Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270103006681/bm1530sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270103006681/bm1530Isup2.hkl |
CCDC reference: 214166
To a suspension of NaH (0.565 g, 11.78 mmol) in DMF (30 ml), cooled to 273 K, was added in small portions calix[4]arene (1.000 g, 2.36 mmol). After stirring for 2 h, CH2BrCl (6.097 g, 47.12 mmol) was added dropwise over a period of 15 min. After 3 h, cooling was stopped and the solution was stirred for a further 12 h at room temperature. Excess NaH was decomposed with MeOH (10 ml) and the solvent was removed in vacuo. The residue was taken up in CH2Cl2 (100 ml), washed with 1 M HCl (50 ml), then with water (2 × 50 ml). The organic layer was dried with MgSO4, then filtered. Evaporation of the solvent afforded a solid that was purified by flash chromatography using CH2Cl2/hexane (1:1 v/v) as eluent. After evaporation of the solvent and recrystallization from CH2Cl2–MeOH (1:5 v/v), colourless crystals were obtained (SiO2, RF = 0.54, CH2Cl2/hexane, 1:1 v/v). Yield: 0.600 g, 57%; m.p. > 523 K; FAB mass spectrum: m/z 448 (M+, 100%). Analysis found: C 70.02, H 5.09%; calculated for C30H24O4·CH2Cl2 (448.52 + 84.93): C 69.80, H 4.91%.
H atoms were included using a riding model with fixed C—H bond lengths of 0.95 (Csp2) or 0.99 Å (methylene). Uiso(H) values were fixed at 1.2Ueq of the parent atom.
Data collection: XSCANS (Fait, 1991); cell refinement: XSCANS; data reduction: XSCANS; program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: XP (Siemens, 1994); software used to prepare material for publication: SHELXL97.
C30H24O4·CH2Cl2 | F(000) = 1112 |
Mr = 533.42 | Dx = 1.423 Mg m−3 |
Monoclinic, C2/c | Mo Kα radiation, λ = 0.71073 Å |
a = 16.042 (2) Å | Cell parameters from 64 reflections |
b = 9.4781 (10) Å | θ = 8–27° |
c = 17.599 (2) Å | µ = 0.30 mm−1 |
β = 111.49 (1)° | T = 173 K |
V = 2489.9 (5) Å3 | Block, colourless |
Z = 4 | 0.7 × 0.6 × 0.5 mm |
Siemens P4 diffractometer | Rint = 0.014 |
Radiation source: fine-focus sealed tube | θmax = 25.0°, θmin = 3.1° |
Graphite monochromator | h = −18→7 |
ω scans | k = 0→11 |
3350 measured reflections | l = −20→19 |
2173 independent reflections | 3 standard reflections every 247 reflections |
1894 reflections with I > 2σ(I) | intensity decay: none |
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.035 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.093 | H-atom parameters constrained |
S = 1.07 | w = 1/[σ2(Fo2) + (0.0493P)2 + 1.8139P] where P = (Fo2 + 2Fc2)/3 |
2173 reflections | (Δ/σ)max < 0.001 |
168 parameters | Δρmax = 0.22 e Å−3 |
0 restraints | Δρmin = −0.39 e Å−3 |
C30H24O4·CH2Cl2 | V = 2489.9 (5) Å3 |
Mr = 533.42 | Z = 4 |
Monoclinic, C2/c | Mo Kα radiation |
