Influence of chelating ligands on photomagnetic properties of two erbium(III) coordination polymers

The magnetization dynamics of lanthanide coordination compounds are fundamentals governing their potential applications such as information storage or molecular switches. Herein, two two-dimensional coordination polymers [Er(CA)1.5(bpy) (DMF)]n (1) and [Er(CA)1.5(phen) (DMF)]n (2) (H2CA = 2,5-dichloro-3,6-dihydroxy-p-quinone, bpy = 2,2′-bipyridine, phen = 1,10-phenanthroline) were synthesized and fully characterized. By the irradiation of ultraviolet light, 1 and 2 were converted to 1a and 2a which contain light-generated radicals, inducing an increase of χMT at room temperature. A detailed study of the dynamic magnetic property shows that the magnetization dynamics observed for 1 and 1a are dominated by Raman process, but Orbach and Raman processes are observed in 2 and 2a. The structural factors influencing the magnetic properties of this photomagnetic system are discussed.