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Ramos ML, Justino LLG, Barata R, Costa T, Burrows HD. Complexes of In(III) with 8-hydroxyquinoline-5-sulfonate in solution: structural studies and the effect of cationic surfactants on the photophysical behaviour. Dalton Trans 2021; 50:16970-16983. [PMID: 34752595 DOI: 10.1039/d1dt02858h] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Following previous studies on the complexation in aqueous solutions of 8-hydroxyquinoline-5-sulfonate (8-HQS) with the trivalent metal ions, Al(III) and Ga(III) and various other metal ions, using multinuclear NMR, DFT calculations, UV-vis absorption and luminescence techniques, we have extended our studies on 8-HQS complexation to the trivalent metal ion In(III). The study combines the high sensitivity of luminescence techniques and the selectivity of multinuclear NMR spectroscopy with the structural details accessible through DFT calculations, and aims to obtain a complete understanding of the complexation between the In3+ metal ion and 8-HQS, and how this influences the luminescence behaviour. A full speciation study has been performed and, as has been reported for the complexes of 8-hydroxyquinoline (8-HQ), the dominant complexes of 8-HQS with In(III) show marked differences in the complexation behaviour when compared with the equivalent complexes with the other group 13 cations Al(III) and Ga(III). While all three complexes have a 1 : 3 (metal : ligand) stoichiometry, those with Al(III) and Ga(III) show a mer-geometry of the ligands around the metal centre, whereas the fac-geometry is observed for the complexes with In(III). On binding to metal ions, 8-HQS shows a marked increase in the intensity of the fluorescence emission band compared to that of the virtually non-luminescent free ligand. However, the increase for In(III) is less pronounced than with Al(III) or Ga(III). These observations have important implications for the application of the complexes in sensing, light emitting devices (e.g. OLEDs), or as electron transport layers in photovoltaics for solar energy conversion. Furthermore, surfactant complexation is known to improve the fluorescence intensity in metal complexes with 8-HQS, by inhibiting the ligand exchange, as we have reported for complexes of HQS with Al(III) and Ga(III). Accordingly, in view of the development of applications in either sensing or optoelectronics, our interest also includes the study of HQS complexes of In(III) in the presence of cationic surfactants, in comparison with previous results with Al(III) and Ga(III).
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Affiliation(s)
- M Luísa Ramos
- Chemistry Department and Coimbra Chemistry Centre, University of Coimbra, 3004-535 Coimbra, Portugal.
| | - Licínia L G Justino
- Chemistry Department and Coimbra Chemistry Centre, University of Coimbra, 3004-535 Coimbra, Portugal.
| | - Rui Barata
- Chemistry Department and Coimbra Chemistry Centre, University of Coimbra, 3004-535 Coimbra, Portugal.
| | - Telma Costa
- Chemistry Department and Coimbra Chemistry Centre, University of Coimbra, 3004-535 Coimbra, Portugal.
| | - Hugh D Burrows
- Chemistry Department and Coimbra Chemistry Centre, University of Coimbra, 3004-535 Coimbra, Portugal.
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Ramos ML, Justino LLG, Barata R, Costa T, Nogueira BA, Fausto R, Burrows HD. Oxocomplexes of U(vi) with 8-hydroxyquinoline-5-sulfonate in solution: structural studies and photophysical behaviour. Dalton Trans 2017; 46:9358-9368. [PMID: 28548670 DOI: 10.1039/c7dt01324h] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Multinuclear (1H and 13C) NMR, and Raman spectroscopy, combined with DFT calculations, provide detailed information on the complexation between U(vi) oxoions and 8-hydroxyquinoline-5-sulfonate (8-HQS) in aqueous solution. Over the concentration region studied, U(vi) oxoions (uranyl ions) form one dominant complex with 8-HQS in water in the pH range 3-6, a mononuclear 1 : 2 (metal : ligand) complex, with the metal centre (UO22+) coordinated to two 8-HQS ligands, together with one or more water molecules. An additional minor 1 : 1 complex has also been detected for solutions with a 1 : 1 metal : ligand molar ratio. The geometry of the dominant complex is proposed based on the combination of the NMR and Raman results with DFT calculations. Further information on the electronic structure of the complex has been obtained from UV/visible absorption and luminescence spectra. The complex of U(vi) and 8-HQS is non-luminescent, in contrast to what has been observed with this ligand and many other metal ions. We suggest that this is due to the presence of low-lying ligand-to-metal charge transfer (LMCT) states below the emitting ligand-based and uranyl-based levels which quench their emission. These studies have fundamental importance and are also relevant in the context of environmental studies, and the water soluble ligand 8-HQS has been chosen for application in uranium remediation of aqueous environments.