a = 16.042 (2) Å | µ = 0.30 mm−1 |
b = 9.4781 (10) Å | T = 173 K |
c = 17.599 (2) Å | 0.7 × 0.6 × 0.5 mm |
β = 111.49 (1)° |
Siemens P4 diffractometer | Rint = 0.014 |
3350 measured reflections | 3 standard reflections every 247 reflections |
2173 independent reflections | intensity decay: none |
1894 reflections with I > 2σ(I) |
R[F2 > 2σ(F2)] = 0.035 | 0 restraints |
wR(F2) = 0.093 | H-atom parameters constrained |
S = 1.07 | Δρmax = 0.22 e Å−3 |
2173 reflections | Δρmin = −0.39 e Å−3 |
168 parameters |
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. Operator: $2 − x, y, −z + 1/2 Least-squares planes (x,y,z in crystal coordinates) and deviations from them (* indicates atom used to define plane) − 6.0691 (0.0088) x + 8.0518 (0.0033) y + 8.4601 (0.0092) z = 6.3362 (0.0034) * 0.0064 (0.0010) C11 * −0.0040 (0.0010) C12 * −0.0010 (0.0010) C13 * 0.0035 (0.0010) C14 * −0.0012 (0.0010) C15 * −0.0037 (0.0010) C16 Rms deviation of fitted atoms = 0.0038 0.0000 (0.0000) x + 9.4781 (0.0017) y + 0.0000 (0.0000) z = 3.3408 (0.0012) Angle to previous plane (with approximate e.s.d.) = 31.84 (0.03) * −0.3656 (0.0011) C17 * 0.3656 (0.0011) C27 * −0.3656 (0.0011) C17_$2 * 0.3656 (0.0011) C27_$2 − 2.9093 (0.0027) C99 Rms deviation of fitted atoms = 0.3656 9.4048 (0.0077) x + 3.1552 (0.0053) y + 8.3147 (0.0090) z = 5.5962 (0.0025) Angle to previous plane (with approximate e.s.d.) = 70.56 (0.04) * 0.0180 (0.0010) C21 * −0.0082 (0.0010) C22 * −0.0072 (0.0010) C23 * 0.0126 (0.0010) C24 * −0.0028 (0.0010) C25 * −0.0124 (0.0009) C26 Rms deviation of fitted atoms = 0.0113 |
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 | ||
O1 | −0.03403 (7) | 0.42569 (11) | 0.31439 (6) | 0.0280 (3) | |
O2 | 0.11689 (7) | 0.49167 (10) | 0.37375 (6) | 0.0283 (3) | |
C1 | 0.02659 (11) | 0.53078 (16) | 0.35714 (10) | 0.0298 (4) | |
H1A | 0.0185 | 0.5500 | 0.4093 | 0.036* | |
H1B | 0.0132 | 0.6188 | 0.3246 | 0.036* | |
C11 | −0.08144 (10) | 0.35402 (15) | 0.35435 (9) | 0.0237 (3) | |
C12 | −0.17184 (10) | 0.33321 (15) | 0.30808 (9) | 0.0239 (3) | |
C13 | −0.22337 (10) | 0.25816 (16) | 0.34289 (9) | 0.0262 (3) | |
H13 | −0.2853 | 0.2433 | 0.3125 | 0.031* | |
C14 | −0.18526 (11) | 0.20460 (16) | 0.42173 (9) | 0.0285 (4) | |
H14 | −0.2210 | 0.1539 | 0.4452 | 0.034* | |
C15 | −0.09503 (11) | 0.22573 (16) | 0.46581 (9) | 0.0272 (3) | |
H15 | −0.0695 | 0.1884 | 0.5195 | 0.033* | |
C16 | −0.04048 (10) | 0.30035 (15) | 0.43361 (9) | 0.0247 (3) | |
C17 | 0.05941 (10) | 0.31391 (16) | 0.48318 (9) | 0.0271 (3) | |
H17A | 0.0734 | 0.4140 | 0.4987 | 0.032* | |
H17B | 0.0739 | 0.2585 | 0.5341 | 0.032* | |
C21 | 0.14032 (10) | 0.34996 (15) | 0.38371 (8) | 0.0235 (3) | |
C22 | 0.11842 (9) | 0.26379 (16) | 0.43802 (8) | 0.0243 (3) | |
C23 | 0.15267 (10) | 0.12747 (17) | 0.45113 (9) | 0.0274 (3) | |
