Optical and magnetic properties of lanthanide(III) complexes with quercetin-5′-sulfonic acid in the solid state and silica glass

The lanthanide [Ln(QSA)3(H2O)](H2O)5 complexes in the polycrystalline state and embedded in the silica glass, where Ln = La, Pr, Nd, Eu, Sm, Dy, Er, Gd, Ho, Tb, were studied and characterized using spectroscopic methods. The europium complex was additionally studied theoretically based on the DFT approach which provided molecular structure and electron transition assignment. The emission spectra measured at 293 and 77 K proved the transformation of excitation pulses into the phonon energy. The EPR studies of the Er, Gd, Dy and Sm derivatives were used to determine spin Hamiltonian parameters and g – components. The antiferromagnetic interactions were found and the local monoclinic symmetry of the coordination polyhedron was proposed.