6,6′-Oxydichroman

Abstract

The title compound, C₁₈H₁₈O₃, was synthesized from dichroman in concentrated sulfuric acid. The mol­ecule has a twofold axis passing through the central O atom. The dihedral angle between the two symmetry-related benzene rings is 63.6 (3)°. Weak C—H⋯π inter­actions are present in the structure.

Related literature

For related literature, see: Allen et al. (1987 ▶); Li et al. (2006 ▶, 2007 ▶); Xiao, Shi et al. (2007 ▶); Xiao, Xue et al. (2007 ▶); Huang et al. (2007 ▶); Zhang et al. (2007 ▶); Shi et al. (2007 ▶); Cao et al. (2007 ▶); Ruan et al. (2006 ▶).

Experimental

Crystal data

• C₁₈H₁₈O₃

• M _r = 282.32

• Orthorhombic,

• a = 17.515 (4) Å

• b = 29.660 (6) Å

• c = 5.7680 (12) Å

• V = 2996.4 (10) ų

• Z = 8

• Mo Kα radiation

• μ = 0.08 mm⁻¹

• T = 298 (2) K

• 0.23 × 0.20 × 0.20 mm

Data collection

• Bruker APEX area-detector diffractometer

• Absorption correction: multi-scan (SADABS; Sheldrick, 1996 ▶) T _min = 0.981, T _max = 0.983

• 4727 measured reflections

• 855 independent reflections

• 810 reflections with I > 2σ(I)

• R _int = 0.073

Refinement

• R[F ² > 2σ(F ²)] = 0.073

• wR(F ²) = 0.216

• S = 1.13

• 855 reflections

• 96 parameters

• 1 restraint

• H-atom parameters constrained

• Δρ_max = 0.32 e Å⁻³

• Δρ_min = −0.55 e Å⁻³

Data collection: SMART (Siemens, 1996 ▶); cell refinement: SMART; data reduction: SAINT (Siemens, 1996 ▶); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997a ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997a ▶); molecular graphics: SHELXTL (Sheldrick, 1997b ▶); software used to prepare material for publication: SHELXTL.

Supplementary Material

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

Table 1. Hydrogen-bond geometry (Å, °).

Cg1 is the centroid of the ring C1–C6.

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C8—H8B⋯Cg1i	0.97	2.91	3.856 (6)	167

Symmetry code: (i) .

supplementary crystallographic information

Comment

Synthesized organic compounds with a pyran cycle are found being good biological activities (Li et al., 2007; Xiao, Shi et al., 2007; Xiao, Xue et al., 2007; Huang et al., 2007; Zhang et al., 2007; Shi et al., 2007; Cao et al., 2007; Ruan et al., 2006; Li et al., 2006). So we prepared a series of derivatives with pyran cycles. Here we report the crystal structure of the title compound.

The title compound consists of an oxygen atom bridged two chroman (Fig. 1). The molecule has a twofold axis symmetry position at the central O1 atom. The dihedal angle between the two symmetry-related benzene rings is 63.6 (3)°. In each chroman, all the atoms, except C8 atom, are nearly coplanar, with mean deviation from plane by 0.021 (4) Å. C8 atom is located 0.577 (4)Å above the plane defined by other non-hydrogen atoms. All the bond values are within normal ranges (Allen et al., 1987). There exists weak C8–H8B···Cg1 interaction (Cg1:C1—C6) (Table 1, Fig. 2).

Experimental

Dichroman was disolved in toluene solution and a few drops of concentrated sulfuric acid was added. The above solution was refluxed for two hours. After the solution was cooled to room temperature colorless microcrystals were precipitated. They were filtered, washed with toluene for three times. Yield: 32%.

Refinement

C-bound H atoms were included in the riding model approximation with C—H = 0.93 Å, and with U_iso(H) = 1.2U_eq(C). 631 Friedel pairs were averaged before the final refinement as the absolute configuration could not be determined unambiguously.

Figures

Fig. 1.

The molecular structure of (I), showing 30% probability displacement ellipsoids and the atom-numbering scheme. Symmetry code (i): -x, 1 - y, z.

Fig. 2.

Molecular packing of (I) viewed down the c axis. The weak C–H···Cg interactions are shown as dashed lines.

