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

Hydrothermal reactions of trivalent lanthanide salts with a rigid ligand 3,4-pyrazoledicarboxylic acid (H3pdc) yielded a series of lanthanide compounds, namely, [Ln(H(2)pdc)(3)(H2O)(4)]center dot xH(2)O (Ln = Ce(1), Pr(2), Nd(3) and Sm(4)). In the presence of oxalate as ancillary ligand, 2D coordination polymers {[Ln(mu(2)-Hpdc)(mu(2)-C2O4)(1/2)(H2O)(2)]center dot 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 (4.5(2))(4.5(3).7.8) topology. Magnetic susceptibility data show that compounds 6 and 7 exhibit antiferromagnetic couplings between the adjacent magnetic centers. (C) 2015 Elsevier B.V. All rights reserved.