H23 | 0.1387 | 0.0676 | 0.4881 | 0.033* | |
C24 | 0.20676 (10) | 0.07750 (17) | 0.41129 (9) | 0.0305 (4) | |
H24 | 0.2310 | −0.0151 | 0.4219 | 0.037* | |
C25 | 0.22533 (10) | 0.16301 (17) | 0.35598 (9) | 0.0280 (3) | |
H25 | 0.2615 | 0.1277 | 0.3279 | 0.034* | |
C26 | 0.19200 (9) | 0.30025 (16) | 0.34045 (8) | 0.0242 (3) | |
C27 | 0.21231 (10) | 0.39104 (17) | 0.27827 (9) | 0.0275 (3) | |
H27A | 0.2781 | 0.3982 | 0.2940 | 0.033* | |
H27B | 0.1888 | 0.4873 | 0.2793 | 0.033* | |
C99 | 0.0000 | 0.0455 (3) | 0.2500 | 0.0362 (5) | |
H99 | −0.0486 | 0.1070 | 0.2146 | 0.043* | |
Cl | −0.04111 (4) | −0.05813 (7) | 0.31110 (4) | 0.0704 (2) |
U11 | U22 | U33 | U12 | U13 | U23 | |
O1 | 0.0285 (6) | 0.0328 (6) | 0.0256 (5) | −0.0035 (5) | 0.0132 (4) | 0.0018 (4) |
O2 | 0.0294 (6) | 0.0220 (5) | 0.0357 (6) | −0.0041 (4) | 0.0147 (5) | −0.0064 (4) |
C1 | 0.0345 (8) | 0.0218 (7) | 0.0381 (8) | 0.0005 (6) | 0.0193 (7) | −0.0013 (6) |
C11 | 0.0290 (8) | 0.0214 (7) | 0.0253 (7) | 0.0014 (6) | 0.0155 (6) | −0.0012 (6) |
C12 | 0.0280 (8) | 0.0209 (7) | 0.0253 (7) | 0.0050 (6) | 0.0127 (6) | −0.0006 (6) |
C13 | 0.0262 (8) | 0.0245 (7) | 0.0296 (8) | 0.0006 (6) | 0.0121 (6) | −0.0025 (6) |
C14 | 0.0352 (9) | 0.0245 (8) | 0.0307 (8) | −0.0031 (6) | 0.0181 (7) | 0.0002 (6) |
C15 | 0.0354 (8) | 0.0264 (8) | 0.0217 (7) | 0.0009 (7) | 0.0126 (6) | 0.0000 (6) |
C16 | 0.0304 (8) | 0.0224 (7) | 0.0233 (7) | 0.0006 (6) | 0.0122 (6) | −0.0041 (6) |
C17 | 0.0309 (8) | 0.0302 (8) | 0.0209 (7) | −0.0020 (6) | 0.0104 (6) | −0.0031 (6) |
C21 | 0.0226 (7) | 0.0232 (7) | 0.0214 (7) | −0.0031 (6) | 0.0044 (6) | −0.0063 (6) |
C22 | 0.0228 (7) | 0.0286 (8) | 0.0180 (7) | −0.0030 (6) | 0.0033 (6) | −0.0055 (6) |
C23 | 0.0284 (8) | 0.0303 (8) | 0.0193 (7) | −0.0014 (6) | 0.0038 (6) | −0.0003 (6) |
C24 | 0.0304 (8) | 0.0301 (8) | 0.0244 (7) | 0.0058 (7) | 0.0024 (6) | −0.0016 (6) |
C25 | 0.0243 (8) | 0.0349 (8) | 0.0220 (7) | 0.0029 (6) | 0.0051 (6) | −0.0067 (6) |
C26 | 0.0196 (7) | 0.0290 (8) | 0.0204 (7) | −0.0051 (6) | 0.0033 (6) | −0.0068 (6) |
C27 | 0.0241 (7) | 0.0304 (8) | 0.0295 (8) | −0.0071 (6) | 0.0114 (6) | −0.0066 (6) |
C99 | 0.0312 (12) | 0.0349 (12) | 0.0345 (12) | 0.000 | 0.0026 (10) | 0.000 |
Cl | 0.0486 (3) | 0.0926 (5) | 0.0648 (4) | −0.0202 (3) | 0.0147 (3) | 0.0214 (3) |
O1—C11 | 1.3879 (17) | C17—H17A | 0.9900 |
O1—C1 | 1.4028 (18) | C17—H17B | 0.9900 |
O2—C21 | 1.3884 (18) | C21—C22 | 1.396 (2) |
O2—C1 | 1.4181 (19) | C21—C26 | 1.397 (2) |
C1—H1A | 0.9900 | C22—C23 | 1.390 (2) |
C1—H1B | 0.9900 | C23—C24 | 1.384 (2) |
C11—C12 | 1.393 (2) | C23—H23 | 0.9500 |
C11—C16 | 1.402 (2) | C24—C25 | 1.380 (2) |
C12—C13 | 1.391 (2) | C24—H24 | 0.9500 |
C12—C27i | 1.519 (2) | C25—C26 | 1.395 (2) |
