Photo-induced magnetic properties of the [Cu^II(bapa)]₂[Mo^IV(CN)₈]·7H₂O molecular ribbon

Abstract

International audienceA unique one-dimensional ribbon [Cu(bapa)]2[Mo(CN)8]·7H2O (1) (bapa = bis(3-aminopropyl)amine), consisting of {[Cu(bapa)]3[Mo(CN)8]2}2− trigonal bipyramids and {[Cu(bapa)]2[Mo(CN)8]2}4− rhombuses linked through [Cu(bapa)]2+, was obtained and its photomagnetic properties were investigated. After irradiation at selected wavelengths (405 and 532 nm) or with white light, a global increase of the magnetic moment was observed. The initial state of the compound can be fully recovered by heating the sample above the temperature of relaxation of 253 K. This work was completed with photoreversibility studies with red and IR light irradiation which confirm a partial light-induced reversibility of the photomagnetic effect in 1. Finally, the photomagnetic phenomenon in 1 is discussed in accordance with two processes: the spin crossover on Mo(IV) centres and the metal-to-metal charge transfer mechanism in the Cu(II)–Mo(IV) pair

Multifunctionality in Molecular Magnetism

“…Other spectroscopic methods (EPR, XMCD, IR) and theoretical investigations also suggested the very rare LIESST effect. 65 Therefore, in the Mo IV -Cu II systems, such as [Cu II 66 , both mechanisms can be operational. The photomagnetic effect was probed with different wavelengths, however, it was still not possible to define the mechanism.…”

Direct Evidence of a Photoinduced Electron Transfer in Diluted “Molybdenum‐Copper” Molecular Compounds

“…Molybdenum‐copper complexes have attracted great attention over the past decade due to the interesting photomagnetic phenomena that have been reported for these systems . Most of the compounds display a reversible photoinduced magnetic bistability that has been developed into various forms: three‐dimensional networks, molecular complexes, high nuclearity clusters,, chains,, nanoparticles, and films . In addition, the integration of Mo‐Cu complexes viewed as magnetic switches into sophisticated architectures, has been performed with success as well as their transformation into promising materials with various properties , .…”

Steuerung des Metall‐Metall‐Charge‐Transfers zur Erzeugung schaltbarer Materialien

“…Eines bezieht sich auf die MMCT‐funktionale Einheit im engeren Sinn. Bis heute sind zahlreiche MMCT‐Verbindungen bekannt geworden, während der Mechanismus von photoschaltbarem MMCT noch immer umstritten ist und weitere Untersuchungen erfordert . Ultraschnelle spektroskopische Methoden könnten zur Aufhellung des MMCT‐Prozesses beitragen.…”