Crystal data

C18H18O3	F000 = 1200
Mr = 282.32	Dx = 1.252 Mg m−3
Orthorhombic, Fdd2	Mo Kα radiation λ = 0.71073 Å
Hall symbol: F 2 -2d	Cell parameters from 872 reflections
a = 17.515 (4) Å	θ = 2.5–24.3º
b = 29.660 (6) Å	µ = 0.08 mm−1
c = 5.7680 (12) Å	T = 298 (2) K
V = 2996.4 (10) Å3	Prism, colorless
Z = 8	0.23 × 0.20 × 0.20 mm

Data collection

Bruker APEX area-detector diffractometer	855 independent reflections
Radiation source: fine-focus sealed tube	810 reflections with I > 2σ(I)
Monochromator: graphite	Rint = 0.073
T = 298(2) K	θmax = 26.5º
φ and ω scans	θmin = 2.7º
Absorption correction: multi-scan(SADABS; Sheldrick, 1996)	h = −21→21
Tmin = 0.981, Tmax = 0.983	k = −36→32
4727 measured reflections	l = −7→6

Refinement

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)] = 0.073	H-atom parameters constrained
wR(F2) = 0.216	w = 1/[σ2(Fo2) + (0.1367P)2 + 4.7011P] where P = (Fo2 + 2Fc2)/3
S = 1.13	(Δ/σ)max < 0.001
855 reflections	Δρmax = 0.32 e Å−3
96 parameters	Δρmin = −0.55 e Å−3
1 restraint	Extinction correction: none
Primary atom site location: structure-invariant direct methods	Absolute structure: Flack (1983), 631 Friedel pairs

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	0.5000	0.5000	0.0623 (13)	0.090 (2)
O2	0.7616 (2)	0.44456 (13)	0.5838 (9)	0.0779 (14)
C1	0.6782 (2)	0.43486 (12)	0.2525 (7)	0.0378 (9)
C2	0.6140 (2)	0.44952 (12)	0.1313 (7)	0.0387 (9)
H2	0.6008	0.4345	−0.0045	0.046*
C3	0.5687 (2)	0.48541 (13)	0.2029 (8)	0.0386 (9)
C4	0.5900 (2)	0.50701 (12)	0.4073 (8)	0.0412 (9)
H4	0.5609	0.5310	0.4615	0.049*
C5	0.6539 (2)	0.49345 (13)	0.5317 (8)	0.0413 (9)
H5	0.6670	0.5087	0.6669	0.050*
C6	0.69851 (19)	0.45734 (12)	0.4570 (7)	0.0360 (8)
C7	0.7245 (3)	0.39470 (15)	0.1747 (9)	0.0561 (12)
H7A	0.7590	0.4039	0.0521	0.067*
H7B	0.6904	0.3719	0.1122	0.067*
C8	0.7703 (3)	0.37452 (17)	0.3725 (12)	0.0640 (14)
H8A	0.7361	0.3583	0.4754	0.077*
H8B	0.8067	0.3531	0.3104	0.077*
C9	0.8113 (3)	0.40910 (16)	0.5053 (11)	0.0614 (15)
H9A	0.8355	0.3951	0.6384	0.074*
H9B	0.8511	0.4220	0.4091	0.074*

Atomic displacement parameters (Ų)

	U11	U22	U33	U12	U13	U23
O1	0.081 (4)	0.128 (5)	0.060 (4)	0.032 (3)	0.000	0.000
O2	0.074 (2)	0.075 (2)	0.085 (3)	0.0149 (17)	−0.036 (2)	−0.021 (2)
C1	0.0383 (17)	0.0360 (17)	0.039 (2)	0.0011 (13)	−0.0009 (17)	−0.0039 (17)
C2	0.0395 (18)	0.0405 (17)	0.0360 (19)	0.0017 (14)	−0.0002 (17)	−0.0066 (16)
C3	0.0315 (16)	0.0445 (17)	0.040 (2)	0.0029 (13)	0.0022 (16)	0.0016 (17)
C4	0.0379 (18)	0.0384 (17)	0.047 (2)	0.0051 (14)	0.0054 (17)	−0.0053 (18)
C5	0.0408 (19)	0.0434 (19)	0.040 (2)	−0.0047 (15)	−0.0021 (17)	−0.0125 (17)
C6	0.0313 (15)	0.0370 (16)	0.040 (2)	−0.0023 (13)	−0.0014 (16)	0.0013 (16)
C7	0.065 (3)	0.053 (2)	0.051 (3)	0.019 (2)	−0.011 (2)	−0.010 (2)
C8	0.059 (3)	0.057 (2)	0.076 (4)	0.020 (2)	−0.010 (3)	−0.003 (3)
C9	0.048 (2)	0.064 (3)	0.072 (4)	0.0163 (19)	−0.018 (3)	−0.001 (3)

