UV–Vis and fluorimetric Al3+, Zn2+, Cd2+ and Pb2+ complexation studies of two 3-hydroxyflavones and a 3-hydroxythioflavone
The complexation of Al3+, Zn2+, Cd2+ and Pb2+ by the 3-hydroxyflavones: 3-hydroxy-2-(2-methoxyphenyl)-4H-1-benzopyran-4-one (H1) and 3-hydroxy-2-(4-methoxyphenyl)-4H-1-benzopyran-4-one (H2), and by the 3-methoxythioflavone: 3-hydroxy-2-(2-methoxyphenyl)-4H-1-benzopyran-4-thione (H3) have been studie...
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| Format: | Journal Article |
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Elsevier
2007
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| Online Access: | http://hdl.handle.net/20.500.11937/18940 |
| _version_ | 1848749891411509248 |
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| author | Valente, J. Buntine, Mark Lincoln, S. Ward, D. |
| author_facet | Valente, J. Buntine, Mark Lincoln, S. Ward, D. |
| author_sort | Valente, J. |
| building | Curtin Institutional Repository |
| collection | Online Access |
| description | The complexation of Al3+, Zn2+, Cd2+ and Pb2+ by the 3-hydroxyflavones: 3-hydroxy-2-(2-methoxyphenyl)-4H-1-benzopyran-4-one (H1) and 3-hydroxy-2-(4-methoxyphenyl)-4H-1-benzopyran-4-one (H2), and by the 3-methoxythioflavone: 3-hydroxy-2-(2-methoxyphenyl)-4H-1-benzopyran-4-thione (H3) have been studied spectrophotometrically and fluorimetrically to determine the corresponding complexation constants, Ksp and Kfl, in 5:95 water:ethanol (v/v) solution for which [HClO4] was either 10-2 or 10-5 mol dm-3 and I = 0.10 mol dm-3 (NaClO4) at 298.2 K. Complexation occurs dominantly through the deprotonated ligand for [Al(1)]2+ and [Al(2)]2+ for which log Ksp = 4.51 and 4.73, respectively, in 10-2 mol dm-3 HClO4 and 4.21 and 4.61 in 10-5 mol dm-3 HClO4. For Pb2+ complexation by H1, H2 and H3 is characterized by log Ksp = 2.20, 2.57 and 3.22, respectively, in 10-2 mol dm-3 HClO4 and 4.70, 5.38 and 5.74 in 10-5 mol dm-3 HClO4. Equilibrium mixtures of [Pb(H1)]2+ and [Pb1]+, [Pb(H2)]2+ and [Pb2]+, and [Pb(H3)]2+ and [Pb3]+ appear to be formed. Complexation of Zn2+ and Cd2+ by all three ligands was only detected in 10-5 mol dm-3 HClO4. For Zn2+ complexation by H1, H2 and H3 log Ksp = 3.22, 3.74 and 4.46 and for Cd2+ the corresponding values are 2.39, 2.40 and 3.72 for Cd2+. Only [Al1]2+ and [Al2]2+ show significant fluorescence and are characterized by log Kfl = 6.30 and 7.49 in 10-2 mol dm-3 HClO4. |
| first_indexed | 2025-11-14T07:28:08Z |
| format | Journal Article |
| id | curtin-20.500.11937-18940 |
| institution | Curtin University Malaysia |
| institution_category | Local University |
| last_indexed | 2025-11-14T07:28:08Z |
| publishDate | 2007 |
