Tetrathiafulvalene-based lanthanide coordination complexes: Synthesis, crystal structure, optical and electrochemical characterization - 19/10/12
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Abstract |
The explorative lanthanide coordination chemistry of 4′,5′-bis-(propylthio)tetrathiafulvenyl[i]dipyrido[3,2-a:2′,3′-c]phenazine (TTF-dppz) is described. Thereby, four new Ln(III) complexes, [Ln(NO3)3(TTF-dppz)2] with Ln(III)=Nd (1), Eu (2), Gd (3), Tb (4), have been prepared and characterized. An X-ray crystallographic study of [Gd(NO3)3(TTF-dppz)2] (3) shows that the Gd(III) ion is coordinated to six oxygen atoms from three bidentate nitrate ligands and four nitrogen atoms from two bidentate TTF-dppz molecules forming a distorted bicapped square antiprism coordination geometry. The UV-vis spectra of the four Ln(III) complexes show very strong absorption bands in the UV region consistent with ligand centred electronic π-π* transitions and an intense broad absorption band in the visible region corresponding to a spin-allowed electronic π-π* 1ILCT transition from the TTF-dppz ligand. Upon coordination, the 1ILCT band of the free TTF-dppz ligand is bathochromically shifted. The electrochemical studies reveal that all complexes undergo two reversible oxidation and one (quasi)reversible reduction processes, ascribed to the successive oxidations of the TTF moiety and the reduction of the dppz unit, respectively. Moreover, the magnetic properties of complexes 3 and 4 are discussed.
Le texte complet de cet article est disponible en PDF.Keywords : Lanthanide complexes, Tetrathiafulvalene, X-ray crystal structure, Electrochemistry, Magnetic susceptibility, Charge transfer
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Vol 15 - N° 10
P. 838-844 - octobre 2012 Retour au numéroBienvenue sur EM-consulte, la référence des professionnels de santé.
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