystalClear; data reduction: CrystalClear; program(s) used to solve structure: SIR2004 (Burla et al., 2005 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: PLATON (Spek, 2003 ▶) and Mercury (Macrae et al., 2006 ▶); software used to prepare material for publication: WinGX (Farrugia, 1999 ▶).

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536808013664/xu2425sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808013664/xu2425Isup2.hkl

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

C26H22O4	F000 = 840
Mr = 398.44	Dx = 1.252 Mg m−3
Monoclinic, P21/c	Melting point = 528–529 K
Hall symbol: -P 2ybc	Mo Kα radiation λ = 0.71073 Å
a = 12.391 (4) Å	Cell parameters from 5564 reflections
b = 10.313 (3) Å	θ = 3.2–27.5º
c = 16.611 (5) Å	µ = 0.08 mm−1
β = 95.323 (4)º	T = 173 (1) K
V = 2113.5 (11) Å3	Block, yellow
Z = 4	0.47 × 0.35 × 0.10 mm

Rigaku/MSC Mercury CCD diffractometer	4775 independent reflections
Radiation source: rotating-anode X-ray tube	4206 reflections with I > 2σ(I)
Monochromator: Graphite Monochromator	Rint = 0.028
Detector resolution: 14.6199 pixels mm-1	θmax = 27.5º
T = 173(1) K	θmin = 3.2º
φ and ω scans	h = −16→11
Absorption correction: none	k = −13→11
16248 measured reflections	l = −21→21

Refinement on F2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.055	H-atom parameters constrained
wR(F2) = 0.120	w = 1/[σ2(Fo2) + (0.044P)2 + 0.7208P] where P = (Fo2 + 2Fc2)/3
S = 1.12	(Δ/σ)max < 0.001
4775 reflections	Δρmax = 0.20 e Å−3
271 parameters	Δρmin = −0.16 e Å−3
Primary atom site location: structure-invariant direct methods	Extinction correction: none

Experimental. IR (KBr, cm-1): 3002, 2836, 2209, 1582, 1514, 1474, 1429, 1300, 1258, 1113, 1034, 843, 772, 718; 1H NMR (CDCl3, δ p.p.m.): 3.92 (s, 12H), 6.56 (d, J = 8.4 Hz, 4H), 7.25 (t, J = 8.4 Hz, 2H), 7.54 (s, 4H); 13C NMR (CDCl3, δ p.p.m.): 56.1, 83.5, 97.8, 101.5, 103.5, 123.4, 130.0, 131.5, 161.5; MS (EI): m/z 399 (M+ + 1), 161.

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.

