A large calixarene-like metacyclophane, 4′,9′,4″,9″-tetra-
Calixarenes are cyclic compounds consisting of aromatic rings and methylene bridge chains. In search for novel supramolecular hosts, numerous efforts have been deployed to decorate the upper or lower rim of calixarenes with various functional groups [
Members of the metacyclophane family [
In this study, we report the synthesis of “oxametabiphenilophanes,” a new class of metacyclophanes that incorporate oxygen atoms in bridges and two biphenyl parts thus giving rigidity to the molecules (Scheme
4′,9′,4′′,9′′-tetra-
All reagents and solvents were obtained from commercial sources and used as received. The 1H-NMR spectrum was recorded by a JEOL JNM A-500 spectrometer in CDCl3 with tetramethylsilane as an internal reference. The electron impact mass spectrum (EI-MS) of the compound was obtained in dichloromethane as the solvent using a JEOL JMS-SX102A spectrometer. The instrument was operated in the positive ion mode over an
3,3′-Bischloromethyl-2,2′-dimethoxy-5,5′-di-
Single crystals were obtained by vapor diffusion of a dichloromethane/hexane solution of the metabiphenylophane at room temperature.
M.p. 286°C–288°C. 1H NMR (500 MHz, CDCl3) 1.33 (s, 36 H,
Crystallographic data for 4′,9′,4′′,9′′-tetra-
Empirical f | C48H64O6 | |
Formula weight | 736.99 | |
Temperature | 90 K | |
Wavelength | 0.71073 Å | |
Crystal system | Monoclinic | |
Space group |
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Unit cell dimensions |
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Volume | 4256.5(8) Å−3 | |
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4 | |
Density (calculated) | 1.150 g/cm3 | |
Absorption coefficient | 0.074 mm−1 | |
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1600 | |
Crystal size | 0.400 |
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Theta range for data collection | 1.17° to 28.65° | |
Index ranges | −26 ≤ |
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Reflections collected | 48529 | |
Independent reflections | 10321 [ |
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Reflections [ |
9126 | |
Completeness to theta = 28.65° | 94.4% | |
Absorption correction | Empirical | |
Refinement method | Full-matrix least-squares on |
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Data/restraints/parameters | 10321/0/503 | |
Goodness-of-fit on |
1.072 | |
Final |
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Largest diff. peak and hole |
0.476 and −0.331 eÅ−3 |
A colorless prismatic crystal of 4′,9′,4′′,9′′-tetra-
These measurements were performed at 90 K to a maximum 2
An empirical absorption correction provided transmission factors ranging from 0.880 to 0.980 [
The structure was solved by the SHELXS-97 direct method [
The final cycle for the full-matrix least-squares refinement on
The CIF data only showed one “Alert B” in the online check report of the Cambridge Crystal Data Centre (CCDC). This alert is related to the completeness of theta, which equaled 94.4% due to the crystal shape. Alerts A and C were not observed.
Crystal details such as the atomic coordinates, displacement parameters, bond lengths, and bond angles appear in the Additional Information Section.
The dioxa[3.3]metacyclophane was synthesized from the precursors biphenyl derivatives 3,3′-bischloromethyl-2,2′-dimethoxy-5,5′-di-
The EI mass spectrum of the compound
The molecular structure seems to be rigid in deuterated chloroform at 297 K, but the structure is readily moved by raising the measurement temperature.
To the best of our knowledge, this is the first time that the exact structure and crystal packing of this cyclophane have been characterized using X-ray analysis.
Compound
Selected bond lengths (Å) and angles (°) in 4′,9′,4′′,9′′-tetra-
O1–C9 | 1.4308(13) | O4–C31 | 1.4355(13) |
O1–C10 | 1.4340(13) | O4–C32 | 1.4345(13) |
O2–C7 | 1.3878(12) | O5–C34 | 1.3807(12) |
O2–C17 | 1.4365(14) | O5–C35 | 1.4329(13) |
O3–C29 | 1.3804(12) | O6–C38 | 1.3839(12) |
O3–C30 | 1.4421(13) | O6–C39 | 1.4275(15) |
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C9–O1–C10 | 114.17(8) | C31–O4–C32 | 112.97(8) |
O1–C9–C8 | 114.15(8) | O4–C31–C28 | 111.80(8) |
O1–C10–C12 | 114.25(9) | O4–C32–C33 | 108.01(8) |
C7–O2–C17 | 114.30(8) | C35–O5–C34 | 114.57(8) |
C30–O3–C29 | 116.28(8) | C39–O6–C38 | 113.29(9) |
(a) Top and (b) side views of 4′,9′,4′′,9′′-Tetra-
In general, cyclic compounds, such as calixarenes and large-sized metacyclophanes, display many conformations in solution. For example, tetrahydroxycalix[4]arene exhibits four typical conformations, including cone, partial cone, 1,2-alternate, and 1,3-alternate (Figure
Crystal packing of 4′,9′,4′′,9′′-tetra-
Some intermolecular short contacts existed in the crystal, which are shown in Figure
Short contacts (Å) between neighboring 4′,9′,4′′,9′′-tetra-
C9–C |
3.337(9) | H45A–H44 |
2.384 |
C9–H9 |
2.814 | H44A–H45 |
2.384 |
H9A–C |
2.814 |
Short contacts between neighboring 4′,9′,4′′,9′′-tetra-
Intramolecular cavity is filled with the methoxy substituent of 4′,9′,4′′,9′′-tetra-
The structure of dioxa[3.3]metabiphenilophane
The large metacyclophane 4′,9′,4′′,9′′-tetra-
CCDC no. 1012517 contains the supplementary crystallographic data for the compound (2S, 5S) tert-butyl 3-oxo-2-oxa-5-azabicyclo[2.2.2]octane-5-carboxylate. The data can be obtained free of charge via
The authors declare that there is no conflict of interests regarding the publication of this paper.
The authors are grateful for the Center for Instrumental Analysis, Kyushu Institute of Technology (KITCIA), for the EI_MS, 1H NMR, and X-ray analyses. The authors also thank Dr. Kenji Yoza (Bruker AXS JAPAN) for experimental assistance during the final stages of the X-ray analysis.