ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Ligand-driven light-induced spin transition in spin crossover compounds

Barbora Brachňaková and Ivan Šalitroš

Slovak University of Technology Bratislava, Bratislava, Slovakia

E-mail: ivan.salitros@stuba.sk

Abstract: Spin crossover (SCO) coordination compounds that show bistability between low spin and high spin states are promising light-controllable molecular switches. Selective wavelength irradiation of the coordination centre at low temperatures is known as a light-induced excited spin state trapping (LIESST effect) and it leads to the modulation of physical properties of SCO materials on the macroscopic as well as on the molecular level. Another way to trigger the spin state conversion by light is based on the isomerization of photoactive ligand moieties. The ligand field strength is changed due to light-induced photoisomerization and, therefore, corresponding cis–trans or ring-closing/ring-opening isomeric couples might exhibit different spin states at isothermal conditions. Such an approach is called as ligand driven light-induced spin change (LD LISC effect). From the application point of view, it presents a promising alternative to the LIESST effect because it can operate at room temperature. This article is focused on the most interesting iron and cobalt SCO compounds with photoisomerizable ligands and provides the overview of achieving results based on the LD LISC effect.

Keywords: Spin crossover ; Light Switching ; Photoisomerization ; Photomagnetism ; LIESST effect ; Fe(II) and Co(II) complexes 

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-017-0377-3

Chemical Papers 72 (4) 773–798 (2018)