Lanthanide chains containing the naphthalenyl nitronyl nitroxide radical.

In this contribution we report the synthesis, structure and magnetic properties of a family of lanthanide-based one dimensional compounds [Ln(hfac)(NaphNN)] , where Ln = 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-1-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)(NaphNN)] (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.