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Affiliation(s)
- M Luísa Ramos
- Centro de Química and Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal.
| | - Licínia L G Justino
- Centro de Química and Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal.
| | - Rui Barata
- Centro de Química and Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal.
| | - Telma Costa
- Centro de Química and Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal.
| | - Bernardo A Nogueira
- Centro de Química and Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal.
| | - Rui Fausto
- Centro de Química and Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal.
| | - Hugh D Burrows
- Centro de Química and Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal.
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Ramos ML, Justino LLG, Abreu PE, Fonseca SM, Burrows HD. Oxocomplexes of Mo(VI) and W(VI) with 8-hydroxyquinoline-5-sulfonate in solution: structural studies and the effect of the metal ion on the photophysical behaviour. Dalton Trans 2015; 44:19076-89. [PMID: 26498366 DOI: 10.1039/c5dt03473f] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Multinuclear ((1)H, (13)C, (95)Mo and (183)W) NMR spectroscopy, combined with DFT calculations, provides detailed information on the complexation between the Mo(VI) and W(VI) oxoions and 8-hydroxyquinoline-5-sulfonate (8-HQS) in aqueous solution. Over the concentration region studied, Mo(VI) and W(VI) oxoions form three homologous complexes with 8-HQS in water in the pH range 2-8. Two of these, detected at pH < 6, are mononuclear 1 : 2 (metal : ligand) isomers, with the metal centre (MO2(2+)) coordinated to two 8-HQS ligands. An additional complex, dominant at slightly higher pH values (5-8) for solutions with a 1 : 1 metal : ligand molar ratio, has a binuclear M2O5(2+) centre coordinated to two 8-HQS ligands. The two metal atoms are bridged by three oxygen atoms, two coming from 8-HQS, together with the M-O-M bridge of the bimetallic centre. We show that the long-range exchange corrected BOP functional with local response dispersion (LCBOPLRD), together with explicit solvent molecules, leads to geometries that readily converge to equilibrium structures having realistic bridging O8-HQS-M bonds. Previous attempts to calculate the structures of such binuclear complexes using DFT with the B3LYP functional have failed due to difficulties in treating the weak interaction in these bridged structures. We believe that the LCBOPLRD method may be of more general application in theoretical studies in related binuclear metal complexes. UV/visible absorption and luminescence spectra of all the complexes have also been recorded. The complex between Mo(vi) and 8-HQS is only weakly luminescent, in contrast to what has been observed with this ligand and many other metal ions. We suggest that this is due to the presence of low-lying ligand-to-metal charge transfer (LMCT) states close to the emitting ligand-based level which quench the emission. However, with W(VI), DFT calculations show that the LMCT states are now much higher in energy than the ligand based levels, leading to a marked increase in fluorescence.
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Affiliation(s)
- M Luísa Ramos
- Centro de Química and Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal.
