supplementary materials


zq2201 scheme

Acta Cryst. (2013). E69, o1167    [ doi:10.1107/S1600536813017297 ]

(E)-2-Methoxy-9-(2-methoxy-9H-xanthen-9-ylidene)-9H-xanthene

X.-Y. Tian and Q.-H. Song

Abstract top

The title compound, C28H20O4, was synthesized by a bimolecular Zn-HCl reduction in glacial acetic acid using the methoxy-substituted xanthone as a starting material. The crystal structure shows that the 2,2'-methoxybixanthenylidene unit is an E-type conformation anti-folded conformer. The molecule lies on an inversion center. The methoxy group is almost coplanar with the attached benzene ring, with a C-O-C-C torsion angle of 179.38 (14)°.

Comment top

The 2,2'-substituted bixanthenylidenes have two conformers (Z, E), which are unstable at room temperature (Korenstein et al., 1976). Z, E isomerization, with a low activation energy of 2,2'-disubstituted bixanthenylidenes, occurs easily at room temperature, and the ratio of Z/E in solution depends on the bulkiness of the the 2 and 2' substituents (Agranat & Tapuhi, 1979), 1:1.13 for the title compound. The crystal structure of the title compound shows that the E-type conformer lies on an inversion center located in the middle of the C8=C8i double bond (symmetry code: i = -x+1, -y+1, -z+1). The methoxy group is almost coplanar with the phenyl ring with a C1—O1—C2—C3 torsion angle of 179.38 (14) degrees (Fig.1). For related structures, see: Mills & Nyburg (1963); Shi et al. (2012).

Related literature top

For background to dixanthylidenes, see: Korenstein et al. (1976); Agranat & Tapuhi (1979); Mao et al. (2011). For related structures, see: Mills & Nyburg (1963); Shi et al. (2012).

Experimental top

2-Methoxyxanthone (8.8 mmol) was refluxed overnight in oxalyl dichloride (10 ml). The excess of oxalyl dichloride was removed, and the residue was dissolved in freshly distilled p-xylene (30 ml). Activated Cu powder (3.81 g, 60.0 mmol) was added and refluxed for 7 h with occasional shaking. The reaction solution was filtered, and the filter was concentrated and crystallized to give the title compound (Mao et al., 2011). The title compound was dissolved in 10 ml of THF, and then adding 2 ml of toluene to the solution. The mixture solution was placed in a open flask upon standing at 45–50° C for 5 days, single crystals appeared, and were separated from the solvent by decantation.

Refinement top

All hydrogen positions were calculated after each cycle of refinement using a riding model, with C—H = 0.93 Å and Uiso(H) = 1.2Ueq(C) for aromatic H atoms, and with C—H = 0.96 Å and Uiso(H) = 1.5Ueq(C) for methyl H atoms.