C13—C14 | 1.391 (2) | C25—H25 | 0.9500 |
C13—H13 | 0.9500 | C26—C27 | 1.518 (2) |
C14—C15 | 1.384 (2) | C27—H27A | 0.9900 |
C14—H14 | 0.9500 | C27—H27B | 0.9900 |
C15—C16 | 1.396 (2) | C99—Cli | 1.7539 (15) |
C15—H15 | 0.9500 | C99—Cl | 1.7539 (15) |
C16—C17 | 1.524 (2) | C99—H99 | 0.9900 |
C17—C22 | 1.518 (2) | ||
C11—O1—C1 | 118.47 (11) | C16—C17—H17B | 108.8 |
C21—O2—C1 | 119.19 (11) | H17A—C17—H17B | 107.7 |
O1—C1—O2 | 112.33 (12) | O2—C21—C22 | 121.86 (13) |
O1—C1—H1A | 109.1 | O2—C21—C26 | 116.40 (13) |
O2—C1—H1A | 109.1 | C22—C21—C26 | 121.61 (14) |
O1—C1—H1B | 109.1 | C23—C22—C21 | 118.30 (13) |
O2—C1—H1B | 109.1 | C23—C22—C17 | 119.23 (13) |
H1A—C1—H1B | 107.9 | C21—C22—C17 | 122.47 (13) |
O1—C11—C12 | 114.81 (12) | C24—C23—C22 | 121.15 (14) |
O1—C11—C16 | 122.53 (13) | C24—C23—H23 | 119.4 |
C12—C11—C16 | 122.58 (13) | C22—C23—H23 | 119.4 |
C13—C12—C11 | 118.31 (13) | C25—C24—C23 | 119.58 (14) |
C13—C12—C27i | 121.31 (13) | C25—C24—H24 | 120.2 |
C11—C12—C27i | 120.37 (13) | C23—C24—H24 | 120.2 |
C14—C13—C12 | 120.72 (14) | C24—C25—C26 | 121.30 (14) |
C14—C13—H13 | 119.6 | C24—C25—H25 | 119.4 |
C12—C13—H13 | 119.6 | C26—C25—H25 | 119.4 |
C15—C14—C13 | 119.57 (14) | C25—C26—C21 | 117.98 (14) |
C15—C14—H14 | 120.2 | C25—C26—C27 | 120.11 (13) |
C13—C14—H14 | 120.2 | C21—C26—C27 | 121.91 (13) |
C14—C15—C16 | 121.88 (14) | C26—C27—C12i | 112.98 (12) |
C14—C15—H15 | 119.1 | C26—C27—H27A | 109.0 |
C16—C15—H15 | 119.1 | C12i—C27—H27A | 109.0 |
C15—C16—C11 | 116.91 (14) | C26—C27—H27B | 109.0 |
C15—C16—C17 | 119.63 (13) | C12i—C27—H27B | 109.0 |
C11—C16—C17 | 123.40 (13) | H27A—C27—H27B | 107.8 |
C22—C17—C16 | 113.62 (12) | Cli—C99—Cl | 111.87 (14) |
C22—C17—H17A | 108.8 | Cli—C99—H99 | 109.2 |
C16—C17—H17A | 108.8 | Cl—C99—H99 | 109.2 |
C22—C17—H17B | 108.8 | ||
C11—O1—C1—O2 | 111.24 (14) | C1—O2—C21—C22 | −51.89 (19) |
C21—O2—C1—O1 | −29.61 (18) | C1—O2—C21—C26 | 132.11 (14) |
C1—O1—C11—C12 | 136.93 (13) | O2—C21—C22—C23 | −173.03 (12) |
C1—O1—C11—C16 | −46.25 (19) | C26—C21—C22—C23 | 2.8 (2) |
O1—C11—C12—C13 | 177.96 (12) | O2—C21—C22—C17 | 6.6 (2) |
C16—C11—C12—C13 | 1.1 (2) | C26—C21—C22—C17 | −177.60 (13) |
O1—C11—C12—C27i | −1.83 (19) | C16—C17—C22—C23 | −96.46 (16) |
C16—C11—C12—C27i | −178.65 (13) | C16—C17—C22—C21 | 83.90 (17) |
C11—C12—C13—C14 | −0.4 (2) | C21—C22—C23—C24 | −0.3 (2) |
C27i—C12—C13—C14 | 179.37 (14) | C17—C22—C23—C24 | −179.97 (13) |
C12—C13—C14—C15 | −0.3 (2) | C22—C23—C24—C25 | −1.6 (2) |
C13—C14—C15—C16 | 0.3 (2) | C23—C24—C25—C26 | 1.2 (2) |
C14—C15—C16—C11 | 0.4 (2) | C24—C25—C26—C21 | 1.1 (2) |
C14—C15—C16—C17 | −176.86 (13) | C24—C25—C26—C27 | −179.01 (13) |
O1—C11—C16—C15 | −177.67 (12) | O2—C21—C26—C25 | 172.86 (12) |
C12—C11—C16—C15 | −1.1 (2) | C22—C21—C26—C25 | −3.1 (2) |