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He Y, Li J, Wu HH, Chai X, Yang J, Wang YF, Zhang P, Zhu Y, Gao XM. A new caffeoylgluconic acid derivative from the nearly ripe fruits of Evodia rutaecarpa. Nat Prod Res 2015; 29:1243-8. [DOI: 10.1080/14786419.2015.1024116] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Ying He
- Tianjin State Key Laboratory of Modern Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin 300193, P.R. China
- Tianjin Key Laboratory of TCM Chemistry and Analysis, Tianjin University of Traditional Chinese Medicine, Tianjin 300193, P.R. China
| | - Jie Li
- Tianjin State Key Laboratory of Modern Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin 300193, P.R. China
- Tianjin Key Laboratory of TCM Chemistry and Analysis, Tianjin University of Traditional Chinese Medicine, Tianjin 300193, P.R. China
| | - Hong-Hua Wu
- Tianjin State Key Laboratory of Modern Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin 300193, P.R. China
- Tianjin Key Laboratory of TCM Chemistry and Analysis, Tianjin University of Traditional Chinese Medicine, Tianjin 300193, P.R. China
| | - Xin Chai
- Tianjin State Key Laboratory of Modern Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin 300193, P.R. China
- Tianjin Key Laboratory of TCM Chemistry and Analysis, Tianjin University of Traditional Chinese Medicine, Tianjin 300193, P.R. China
| | - Jing Yang
- Tianjin State Key Laboratory of Modern Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin 300193, P.R. China
- Tianjin Key Laboratory of TCM Chemistry and Analysis, Tianjin University of Traditional Chinese Medicine, Tianjin 300193, P.R. China
| | - Yue-Fei Wang
- Tianjin State Key Laboratory of Modern Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin 300193, P.R. China
- Tianjin Key Laboratory of TCM Chemistry and Analysis, Tianjin University of Traditional Chinese Medicine, Tianjin 300193, P.R. China
| | - Peng Zhang
- Tianjin State Key Laboratory of Modern Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin 300193, P.R. China
- Tianjin Key Laboratory of TCM Chemistry and Analysis, Tianjin University of Traditional Chinese Medicine, Tianjin 300193, P.R. China
| | - Yan Zhu
- Tianjin State Key Laboratory of Modern Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin 300193, P.R. China
- Tianjin Key Laboratory of TCM Chemistry and Analysis, Tianjin University of Traditional Chinese Medicine, Tianjin 300193, P.R. China
| | - Xiu-Mei Gao
- Tianjin State Key Laboratory of Modern Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin 300193, P.R. China
- Tianjin Key Laboratory of TCM Chemistry and Analysis, Tianjin University of Traditional Chinese Medicine, Tianjin 300193, P.R. China
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Ramos ML, Justino LLG, Fonseca SM, Burrows HD. NMR, DFT and luminescence studies of the complexation of V(v) oxoions in solution with 8-hydroxyquinoline-5-sulfonate. NEW J CHEM 2015. [DOI: 10.1039/c4nj01873g] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The complexation of vanadium(v) with 8-HQS is accompanied by marked changes in the multinuclear NMR and UV/visible absorption spectra of 8-HQS, but does not lead to a significant increase in fluorescence.
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Affiliation(s)
- M. Luísa Ramos
- Centro de Química de Coimbra and Department of Chemistry
- University of Coimbra
- 3004-535 Coimbra
- Portugal
| | - Licínia L. G. Justino
- Centro de Química de Coimbra and Department of Chemistry
- University of Coimbra
- 3004-535 Coimbra
- Portugal
| | - Sofia M. Fonseca
- Centro de Química de Coimbra and Department of Chemistry
- University of Coimbra
- 3004-535 Coimbra
- Portugal
| | - Hugh D. Burrows
- Centro de Química de Coimbra and Department of Chemistry
- University of Coimbra
- 3004-535 Coimbra
- Portugal
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Ramos ML, de Sousa ARE, Justino LLG, Fonseca SM, Geraldes CFGC, Burrows HD. Structural and photophysical studies on gallium(iii) 8-hydroxyquinoline-5-sulfonates. Does excited state decay involve ligand photolabilisation? Dalton Trans 2013; 42:3682-94. [PMID: 23299787 DOI: 10.1039/c2dt32587j] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- M Luísa Ramos
- Departamento de Química, Universidade de Coimbra, 3004-535 Coimbra, Portugal.
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Ramos ML, Justino LLG, Burrows HD. Structural considerations and reactivity of peroxocomplexes of V(v), Mo(vi) and W(vi). Dalton Trans 2011; 40:4374-83. [DOI: 10.1039/c0dt01095b] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Ramos ML, Justino LLG, Gil VMS, Burrows HD. NMR and DFT studies of the complexation of W(VI) and Mo(VI) with 3-phospho-D-glyceric and 2-phospho-D-glyceric acids. Dalton Trans 2009:9616-24. [PMID: 19859617 DOI: 10.1039/b905933d] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Multinuclear ((1)H, (13)C, (17)O, (31)P, (95)Mo, (183)W) magnetic resonance spectroscopy (1D and 2D) has been used to study the complexation of molybdate(VI) and tungstate(VI) with 3-phospho-D-glyceric and 2-phospho-D-glyceric acids. 3-Phospho-D-glyceric acid forms four and five complexes, respectively, with molybdate and tungstate. These have MO(2)(2+) centres, and involve the carboxylate and the adjacent OH groups. Two isomeric 1:2 (metal-ligand) complexes are detected, in addition to one mononuclear species having MO(3) centres and involving the ligand in a tridentate chelation and a dominant 12:4 species with both tungstate(VI) and molybdate(VI). The dominant 12:4 species can be seen as two 1:2 complexes bound together in a ring through two diphosphometalate moieties, derived from heptamolybdate or heptatungstate, respectively, by inclusion of two phosphate groups from the ligands. Tungstate is also able to form an additional 2:1 tridentate species. 2-Phospho-D-glyceric acid does not interact with tungstate but is able to form one phosphomolybdate species with molybdate, which can be regarded as a heptamolybdate derivative. Density functional theory (DFT) calculations were performed for 1:2 complexes, including calculations on the relative energies of the 1:2 complexes detected in related systems, to validate previously proposed structures. The results are compared with those obtained from multinuclear NMR spectroscopy.
