K⊂{[Fe(Tp)(CN)][Co(Tp)][Co(Tp)]}: a neutral soluble model complex of photomagnetic Prussian blue analogues

• Published in: Chemical science (Cambridge) 2016, Vol.7 (8), p.4825-4831
• Main Authors: Garnier, D, Jiménez, J.-R, Li, Y, von Bardeleben, J, Journaux, Y, Augenstein, T, Moos, E. M. B, Gamer, M. T, Breher, F, Lescouëzec, R
• Format: Article
• Language: English
• Subjects: Chemical Sciences; Coordination chemistry; Inorganic chemistry
• ISSN: 2041-6520; 2041-6539
• DOI: 10.1039/c6sc01435f

Straightforward access to a new cyanide-bridged {Fe 4 Co 4 } "molecular box" containing a potassium ion, namely K⊂{[Fe II (Tp)(CN) 3 ] 4 [Co III ( pz Tp)] 3 [Co II ( pz Tp)]} ( 1 ) (with Tp and pz Tp = tris- and tetrakis(pyrazolyl)borate, respectively), is provided, alongside its full characterisation. A detailed analysis of the molecular structure (X-ray diffraction, mass spectrometry, NMR spectroscopy) and electronic properties (EPR spectroscopy, SQUID magnetometry, UV/Vis spectroscopy, cyclic voltammetry) reveals that 1 shows slow magnetic relaxation and a remarkable photomagnetic effect at low temperature which is reminiscent of some FeCo Prussian Blue Analogues (PBAs), and is ascribed to a photo-induced electron transfer. However, in contrast with these inorganic polymers, the overall neutral compound 1 is soluble and remarkably stable in organic solvents such as CH 2 Cl 2 . Moreover, 1 shows interesting redox versatility, with electrochemical experiments revealing the possible access to six stable redox states. We report a new K⊂[Fe 4 Co 4 ] cyanide box: a true soluble model of the photomagnetic FeCo Prussian blue analogues, which also shows photo-switchable SMM properties and remarkable redox versatility.