Computing details top

Data collection: CrysAlis PRO (Oxford Diffraction, 2007); cell refinement: CrysAlis PRO (Oxford Diffraction, 2007); data reduction: CrysAlis PRO (Oxford Diffraction, 2007); 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: SHELXL97 (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. The structure of the title compound, showing 50% probability displacement ellipsoids and the atom-numbering scheme (symmetry code: i = -x+1, -y+1, -z+1).
(E)-2-Methoxy-9-(2-methoxy-9H-xanthen-9-ylidene)-9H-xanthene top
Crystal data top
C28H20O4F(000) = 440
Mr = 420.28Dx = 1.337 Mg m3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybcCell parameters from 2041 reflections
a = 8.5699 (7) Åθ = 2.7–29.1°
b = 7.5200 (6) ŵ = 0.09 mm1
c = 16.6101 (18) ÅT = 291 K
β = 102.682 (7)°Block, colourless
V = 1044.33 (16) Å30.42 × 0.40 × 0.32 mm
Z = 2
Data collection top
Oxford Diffraction Gemini S Ultra
diffractometer
2205 independent reflections
Radiation source: Enhance (Mo) X-ray Source1264 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.029
Detector resolution: 15.9149 pixels mm-1θmax = 26.7°, θmin = 3.0°
ω scansh = 107
Absorption correction: multi-scan
(CrysAlis PRO; Oxford Diffraction, 2007)
k = 79
Tmin = 0.964, Tmax = 0.972l = 2121
6419 measured reflections
Refinement top
Refinement on F20 restraints
Least-squares matrix: fullH-atom parameters constrained
R[F2 > 2σ(F2)] = 0.037 w = 1/[σ2(Fo2) + (0.0079P)2 + 0.150P]
where P = (Fo2 + 2Fc2)/3
wR(F2) = 0.060(Δ/σ)max < 0.001
S = 1.00Δρmax = 0.16 e Å3
2205 reflectionsΔρmin = 0.17 e Å3
146 parameters
Crystal data top
C28H20O4V = 1044.33 (16) Å3
Mr = 420.28Z = 2
Monoclinic, P21/cMo Kα radiation
a = 8.5699 (7) ŵ = 0.09 mm1
b = 7.5200 (6) ÅT = 291 K
c = 16.6101 (18) Å0.42 × 0.40 × 0.32 mm
β = 102.682 (7)°
Data collection top
Oxford Diffraction Gemini S Ultra
diffractometer
2205 independent reflections
Absorption correction: multi-scan
(CrysAlis PRO; Oxford Diffraction, 2007)
1264 reflections with I > 2σ(I)
Tmin = 0.964, Tmax = 0.972Rint = 0.029
6419 measured reflectionsθmax = 26.7°
Refinement top
R[F2 > 2σ(F2)] = 0.037H-atom parameters constrained
wR(F2) = 0.060Δρmax = 0.16 e Å3
S = 1.00Δρmin = 0.17 e Å3
2205 reflectionsAbsolute structure: ?
146 parametersAbsolute structure parameter: ?
0 restraintsRogers parameter: ?
Special details top

Experimental. CrysAlisPro, Oxford Diffraction Ltd., Version 1.171.33.34d (release 27-02-2009 CrysAlis171 .NET) Empirical absorption correction using spherical harmonics, implemented in SCALE3 ABSPACK scaling algorithm.