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Affiliation(s)
- M Luísa Ramos
- Departmento de Química, Universidade de Coimbra, 3004-535, Coimbra, Portugal.
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Zhao MY, Yang XW. Two new acylgluconic acids from the nearly ripe fruits of Evodia rutaecarpa. JOURNAL OF ASIAN NATURAL PRODUCTS RESEARCH 2008; 10:769-773. [PMID: 18696330 DOI: 10.1080/10286020802031080] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Two new acylgluconic acids, trans-feruloylgluconic acid (1) and trans-caffeoylgluconic acid (2), together with three known compounds, myo-inositol (3), phthalic acid dibutyl ester (4), and wuzhuyuamide-I (5), were isolated from the water soluble part of the dried nearly ripe fruits of Evodia rutaecarpa (Juss.) Benth. Their structures were determined by spectroscopic methods, including IR, UV, ESITOFMS, HRSIMS, 1D and 2D NMR spectral analyses.
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Affiliation(s)
- Meng-Yao Zhao
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing, China
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Maiti SK, Dinda S, Banerjee S, Mukherjee AK, Bhattacharyya R. Oxidoperoxidotungsten(VI) Complexes with Secondary Hydroxamic Acids: Synthesis, Structure and Catalytic Uses in Highly Efficient, Selective and Ecologically Benign Oxidation of Olefins, Alcohols, Sulfides and Amines with H2O2 as a Terminal Oxidant. Eur J Inorg Chem 2008. [DOI: 10.1002/ejic.200701043] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Jáč P, Polášek M, Batista AIV, Kaderová L. Tungstate as complex-forming reagent facilitating separation of selected polyphenols by capillary electrophoresis and its comparison with borate. Electrophoresis 2008; 29:843-51. [DOI: 10.1002/elps.200700598] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Rotondo A, Rotondo E, Casella GA, Grasso G. Tin(iv) catalyzed d-galacturonic acid anomerization. Dalton Trans 2008:596-601. [DOI: 10.1039/b710676a] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Pezzotti F, Therisod M. Enzymatic synthesis of aldonic acids. Carbohydr Res 2006; 341:2290-2. [PMID: 16806132 DOI: 10.1016/j.carres.2006.05.023] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2006] [Revised: 05/19/2006] [Accepted: 05/25/2006] [Indexed: 11/29/2022]
Abstract
Several aldonic acids (D-mannonic, D-galactonic, D-xylonic, 2-deoxy-D-arabinohexonic (2-deoxy-D-gluconic)) were prepared on a scale of several grams by a simple oxidation catalyzed by glucose oxidase in pure water.
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Affiliation(s)
- F Pezzotti
- Laboratoire de Chimie Bioorganique et Bioinorganique, UMR 8182, ICMMO, Université Paris-Sud, 91405 Orsay, France
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Ramos L, Gil VMS. Multinuclear NMR study of the complexes of 6-phospho-d-gluconic acid with W(VI) and Mo(VI). Carbohydr Res 2004; 339:2225-32. [PMID: 15337450 DOI: 10.1016/j.carres.2004.06.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2004] [Accepted: 06/22/2004] [Indexed: 11/19/2022]
Abstract
Multinuclear ((1)H, (13)C, (17)O, (31)P, (95)Mo, (183)W) magnetic resonance spectroscopy (1D and 2D) has been used to show that 6-phospho-d-gluconic acid forms three complexes with tungsten(VI) and six complexes with molybdenum(VI) in aqueous solution, depending on pH and concentration. Two isomeric 1:2 (metal-ligand) complexes are detected both with tungstate(VI) and molybdate(VI), having MO(2)(2+) centres and involving the carboxylate and the adjacent OH groups in addition to one 2:1 (metal-ligand) complex possessing a M(2)O(5)(2+) centre, with the ligand being coordinated by the carboxylate group and the three consecutive OH groups in positions 2, 3 and 4. Molybdate(VI) forms three additional species, which are not detected with tungstate. One of them is a 2:1 complex with a Mo(2)O(5)(2+) centre, with the ligand being tetradentate via O-3, O-4, O-5 and the phosphate group. The other two are 12:4 species, which can be seen as two 1:2 complexes bound together in a ring through two diphosphomolybdate moieties each derived from heptamolybdate by inclusion of two phosphate groups from the ligands.
