Potentiometry and NMR studies of 1,5,9-triazacyclododecane-N,N',N''-triacetic acid and its metal ion complexes
Autor(a) principal: | |
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Data de Publicação: | 1990 |
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/10316/10518 https://doi.org/10.1021/ic00326a003 |
Resumo: | A new chelating macrocycle, 1,5,9-triazacyclododecane-N,N’,N’’-triacetiacc id (DOTRA), has been synthesized, and its complexes with Zn2’, Cd2+, Ca2+, Mg2+, and Mn2+ have been examined by potentiometry and NMR spectroscopy. The first protonation constant of the free ligand (log K, = 12.8) was determined spectrophotometrically, while the remaining were evaluated from potentiometric data (log K2 = 7.55, log K, = 3.65, log K4 = 2.1). DOTRA forms complexes with Mn2+, Mg2’, and Ca2+ rather slowly but reacts much more rapidly with Zn2+ and Cd2+. As reported previously for the nine-membered-ring triaza analogue NOTA, DOTRA also forms a more stable complex with Mg2+ than with Ca2+ (log K,, = 7.1 versus 6.0). High-resolution NMR spectra of the Zn2+, Cd2+, and Mgzt complexes (log K,, = 19.0, 15.7, and 7.1, respectively) indicate the three six-membered chelate rings are symmetrical and quite rigid in aqueous solution, as evidenced by nonequivalence of all six chelate ring protons. |
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Potentiometry and NMR studies of 1,5,9-triazacyclododecane-N,N',N''-triacetic acid and its metal ion complexesA new chelating macrocycle, 1,5,9-triazacyclododecane-N,N’,N’’-triacetiacc id (DOTRA), has been synthesized, and its complexes with Zn2’, Cd2+, Ca2+, Mg2+, and Mn2+ have been examined by potentiometry and NMR spectroscopy. The first protonation constant of the free ligand (log K, = 12.8) was determined spectrophotometrically, while the remaining were evaluated from potentiometric data (log K2 = 7.55, log K, = 3.65, log K4 = 2.1). DOTRA forms complexes with Mn2+, Mg2’, and Ca2+ rather slowly but reacts much more rapidly with Zn2+ and Cd2+. As reported previously for the nine-membered-ring triaza analogue NOTA, DOTRA also forms a more stable complex with Mg2+ than with Ca2+ (log K,, = 7.1 versus 6.0). High-resolution NMR spectra of the Zn2+, Cd2+, and Mgzt complexes (log K,, = 19.0, 15.7, and 7.1, respectively) indicate the three six-membered chelate rings are symmetrical and quite rigid in aqueous solution, as evidenced by nonequivalence of all six chelate ring protons.American Chemical Society1990-01info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/articlehttp://hdl.handle.net/10316/10518http://hdl.handle.net/10316/10518https://doi.org/10.1021/ic00326a003engInorganic Chemistry. 29:1 (1990) 5-90020-1669Cortes, S.Brucher, E.Geraldes, C. F. G. C.Sherry, A. D.info: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:RCAAP2021-10-26T13:37:39Zoai:estudogeral.uc.pt:10316/10518Portal AgregadorONGhttps://www.rcaap.pt/oai/openaireopendoar:71602024-03-19T21:01:31.171711Repositório 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 |
Potentiometry and NMR studies of 1,5,9-triazacyclododecane-N,N',N''-triacetic acid and its metal ion complexes |
title |
Potentiometry and NMR studies of 1,5,9-triazacyclododecane-N,N',N''-triacetic acid and its metal ion complexes |
spellingShingle |
Potentiometry and NMR studies of 1,5,9-triazacyclododecane-N,N',N''-triacetic acid and its metal ion complexes Cortes, S. |
title_short |
Potentiometry and NMR studies of 1,5,9-triazacyclododecane-N,N',N''-triacetic acid and its metal ion complexes |
title_full |
Potentiometry and NMR studies of 1,5,9-triazacyclododecane-N,N',N''-triacetic acid and its metal ion complexes |
title_fullStr |
Potentiometry and NMR studies of 1,5,9-triazacyclododecane-N,N',N''-triacetic acid and its metal ion complexes |
title_full_unstemmed |
Potentiometry and NMR studies of 1,5,9-triazacyclododecane-N,N',N''-triacetic acid and its metal ion complexes |
title_sort |
Potentiometry and NMR studies of 1,5,9-triazacyclododecane-N,N',N''-triacetic acid and its metal ion complexes |
author |
Cortes, S. |
author_facet |
Cortes, S. Brucher, E. Geraldes, C. F. G. C. Sherry, A. D. |
author_role |
author |
author2 |
Brucher, E. Geraldes, C. F. G. C. Sherry, A. D. |
author2_role |
author author author |
dc.contributor.author.fl_str_mv |
Cortes, S. Brucher, E. Geraldes, C. F. G. C. Sherry, A. D. |
description |
A new chelating macrocycle, 1,5,9-triazacyclododecane-N,N’,N’’-triacetiacc id (DOTRA), has been synthesized, and its complexes with Zn2’, Cd2+, Ca2+, Mg2+, and Mn2+ have been examined by potentiometry and NMR spectroscopy. The first protonation constant of the free ligand (log K, = 12.8) was determined spectrophotometrically, while the remaining were evaluated from potentiometric data (log K2 = 7.55, log K, = 3.65, log K4 = 2.1). DOTRA forms complexes with Mn2+, Mg2’, and Ca2+ rather slowly but reacts much more rapidly with Zn2+ and Cd2+. As reported previously for the nine-membered-ring triaza analogue NOTA, DOTRA also forms a more stable complex with Mg2+ than with Ca2+ (log K,, = 7.1 versus 6.0). High-resolution NMR spectra of the Zn2+, Cd2+, and Mgzt complexes (log K,, = 19.0, 15.7, and 7.1, respectively) indicate the three six-membered chelate rings are symmetrical and quite rigid in aqueous solution, as evidenced by nonequivalence of all six chelate ring protons. |
publishDate |
1990 |
dc.date.none.fl_str_mv |
1990-01 |
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/10316/10518 http://hdl.handle.net/10316/10518 https://doi.org/10.1021/ic00326a003 |
url |
http://hdl.handle.net/10316/10518 https://doi.org/10.1021/ic00326a003 |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.relation.none.fl_str_mv |
Inorganic Chemistry. 29:1 (1990) 5-9 0020-1669 |
dc.rights.driver.fl_str_mv |
info:eu-repo/semantics/openAccess |
eu_rights_str_mv |
openAccess |
dc.publisher.none.fl_str_mv |
American Chemical Society |
publisher.none.fl_str_mv |
American Chemical Society |
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) |
collection |
Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
repository.name.fl_str_mv |
Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação |
repository.mail.fl_str_mv |
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1799133906403852288 |