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 (Å2) top
xyzUiso*/Ueq
O10.37126 (14)0.03674 (16)0.29797 (7)0.0612 (4)
O20.15571 (11)0.62217 (15)0.36978 (6)0.0464 (3)
C10.4953 (2)0.1274 (2)0.35211 (12)0.0720 (6)
H1A0.51400.23960.32830.108*
H1B0.46540.14710.40380.108*
H1C0.59120.05720.36110.108*
C20.32826 (18)0.1287 (2)0.32026 (10)0.0419 (4)
C30.20616 (18)0.2107 (2)0.26345 (10)0.0471 (4)
H30.16110.15370.21410.057*
C40.15201 (17)0.3756 (2)0.27995 (10)0.0453 (4)
H40.06920.42980.24240.054*
C50.22169 (16)0.4607 (2)0.35303 (9)0.0381 (4)
C60.34973 (16)0.3863 (2)0.40865 (9)0.0335 (4)
C70.39884 (17)0.2148 (2)0.39259 (9)0.0374 (4)
H70.47930.15860.43080.045*
C80.42069 (14)0.49291 (19)0.48303 (9)0.0331 (4)
C90.29155 (16)0.58847 (19)0.51278 (9)0.0340 (4)
C100.16438 (17)0.6537 (2)0.45337 (10)0.0389 (4)
C110.04103 (17)0.7507 (2)0.47368 (11)0.0484 (5)
H110.04050.79700.43260.058*
C120.04121 (19)0.7774 (2)0.55581 (11)0.0501 (5)
H120.03980.84410.57040.060*
C130.16141 (18)0.7056 (2)0.61689 (11)0.0466 (4)
H130.15930.72070.67220.056*
C140.28401 (16)0.6117 (2)0.59522 (10)0.0397 (4)
H140.36350.56260.63650.048*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O10.0783 (9)0.0499 (8)0.0496 (8)0.0048 (7)0.0012 (6)0.0137 (7)
O20.0441 (7)0.0518 (7)0.0374 (7)0.0114 (6)0.0043 (5)0.0007 (6)
C10.0937 (16)0.0533 (12)0.0666 (14)0.0160 (12)0.0122 (12)0.0051 (12)
C20.0445 (10)0.0415 (10)0.0395 (11)0.0044 (8)0.0088 (8)0.0064 (9)
C30.0441 (10)0.0614 (12)0.0319 (10)0.0077 (9)0.0003 (7)0.0105 (9)
C40.0365 (9)0.0615 (12)0.0336 (10)0.0011 (9)0.0019 (7)0.0005 (9)
C50.0331 (9)0.0438 (10)0.0356 (10)0.0003 (8)0.0032 (7)0.0019 (8)
C60.0263 (8)0.0423 (10)0.0295 (9)0.0025 (7)0.0010 (6)0.0003 (8)
C70.0344 (9)0.0429 (10)0.0320 (9)0.0009 (8)0.0012 (7)0.0002 (8)
C80.0326 (8)0.0341 (9)0.0299 (9)0.0004 (7)0.0007 (6)0.0020 (7)
C90.0300 (9)0.0343 (10)0.0362 (10)0.0012 (7)0.0039 (7)0.0003 (8)
C100.0361 (9)0.0398 (10)0.0384 (11)0.0001 (8)0.0027 (7)0.0014 (8)
C110.0351 (10)0.0475 (11)0.0581 (12)0.0091 (8)0.0003 (8)0.0009 (10)
C120.0409 (10)0.0473 (11)0.0640 (14)0.0060 (8)0.0159 (9)0.0050 (10)
C130.0451 (11)0.0496 (11)0.0473 (11)0.0002 (8)0.0149 (9)0.0012 (9)
C140.0342 (9)0.0430 (10)0.0404 (11)0.0020 (8)0.0047 (7)0.0020 (9)
Geometric parameters (Å, º) top
O1—C21.3716 (18)C6—C81.4865 (19)
O1—C11.4086 (19)C7—H70.9300
O2—C51.3930 (17)C8—C8i1.357 (2)
O2—C101.3942 (17)C8—C91.4918 (17)
C1—H1A0.9600C9—C101.3892 (19)
C1—H1B0.9600C9—C141.3960 (19)
C1—H1C0.9600C10—C111.3857 (19)
C2—C71.3816 (19)C11—C121.379 (2)
C2—C31.390 (2)C11—H110.9300
C3—C41.373 (2)C12—C131.387 (2)
C3—H30.9300C12—H120.9300
C4—C51.3861 (19)C13—C141.3777 (18)
C4—H40.9300C13—H130.9300
C5—C61.3878 (18)C14—H140.9300
C6—C71.400 (2)
C2—O1—C1118.46 (14)C2—C7—H7119.9
C5—O2—C10114.32 (12)C6—C7—H7119.9
O1—C1—H1A109.5C8i—C8—C6125.28 (16)
O1—C1—H1B109.5C8i—C8—C9124.96 (17)
H1A—C1—H1B109.5C6—C8—C9109.71 (11)
O1—C1—H1C109.5C10—C9—C14117.04 (13)
H1A—C1—H1C109.5C10—C9—C8117.27 (13)
H1B—C1—H1C109.5C14—C9—C8125.63 (13)
O1—C2—C7124.57 (15)C11—C10—C9122.30 (15)
O1—C2—C3115.21 (15)C11—C10—O2117.08 (14)
C7—C2—C3120.22 (15)C9—C10—O2120.62 (13)
C4—C3—C2120.15 (15)C12—C11—C10118.85 (15)
C4—C3—H3119.9C12—C11—H11120.6
C2—C3—H3119.9C10—C11—H11120.6
C3—C4—C5119.50 (15)C11—C12—C13120.42 (15)
C3—C4—H4120.2C11—C12—H12119.8
C5—C4—H4120.2C13—C12—H12119.8
C4—C5—C6121.49 (15)C14—C13—C12119.68 (16)
C4—C5—O2117.49 (14)C14—C13—H13120.2
C6—C5—O2121.00 (14)C12—C13—H13120.2
C5—C6—C7118.14 (14)C13—C14—C9121.50 (15)
C5—C6—C8117.06 (13)C13—C14—H14119.3
C7—C6—C8124.75 (13)C9—C14—H14119.3
C2—C7—C6120.30 (15)
C1—O1—C2—C70.3 (2)C5—C6—C8—C937.73 (17)
C1—O1—C2—C3179.38 (14)C7—C6—C8—C9139.75 (14)
O1—C2—C3—C4179.07 (13)C8i—C8—C9—C10140.63 (19)
C7—C2—C3—C41.8 (2)C6—C8—C9—C1036.97 (18)
C2—C3—C4—C51.0 (2)C8i—C8—C9—C1442.2 (3)
C3—C4—C5—C62.7 (2)C6—C8—C9—C14140.17 (15)
C3—C4—C5—O2175.69 (13)C14—C9—C10—C115.3 (2)
C10—O2—C5—C4147.12 (13)C8—C9—C10—C11177.34 (14)
C10—O2—C5—C631.24 (19)C14—C9—C10—O2174.28 (13)
C4—C5—C6—C75.4 (2)C8—C9—C10—O23.1 (2)
O2—C5—C6—C7172.91 (12)C5—O2—C10—C11147.58 (13)
C4—C5—C6—C8176.96 (12)C5—O2—C10—C932.0 (2)
O2—C5—C6—C84.7 (2)C9—C10—C11—C122.6 (2)
O1—C2—C7—C6178.01 (13)O2—C10—C11—C12176.93 (15)
C3—C2—C7—C61.0 (2)C10—C11—C12—C131.1 (2)
C5—C6—C7—C24.5 (2)C11—C12—C13—C142.1 (2)
C8—C6—C7—C2178.03 (13)C12—C13—C14—C90.8 (2)
C5—C6—C8—C8i139.87 (19)C10—C9—C14—C134.3 (2)
C7—C6—C8—C8i42.7 (3)C8—C9—C14—C13178.55 (14)
Symmetry code: (i) x+1, y+1, z+1.

