A 3-fold "Butterfly Valve" in Command of the Encapsulation's Kinetic Stability. Molecular Baskets at Work
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2008
Authors
Wang, Bao-YuBao, Xiaoguang
Yan, Zhiqing
Maslak, Veselin
Hadad, Christopher M.
Bađić, Jovica D.
Article (Published version)
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Molecular basket 1, composed of a semirigid tris-norbornadiene framework and three revolving pyridine-based gates at the rim, has been built to "dynamically" enclose space and as such regulate molecular encapsulation. The gates were shown to fold via intramolecular hydrogen bonding and thereby form a G(3v) symmetrical receptor: the (1)H NMR resonance for the amide N-H protons of the pyridine gates appeared downfield (delta = 10.98 ppm), and the N-H vibrational stretch (IR) was observed at 3176 cm(-1). Accordingly, density functional theory (DFT, B3LYP) investigations revealed for the closed conformers of 1 to be energetically the most stable and dominant. The gearing of the pyridine "gates", about their axis, led to the interconversion of two dynamic enantiomers 1(A) and 1(B) comprising the clockwise and counterclockwise seam of intramolecular hydrogen bonds. Dynamic (1)H NMR spectroscopic measurements and line-shape simulations suggested that the energy barrier of 10.0 kcal/mol (Delta... G(A/B)(double dagger), 298 K) is required for the 1(A/B) interconversion, when CCl(4) occupies the cavity of 1. Likewise, the activation free energy for CCl4 departing the basket was found to be 13.1 kcal/mol (Delta G(double dagger), 298 K), whereas the thermodynamic stability of 1:CCl(4) complex was -2.7 kcal/mol (Delta G degrees, 298 K). In view of that, CCI4 (but also (CH(3))(3)CBr) was proposed to escape from, and a molecule of solvent to enter, the basket when the gates rotate about their axis: the exit of CCl(4) requires the activation energy of 12.7 kcal/mol (Delta G(A/B)(double dagger) + Delta G degrees), similar to the experimentally found 13.1 kcal/mol (Delta G(double dagger)).
Source:
Journal of the American Chemical Society, 2008, 130, 45, 15127-15133Publisher:
- Amer Chemical Soc, Washington
Funding / projects:
- National Science Foundation [CHE0716355]
- Ohio State University
DOI: 10.1021/ja8041977
ISSN: 0002-7863
PubMed: 18937455
WoS: 000260682300054
Scopus: 2-s2.0-57349189466
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Hemijski fakultet / Faculty of ChemistryTY - JOUR AU - Wang, Bao-Yu AU - Bao, Xiaoguang AU - Yan, Zhiqing AU - Maslak, Veselin AU - Hadad, Christopher M. AU - Bađić, Jovica D. PY - 2008 UR - https://cherry.chem.bg.ac.rs/handle/123456789/981 AB - Molecular basket 1, composed of a semirigid tris-norbornadiene framework and three revolving pyridine-based gates at the rim, has been built to "dynamically" enclose space and as such regulate molecular encapsulation. The gates were shown to fold via intramolecular hydrogen bonding and thereby form a G(3v) symmetrical receptor: the (1)H NMR resonance for the amide N-H protons of the pyridine gates appeared downfield (delta = 10.98 ppm), and the N-H vibrational stretch (IR) was observed at 3176 cm(-1). Accordingly, density functional theory (DFT, B3LYP) investigations revealed for the closed conformers of 1 to be energetically the most stable and dominant. The gearing of the pyridine "gates", about their axis, led to the interconversion of two dynamic enantiomers 1(A) and 1(B) comprising the clockwise and counterclockwise seam of intramolecular hydrogen bonds. Dynamic (1)H NMR spectroscopic measurements and line-shape simulations suggested that the energy barrier of 10.0 kcal/mol (Delta G(A/B)(double dagger), 298 K) is required for the 1(A/B) interconversion, when CCl(4) occupies the cavity of 1. Likewise, the activation free energy for CCl4 departing the basket