Octacyanidotungstate(IV) Coordination Chains Demonstrate a Light‐Induced Excited Spin State Trapping Behavior and Magnetic Exchange Photoswitching

Abstract

A huge increase in the magnetization of two coordination chains based on tetravalent octacyanidometalates (W and Mo ) is observed on irradiation with 436 nm light, while no such behavior is observed for the Nb analogue. A photomagnetic response based solely on [W (CN) ] is demonstrated for the first time. The observed behavior is attributed to the light-induced excited spin state trapping (LIESST) effect at the octacyanidometalate, and to the resulting magnetic exchange ON/OFF photoswitching between the Mn center and the photoinduced high-spin (S=1) W or Mo centers.

Photoinduced Mo−CN Bond Breakage in Octacyanomolybdate Leading to Spin Triplet Trapping

“…The first photomagnetic characterization of 1 using UV light was reported in 2000, and a photooxidation from Mo 4+ to Mo 5+ was suggested . Recently, a spin crossover was proposed to interpret the photoinduced magnetism in a MoZn 2 complex and in (H 4 cyclam)[Mo IV (CN) 8 ]⋅1.5 H 2 O (cyclam=1,4,8,11‐tetraazacyclodecane) . In this work, we demonstrate unambiguously that the reversible photomagnetism in 1 is associated not only with a spin change but also with a profound structural modification of the complex.…”

“…[4c] Recently,aspin crossover was proposed to interpret the photoinduced magnetism in aM oZn 2 complex [9] and in (H 4 cyclam)[Mo IV (CN) 8 ]·1.5 H 2 O( cyclam = 1,4,8,11-tetraazacyclodecane). [10] In this work, we demonstrate unambiguously that the reversible photomagnetism in 1 is associated not only with as pin change but also with ap rofound structural modification of the complex.Complex 1 was synthesized as described previously. [11] We performed theoretical investigations of 1 using the CASSCF/ CASPT2 and TD-DFT approaches to determine the excitation energies.…”

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.…”

Humidity‐Induced Switching between Two Magnetic and Structural Phases in a CoII‐[WV(CN)8] Molecular Magnet

“…Since the discoveryo ft he first molecular magnets, [1,2] the idea of functionalising thesematerials has attracted considerable interest from scientists in differentf ieldso fr esearch. [3][4][5] Porous molecular magnets [6,7] as well as conducting, [8] luminescent [9] and non-centrosymmetric [10] molecular magnets and photomagnetic molecular materials [11] are the result of the direct implementation of this idea, and they belong to distinct classes of multifunctional molecular materials that show an alteration of their magnetic properties in the presence of externalp hysical and/or chemical stimuli. The responsiveness to such stimuli is of importance for applications involving detection, switching functions or data storage media.…”