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The title 17-crown-5 unit, C24H24O5, comprising three benzo groups and diethyl­ene glycol was prepared from the reaction of α,α′-di­bromo-o-xyl­ene and bisphenol in the presence of sodium hydride as base. This mol­ecule offers a cavity suitable for host–guest complexes.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536801005505/tk6010sup1.cif
Contains datablocks global, kim149

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S1600536801005505/tk6010Isup2.hkl
Contains datablock I

CCDC reference: 165652

Key indicators

  • Single-crystal X-ray study
  • T = 293 K
  • Mean [sigma](C-C) = 0.008 Å
  • Disorder in main residue
  • R factor = 0.045
  • wR factor = 0.107
  • Data-to-parameter ratio = 11.1

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry
Yellow Alert Alert Level C:
STRVAL_01 From the CIF: _refine_ls_abs_structure_Flack 0.000 From the CIF: _refine_ls_abs_structure_Flack_su 3.000 Alert C Flack test results are meaningless. PLAT_301 Alert C Main Residue Disorder ........................ 6.00 Perc. General Notes
REFLT_03 From the CIF: _diffrn_reflns_theta_max 29.95 From the CIF: _reflns_number_total 1597 Count of symmetry unique reflns 1624 Completeness (_total/calc) 98.34% TEST3: Check Friedels for noncentro structure Estimate of Friedel pairs measured 0 Fraction of Friedel pairs measured 0.000 Are heavy atom types Z>Si present no Please check that the estimate of the number of Friedel pairs is correct. If it is not, please give the correct count in the _publ_section_exptl_refinement section of the submitted CIF.
0 Alert Level A = Potentially serious problem
0 Alert Level B = Potential problem
2 Alert Level C = Please check

Comment top

Since the first report on crown ethers (Pedersen, 1967), a great number of crown compounds containing one or more aromatic subunits have been investigated (Gokel & Korzeniowski, 1982; Izatt & Christensen, 1978, 1979, 1981; Vögtle & Weber, 1985; Lindoy, 1989; Weber et al., 1989). A number of crown compounds bearing two macrocyclic polyether rings within the molecule, which are referred to as biscrowns, have also been synthesized (Timko et al., 1974; Frensch & Vögtle, 1979; Rebek et al., 1980; Lee et al., 1992). In our previous paper, we reported the preparation of a new crown ether, (I), and its solid-state structure, which could be a precursor of the common-nuclear biscrown ether, bearing a benzene ring (Sim et al., 2001).

We now report a new preparation of crown ether (II) and its solid-state structure, which is the parent crown ether unit of (I). The preparation of (II) has been reported by Weber and Vögtle (1976), but the yield was rather low when KOH with dimethylformamide (DMF) was used. Therefore, alternative reaction conditions were examined so as to optimize the cyclization yield. In the reaction of α,α'-dibromo-o-xylene with 1,5-bis(2-hydroxyphenoxy)-3-oxapentane, the use of n-BuLi with tetrahydrofuran (THF) gave a 65% yield. Sodium hydride and THF provided a 72% yield but potassium tert-butoxide with THF gave only a moderate 50% yield. Herein, we report the optimized reaction conditions (sodium hydride and THF) for (II), as well as its solid-state structure.

Compound (II), with the atomic labelling scheme, is shown in Fig. 1. There is crystallographic mirror symmetry in (II) so that half a molecule comprises the asymmetric unit. In the diethylene glycol chain-bridging benzo groups B and B', the C10—O2—C11 [116.5 (4)°] and C12—O3—-C12i [111.3 (5)°] angles are slightly greater than tetrahedral, while the O2—C11—C12 [106.7 (5)°] and O3—C12—C11 [108.5 (3)°] angles are very close to tetrahedral [symmetry operation: (i) 2 - x, y, z]. The dihedral angle between rings B and B' is 83.4 (1)°. In the A-to-B ring connectivity, the C3—C4—O1—C5 torsion angle is 174.9 (5)° [for the minor component of the disorder associated with C4, C3—C4'—O1—C5 is -148.6 (5)°] which indicates that ring A is situated trans to ring B, with a dihedral angle of 69.2 (1)° between them. In the diethylene glycol group, the O—C—C—O and two C—O—O—C torsion angles are gauche and trans, respectively, as there is one extra atom in the diethylene glycol backbone. All these conformations are very similar to those found in (I) (Sim et al., 2001). The interatomic distances O1···O3 of 4.580 (5) Å, O1···O2i of 5.344 (5) Å and O2···O2i of 4.941 (6) Å suggest sufficient room for the introduction of a guest atom/molecule inside the cavity. The closest intermolecular distance of 2.41 Å occurs between H11b and H12bii which suggests that the molecular packing is governed by van der Waals forces [symmetry operation: (ii) x, 1 - y, 0.5 + z].

