Redox behaviour, electrochromic properties and photoluminescence of potassium lanthano phosphomolybdate sandwich-type compounds
Autor(a) principal: | |
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Data de Publicação: | 2013 |
Outros Autores: | , , , , , |
Tipo de documento: | Artigo |
Idioma: | eng |
Título da fonte: | Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
Texto Completo: | http://hdl.handle.net/10773/19590 |
Resumo: | Sandwich-type phosphomolybdates with general formula K-n[Ln(III)(PMo11O39)(2)], where Ln(III) = Sm, Eu, Gd, Tb and Dy, were prepared and characterized by several techniques. The crystal structure of Sm(PMo11)(2) and Gd(PMo11)(2) were studied and showed that they crystallise in a P2(1)/c space group. All Ln(PMo11) 2 revealed four Mo-based electrochemical reduction processes with very similar E-1/2 values (approximate to 0.5, approximate to 0.3, approximate to 0.02 and approximate to-0.1 V) for all the Ln(III) atoms. The two more positive reduction processes correspond to pH independent one-electron reduction processes, whereas the two more negative processes correspond to pH dependent two-electron reduction processes. Electrolysis at two different potentials, 0.1 V - related to the two one-electron reduction processes - and -0.3 V - related to the two more negative two-electron reduction processes, confirmed the electrochromic properties of the Ln(PMo11)(2) species: their original yellow coloured solutions turned blue, corresponding to the appearance of four new electronic bands in the near UV-Vis-near IR region. These electronic bands were tentatively assigned based on their molar absorption coefficients (epsilon) and absorbance (Abs) variation as a function of electrolysis time: bands A (lambda(max) approximate to 855-870 nm) and B (lambda(max) approximate to 670-695 nm) were assigned to Mo-V -> Mo-VI intervalence charge transfer transitions, band C (lambda(max) approximate to 525 nm) to d-d transition due to d(1) configuration of the reduced addenda atom (Mo-V) and band D (lambda approximate to 310-315 nm) to an O -> Mo-V charge transfer transition (CTT). The emission features of the Eu(PMo11)(2) and Tb(PMo11)(2) samples reveal broad emission in the UV/vis spectral region resulting from d-d transition transitions. The Eu(PMo11)(2) also display the typical Eu3+ D-5(0) -> F-7(0-4) transitions, when excited through the O -> Eu-III and O -> Mo-VI CCTs. |
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Redox behaviour, electrochromic properties and photoluminescence of potassium lanthano phosphomolybdate sandwich-type compoundsHETEROPOLY COMPLEXELECTROCHEMICAL-BEHAVIORAQUEOUS-SOLUTIONRARE-EARTHANIONSPECTRANEODYMIUMELEMENTSHISTORYSERIESSandwich-type phosphomolybdates with general formula K-n[Ln(III)(PMo11O39)(2)], where Ln(III) = Sm, Eu, Gd, Tb and Dy, were prepared and characterized by several techniques. The crystal structure of Sm(PMo11)(2) and Gd(PMo11)(2) were studied and showed that they crystallise in a P2(1)/c space group. All Ln(PMo11) 2 revealed four Mo-based electrochemical reduction processes with very similar E-1/2 values (approximate to 0.5, approximate to 0.3, approximate to 0.02 and approximate to-0.1 V) for all the Ln(III) atoms. The two more positive reduction processes correspond to pH independent one-electron reduction processes, whereas the two more negative processes correspond to pH dependent two-electron reduction processes. Electrolysis at two different potentials, 0.1 V - related to the two one-electron reduction processes - and -0.3 V - related to the two more negative two-electron reduction processes, confirmed the electrochromic properties of the Ln(PMo11)(2) species: their original yellow coloured solutions turned blue, corresponding to the appearance of four new electronic bands in the near UV-Vis-near IR region. These electronic bands were tentatively assigned based on their molar absorption coefficients (epsilon) and absorbance (Abs) variation as a function of electrolysis time: bands A (lambda(max) approximate to 855-870 nm) and B (lambda(max) approximate to 670-695 nm) were assigned to Mo-V -> Mo-VI intervalence charge transfer transitions, band C (lambda(max) approximate to 525 nm) to d-d transition due to d(1) configuration of the reduced addenda atom (Mo-V) and band D (lambda approximate to 310-315 nm) to an O -> Mo-V charge transfer transition (CTT). The emission features of the Eu(PMo11)(2) and Tb(PMo11)(2) samples reveal broad emission in the UV/vis spectral region resulting from d-d transition transitions. The Eu(PMo11)(2) also display the typical Eu3+ D-5(0) -> F-7(0-4) transitions, when excited through the O -> Eu-III and O -> Mo-VI CCTs.ROYAL SOC CHEMISTRY2017-12-07T19:17:54Z2013-01-01T00:00:00Z2013info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/articleapplication/pdfhttp://hdl.handle.net/10773/19590eng2046-206910.1039/c3ra41697fFernandes, Diana M.Cunha-Silva, LuisFerreira, Rute A. S.Balula, Salete S.Carlos, Luis D.de Castro, BaltazarFreire, Cristinainfo:eu-repo/semantics/openAccessreponame:Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)instname:Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãoinstacron:RCAAP2024-02-22T11:38:06Zoai:ria.ua.pt:10773/19590Portal AgregadorONGhttps://www.rcaap.pt/oai/openaireopendoar:71602024-03-20T02:54:21.331740Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãofalse |
dc.title.none.fl_str_mv |
