The similar reactivity of lanthanides generally leads to statistically populated polynuclear complexes, making the rational design of ordered hetero-lanthanide compounds extremely challenging. Here we report on the site selectivity in hetero-lanthanide tetranuclear complexes afforded by the relatively simple ditopic pyterpyNO ligand (4'-(4-pyridil)-2,2':6',2"-terpyridine N-oxide). The sequential room temperature reaction of RE2(tta)(6)(pyterpyNO)(2) (where RE=Y, (1); Eu, (2), Dy, (3) Htta=2-thenoyltrifluoroacetone) with La(tta)(3)dme (dme=dimethoxyethane) yielded Y2La2(tta)(12)(pyterpyNO)(2) (4), Dy2La2(tta)(12)(pyterpyNO)(2) (5) and Eu2La2(tta)(12)(pyterpyNO)(2) (6). Single crystals X-ray diffraction studies showed that 4, 5 and 6 are isostructural, featuring a tetranuclear structure with two different metal coordination sites with coordination numbers 8 (CN8) and 9 (CN9). The two smaller cations are mainly bridged by the O-donor atoms of the NO groups of two pyterpyNO ligands (CN8), while the larger lanthanum centres are bound by a terpyridine unit (CN9). Size selectivity has been studied with structural and magnetic studies in the solid state and through F-19 NMR and photoluminescence studies in solution, showing a direct dependence on the difference of ionic radii of the ions and yielding a 91 % selectivity for 4. Furthermore, F-19 NMR, X-ray and PL studies pointed out that the nature of the product is independent from the synthetic route for compound Eu2Y2(tta)(12)(pyterpyNO)(2) (7), keeping the ion selectivity also for a self-assembly reaction. Unexpectedly, these studies have evidenced that selectivity is not exclusively governed by electrostatic interactions related to size dimensions.

Size Selectivity in Heterolanthanide Molecular Complexes with a Ditopic Ligand

Bellucci, Luca;Fioravanti, Lorenzo;Marchetti, Fabio;Pineider, Francesco;Samaritani, Simona;Labella, Luca
Ultimo
2022-01-01

Abstract

The similar reactivity of lanthanides generally leads to statistically populated polynuclear complexes, making the rational design of ordered hetero-lanthanide compounds extremely challenging. Here we report on the site selectivity in hetero-lanthanide tetranuclear complexes afforded by the relatively simple ditopic pyterpyNO ligand (4'-(4-pyridil)-2,2':6',2"-terpyridine N-oxide). The sequential room temperature reaction of RE2(tta)(6)(pyterpyNO)(2) (where RE=Y, (1); Eu, (2), Dy, (3) Htta=2-thenoyltrifluoroacetone) with La(tta)(3)dme (dme=dimethoxyethane) yielded Y2La2(tta)(12)(pyterpyNO)(2) (4), Dy2La2(tta)(12)(pyterpyNO)(2) (5) and Eu2La2(tta)(12)(pyterpyNO)(2) (6). Single crystals X-ray diffraction studies showed that 4, 5 and 6 are isostructural, featuring a tetranuclear structure with two different metal coordination sites with coordination numbers 8 (CN8) and 9 (CN9). The two smaller cations are mainly bridged by the O-donor atoms of the NO groups of two pyterpyNO ligands (CN8), while the larger lanthanum centres are bound by a terpyridine unit (CN9). Size selectivity has been studied with structural and magnetic studies in the solid state and through F-19 NMR and photoluminescence studies in solution, showing a direct dependence on the difference of ionic radii of the ions and yielding a 91 % selectivity for 4. Furthermore, F-19 NMR, X-ray and PL studies pointed out that the nature of the product is independent from the synthetic route for compound Eu2Y2(tta)(12)(pyterpyNO)(2) (7), keeping the ion selectivity also for a self-assembly reaction. Unexpectedly, these studies have evidenced that selectivity is not exclusively governed by electrostatic interactions related to size dimensions.
2022
Bellucci, Luca; Fioravanti, Lorenzo; Armelao, Lidia; Bottaro, Gregorio; Marchetti, Fabio; Pineider, Francesco; Poneti, Giordano; Samaritani, Simona; Labella, Luca
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11568/1161157
 Attenzione

Attenzione! I dati visualizzati non sono stati sottoposti a validazione da parte dell'ateneo

Citazioni
  • ???jsp.display-item.citation.pmc??? 2
  • Scopus 2
  • ???jsp.display-item.citation.isi??? 2
social impact