Experimental details

Crystal data
Chemical formulaC28H20O4
Mr420.28
Crystal system, space groupMonoclinic, P21/c
Temperature (K)291
a, b, c (Å)8.5699 (7), 7.5200 (6), 16.6101 (18)
β (°) 102.682 (7)
V3)1044.33 (16)
Z2
Radiation typeMo Kα
µ (mm1)0.09
Crystal size (mm)0.42 × 0.40 × 0.32
Data collection
DiffractometerOxford Diffraction Gemini S Ultra
diffractometer
Absorption correctionMulti-scan
(CrysAlis PRO; Oxford Diffraction, 2007)
Tmin, Tmax0.964, 0.972
No. of measured, independent and
observed [I > 2σ(I)] reflections
6419, 2205, 1264
Rint0.029
(sin θ/λ)max1)0.633
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.037, 0.060, 1.00
No. of reflections2205
No. of parameters146
No. of restraints0
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.16, 0.17

Computer programs: CrysAlis PRO (Oxford Diffraction, 2007), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ORTEP-3 for Windows (Farrugia, 2012).

Acknowledgements top

This work was supporting by the National Natural Science Foundation of China (grant Nos. 20972149 and 21272224).

references
References top

Agranat, I. & Tapuhi, Y. (1979). J. Am. Chem. Soc. 101, 665–671.

Farrugia, L. J. (2012). J. Appl. Cryst. 45, 849–854.

Korenstein, R., Muszkat, K. A., Slifkin, M. A. & Fischer, E. (1976). J. Chem. Soc. Perkin Trans. 2, pp. 438–443.

Mao, M., Wu, Q.-Q., Ren, M.-G. & Song, Q.-H. (2011). Org. Biomol Chem. 9, 3165–3169.

Mills, J. F. D. & Nyburg, S. C. (1963). J. Chem. Soc. pp. 308–321.

Oxford Diffraction (2007). CrysAlis PRO. Oxford Diffraction Ltd, Abingdon, England.

Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122.

Shi, J., Chang, N., Li, C., Mei, J., Deng, C., Luo, X., Liu, Z., Bo, Z., Dong, Y. Q. & Tang, B. Z. (2012). Chem. Commun. 48, 10675–10677.