Redox behaviour, electrochromic properties and photoluminescence of potassium lanthano phosphomolybdate sandwich-type compounds |
title |
Redox behaviour, electrochromic properties and photoluminescence of potassium lanthano phosphomolybdate sandwich-type compounds |
spellingShingle |
Redox behaviour, electrochromic properties and photoluminescence of potassium lanthano phosphomolybdate sandwich-type compounds Fernandes, Diana M. HETEROPOLY COMPLEX ELECTROCHEMICAL-BEHAVIOR AQUEOUS-SOLUTION RARE-EARTH ANION SPECTRA NEODYMIUM ELEMENTS HISTORY SERIES |
title_short |
Redox behaviour, electrochromic properties and photoluminescence of potassium lanthano phosphomolybdate sandwich-type compounds |
title_full |
Redox behaviour, electrochromic properties and photoluminescence of potassium lanthano phosphomolybdate sandwich-type compounds |
title_fullStr |
Redox behaviour, electrochromic properties and photoluminescence of potassium lanthano phosphomolybdate sandwich-type compounds |
title_full_unstemmed |
Redox behaviour, electrochromic properties and photoluminescence of potassium lanthano phosphomolybdate sandwich-type compounds |
title_sort |
Redox behaviour, electrochromic properties and photoluminescence of potassium lanthano phosphomolybdate sandwich-type compounds |
author |
Fernandes, Diana M. |
author_facet |
Fernandes, Diana M. Cunha-Silva, Luis Ferreira, Rute A. S. Balula, Salete S. Carlos, Luis D. de Castro, Baltazar Freire, Cristina |
author_role |
author |
author2 |
Cunha-Silva, Luis Ferreira, Rute A. S. Balula, Salete S. Carlos, Luis D. de Castro, Baltazar Freire, Cristina |
author2_role |
author author author author author author |
dc.contributor.author.fl_str_mv |
Fernandes, Diana M. Cunha-Silva, Luis Ferreira, Rute A. S. Balula, Salete S. Carlos, Luis D. de Castro, Baltazar Freire, Cristina |
dc.subject.por.fl_str_mv |
HETEROPOLY COMPLEX ELECTROCHEMICAL-BEHAVIOR AQUEOUS-SOLUTION RARE-EARTH ANION SPECTRA NEODYMIUM ELEMENTS HISTORY SERIES |
topic |
HETEROPOLY COMPLEX ELECTROCHEMICAL-BEHAVIOR AQUEOUS-SOLUTION RARE-EARTH ANION SPECTRA NEODYMIUM ELEMENTS HISTORY SERIES |
description |
Sandwich-type phosphomolybdates with general formula K-n[Ln(III)(PMo11O39)(2)], where Ln(III) = Sm, Eu, Gd, Tb and Dy, were prepared and characterized by several techniques. The crystal structure of Sm(PMo11)(2) and Gd(PMo11)(2) were studied and showed that they crystallise in a P2(1)/c space group. All Ln(PMo11) 2 revealed four Mo-based electrochemical reduction processes with very similar E-1/2 values (approximate to 0.5, approximate to 0.3, approximate to 0.02 and approximate to-0.1 V) for all the Ln(III) atoms. The two more positive reduction processes correspond to pH independent one-electron reduction processes, whereas the two more negative processes correspond to pH dependent two-electron reduction processes. Electrolysis at two different potentials, 0.1 V - related to the two one-electron reduction processes - and -0.3 V - related to the two more negative two-electron reduction processes, confirmed the electrochromic properties of the Ln(PMo11)(2) species: their original yellow coloured solutions turned blue, corresponding to the appearance of four new electronic bands in the near UV-Vis-near IR region. These electronic bands were tentatively assigned based on their molar absorption coefficients (epsilon) and absorbance (Abs) variation as a function of electrolysis time: bands A (lambda(max) approximate to 855-870 nm) and B (lambda(max) approximate to 670-695 nm) were assigned to Mo-V -> Mo-VI intervalence charge transfer transitions, band C (lambda(max) approximate to 525 nm) to d-d transition due to d(1) configuration of the reduced addenda atom (Mo-V) and band D (lambda approximate to 310-315 nm) to an O -> Mo-V charge transfer transition (CTT). The emission features of the Eu(PMo11)(2) and Tb(PMo11)(2) samples reveal broad emission in the UV/vis spectral region resulting from d-d transition transitions. The Eu(PMo11)(2) also display the typical Eu3+ D-5(0) -> F-7(0-4) transitions, when excited through the O -> Eu-III and O -> Mo-VI CCTs. |
publishDate |
2013 |
dc.date.none.fl_str_mv |
2013-01-01T00:00:00Z 2013 2017-12-07T19:17:54Z |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/article |
format |
article |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
http://hdl.handle.net/10773/19590 |
url |
http://hdl.handle.net/10773/19590 |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.relation.none.fl_str_mv |
2046-2069 10.1039/c3ra41697f |
dc.rights.driver.fl_str_mv |
info:eu-repo/semantics/openAccess |
eu_rights_str_mv |
openAccess |
dc.format.none.fl_str_mv |
application/pdf |
dc.publisher.none.fl_str_mv |
ROYAL SOC CHEMISTRY |
publisher.none.fl_str_mv |
ROYAL SOC CHEMISTRY |
dc.source.none.fl_str_mv |
reponame:Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) instname:Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação instacron:RCAAP |
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Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação |
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RCAAP |
institution |
RCAAP |
reponame_str |
Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
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Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
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Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação |
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1799137595606695936 |