Cyclodextrin and modified cyclodextrin complexes of E-4-tert-butylphenyl-4 '-oxyazobenzene: UV-visible, H-1 NMR and ab initio studies
alpha-Cyclodextrin, beta-cyclodextrin, N-(6(A)-deoxy-alpha-cyclodextrin-6(A)-yl)-N'-(6(A)-deoxy-beta-cyclodextrin-6(A)-yl)urea and N,N-bis(6(A)-deoxy-beta-cyclodextrin-6(A)-yl)urea (alpha CD, beta CD, 1 and 2) form inclusion complexes with E-4-tert-butylphenyl- 4'-oxyazobenzene, E-3(-). In...
| Main Authors: | , , , , , , |
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| Format: | Journal Article |
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The Royal Society of Chemistry
2005
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| Online Access: | http://hdl.handle.net/20.500.11937/15086 |
| _version_ | 1848748799337431040 |
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| author | May, B. Gerber, J. Clements, P. Buntine, Mark Brittain, D. Lincoln, S. Easton, C. |
| author_facet | May, B. Gerber, J. Clements, P. Buntine, Mark Brittain, D. Lincoln, S. Easton, C. |
| author_sort | May, B. |
| building | Curtin Institutional Repository |
| collection | Online Access |
| description | alpha-Cyclodextrin, beta-cyclodextrin, N-(6(A)-deoxy-alpha-cyclodextrin-6(A)-yl)-N'-(6(A)-deoxy-beta-cyclodextrin-6(A)-yl)urea and N,N-bis(6(A)-deoxy-beta-cyclodextrin-6(A)-yl)urea (alpha CD, beta CD, 1 and 2) form inclusion complexes with E-4-tert-butylphenyl- 4'-oxyazobenzene, E-3(-). In aqueous solution at pH 10.0, 298.2 K and I = 0.10 mol dm(-3) (NaClO4) spectrophotometric UV-visible studies yield the sequential formation constants: K-11 = (2.83 +/- 0.28) x 10(5) dm(3) mol(-1) for alpha CD.E-3(-), K-21 = (6.93 +/- 0.06) x 10(3) dm(3) mol(-1) for (alpha CD)(2).E-3(-), K-11 = (1.24 +/- 0.12) x 10(5) dm(3) mol(-1) for beta CD.E-3(-), K-21 = (1.22 +/- 0.06) x 10(4) dm(3) mol(-1) for (beta CD)(2).E-3(-), K-11 = (3.08 +/- 0.03) x 10(5) dm(3) mol(-1) for 1.E-3(-), K-11 = (8.05 +/- 0.63) x 10(4) dm(3) mol(-1) for 2.E-3(-) and K-12 = (2.42 +/- 0.53) x 10(4) dm(3) mol(-1) for 2.(E-3(-))(2). H-1 ROESY NMR studies show that complexation of E-3(-) in the annuli of alpha CD, beta CD, 1 and 2 occurs. A variable-temperature H-1 NMR study yields k(298 K) = 6.7 +/- 0.5 and 5.7 +/- 0.5 s(-1), Delta H double dagger = 61.7 +/- 2.7 and 88.1 +/- 4.2 kJ mol(-1) and Delta S double dagger = -22.2 +/- 8.7 and 65 +/- 13 J K-1 mol(-1) for the interconversion of the dominant includomers (complexes with different orientations of alpha CD) of alpha CD.E-3(-) and (alpha CD)(2).E-3(-), respectively. The existence of E-3(-) as the sole isomer was investigated through an ab initio study. |
| first_indexed | 2025-11-14T07:10:47Z |
| format | Journal Article |
| id | curtin-20.500.11937-15086 |
| institution | Curtin University Malaysia |
| institution_category | Local University |
| last_indexed | 2025-11-14T07:10:47Z |
| publishDate | 2005 |