	x	y	z	Uiso*/Ueq
C1	0.78035 (10)	−0.11242 (15)	0.26308 (8)	0.0283 (3)
C2	0.78339 (11)	−0.21811 (16)	0.31655 (9)	0.0316 (3)
C3	0.86038 (12)	−0.22279 (19)	0.38320 (10)	0.0417 (4)
H3	0.8632	−0.2949	0.4189	0.050*
C4	0.93251 (13)	−0.1214 (2)	0.39674 (10)	0.0476 (5)
H4	0.9849	−0.1250	0.4422	0.057*
C5	0.93074 (12)	−0.0146 (2)	0.34601 (10)	0.0437 (4)
H5	0.9809	0.0542	0.3567	0.052*
C6	0.85420 (11)	−0.00986 (16)	0.27909 (9)	0.0332 (3)
C7	0.70162 (11)	−0.10222 (14)	0.19462 (8)	0.0269 (3)
C8	0.63967 (11)	−0.08077 (13)	0.13629 (8)	0.0270 (3)
C9	0.56837 (10)	−0.04176 (13)	0.06729 (8)	0.0238 (3)
C10	0.47959 (11)	−0.11676 (14)	0.03736 (8)	0.0274 (3)
H10	0.4653	−0.1967	0.0628	0.033*
C11	0.58769 (11)	0.07592 (14)	0.02880 (8)	0.0269 (3)
H11	0.6476	0.1281	0.0484	0.032*
C12	0.70206 (18)	−0.4179 (2)	0.35277 (12)	0.0591 (5)
H12A	0.6438	−0.4770	0.3325	0.089*
H12B	0.6878	−0.3857	0.4063	0.089*
H12C	0.7714	−0.4643	0.3568	0.089*
C13	0.90402 (17)	0.2050 (2)	0.24194 (13)	0.0617 (6)
H13A	0.8873	0.2678	0.1983	0.093*
H13B	0.9815	0.1843	0.2460	0.093*
H13C	0.8854	0.2423	0.2931	0.093*
C14	0.70955 (10)	0.10378 (14)	0.44408 (9)	0.0280 (3)
C15	0.70353 (11)	0.00310 (15)	0.50009 (10)	0.0333 (3)
C16	0.62828 (13)	−0.09645 (16)	0.48519 (11)	0.0414 (4)
H16	0.6247	−0.1658	0.5225	0.050*
C17	0.55901 (13)	−0.09237 (17)	0.41523 (12)	0.0451 (4)
H17	0.5071	−0.1597	0.4054	0.054*
C18	0.56229 (12)	0.00605 (17)	0.35890 (10)	0.0401 (4)
H18	0.5134	0.0065	0.3114	0.048*
C19	0.63847 (11)	0.10420 (14)	0.37318 (9)	0.0302 (3)
C20	0.78731 (11)	0.20559 (14)	0.45872 (9)	0.0281 (3)
C21	0.85122 (11)	0.29250 (14)	0.46985 (9)	0.0287 (3)
C22	0.92644 (10)	0.39768 (13)	0.48466 (8)	0.0251 (3)
C23	0.91450 (11)	0.48457 (15)	0.54763 (9)	0.0311 (3)
H23	0.8561	0.4744	0.5803	0.037*
C24	1.01269 (11)	0.41447 (15)	0.43720 (9)	0.0320 (3)
H24	1.0215	0.3561	0.3941	0.038*
C25	0.76768 (17)	−0.0831 (2)	0.62854 (14)	0.0679 (7)
H25A	0.8233	−0.0663	0.6732	0.102*
H25B	0.7787	−0.1696	0.6063	0.102*
H25C	0.6958	−0.0787	0.6485	0.102*
C26	0.58057 (15)	0.21684 (19)	0.25079 (11)	0.0494 (5)
H26A	0.5990	0.2945	0.2209	0.074*
H26B	0.5055	0.2231	0.2644	0.074*
H26C	0.5886	0.1399	0.2173	0.074*
O1	0.70668 (9)	−0.31087 (11)	0.29821 (6)	0.0383 (3)
O2	0.84253 (9)	0.08962 (12)	0.22507 (7)	0.0428 (3)
O3	0.77520 (9)	0.01165 (12)	0.56704 (7)	0.0462 (3)
O4	0.65148 (8)	0.20675 (11)	0.32338 (6)	0.0374 (3)

