View
Publication Type
Journal Article
UWI Author(s)
Author, Analytic
Howell, Robertha C.; Spence, Kirk V.; Kahwa, Ishenkumba A.; Williams, David J.
Author Affiliation, Ana.
Department of Chemistry
Article Title
Structure and luminescence of the neutral dinuclear lanthanide (III) complexes [{Ln(api)}2] {H3api = 2-(2-hydroxyphenyl)-1,3-bis[4-(2-hydroxyphenyl)-3-azabut-3-enyl]-1,3-imidazolidine}
Medium Designator
n/a
Connective Phrase
n/a
Journal Title
Journal of the Chemical Society. Dalton transaction
Translated Title
n/a
Reprint Status
Refereed
Date of Publication
1998
Volume ID
n/a
Issue ID
16
Page(s)
2727-33
Language
n/a
Connective Phrase
n/a
Location/URL
n/a
ISSN
n/a
Notes
n/a
Abstract
Dinuclear compounds of lanthanide(III) (Ln3+) ions with api3- [{Ln(api)}2] {H3api = 2-(2-hydroxyphenyl)-1,3-bis[4-(2-hydroxyphenyl)-3-azabut-3-enyl]-1,3-imidazoline} were synthesized and characterized in micro-crystalline form and frozen aqueous solutions in order to establish the ability of triply charged chelates to stabilize Ln3+ - Ln3+ couples. The crystal structure of the [{Sm(api)}2] complex confirms the dinuclear sandwich binding in which the pair of Ln3+ ions is trapped between the two chelates to yield and eight-fold ca. square antiprismatic co-ordination geometry on each Ln3+ ion. Luminiscence decay dynamic studies reveal thermal quenching of Tb3+(5D4) [thermal barrier Ea (1.2 0.2) x 103 cm-1] and Eu3+(5D0) [Ea (4.7 0.2) x 103 cm-1] emmission from [{Tb(api)}2] and [{Eu(api)}2] respectively. Luminescence decay dynamics of homodinuclear [{Ln(api)}2] (Ln = La, Gd, Eu or Tb) and heterodinuclear [{Tb1-xEux(api)}2] complexes in polycrystalline and frozen aqueous solutions as well as the small proton NMR relaxitivity of [{Gd(api)}2] and low toxicity (to mice) of [{La(api)}2] show qualitatively that members of the [{Ln(api)}2] system are stable in water and merit further study in search of potentially useful tunable biomedical probes.....
read more