Lanthanide(III)-based coordination monomers and polymers of 3,4-pyrazoledicarboxylate: Extended synergy within the ligand, structures and magnetic properties

Abstract

Hydrothermal reactions of trivalent lanthanide salts with a rigid ligand 3,4-pyrazoledicarboxylic acid (H3pdc) yielded a series of lanthanide compounds, namely, [Ln(H2pdc)3(H2O)4]·xH2O (Ln=Ce(1), Pr(2), Nd(3) and Sm(4)). In the presence of oxalate as ancillary ligand, 2D coordination polymers {[Ln(μ2-Hpdc)(μ2-C2O4)1/2(H2O)2]·H2O}n (Ln=Ce(5), Pr(6), Nd(7) and Sm(8)) are formed. Structure analyses reveal that compounds 1–4 are isostructural, featuring mononuclear structures. Whereas 5–8 are also isostructural and exhibit (3,4)-connected 2D layer structures with (4.52)(4.53.7.8) topology. Magnetic susceptibility data show that compounds 6 and 7 exhibit antiferromagnetic couplings between the adjacent magnetic centers.