The First Observation of Hidden Hysteresis in an Iron(III) Spin‐Crossover Complex. (17th July 2019)

• Record Type: Journal Article
• Authors: Boonprab, Theerapoom; Lee, Seok J.; Telfer, Shane G.; Murray, Keith S.; Phonsri, Wasinee; Chastanet, Guillaume; Collet, Eric; Trzop, Elzbieta; Jameson, Guy N. L.; Harding, Phimphaka; Harding, David J.
• Is Part Of: Angewandte Chemie. Volume 131:Number 34(2019)
• Page Start: 11937
• Page End: 11941
• Publication Date: 2019-07-17
• Subjects: Eisen(III)-Komplexe -- Lichtinduzierte thermische Hysterese -- Photomagnetismus -- Spin Crossover -- Versteckte Hysterese; Chemistry -- Periodicals; 540
• DOI: 10.1002/ange.201907619
• Languages: English
• ISSNs: 0044-8249

Abstract

Abstract: Molecular magnetic switches are expected to form the functional components of future nanodevices. Herein we combine detailed (photo‐) crystallography and magnetic studies to reveal the unusual switching properties of an iron(III) complex, between low (LS) and high (HS) spin states. On cooling, it exhibits a partial thermal conversion associated with a reconstructive phase transition from a [HS‐HS] to a [LS‐HS] phase with a hysteresis of 25 K. Photoexcitation at low temperature allows access to a [LS‐LS] phase, never observed at thermal equilibrium. As well as reporting the first iron(III) spin crossover complex to exhibit reverse‐LIESST (light‐induced excited spin state trapping), we also reveal a hidden hysteresis of 30 K between the hidden [LS‐LS] and [HS‐LS] phases. Moreover, we demonstrate that Fe III spin‐crossover (SCO) complexes can be just as effective as Fe II systems, and with the advantage of being air‐stable, they are ideally suited for use in molecular electronics. Abstract : Thermisches und optisches Schalten in einem Eisen(III)‐Spin‐Crossover‐Komplex offenbart eine versteckte Hysterese von 30 K. Die Ergebnisse zeigen, dass Fe III ‐Spin‐Crossover‐Komplexe ebenso effektiv wie Fe II ‐Systeme sein können, und mit dem Vorteil der Luftstabilität sind sie geeignet für die Verwendung in der molekularen Elektronik.