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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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Biswas R, Kundu A, Saha M, Kaur V, Banerjee B, Dhayal RS, Patil RA, Ma YR, Sen T, Haldar KK. Rational design of marigold-shaped composite Ni3V2O8 flowers: a promising catalyst for the oxygen evolution reaction. NEW J CHEM 2020. [DOI: 10.1039/d0nj01596b] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Ni3V2O8 flowers designed by the thermal decay of molecular precursors show excellent OER activity with an overpotential of 328 mV.
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Affiliation(s)
| | - Avinava Kundu
- Department of Chemistry
- Central University of Punjab
- Bathinda
- India
| | - Monochura Saha
- Indian Institute of Science Education and Research Kolkata
- Nadia 741246
- India
| | | | - Biplab Banerjee
- Department of Chemistry
- Central University of Punjab
- Bathinda
- India
| | | | - Ranjit A. Patil
- Department of Physics
- National Dong Hwa University
- Hualien 97401
- Taiwan
| | - Yuan-Ron Ma
- Department of Physics
- National Dong Hwa University
- Hualien 97401
- Taiwan
| | - Tapasi Sen
- Institute of Nano Science and Technology
- Mohali
- India
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Probing the synthetic protocols and coordination chemistry of oxido-, dioxido-, oxidoperoxido-vanadium and related complexes of higher nuclearity. Coord Chem Rev 2019. [DOI: 10.1016/j.ccr.2018.12.010] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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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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Two 8-Hydroxyquinolinate Based Supramolecular Coordination Compounds: Synthesis, Structures and Spectral Properties. MATERIALS 2017; 10:ma10030313. [PMID: 28772672 PMCID: PMC5503320 DOI: 10.3390/ma10030313] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Revised: 03/03/2017] [Accepted: 03/16/2017] [Indexed: 02/04/2023]
Abstract
Two new Cr(III) complexes based on 2-substituted 8-hydroxyquinoline ligands, namely [Cr(L1)3] (1), (HL1=(E)-2-[2-(4-nitro-phenyl)-vinyl]-8-hydroxy-quinoline) and [Cr(L2)3] (2), (HL2=(E)-2-[2-(4-chloro-phenyl)vinyl]-8-hydroxy-quinoline), were prepared by a facile hydrothermal method and characterized thoroughly by single crystal X-ray diffraction, powder X-ray diffraction, FTIR, TGA, ESI-MS, UV-Visible absorption spectra and fluorescence emission spectra. Single crystal X-ray diffraction analyses showed that the two compounds featured 3D supramolecular architectures constructed from noncovalent interactions, such as π···π stacking, C-H···π, C-H···O, C-Cl···π, C-H···Cl interactions. The thermogravimetric analysis and ESI-MS study of compounds 1 and 2 suggested that the Cr(III) complexes possessed good stability both in solid and solution. In addition, the ultraviolet and fluorescence response of the HL1 and HL2 shown marked changes upon their complexation with Cr(III) ion, which indicated that the two 8-hydroxyquinolinate based ligand are promising heavy metal chelating agent for Cr3+.
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Burrows HD, Costa T, Ramos ML, Valente AJM, Stewart B, Justino LLG, Almeida AIA, Catarina NL, Mallavia R, Knaapila M. Self-assembled systems of water soluble metal 8-hydroxyquinolates with surfactants and conjugated polyelectrolytes. Phys Chem Chem Phys 2016; 18:16629-40. [PMID: 26817700 DOI: 10.1039/c5cp07085f] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
We have studied the interaction of 8-hydroxyquinoline-5-sulfonate (8-HQS) with the metal ions Al(iii) and Zn(ii) in aqueous solution in the presence of tetraalkylammonium surfactants using UV/vis absorption, fluorescence, NMR spectroscopy and electrical conductivity measurements, complemented by DFT calculations and molecular dynamics (MD) simulations. Under appropriate conditions, complexes between 8-HQS and metal ions form rapidly, and have similar electronic, spectroscopic and photophysical properties to the corresponding metal quinolates, such as Alq3. These interact with the cationic surfactants, leading to marked increases in fluorescence intensity. However, significant differences are seen in the behavior of the two metal ions. With aluminium, a stable [Al(8-QS)3](3-) anion is formed, and interacts, predominantly through electrostatic interactions, with the surfactant, without disrupting the metal ion coordination sphere. In contrast, with Zn(ii), there is a competition between the metal ion and surfactants in the interaction with 8-HQS, although the [Zn(8-QS)2(H2O)2](2-) species is stable at appropriate pH and surfactant concentration. The studies are extended to systems with the conjugated polyelectrolyte (CPE) poly-(9,9-bis(6-N,N,N-trimethylammonium)hexyl)-fluorene-phenylene bromide (HTMA-PFP), which has a similar alkylammonium chain to the surfactants. Mixing metal salt, 8-HQS and HTMA-PFP in the presence of a nonionic surfactant leads to the formation of a metal complex/CPE supramolecular assembly between the conjugated polyelectrolyte and the metal/8-HQS complex, as demonstrated by electronic energy transfer. The potential of these systems in sensing, light harvesting, and electron injection/transport layers in organic semiconductor devices is discussed.
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Affiliation(s)
- Hugh D Burrows
- Centro de Química, Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal.
| | - Telma Costa
- Centro de Química, Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal.
| | - M Luisa Ramos
- Centro de Química, Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal.
| | - Artur J M Valente
- Centro de Química, Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal.
| | - Beverly Stewart
- Centro de Química, Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal.
| | - Licinia L G Justino
- Centro de Química, Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal.
| | - Aline I A Almeida
- Centro de Química, Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal.
| | - Nathanny Lessa Catarina
- Centro de Química, Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal.
| | - Ricardo Mallavia
- Instituto de Biología Molecular y Celular, Universidad Miguel Hernandez de Elche, Avda. de la Universidad s/n, 03202 Elche, Spain
| | - Matti Knaapila
- Department of Physics, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
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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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Freitas AR, Silva M, Ramos ML, Justino LLG, Fonseca SM, Barsan MM, Brett CMA, Silva MR, Burrows HD. Synthesis, structure, and spectral and electrochemical properties of chromium(iii) tris-(8-hydroxyquinolinate). Dalton Trans 2015; 44:11491-503. [DOI: 10.1039/c5dt00727e] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Having the HOMO of chromium(iii) tris-(8-hydroxyquinolinate) mainly on metal 3d orbitals and the LUMO on the ligand leads to increased electrochemical stability.
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Affiliation(s)
- Ana R. Freitas
- Centro de Química and Department of Chemistry
- University of Coimbra
- 3004-535 Coimbra
- Portugal
| | - Mónica Silva
- Centro de Química and Department of Chemistry
- University of Coimbra
- 3004-535 Coimbra
- Portugal
| | - 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
| | - Sofia M. Fonseca
- Centro de Química and Department of Chemistry
- University of Coimbra
- 3004-535 Coimbra
- Portugal
| | | | | | - M. Ramos Silva
- CEMDRX
- Department of Physics
- University of Coimbra
- 3004-516 Coimbra
- Portugal
| | - Hugh D. Burrows
- Centro de Química and Department of Chemistry
- University of Coimbra
- 3004-535 Coimbra
- Portugal
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