Structural investigation of one- and three-dimensional lanthanide(III) coordination polymers based on functionalized terpyridine carboxylate and aromatic dicarboxylate ligands.

Three series of lanthanide coordination polymers, namely catena-poly[[lanthanide(III)-μ-(benzene-1,2-dicarboxylato)-μ-[2-(2,2':6',2''-terpyridin-4'-yl)benzoato]] monohydrate], {[Ln(CHO)(CHNO)]·HO} or {[Ln(1,2-bdc)(L)]·HO}, with lanthanide (Ln) = dysprosium (Dy, 1), holmium (Ho, 2) and erbium (Er, 3), poly[bis(μ-benzene-1,3-dicarboxylato)bis[μ-2-(2,2':6',2''-terpyridin-4'-yl)benzoato]dilanthanide(III)], [Ln(CHO)(CHNO)] or [Ln(1,3-bdc)(L)], with Ln = gadolinium (Gd, 4), Ho (5) and Er (6), and poly[(μ-benzene-1,4-dicarboxylato)[μ-2-(2,2':6',2''-terpyridin-4'-yl)benzoato]lanthanide(III)], [Ln(CHO)(CHNO)] or [Ln(1,4-bdc)(L)], with Ln = Dy (7), Ho (8), Er (9) and ytterbium (Yb, 10), were synthesized under hydrothermal conditions and characterized by elemental analysis, IR and single-crystal X-ray diffraction. Compounds 1-3 possess one-dimensional loop chains with Ln(COO) units, which are extended into three-dimensional (3D) supramolecular structures by π-π interactions. Isostructural compounds 5 and 6 show 6-connected 3D networks, with pcu topology consisting of Ln(COO) units.

Dy(iii) zig-zag chains assembled in a 3D framework with single-molecule magnet behaviour.

A new lanthanide-based framework, [Dy(STP)(1,2-bdc)]n (1), was constructed. It represents dysprosium(iii) 1D zigzag chains in a 3D framework and displays single-molecule magnet (SMM) behaviour with an energy barrier of 55.76 K under zero dc field.