| publisher | The Royal Society of Chemistry |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | curtin-20.500.11937-150862017-09-13T15:04:05Z Cyclodextrin and modified cyclodextrin complexes of E-4-tert-butylphenyl-4 '-oxyazobenzene: UV-visible, H-1 NMR and ab initio studies May, B. Gerber, J. Clements, P. Buntine, Mark Brittain, D. Lincoln, S. Easton, C. DIMERS ALPHA-CYCLODEXTRIN PHOTOISOMERIZATION SIZE GUEST INCLUSION THERMODYNAMICS AZOBENZENE alpha-Cyclodextrin, beta-cyclodextrin, N-(6(A)-deoxy-alpha-cyclodextrin-6(A)-yl)-N'-(6(A)-deoxy-beta-cyclodextrin-6(A)-yl)urea and N,N-bis(6(A)-deoxy-beta-cyclodextrin-6(A)-yl)urea (alpha CD, beta CD, 1 and 2) form inclusion complexes with E-4-tert-butylphenyl- 4'-oxyazobenzene, E-3(-). In aqueous solution at pH 10.0, 298.2 K and I = 0.10 mol dm(-3) (NaClO4) spectrophotometric UV-visible studies yield the sequential formation constants: K-11 = (2.83 +/- 0.28) x 10(5) dm(3) mol(-1) for alpha CD.E-3(-), K-21 = (6.93 +/- 0.06) x 10(3) dm(3) mol(-1) for (alpha CD)(2).E-3(-), K-11 = (1.24 +/- 0.12) x 10(5) dm(3) mol(-1) for beta CD.E-3(-), K-21 = (1.22 +/- 0.06) x 10(4) dm(3) mol(-1) for (beta CD)(2).E-3(-), K-11 = (3.08 +/- 0.03) x 10(5) dm(3) mol(-1) for 1.E-3(-), K-11 = (8.05 +/- 0.63) x 10(4) dm(3) mol(-1) for 2.E-3(-) and K-12 = (2.42 +/- 0.53) x 10(4) dm(3) mol(-1) for 2.(E-3(-))(2). H-1 ROESY NMR studies show that complexation of E-3(-) in the annuli of alpha CD, beta CD, 1 and 2 occurs. A variable-temperature H-1 NMR study yields k(298 K) = 6.7 +/- 0.5 and 5.7 +/- 0.5 s(-1), Delta H double dagger = 61.7 +/- 2.7 and 88.1 +/- 4.2 kJ mol(-1) and Delta S double dagger = -22.2 +/- 8.7 and 65 +/- 13 J K-1 mol(-1) for the interconversion of the dominant includomers (complexes with different orientations of alpha CD) of alpha CD.E-3(-) and (alpha CD)(2).E-3(-), respectively. The existence of E-3(-) as the sole isomer was investigated through an ab initio study. 2005 Journal Article http://hdl.handle.net/20.500.11937/15086 10.1039/b415594g The Royal Society of Chemistry restricted |
| spellingShingle | DIMERS ALPHA-CYCLODEXTRIN PHOTOISOMERIZATION SIZE GUEST INCLUSION THERMODYNAMICS AZOBENZENE May, B. Gerber, J. Clements, P. Buntine, Mark Brittain, D. Lincoln, S. Easton, C. Cyclodextrin and modified cyclodextrin complexes of E-4-tert-butylphenyl-4 '-oxyazobenzene: UV-visible, H-1 NMR and ab initio studies |
| title | Cyclodextrin and modified cyclodextrin complexes of E-4-tert-butylphenyl-4 '-oxyazobenzene: UV-visible, H-1 NMR and ab initio studies |
| title_full | Cyclodextrin and modified cyclodextrin complexes of E-4-tert-butylphenyl-4 '-oxyazobenzene: UV-visible, H-1 NMR and ab initio studies |
| title_fullStr | Cyclodextrin and modified cyclodextrin complexes of E-4-tert-butylphenyl-4 '-oxyazobenzene: UV-visible, H-1 NMR and ab initio studies |
| title_full_unstemmed | Cyclodextrin and modified cyclodextrin complexes of E-4-tert-butylphenyl-4 '-oxyazobenzene: UV-visible, H-1 NMR and ab initio studies |
| title_short | Cyclodextrin and modified cyclodextrin complexes of E-4-tert-butylphenyl-4 '-oxyazobenzene: UV-visible, H-1 NMR and ab initio studies |
| title_sort | cyclodextrin and modified cyclodextrin complexes of e-4-tert-butylphenyl-4 '-oxyazobenzene: uv-visible, h-1 nmr and ab initio studies |
| topic | DIMERS ALPHA-CYCLODEXTRIN PHOTOISOMERIZATION SIZE GUEST INCLUSION THERMODYNAMICS AZOBENZENE |
| url | http://hdl.handle.net/20.500.11937/15086 |