Lanthanide chains containing the naphthalenyl nitronyl nitroxide radical

Abstract

In this contribution we report the synthesis, structure and magnetic properties of a family of lanthanide-based one dimensional compounds [Ln(hfac)₃(NaphNN)]_n, where Ln^III = Gd (1), Dy(2), Tb(3) and NaphNN is the nitronyl nitroxide (NN) radical 2-(1′-naphthalenyl)-4,4,5,5-tetramethyl-4,5-dihydro-1H-Imidazole-3-oxide-1-oxyl. The crystal structure reveals well isolated chains with a twofold helical axis. Magnetic investigation of the gadolinium(III) chains showed relevant intrachain interactions between Gd–NN nearest neighbors and also Gd–Gd and NN–NN next nearest neighbors. The magnetic interaction parameters were obtained by fitting the data with a six membered ring model. The stronger antiferromagnetic interaction between NN radicals was confirmed by investigation of the mononuclear complex [Y(hfac)₃(NaphNN)₂] (4) with a similar coordination environment. The dynamic magnetic properties of 2 and 3 were investigated by using the temperature and frequency dependence of the magnetic susceptibility evidencing single chain magnet dynamics under a zero dc field.