Distributive Nd-to-Yb Energy Transfer within Pure [YbNdYb] Heterometallic Molecules

• Published in: Inorganic chemistry Vol. 62; no. 7; pp. 3106 - 3115
• Main Authors: Maniaki, Diamantoula, Sickinger, Annika, Barrios Moreno, Leoní A., Aguilà, David, Roubeau, Olivier, Settineri, Nicholas S., Guyot, Yannick, Riobé, François, Maury, Olivier, Galán, Laura Abad, Aromí, Guillem
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 20.02.2023; American Chemical Society (ACS)
• Subjects: INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; Physics
• ISSN: 0020-1669; 1520-510X
• DOI: 10.1021/acs.inorgchem.2c03940

Facile access to site-selective hetero-lanthanide molecules will open new avenues in the search of novel photophysical phenomena based on Ln-to-Ln′ energy transfer (ET). This challenge demands strategies to segregate efficiently different Ln metal ions among different positions in a molecule. We report here the one-step synthesis and structure of a pure [YbNdYb] (1) coordination complex featuring short Yb···Nd distances, ideal to investigate a potential distributive (i.e., from one donor to two acceptors) intramolecular ET from one Nd3+ ion to two Yb3+ centers within a well-characterized molecule. The difference in ionic radius is the mechanism allowing to allocate selectively both types of metal ion within the molecular structure, exploited with the simultaneous use of two β-diketone-type ligands. To assist the photophysical investigation of this heterometallic species, the analogues [YbLaYb] (2) and [LuNdLu] (3) have also been prepared. Sensitization of Yb3+ and Nd3+ in the last two complexes, respectively, was observed, with remarkably long decay times, facilitating the determination of the Nd-to-Yb ET within the [YbNdYb] composite. This ET was demonstrated by comparing the emission of iso-absorbant solutions of 1, 2, and 3 and through lifetime determinations in solution and solid state. The comparatively high efficiency of this process corroborates the facilitating effect of having two acceptors for the nonradiative decay of Nd3+ created within the [YbNdYb] molecule.