	U11	U22	U33	U12	U13	U23
C1	0.0245 (6)	0.0386 (8)	0.0220 (7)	0.0056 (6)	0.0025 (5)	−0.0012 (6)
C2	0.0286 (7)	0.0411 (9)	0.0249 (7)	0.0099 (6)	0.0010 (5)	0.0001 (6)
C3	0.0373 (8)	0.0587 (11)	0.0279 (8)	0.0169 (8)	−0.0038 (6)	0.0035 (7)
C4	0.0310 (8)	0.0764 (14)	0.0334 (9)	0.0144 (8)	−0.0082 (6)	−0.0078 (9)
C5	0.0270 (7)	0.0650 (12)	0.0391 (9)	−0.0019 (7)	0.0031 (6)	−0.0161 (9)
C6	0.0294 (7)	0.0447 (9)	0.0263 (7)	0.0011 (6)	0.0077 (6)	−0.0052 (7)
C7	0.0307 (7)	0.0261 (7)	0.0240 (7)	0.0023 (5)	0.0028 (5)	0.0014 (5)
C8	0.0315 (7)	0.0251 (7)	0.0244 (7)	0.0023 (5)	0.0021 (5)	0.0016 (6)
C9	0.0260 (6)	0.0248 (7)	0.0206 (6)	0.0037 (5)	0.0023 (5)	−0.0001 (5)
C10	0.0320 (7)	0.0230 (7)	0.0272 (7)	−0.0013 (5)	0.0023 (5)	0.0050 (5)
C11	0.0267 (6)	0.0255 (7)	0.0278 (7)	−0.0030 (5)	−0.0006 (5)	0.0005 (6)
C12	0.0762 (13)	0.0491 (12)	0.0504 (12)	−0.0019 (10)	−0.0032 (10)	0.0238 (9)
C13	0.0676 (12)	0.0600 (13)	0.0596 (13)	−0.0301 (10)	0.0166 (10)	−0.0093 (10)
C14	0.0229 (6)	0.0256 (7)	0.0358 (8)	−0.0026 (5)	0.0049 (5)	−0.0056 (6)
C15	0.0274 (6)	0.0305 (8)	0.0426 (9)	−0.0034 (6)	0.0054 (6)	−0.0011 (7)
C16	0.0392 (8)	0.0315 (8)	0.0552 (11)	−0.0087 (7)	0.0129 (7)	−0.0013 (8)
C17	0.0361 (8)	0.0408 (10)	0.0597 (11)	−0.0162 (7)	0.0118 (8)	−0.0179 (9)
C18	0.0286 (7)	0.0485 (10)	0.0432 (9)	−0.0069 (7)	0.0033 (6)	−0.0195 (8)
C19	0.0254 (6)	0.0314 (8)	0.0343 (8)	0.0004 (5)	0.0056 (6)	−0.0098 (6)
C20	0.0256 (6)	0.0285 (7)	0.0300 (7)	0.0002 (5)	0.0012 (5)	−0.0003 (6)
C21	0.0274 (6)	0.0284 (7)	0.0295 (7)	−0.0016 (5)	−0.0018 (5)	0.0024 (6)
C22	0.0245 (6)	0.0252 (7)	0.0244 (7)	−0.0023 (5)	−0.0042 (5)	0.0049 (5)
C23	0.0289 (7)	0.0376 (8)	0.0271 (7)	−0.0072 (6)	0.0044 (5)	−0.0015 (6)
C24	0.0325 (7)	0.0346 (8)	0.0289 (7)	−0.0055 (6)	0.0031 (6)	−0.0072 (6)
C25	0.0531 (11)	0.0773 (16)	0.0714 (14)	−0.0161 (10)	−0.0051 (10)	0.0420 (13)
C26	0.0521 (10)	0.0511 (11)	0.0417 (10)	0.0142 (8)	−0.0138 (8)	−0.0071 (8)
O1	0.0445 (6)	0.0364 (6)	0.0326 (6)	0.0021 (5)	−0.0033 (5)	0.0101 (5)
O2	0.0515 (7)	0.0427 (7)	0.0349 (6)	−0.0140 (5)	0.0081 (5)	−0.0049 (5)
O3	0.0429 (6)	0.0470 (7)	0.0468 (7)	−0.0138 (5)	−0.0057 (5)	0.0164 (6)
O4	0.0366 (5)	0.0418 (7)	0.0326 (6)	0.0005 (5)	−0.0035 (4)	−0.0025 (5)