O1—C11—C16—C17 | −0.6 (2) | O2—C21—C26—C27 | −7.00 (19) |
C12—C11—C16—C17 | 175.99 (13) | C22—C21—C26—C27 | 176.99 (13) |
C15—C16—C17—C22 | 125.23 (15) | C25—C26—C27—C12i | 64.44 (18) |
C11—C16—C17—C22 | −51.79 (19) | C21—C26—C27—C12i | −115.70 (15) |
Symmetry code: (i) −x, y, −z+1/2. |
D—H···A | D—H | H···A | D···A | D—H···A |
C27—H27A···Clii | 0.99 | 2.83 | 3.8128 (17) | 170 |
Symmetry code: (ii) x+1/2, y+1/2, z. |
Experimental details
Crystal data | |
Chemical formula | C30H24O4·CH2Cl2 |
Mr | 533.42 |
Crystal system, space group | Monoclinic, C2/c |
Temperature (K) | 173 |
a, b, c (Å) | 16.042 (2), 9.4781 (10), 17.599 (2) |
β (°) | 111.49 (1) |
V (Å3) | 2489.9 (5) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.30 |
Crystal size (mm) | 0.7 × 0.6 × 0.5 |
Data collection | |
Diffractometer | Siemens P4 diffractometer |
Absorption correction | – |
No. of measured, independent and observed [I > 2σ(I)] reflections | 3350, 2173, 1894 |
Rint | 0.014 |
(sin θ/λ)max (Å−1) | 0.595 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.035, 0.093, 1.07 |
No. of reflections | 2173 |
No. of parameters | 168 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.22, −0.39 |
Computer programs: XSCANS (Fait, 1991), XSCANS, SHELXS97 (Sheldrick, 1990), SHELXL97 (Sheldrick, 1997), XP (Siemens, 1994), SHELXL97.
C11—O1—C1—O2 | 111.24 (14) | C1—O2—C21—C26 | 132.11 (14) |
C21—O2—C1—O1 | −29.61 (18) | O2—C21—C26—C27 | −7.00 (19) |
C1—O1—C11—C12 | 136.93 (13) | C21—C26—C27—C12i | −115.70 (15) |
C16—C11—C12—C27i | −178.65 (13) |
Symmetry code: (i) −x, y, −z+1/2. |
D—H···A | D—H | H···A | D···A | D—H···A |
C27—H27A···Clii | 0.99 | 2.83 | 3.8128 (17) | 170 |
Symmetry code: (ii) x+1/2, y+1/2, z. |
An important property of calix[4]arenes is that they possess cavities that can accommodate neutral guest molecules (see, for example, Vicens & Böhner, 1991; Mandolini & Ungaro, 2000). This behaviour requires the calixarene to be maintained in the cone conformation, although some inclusion complexes have been reported with partial cone conformers (Arduini et al., 2001). The most frequently employed method of locking the cone conformation is to tether large substituents on the narrow rim, thus hindering the transannular rotation of the individual phenol rings. Another method, employed in the present study, consists in linking two pairs of proximal O atoms with short bridging units. The latter method offers the advantage of making the whole calixarene more rigid, a property that is expected to enhance the efficiency of guest complexation. We describe here the synthesis (see Experimental and Scheme) and structure of the title compound, (I), a calix[4]arene locked in the cone conformation, which crystallizes with a well ordered guest molecule of dichloromethane.
