A Magneto‐optical Molecular Device: Interplay of Spin Crossover, Luminescence, Photomagnetism, and Photochromism

Abstract

A bis(pyrazolylpyridyl) ligand, L, containing a central photochromic dithienylethene spacer predictably forms a ferrous [Fe L ] helicate exhibiting spin crossover (SCO). In solution, the compound [Fe L ](ClO ) (1) preserves the magnetic properties and is fluorescent. The structure of 1 is photo-switchable following the reversible ring closure/opening of the central dithienylethene via irradiation with UV/visible light. This photoisomerization switches on and off some emission bands of 1 and provides a means of externally manipulating the magnetic properties of the assembly.

Structure Switching and Modulation of the Magnetic Properties in Diarylethene‐Bridged Metallosupramolecular Compounds by Controlled Coordination‐Driven Self‐Assembly

“…Irie [11] and Clever [12] reported the use of modified diarylethene derivatives to construct photochromic materials and observed light-controlled interconversion between isomeric structures.A sr eported by Matsuda, [13] Oshio, [14] Khusniyarov, [15] Estrader, [16] and our group, [17] magnetic behaviour, including magnetic interactions,s ingle-molecule magnet properties,a nd spin-crossover behaviours,c an be enhanced or switched by light between the open and closed ring isomers of ad iarylethene ligand owing to the changes in the ligand conformation. Additionally,t he open form of diarylethene with heterocyclic aryl groups is known to exhibit two conformations with two rings adopting the mirror (o-L syn ) and C 2 (o-L anti )s ymmetries.R egardless,a sc ompared to the light-control of open and closed ring isomers,the preparation of metal complexes involving o-L syn remains challenging.…”

Reversible light-driven magnetic switching of salen cobalt complex

“…Spin-crossover (SCO) metal complexes have been extensively observed for six-coordinated d 4 -d 7 transition metal ions that offer the possibility of reversible shift between lowspin and high-spin electronic states. As molecular switches, SCO complexes can be efficiently triggered by redox potential, magnetic field, temperature and light so that they are widely expected to be used in data storage materials, display devices and sensors [1][2][3].…”

Dinuclear Copper(II) Complexes Exhibiting Reversible Photochromism

“…One of the most appealing is that of dithienylethenes (Scheme ), which undergo a process of light induced reversible photocyclization, offering various relevant advantages; i ) the photoisomerization is triggered with light of different wavelength for each direction, ii ) in most systems, both isomers are thermally stable, iii ) the switching process is fast and remarkably resistant to fatigue, and iv ) this unit is easily amenable to chemical derivatization. Some groups have prepared ligands that interpose a dithienylethene in between donor atoms, to obtain complexes of metals connected by the photochromic unit . On the same spirit, we have used in this paper the Cu(II) ion as realization of the qubit.…”

“…Some groups have prepared ligands that interpose a dithienylethene in between donor atoms, to obtain complexes of metals connected by the photochromic unit. [10][11][12][13][14][15][16][17][18] On the same spirit, we have used in this paper the Cu(II) ion as realization of the qubit. With a d 9 configuration, it features a true and isolated S = 1/2 ground state, providing the two quantum states to encode the qubit.…”