DFT Conformational Study of Calix[6]arene: Hydrogen Bond

Kim, Kwang‐Ho; Choe, Jong‐In

doi:10.5012/bkcs.2009.30.4.837

Cited by 8 publications

(2 citation statements)

References 23 publications

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“…Interestingly, according to our calculations, the winged cone is the highest energy conformation in the gas phase because the 1,2,3-alternate conformation is less stable than the pinched cone by 11.8 kcal mol –1 . Such a stability order, namely, pinched cone > 1,2,3-alternate > winged cone, was also found in another DFT approach for 1 . However, in that study, only the input of the pinched cone conformation came from a solid-state structure.…”

Section: Resultsmentioning

confidence: 52%

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Winged-Cone Conformation in Hexa-p-tert-butylcalix[6]arene Driven by the Unusually Strong Guest Encapsulation

et al. 2017

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Hexa- p - tert -butylcalix[6]arene (1) is believed to adopt a winged conformation in a solution, featured by four phenyl rings perpendicular to the calix basis and two others at 1,4-positions lying down. However, there is some controversy on the occurrence of this conformation because it has never been found in the solid state of calix[6]arenes, regardless of the substitution pattern at lower and upper rims. Here, we have observed the winged-cone conformation for the first time in a solvate form of 1 with dimethyl sulfoxide (DMSO), dimethylformamide, and pyridine. The DMSO molecule is strongly encapsulated into 1 through two OH···O hydrogen bonds with both flattened phenolic moieties, one lp (S) ···π and four CH···π interactions with the four perpendicular phenyl rings. This host–guest complex has energy lower by 23.4 kcal mol –1 than the isolated species. In addition, another DMSO solvate form with 1,2,3-alternate conformation was also obtained in this study, and its structure is compared with that of the precedent one. A detailed density functional theory study has also been carried out to understand the energetic relationships among cone conformers, intramolecular hydrogen-bonding patterns, and DMSO encapsulation.

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Section: Resultsmentioning

confidence: 52%

“…Such a stability order, namely, pinched cone > 1,2,3-alternate > winged cone, was also found in another DFT approach for 1 . 13 However, in that study, only the input of the pinched cone conformation came from a solid-state structure.…”

Section: Resultsmentioning

confidence: 99%