The structure of the closely related 5,11,17,23-tetra-tert-butyl-substituted analogue, which crystallized without any guest molecule, was published by Neri et al. (1992), but no coordinates were deposited; we redetermined the structure and deposited it in the Cambridge Structural Database (Allen, 2002) under refcode YAHVOS01. It consists of two independent molecules of similar conformation (the r.m.s. deviation of all atoms except the tert-butyl groups is 0.20 Å). The additional bridging reduces the approximate mm2 symmetry of a standard calixarene (with cone conformation) to approximate twofold symmetry (with a distorted or `pinched' cone conformation and an elliptical cavity).
The title compound, lacking tert-butyl substituents, displays exact twofold symmetry [symmetry code: (i) −x, y, −z + 1/2], but the conformation is similar to that reported by Neri et al. (1992), with an r.m.s. deviation of 0.24 Å from molecule 1 of that structure. The methylene bridges cause the O···O distances across the cavity to differ appreciably: O1···O1i = 2.854 (2) Å and O2···O2i = 4.590 (2) Å. The interplanar angles to the calixarene reference plane of atoms C17, C27 and their symmetry equivalents (exactly planar by symmetry) are 148.16 (3) and 109.44 (4)° for C11–C16 and C21–C26, respectively. The centroids of the symmetry-equivalent rings lie 7.54 Å apart for ring C11–C16 and 6.03 Å for ring C21–C26. The latter ring is not eclipsed with its symmetry-generated counterpart (as shown, for example, by the torsion angle C24—Cg—Cgi—C24i of 19°, where Cg is the centroid of ring C21–C26).
The title compound crystallizes with a guest molecule of dichloromethane, which also shows exact twofold symmetry. Host–guest geometry involving calixarenes as hosts has been discussed extensively by Arduini et al. (2001), and the same nomenclature for angles and distances is used here. The dichloromethane molecule forms extremely short C99—H99···π contacts to the ring C21–26 (Fig. 1), with an H···π distance of 2.44 Å. If the C99—H99 bond length is normalized to 1.08 Å, then the `true' value for the contact is even shorter, at 2.35 Å. The favourable directionality of the interaction is shown by the angles α [8.5°; between the vector C99—Cg and the normal to the ring plane] and σ [166°; between the vectors C99—H99 and H99—Cg). A search of the Cambridge Structural Database (Allen, 2002; version of 2003) for short contacts from dichloromethane hydrogen to a calixarene ring centroid revealed 43 hits with a contact distance < 3.1 Å; the five shortest (2.42–2.46 Å) were the refcodes KOCQEY (Parlevliet et al., 2000), NOVNOB (Giannini et al., 1997), PAYHOM (Giusti et al., 1997), TARXOZ (Beer, Drew, Grieve et al., 1996) and ZUVNAF (Beer, Drew, Kan et al., 1996). It is noteworthy that all these structures are calixarenes modified either by internal bridging or, equivalently, by metal complex formation.
The distance from C99 to the ring centroids is 4.373 Å to C11–C16 and 3.411 Å to C21–C26, leading to a Σ4 value (sum of the C···π distances) of 15.568 Å; its distance to the reference plane is 2.909 (3) Å. There is no tilting of the guest molecule relative to the reference plane, with interplanar angles γ (between the CCl2 plane and the reference plane) and η (between CH2 and the reference plane) both being 90° by symmetry.
The crystal packing is further characterized by a C—H···Cl hydrogen bond (Table 2). The overall effect is to form layers of calixarene and solvent molecules parallel to the xy plane (Fig. 2). Within the layers, only translation symmetry is involved. There are two such layers per cell at z ≈ 1/4, 0.75.