Photo-activation of Single Molecule Magnet Behavior in a Manganese-based Complex

Abstract

A major roadblock to fully realizing molecular electronic devices is the ability to control the properties of each molecule in the device. Herein we report the control of the magnetic properties of single-molecule magnets (SMMs), which can be used in memory devices, by using a photo-isomerizable diarthylenthene ligand. Photo-isomerization of the diarylethene ligand bridging two manganese salen complexes with visible light caused a significant change in the SMM behavior due to opening of the six-membered ring of diarylethene ligand, accompanied by reorganization of the entire molecule. The ring-opening activated the frequency-dependent magnetization of the complex. Our results are a major step towards the realization of molecular memory devices composed of SMMs because the SMM behaviour can be turned on and off simply by irradiating the molecule.

Photo-Modulation of Single-Molecule Magnetic Dynamics of a Dysprosium Dinuclear Complex via a Diarylethene Bridge

“…Both in the solid and solution states, the complex with closed form of the DTE ligand underwent faster magnetic relaxation than the complex with the open form of the DTE ligand. Similar behaviour has been reported in our previous work involving an Mn(salen) SMM bridged by a DTE ligand [8]. The closed form of the ligand is fully conjugated from one coordination site to the other one, whereas the open form does not have such conjugation.…”

“…Recently, we have reported a complex in which a photoisomerisable dicarboxylato DTE ligand bridges two Mn(salen) units [8]. The reversible photocyclization of the complex by irradiation with UV or visible light induces an on/off switching of the slow relaxation.…”

Switching Magnetic Properties by a Mechanical Motion

“…It should be noted that the spin state switch is mainly due to the change in the electronic structure of the bridging ligand and not the conformational reorganization that is induced by the closing of the photochromic unit. A similar strategy has been used by Yamashita et al to repeatedly turn on and off the SMM (Single Molecule Magnet) behavior of two Mn(III)-salen complexes that are connected to diarylethene derivatives with two carboxyl groups ( Figure 11) [61]. When the complex with the diarylethene in the closed form is converted to the open form by irradiating with visible light, slow relaxation of the magnetization was observed.…”

A Chinese Pane-Like 2D Metal-Organic Framework Showing Magnetic Relaxation and Luminescence Dual-Functions

“…Recently, lanthanide(III) ions, especially the Dy(III) ion, which contain unique 4f orbital electrons showing strong spin-orbit coupling and high magnetic moment, have been chosen as the metal nodes to construct lanthanide-based MOFs (LnMOFs), endowing single-molecule magnet (SMM) behaviors 5 – 7 . The SMMs feature magnetic hysteresis and slow magnetic relaxation at low temperatures, with potential applications in magnetic devices for high-density information storage, quantum computing and spintronics 8 – 14 . The lanthanide (III) ions, each of which is equivalent to a single-ion magnet due to very weak magnetic exchange interactions between the lanthanide (III) ions containing shielded 4f electrons, may be arranged into highly ordered nodes with nanoscale-separation in the LnMOFs; such materials are convenient for assembly of corresponding molecular magnetic devices.…”