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Affiliation(s)
- Luísa Ramos
- Department of Chemistry, University of Coimbra, P-3004 535 Coimbra, Portugal.
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Luísa Ramos M, Caldeira MM, Gil VM. NMR study of the complexation of D-gulonic acid with tungsten(VI) and molybdenum(VI). Carbohydr Res 2000; 329:387-97. [PMID: 11117322 DOI: 10.1016/s0008-6215(00)00191-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
By using multinuclear (1H, 13C, 17O, 95Mo, 183W) magnetic resonance spectroscopy (1D and 2D), D-gulonic acid is found to form ten and seven complexes, respectively, with tungsten(VI) and molybdenum(VI), in aqueous solution, depending on pH and metal-ligand molar ratios. Two isomeric 1:2 (metal-ligand) complexes involving the carboxylate and the adjacent OH group are present in the pH range 2-9. At intermediate and high pH, molybdate forms a 2:1 tetradentate complex involving the four secondary hydroxyl groups, whereas tungstate forms one 2:1 terdentate species. At low and intermediate pH values, three 2:1 complexes are found for both metals, involving the carboxylate group and three secondary hydroxyl groups, as well as a 5:2 species involving the carboxylate group and all the secondary hydroxyl groups; the concentration of this species increases in time mainly at the expense of 2:1 and 1:2 complexes. Tungstate can also form two additional species, probably a 5:2 species involving the carboxylate group and all the hydroxyl groups, and a 2:1 pentadentate species involving the carboxylate group and all the secondary hydroxyl groups. In alkaline solutions, tungstate is able to form an additional 2:1 pentadentate complex involving all the hydroxyl groups.
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Affiliation(s)
- M Luísa Ramos
- Department of Chemistry, University of Coimbra, Portugal
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Tian W, Yang LM, Xu YZ, Weng SF, Wu JG. Sugar interaction with metal ions. FT-IR study on the structure of crystalline galactaric acid and its K+, NH4+, Ca2+, Ba2+, and La3+ complexes. Carbohydr Res 2000; 324:45-52. [PMID: 10723611 DOI: 10.1016/s0008-6215(99)00276-1] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The FT-IR spectra of galactaric acid and its K+, NH4+, Ca2+, Ba2+, and La3+ salts have been recorded and interpreted. Spectroscopic evidence shows that the dimeric carboxylic groups of the free acid are dissociated upon formation of the salt, and the asymmetric and symmetric stretching vibrations of the anionic COO- group in these salts are observed at about 1600 and 1400 cm-1, respectively. The two carboxylic groups of the galactarate coordinate with Ca2+ ions in a monodentate form. One of the carboxylic groups in the Ba2+ salt coordinates in a monodentate state; another group interacts with three cations in a tetradentate form. In the K+, NH4+, and La3+ salts, the COO- groups coordinate in a polydentate manner with the cations. By comparison of the spectra of the salts with that of the free acid, it is concluded that the hydroxyl groups of the galactarate skeleton take part in metal-oxygen interaction, and the hydrogen-bonding network is rearranged upon sugar metalation. The degree of participation of the sugar OH groups in metal-galactarate interaction is varied from the K+ and NH4+ salts to the Ca2+, Ba2+, and La3+ salts.
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Affiliation(s)
- W Tian
- Department of Chemistry, Peking University, Beijing, PR China
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Ramos M, Caldeira M, Gil VM. NMR spectroscopy study of the complexation of d-gluconic acid with tungsten(VI) and molybdenum(VI). Carbohydr Res 1997. [DOI: 10.1016/s0008-6215(97)00245-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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