Experimental top

To a refluxing suspension of sodium hydride (15.2 mmol) in THF under nitrogen was added dropwise a solution of α,α'-dibromo-o-xylene (3.79 mmol) and 1,5-bis(2-hydroxyphenoxy)-3-oxapentane (3.79 mmol) in THF over a period of 3 h. The mixture was then refluxed for an additional 24 h. After cooling to room temperature, 10% aqueous hydrochloric acid was added. The solvent was removed under reduced pressure and the residual mixture was extracted with dichloromethane. The organic layer was washed with water, dried over anhydrous magnesium sulfate, and evaporated in vacuo. The crude product was chromatographed on a silica-gel column using a mixed solvent of ethyl acetate and n-hexane (1:1) as eluent, and recrystallization from dichloromethane/n-hexane (1:20, v/v) gave (II) as a crystalline solid in 72% yield (m.p. 398–400 K). IR (KBr pellet) 3065, 2880, 1596, 1498, 1258, 1119, 949 and 741 cm-1. 1H NMR (CDCl3): δ 7.65–7.39 (m, 4H, Ar—H), 7.10–6.88 (m, 8H, Ar—H), 5.31 (s, 4H, OCH2Ar), 4.20 (t, 4H, OCH2CH2O) and 3.92 (t, 4H, OCH2CH2O).

Refinement top

C4 was disordered over two positions and their sites were refined anisotropically using the PART command in SHELXL97 (Sheldrick, 1997). All H atoms were located in their idealized positions with Uiso constrained to be 1.2 times the equivalent isotropic displacement of the parent atoms. The number of Friedel pairs measured is 180 and the fraction of Friedel pairs measured is 0.113. As there are no heavy-atom, i.e. Z > Si, types present, the absolute structure was not determined.

Computing details top

Data collection: CAD-4 EXPRESS (Enraf-Nonius, 1994); cell refinement: CAD-4 EXPRESS; data reduction: XCAD4 (Harms & Wocadlo, 1995); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: WinGX (Farrugia, 1999).

Figures top
[Figure 1] Fig. 1. ORTEP-3 (Farrugia, 1997) diagram of (II) showing 35% probability displacement ellipsoids. C atoms are expressed with ellipsoids with only enveloping ellipses and the rest with ellipsoids with octant shading. H atoms have been omitted for clarity. The C4 atom is disordered over two positions.
(kim149) top
Crystal data top
C24H24O5Dx = 1.278 Mg m3
Mr = 392.43Mo Kα radiation, λ = 0.71069 Å
Orthorhombic, Cmc21Cell parameters from 20 reflections
a = 21.585 (4) Åθ = 11.4–14.1°
b = 11.675 (3) ŵ = 0.09 mm1
c = 8.092 (2) ÅT = 293 K
V = 2039.3 (8) Å3Block, colorless
Z = 40.37 × 0.25 × 0.20 mm
F(000) = 832
Data collection top
Enraf-Nonius CAD-4
diffractometer
Rint = 0.011
Radiation source: fine-focus sealed tubeθmax = 30.0°, θmin = 3.2°
Graphite monochromatorh = 030
non–profiled ω/2θ scansk = 016
1650 measured reflectionsl = 115
1597 independent reflections3 standard reflections every 300 min
708 reflections with I > 2σ(I) intensity decay: 1%
Refinement top
Refinement on F2Hydrogen site location: inferred from neighbouring sites
Least-squares matrix: fullH-atom parameters constrained
R[F2 > 2σ(F2)] = 0.045 w = 1/[σ2(Fo2) + (0.036P)2 + 0.0439P]
where P = (Fo2 + 2Fc2)/3
wR(F2) = 0.107(Δ/σ)max < 0.001
S = 0.98Δρmax = 0.11 e Å3
1597 reflectionsΔρmin = 0.14 e Å3
144 parametersExtinction correction: SHELXL97, Fc*kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
1 restraintExtinction coefficient: 0.0098 (9)
Primary atom site location: structure-invariant direct methodsAbsolute structure: Flack (1983)
Secondary atom site location: difference Fourier mapAbsolute structure parameter: 0 (3)
Crystal data top
C24H24O5V = 2039.3 (8) Å3
Mr = 392.43Z = 4
Orthorhombic, Cmc21Mo Kα radiation
a = 21.585 (4) ŵ = 0.09 mm1
b = 11.675 (3) ÅT = 293 K
c = 8.092 (2) Å0.37 × 0.25 × 0.20 mm
Data collection top
Enraf-Nonius CAD-4
diffractometer
Rint = 0.011
1650 measured reflections3 standard reflections every 300 min
1597 independent reflections intensity decay: 1%
708 reflections with I > 2σ(I)
Refinement top
R[F2 > 2σ(F2)] = 0.045H-atom parameters constrained
wR(F2) = 0.107Δρmax = 0.11 e Å3
S = 0.98Δρmin = 0.14 e Å3
1597 reflectionsAbsolute structure: Flack (1983)
144 parametersAbsolute structure parameter: 0 (3)
1 restraint
Special details top