C1—C2	1.404 (2)	C14—C15	1.401 (2)
C1—C6	1.408 (2)	C14—C19	1.404 (2)
C1—C7	1.4318 (19)	C14—C20	1.4306 (19)
C2—O1	1.3630 (19)	C15—O3	1.3601 (19)
C2—C3	1.394 (2)	C15—C16	1.394 (2)
C3—C4	1.380 (3)	C16—C17	1.380 (3)
C3—H3	0.9500	C16—H16	0.9500
C4—C5	1.386 (3)	C17—C18	1.384 (3)
C4—H4	0.9500	C17—H17	0.9500
C5—C6	1.394 (2)	C18—C19	1.389 (2)
C5—H5	0.9500	C18—H18	0.9500
C6—O2	1.362 (2)	C19—O4	1.3614 (19)
C7—C8	1.1996 (19)	C20—C21	1.199 (2)
C8—C9	1.4382 (18)	C21—C22	1.4364 (19)
C9—C10	1.3979 (19)	C22—C23	1.396 (2)
C9—C11	1.4026 (19)	C22—C24	1.3964 (19)
C10—C11i	1.3821 (19)	C23—C24ii	1.385 (2)
C10—H10	0.9500	C23—H23	0.9500
C11—C10i	1.3821 (19)	C24—C23ii	1.385 (2)
C11—H11	0.9500	C24—H24	0.9500
C12—O1	1.433 (2)	C25—O3	1.423 (2)
C12—H12A	0.9800	C25—H25A	0.9800
C12—H12B	0.9800	C25—H25B	0.9800
C12—H12C	0.9800	C25—H25C	0.9800
C13—O2	1.427 (2)	C26—O4	1.4284 (19)
C13—H13A	0.9800	C26—H26A	0.9800
C13—H13B	0.9800	C26—H26B	0.9800
C13—H13C	0.9800	C26—H26C	0.9800
C2—C1—C6	119.00 (13)	C19—C14—C20	120.04 (13)
C2—C1—C7	122.39 (13)	O3—C15—C16	124.64 (15)
C6—C1—C7	118.55 (13)	O3—C15—C14	115.09 (13)
O1—C2—C3	124.40 (15)	C16—C15—C14	120.27 (15)
O1—C2—C1	115.23 (12)	C17—C16—C15	118.74 (16)
C3—C2—C1	120.37 (15)	C17—C16—H16	120.6
C4—C3—C2	119.23 (16)	C15—C16—H16	120.6
C4—C3—H3	120.4	C16—C17—C18	122.47 (15)
C2—C3—H3	120.4	C16—C17—H17	118.8
C3—C4—C5	121.97 (15)	C18—C17—H17	118.8
C3—C4—H4	119.0	C17—C18—C19	118.76 (15)
C5—C4—H4	119.0	C17—C18—H18	120.6
C4—C5—C6	118.97 (16)	C19—C18—H18	120.6
C4—C5—H5	120.5	O4—C19—C18	125.39 (14)
C6—C5—H5	120.5	O4—C19—C14	114.32 (12)
O2—C6—C5	125.10 (15)	C18—C19—C14	120.29 (15)
O2—C6—C1	114.47 (13)	C21—C20—C14	178.63 (16)
C5—C6—C1	120.43 (15)	C20—C21—C22	178.69 (16)
C8—C7—C1	173.14 (15)	C23—C22—C24	118.91 (12)
C7—C8—C9	174.33 (15)	C23—C22—C21	120.06 (12)
C10—C9—C11	118.60 (12)	C24—C22—C21	121.03 (13)
C10—C9—C8	122.25 (13)	C24ii—C23—C22	120.42 (13)
C11—C9—C8	119.15 (12)	C24ii—C23—H23	119.8
C11i—C10—C9	120.72 (13)	C22—C23—H23	119.8
C11i—C10—H10	119.6	C23ii—C24—C22	120.68 (13)