| publisher | Elsevier |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | curtin-20.500.11937-189402017-09-13T13:47:28Z UV–Vis and fluorimetric Al3+, Zn2+, Cd2+ and Pb2+ complexation studies of two 3-hydroxyflavones and a 3-hydroxythioflavone Valente, J. Buntine, Mark Lincoln, S. Ward, D. Fluorescence 3-Hydroxyflavones 3-Hydroxythioflavones Stability constants Metal complexes The complexation of Al3+, Zn2+, Cd2+ and Pb2+ by the 3-hydroxyflavones: 3-hydroxy-2-(2-methoxyphenyl)-4H-1-benzopyran-4-one (H1) and 3-hydroxy-2-(4-methoxyphenyl)-4H-1-benzopyran-4-one (H2), and by the 3-methoxythioflavone: 3-hydroxy-2-(2-methoxyphenyl)-4H-1-benzopyran-4-thione (H3) have been studied spectrophotometrically and fluorimetrically to determine the corresponding complexation constants, Ksp and Kfl, in 5:95 water:ethanol (v/v) solution for which [HClO4] was either 10-2 or 10-5 mol dm-3 and I = 0.10 mol dm-3 (NaClO4) at 298.2 K. Complexation occurs dominantly through the deprotonated ligand for [Al(1)]2+ and [Al(2)]2+ for which log Ksp = 4.51 and 4.73, respectively, in 10-2 mol dm-3 HClO4 and 4.21 and 4.61 in 10-5 mol dm-3 HClO4. For Pb2+ complexation by H1, H2 and H3 is characterized by log Ksp = 2.20, 2.57 and 3.22, respectively, in 10-2 mol dm-3 HClO4 and 4.70, 5.38 and 5.74 in 10-5 mol dm-3 HClO4. Equilibrium mixtures of [Pb(H1)]2+ and [Pb1]+, [Pb(H2)]2+ and [Pb2]+, and [Pb(H3)]2+ and [Pb3]+ appear to be formed. Complexation of Zn2+ and Cd2+ by all three ligands was only detected in 10-5 mol dm-3 HClO4. For Zn2+ complexation by H1, H2 and H3 log Ksp = 3.22, 3.74 and 4.46 and for Cd2+ the corresponding values are 2.39, 2.40 and 3.72 for Cd2+. Only [Al1]2+ and [Al2]2+ show significant fluorescence and are characterized by log Kfl = 6.30 and 7.49 in 10-2 mol dm-3 HClO4. 2007 Journal Article http://hdl.handle.net/20.500.11937/18940 10.1016/j.ica.2007.04.011 Elsevier restricted |
| spellingShingle | Fluorescence 3-Hydroxyflavones 3-Hydroxythioflavones Stability constants Metal complexes Valente, J. Buntine, Mark Lincoln, S. Ward, D. UV–Vis and fluorimetric Al3+, Zn2+, Cd2+ and Pb2+ complexation studies of two 3-hydroxyflavones and a 3-hydroxythioflavone |
| title | UV–Vis and fluorimetric Al3+, Zn2+, Cd2+ and Pb2+ complexation studies of two 3-hydroxyflavones and a 3-hydroxythioflavone |
| title_full | UV–Vis and fluorimetric Al3+, Zn2+, Cd2+ and Pb2+ complexation studies of two 3-hydroxyflavones and a 3-hydroxythioflavone |
| title_fullStr | UV–Vis and fluorimetric Al3+, Zn2+, Cd2+ and Pb2+ complexation studies of two 3-hydroxyflavones and a 3-hydroxythioflavone |
| title_full_unstemmed | UV–Vis and fluorimetric Al3+, Zn2+, Cd2+ and Pb2+ complexation studies of two 3-hydroxyflavones and a 3-hydroxythioflavone |
| title_short | UV–Vis and fluorimetric Al3+, Zn2+, Cd2+ and Pb2+ complexation studies of two 3-hydroxyflavones and a 3-hydroxythioflavone |
| title_sort | uv–vis and fluorimetric al3+, zn2+, cd2+ and pb2+ complexation studies of two 3-hydroxyflavones and a 3-hydroxythioflavone |
| topic | Fluorescence 3-Hydroxyflavones 3-Hydroxythioflavones Stability constants Metal complexes |
| url | http://hdl.handle.net/20.500.11937/18940 |