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Start Over Author "Roubeau, P" Journal inorganic chemistry
37 results on '"Roubeau, P"'

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

Author

Maniaki, Diamantoula, Sickinger, Annika, Moreno, Leoní A Barrios, Aguilà, David, Roubeau, Olivier, Settineri, Nicholas S, Guyot, Yannick, Riobé, François, Maury, Olivier, Galán, Laura Abad, and Aromí, Guillem

Subjects
Inorganic Chemistry, Chemical Sciences, Affordable and Clean Energy, Physical Chemistry (incl. Structural), Other Chemical Sciences, Inorganic & Nuclear Chemistry, Inorganic chemistry, Macromolecular and materials chemistry
Abstract

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.

Published
2023

2. Homoleptic versus Heteroleptic Formation of Mononuclear Fe(II) Complexes with Tris-Imine Ligands

Author

Barrios, Leoní A, Bartual-Murgui, Carlos, Peyrecave-Lleixà, Eugènia, Le Guennic, Boris, Teat, Simon J, Roubeau, Olivier, and Aromí, Guillem

Subjects
Inorganic Chemistry, Chemical Sciences, Physical Chemistry (incl. Structural), Other Chemical Sciences, Inorganic & Nuclear Chemistry, Inorganic chemistry, Macromolecular and materials chemistry
Abstract

We show a marked tendency of Fe(II) to form heteroleptic [Fe(L)(L')](ClO4)2 complexes from pairs of chelating tris-imine 3bpp, tpy, or 2bbp ligands. New synthetic avenues for spin crossover research become thus available, here illustrated with three new heteroleptic compounds with differing magnetic behaviors: [Fe(H4L1)(Cl-tpy)](ClO4)2·C3H6O (1), [Fe(H2L3)(Me3bpp)](ClO4)2·C3H6O (2), [Fe(H4L1)(2bbp)](ClO4)2·3C3H6O (3). Structural studies demonstrate that 1 is in the low-spin (LS) state up to 350 K, while complexes 2 and 3 are, by contrast, in the high-spin (HS) state down to 2 K, as corroborated through magnetic susceptibility measurements. Upon exposure to the atmosphere, the latter exhibits the release of three molecules of acetone per complex, turning into the solvent-free analogue [Fe(H4L1)(2bbp)](ClO4)2 (3a), through a single-crystal-to-single-crystal transformation. This guest extrusion process is accompanied by a spin switch, from HS to LS.

Published
2016

9. Coordination [CoII2] and [CoIIZnII] Helicates Showing Slow Magnetic Relaxation

Author

Diego, Rosa, Pavlov, Alexander, Darawsheh, Mohanad, Aleshin, Dmitry, Nehrkorn, Joscha, Nelyubina, Yulia, Roubeau, Olivier, Novikov, Valentin, and Aromí, Guillem

Abstract

The slow magnetic relaxation of CoIIions in the elusive intermediate geometry between the trigonal prism and antiprism has been studied on the new [Co2L3]4+and [CoZnL3]4+coordination helicates [L is a bis(pyrazolylpyridine) ligand]. Solution paramagnetic 1H NMR and solid-state magnetization measurements unveil single-molecule-magnet behavior with small axial anisotropy, as predicted previously.

Published
2019
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