Benzoyl-Substituted Tetrathia[1.1.1.1]metacyclophanes: High-Yield Synthesis, Crystal Structure, and Redox Properties

Freund, Torsten; Kübel, Christian; Baumgarten, Martin; Enkelmann, Volker; Gherghel, Lileta; Reuter, Ronald; Müllen, Kläus

doi:10.1002/(sici)1099-0690(199804)1998:4<555::aid-ejoc555>3.3.co;2-e

Cited by 5 publications

(5 citation statements)

References 7 publications

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“…This clearly indicates that steric differentiation between nucleophilic sites is not required for efficient ring formation. In accord with a study on S N Ar-based routes to thiacalixarenes, the remarkably high yields obtained for the formation of 3a − 3h over other potentially accessible linear or cyclic structures suggest that ring opening and closing may be reversible under the reaction conditions and that the oxacalix[4]arene architecture may be the thermodynamic product of these cyclizations. Investigations into the mechanistic details of this unusual selectivity are currently underway.…”

supporting

confidence: 70%

Synthesis of Functionalized Oxacalix[4]arenes

2004

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supporting

confidence: 70%

Synthesis of Functionalized Oxacalix[4]arenes

2004

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“…The other chairlike conformation in a crystalline state, however, also has been reported for an unsubstituted calix[4]arene, a methylene-bridged analogue of 2 . There are the other unsubstituted calix[4]arenes, i.e., tetrathia[1.1.1.1]metacyclophane and tetraaza[1.1.1.1]metacyclophane, but in both cases, the 1,3-alternate conformation has been characterized by X-ray analyses. The conformation of tetrasila[1.1.1.1]metacyclophane 2 deviates somewhat from the chairlike conformation; two opposing benzene rings are nearly parallel, but no coplanar orientation of the two aromatic rings is observed.…”

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confidence: 83%

Silicon-Bridged Metacyclophanes as Parent Compounds of Silacalix[n]arenes. Synthesis, Structures, and Conformational Analysis by Semiempirical MO Calculations

1999

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This paper includes the preparation of the unsubstituted silicon-bridged metacyclophanes as parent compounds of silacalix[n]arenes (n = 3, 4). A one-pot reaction gave the two different organosilicon macrocyclics, concomitantly. The structures of the metacyclophanes were unequivocally determined by X-ray crystallography. As a result, it was shown that trisila[1.1.1]metacyclophane (trisilacalix[3]arene, 1) and tetrasila[1.1.1.1]metacyclophane (tetrasilacalix[4]arene, 2) adopted a saddle structure and a 1,2-alternate structure, respectively. The conformations of these silacalixarenes were also analyzed by semiempirical PM3 calculations, which indicated that the conformations of the silacalixarenes in the crystal did not represent an energy minimum. A completely C 3 symmetric cone structure of 1 and a 1,3-alternate structure of 2 were estimated as the most stable conformations, respectively. In addition, a π-complex formation between the silacalixarenes and silver cation was observed by FAB mass spectrometry. This is the first observation of π-complexation of a metal ion by a [1.1.1]metacyclophane derivative.

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“…Electrophiles 5 and 6 efficiently form cyclotetramers at higher temperatures yet furnish a mixture of linear and cyclic oligomers at lower temperatures. These data suggest that oxacalix[4]arenes are thermodynamically favored over alternative linear and cyclic species and that the reaction outcomes at 25 °C for 2 and 3 and at 120 °C for 4 − 6 reflect thermodynamic product control. , Conversely, the more complex product mixtures obtained at 50 °C for 5 and 6 are likely kinetic product distributions.…”

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confidence: 97%