C9—C10—H10	119.6	C23ii—C24—H24	119.7
C10i—C11—C9	120.68 (13)	C22—C24—H24	119.7
C10i—C11—H11	119.7	O3—C25—H25A	109.5
C9—C11—H11	119.7	O3—C25—H25B	109.5
O1—C12—H12A	109.5	H25A—C25—H25B	109.5
O1—C12—H12B	109.5	O3—C25—H25C	109.5
H12A—C12—H12B	109.5	H25A—C25—H25C	109.5
O1—C12—H12C	109.5	H25B—C25—H25C	109.5
H12A—C12—H12C	109.5	O4—C26—H26A	109.5
H12B—C12—H12C	109.5	O4—C26—H26B	109.5
O2—C13—H13A	109.5	H26A—C26—H26B	109.5
O2—C13—H13B	109.5	O4—C26—H26C	109.5
H13A—C13—H13B	109.5	H26A—C26—H26C	109.5
O2—C13—H13C	109.5	H26B—C26—H26C	109.5
H13A—C13—H13C	109.5	C2—O1—C12	117.87 (13)
H13B—C13—H13C	109.5	C6—O2—C13	118.48 (14)
C15—C14—C19	119.45 (13)	C15—O3—C25	117.46 (14)
C15—C14—C20	120.51 (13)	C19—O4—C26	118.12 (13)
C6—C1—C2—O1	177.73 (12)	O3—C15—C16—C17	179.04 (15)
C7—C1—C2—O1	0.57 (19)	C14—C15—C16—C17	−1.2 (2)
C6—C1—C2—C3	−1.7 (2)	C15—C16—C17—C18	0.8 (2)
C7—C1—C2—C3	−178.89 (13)	C16—C17—C18—C19	0.3 (2)
O1—C2—C3—C4	−178.42 (14)	C17—C18—C19—O4	179.83 (14)
C1—C2—C3—C4	1.0 (2)	C17—C18—C19—C14	−0.8 (2)
C2—C3—C4—C5	0.1 (2)	C15—C14—C19—O4	179.83 (12)
C3—C4—C5—C6	−0.4 (2)	C20—C14—C19—O4	−0.16 (18)
C4—C5—C6—O2	179.10 (14)	C15—C14—C19—C18	0.4 (2)
C4—C5—C6—C1	−0.4 (2)	C20—C14—C19—C18	−179.56 (13)
C2—C1—C6—O2	−178.13 (12)	C15—C14—C20—C21	−160 (7)
C7—C1—C6—O2	−0.85 (18)	C19—C14—C20—C21	20 (7)
C2—C1—C6—C5	1.4 (2)	C14—C20—C21—C22	91 (11)
C7—C1—C6—C5	178.71 (13)	C20—C21—C22—C23	2(7)
C2—C1—C7—C8	171.6 (11)	C20—C21—C22—C24	−179 (100)
C6—C1—C7—C8	−5.6 (12)	C24—C22—C23—C24ii	−0.2 (2)
C1—C7—C8—C9	−13 (2)	C21—C22—C23—C24ii	179.38 (13)
C7—C8—C9—C10	−158.3 (14)	C23—C22—C24—C23ii	0.2 (2)
C7—C8—C9—C11	21.2 (15)	C21—C22—C24—C23ii	−179.37 (14)
C11—C9—C10—C11i	0.1 (2)	C3—C2—O1—C12	2.6 (2)
C8—C9—C10—C11i	179.59 (13)	C1—C2—O1—C12	−176.88 (14)
C10—C9—C11—C10i	−0.1 (2)	C5—C6—O2—C13	−7.5 (2)
C8—C9—C11—C10i	−179.60 (12)	C1—C6—O2—C13	171.99 (14)
C19—C14—C15—O3	−179.60 (13)	C16—C15—O3—C25	−4.4 (2)
C20—C14—C15—O3	0.4 (2)	C14—C15—O3—C25	175.75 (16)
C19—C14—C15—C16	0.6 (2)	C18—C19—O4—C26	1.0 (2)
C20—C14—C15—C16	−179.42 (14)	C14—C19—O4—C26	−178.37 (13)