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*/UeqOcc. (<1)
C10.9687 (2)0.8209 (4)0.6581 (7)0.0934 (19)
H10.94680.81250.75630.112*
C20.9388 (2)0.8332 (4)0.5134 (9)0.0940 (18)
H20.89570.83220.51330.113*
C30.96910 (19)0.8471 (4)0.3669 (5)0.0692 (15)
C40.9173 (5)0.8819 (7)0.2460 (12)0.090 (3)0.58
H4A0.93280.93840.16830.108*0.58
H4B0.88300.91540.30620.108*0.58
C4'0.9518 (5)0.8372 (12)0.1759 (15)0.061 (3)0.42
H4A'0.98320.79310.11820.073*0.42
H4B'0.94990.91290.12670.073*0.42
C50.8552 (2)0.8064 (5)0.0406 (6)0.0649 (12)
C60.8196 (2)0.9030 (4)0.0356 (7)0.0818 (15)
H60.82570.96080.11300.098*
C70.7743 (2)0.9148 (5)0.0850 (9)0.111 (2)
H70.75010.98060.08830.134*
C80.7653 (3)0.8303 (7)0.1983 (9)0.123 (2)
H80.73480.83810.27860.148*
C90.8015 (3)0.7334 (6)0.1934 (7)0.0992 (17)
H90.79520.67600.27140.119*
C100.8471 (2)0.7196 (5)0.0747 (6)0.0697 (13)
C110.8905 (2)0.5526 (4)0.2021 (7)0.0989 (16)
H11A0.85340.50650.21380.119*
H11B0.89600.59760.30180.119*
C120.9458 (2)0.4774 (4)0.1736 (7)0.0974 (17)
H12A0.94620.41550.25350.117*
H12B0.94400.44440.06370.117*
O10.89803 (19)0.7865 (3)0.1631 (4)0.0840 (10)
O20.88555 (14)0.6266 (3)0.0595 (4)0.0818 (10)
O31.00000.5450 (3)0.1905 (6)0.0758 (12)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
C10.144 (6)0.070 (3)0.066 (3)0.013 (3)0.047 (4)0.005 (3)
C20.057 (3)0.089 (4)0.136 (6)0.000 (3)0.002 (4)0.041 (4)
C30.087 (4)0.052 (3)0.069 (3)0.017 (2)0.021 (3)0.017 (2)
C40.115 (9)0.062 (6)0.094 (8)0.027 (6)0.045 (7)0.005 (5)
C4'0.052 (8)0.076 (8)0.056 (8)0.033 (7)0.002 (7)0.007 (7)
C50.063 (3)0.077 (4)0.054 (3)0.009 (3)0.006 (3)0.011 (3)
C60.080 (4)0.087 (4)0.078 (4)0.006 (3)0.001 (3)0.012 (3)
C70.074 (4)0.144 (6)0.117 (5)0.010 (4)0.018 (4)0.042 (5)
C80.078 (5)0.187 (7)0.105 (5)0.008 (5)0.027 (5)0.033 (6)
C90.074 (4)0.147 (5)0.077 (4)0.031 (4)0.021 (4)0.005 (4)
C100.067 (3)0.088 (4)0.054 (3)0.011 (3)0.000 (3)0.003 (3)
C110.120 (4)0.101 (4)0.076 (4)0.040 (3)0.016 (4)0.039 (4)
C120.164 (5)0.053 (3)0.076 (4)0.033 (4)0.027 (4)0.018 (3)
O10.104 (3)0.067 (2)0.081 (2)0.0027 (19)0.043 (2)0.007 (2)
O20.099 (2)0.091 (2)0.0552 (19)0.009 (2)0.006 (2)0.015 (2)
O30.101 (3)0.048 (2)0.079 (3)0.0000.0000.000 (3)
Geometric parameters (Å, º) top
C1—C21.345 (6)C5—C101.389 (5)
C1—C1i1.349 (9)C6—C71.388 (7)
C2—C31.363 (6)C7—C81.361 (7)
C3—C3i1.334 (8)C8—C91.375 (6)
C3—C41.540 (8)C9—C101.385 (6)
C3—C4'1.594 (13)C10—O21.372 (5)