Geometric parameters (Å, °)

O1—C3i	1.514 (5)	C4—H4	0.9300
O1—C3	1.514 (6)	C5—C6	1.394 (5)
O2—C6	1.379 (5)	C5—H5	0.9300
O2—C9	1.438 (6)	C7—C8	1.518 (7)
C1—C2	1.393 (5)	C7—H7A	0.9700
C1—C6	1.401 (6)	C7—H7B	0.9700
C1—C7	1.509 (5)	C8—C9	1.468 (7)
C2—C3	1.390 (5)	C8—H8A	0.9700
C2—H2	0.9300	C8—H8B	0.9700
C3—C4	1.393 (6)	C9—H9A	0.9700
C4—C5	1.388 (6)	C9—H9B	0.9700
C3i—O1—C3	115.2 (6)	C5—C6—C1	118.9 (3)
C6—O2—C9	121.3 (4)	C1—C7—C8	111.8 (4)
C2—C1—C6	118.6 (3)	C1—C7—H7A	109.3
C2—C1—C7	122.0 (4)	C8—C7—H7A	109.3
C6—C1—C7	119.3 (3)	C1—C7—H7B	109.3
C3—C2—C1	123.4 (4)	C8—C7—H7B	109.3
C3—C2—H2	118.3	H7A—C7—H7B	107.9
C1—C2—H2	118.3	C9—C8—C7	112.1 (4)
C2—C3—C4	116.8 (3)	C9—C8—H8A	109.2
C2—C3—O1	120.9 (4)	C7—C8—H8A	109.2
C4—C3—O1	122.4 (4)	C9—C8—H8B	109.2
C5—C4—C3	121.4 (3)	C7—C8—H8B	109.2
C5—C4—H4	119.3	H8A—C8—H8B	107.9
C3—C4—H4	119.3	O2—C9—C8	112.3 (4)
C4—C5—C6	121.0 (4)	O2—C9—H9A	109.1
C4—C5—H5	119.5	C8—C9—H9A	109.1
C6—C5—H5	119.5	O2—C9—H9B	109.1
O2—C6—C5	119.8 (4)	C8—C9—H9B	109.1
O2—C6—C1	121.3 (3)	H9A—C9—H9B	107.9
C6—C1—C2—C3	−0.1 (6)	C4—C5—C6—O2	−180.0 (4)
C7—C1—C2—C3	177.7 (4)	C4—C5—C6—C1	0.3 (6)
C1—C2—C3—C4	−0.2 (6)	C2—C1—C6—O2	−179.7 (4)
C1—C2—C3—O1	179.4 (3)	C7—C1—C6—O2	2.4 (6)
C3i—O1—C3—C2	142.1 (4)	C2—C1—C6—C5	0.1 (5)
C3i—O1—C3—C4	−38.3 (3)	C7—C1—C6—C5	−177.8 (4)
C2—C3—C4—C5	0.5 (6)	C2—C1—C7—C8	−158.0 (4)
O1—C3—C4—C5	−179.1 (4)	C6—C1—C7—C8	19.9 (6)
C3—C4—C5—C6	−0.6 (6)	C1—C7—C8—C9	−47.3 (6)
C9—O2—C6—C5	−176.6 (4)	C6—O2—C9—C8	−31.5 (7)
C9—O2—C6—C1	3.2 (7)	C7—C8—C9—O2	53.2 (7)

Symmetry codes: (i) −x+1, −y+1, z.

Hydrogen-bond geometry (Å, °)

D—H···A	D—H	H···A	D···A	D—H···A
C8—H8b···Cg1ii	0.97	2.906	3.856 (6)	166.49

Symmetry codes: (ii) x+1/4, −y+3/4, z−1/4.