was found to be 13.1 kcal/mol (Delta G(double dagger), 298 K), whereas the thermodynamic stability of 1:CCl(4) complex was -2.7 kcal/mol (Delta G degrees, 298 K). In view of that, CCI4 (but also (CH(3))(3)CBr) was proposed to escape from, and a molecule of solvent to enter, the basket when the gates rotate about their axis: the exit of CCl(4) requires the activation energy of 12.7 kcal/mol (Delta G(A/B)(double dagger) + Delta G degrees), similar to the experimentally found 13.1 kcal/mol (Delta G(double dagger)). PB - Amer Chemical Soc, Washington T2 - Journal of the American Chemical Society T1 - A 3-fold "Butterfly Valve" in Command of the Encapsulation's Kinetic Stability. Molecular Baskets at Work VL - 130 IS - 45 SP - 15127 EP - 15133 DO - 10.1021/ja8041977 ER -
@article{ author = "Wang, Bao-Yu and Bao, Xiaoguang and Yan, Zhiqing and Maslak, Veselin and Hadad, Christopher M. and Bađić, Jovica D.", year = "2008", abstract = "Molecular basket 1, composed of a semirigid tris-norbornadiene framework and three revolving pyridine-based gates at the rim, has been built to "dynamically" enclose space and as such regulate molecular encapsulation. The gates were shown to fold via intramolecular hydrogen bonding and thereby form a G(3v) symmetrical receptor: the (1)H NMR resonance for the amide N-H protons of the pyridine gates appeared downfield (delta = 10.98 ppm), and the N-H vibrational stretch (IR) was observed at 3176 cm(-1). Accordingly, density functional theory (DFT, B3LYP) investigations revealed for the closed conformers of 1 to be energetically the most stable and dominant. The gearing of the pyridine "gates", about their axis, led to the interconversion of two dynamic enantiomers 1(A) and 1(B) comprising the clockwise and counterclockwise seam of intramolecular hydrogen bonds. Dynamic (1)H NMR spectroscopic measurements and line-shape simulations suggested that the energy barrier of 10.0 kcal/mol (Delta G(A/B)(double dagger), 298 K) is required for the 1(A/B) interconversion, when CCl(4) occupies the cavity of 1. Likewise, the activation free energy for CCl4 departing the basket was found to be 13.1 kcal/mol (Delta G(double dagger), 298 K), whereas the thermodynamic stability of 1:CCl(4) complex was -2.7 kcal/mol (Delta G degrees, 298 K). In view of that, CCI4 (but also (CH(3))(3)CBr) was proposed to escape from, and a molecule of solvent to enter, the basket when the gates rotate about their axis: the exit of CCl(4) requires the activation energy of 12.7 kcal/mol (Delta G(A/B)(double dagger) + Delta G degrees), similar to the experimentally found 13.1 kcal/mol (Delta G(double dagger)).", publisher = "Amer Chemical Soc, Washington", journal = "Journal of the American Chemical Society", title = "A 3-fold "Butterfly Valve" in Command of the Encapsulation's Kinetic Stability. Molecular Baskets at Work", volume = "130", number = "45", pages = "15127-15133", doi = "10.1021/ja8041977" }
Wang, B., Bao, X., Yan, Z., Maslak, V., Hadad, C. M.,& Bađić, J. D.. (2008). A 3-fold "Butterfly Valve" in Command of the Encapsulation's Kinetic Stability. Molecular Baskets at Work. in Journal of the American Chemical Society Amer Chemical Soc, Washington., 130(45), 15127-15133. https://doi.org/10.1021/ja8041977
Wang B, Bao X, Yan Z, Maslak V, Hadad CM, Bađić JD. A 3-fold "Butterfly Valve" in Command of the Encapsulation's Kinetic Stability. Molecular Baskets at Work. in Journal of the American Chemical Society. 2008;130(45):15127-15133. doi:10.1021/ja8041977 .
Wang, Bao-Yu, Bao, Xiaoguang, Yan, Zhiqing, Maslak, Veselin, Hadad, Christopher M., Bađić, Jovica D., "A 3-fold "Butterfly Valve" in Command of the Encapsulation's Kinetic Stability. Molecular Baskets at Work" in Journal of the American Chemical Society, 130, no. 45 (2008):15127-15133, https://doi.org/10.1021/ja8041977 . .