C4—O11.366 (9)C11—O21.445 (5)
C4'—O11.307 (11)C11—C121.498 (6)
C5—C61.365 (6)C12—O31.418 (4)
C5—O11.375 (5)O3—C12i1.418 (4)
C2—C1—C1i118.7 (3)C8—C7—C6120.1 (6)
C1—C2—C3122.6 (5)C7—C8—C9119.7 (6)
C3i—C3—C2118.6 (3)C8—C9—C10121.3 (6)
C3i—C3—C4136.5 (5)O2—C10—C9125.7 (6)
C2—C3—C4103.7 (6)O2—C10—C5116.2 (5)
C3i—C3—C4'103.5 (4)C9—C10—C5118.1 (5)
C2—C3—C4'136.2 (6)O2—C11—C12106.7 (5)
C4—C3—C4'39.9 (4)O3—C12—C11108.5 (3)
O1—C4—C3108.6 (5)C4'—O1—C447.2 (5)
O1—C4'—C3108.5 (8)C4'—O1—C5125.3 (6)
C6—C5—O1122.7 (5)C4—O1—C5114.9 (5)
C6—C5—C10120.8 (5)C10—O2—C11116.5 (4)
O1—C5—C10116.5 (5)C12i—O3—C12111.3 (5)
C5—C6—C7120.0 (5)
C1i—C1—C2—C30.8 (7)C6—C5—C10—O2179.6 (4)
C1—C2—C3—C3i0.8 (7)O1—C5—C10—O24.0 (5)
C1—C2—C3—C4168.8 (6)C6—C5—C10—C90.6 (6)
C1—C2—C3—C4'163.7 (8)O1—C5—C10—C9175.8 (4)
C3i—C3—C4—O196.6 (8)O2—C11—C12—O371.7 (5)
C2—C3—C4—O196.8 (8)C3—C4'—O1—C455.8 (7)
C4'—C3—C4—O153.4 (8)C3—C4'—O1—C5148.6 (5)
C3i—C3—C4'—O1152.0 (7)C3—C4—O1—C4'58.9 (8)
C2—C3—C4'—O112.6 (14)C3—C4—O1—C5174.9 (5)
C4—C3—C4'—O157.0 (7)C6—C5—O1—C4'74.6 (10)
O1—C5—C6—C7175.7 (4)C10—C5—O1—C4'109.0 (9)
C10—C5—C6—C70.5 (6)C6—C5—O1—C420.7 (8)
C5—C6—C7—C80.1 (8)C10—C5—O1—C4163.0 (7)
C6—C7—C8—C90.4 (10)C9—C10—O2—C1117.6 (6)
C7—C8—C9—C100.2 (9)C5—C10—O2—C11162.6 (3)
C8—C9—C10—O2179.9 (5)C12—C11—O2—C10165.7 (3)
C8—C9—C10—C50.3 (7)C11—C12—O3—C12i176.9 (3)
Symmetry code: (i) x+2, y, z.

Experimental details

Crystal data
Chemical formulaC24H24O5
Mr392.43
Crystal system, space groupOrthorhombic, Cmc21
Temperature (K)293
a, b, c (Å)21.585 (4), 11.675 (3), 8.092 (2)
V3)2039.3 (8)
Z4
Radiation typeMo Kα
µ (mm1)0.09
Crystal size (mm)0.37 × 0.25 × 0.20
Data collection
DiffractometerEnraf-Nonius CAD-4
diffractometer
Absorption correction
No. of measured, independent and
observed [I > 2σ(I)] reflections
1650, 1597, 708
Rint0.011
(sin θ/λ)max1)0.702
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.045, 0.107, 0.98
No. of reflections1597
No. of parameters144
No. of restraints1
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.11, 0.14
Absolute structureFlack (1983)
Absolute structure parameter0 (3)

Computer programs: CAD-4 EXPRESS (Enraf-Nonius, 1994), CAD-4 EXPRESS, XCAD4 (Harms & Wocadlo, 1995), SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), ORTEP-3 (Farrugia, 1997), WinGX (Farrugia, 1999).

 

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