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)-µ2-(benzene-1,2-dicarboxylato)-µ2-[2-(2,2':6',2''-terpyridin-4'-yl)benzoato]] monohydrate], {[Ln(C8H4O4)(C22H14N3O2)]·H2O}n or {[Ln(1,2-bdc)(L)]·H2O}n, with lanthanide (Ln) = dysprosium (Dy, 1), holmium (Ho, 2) and erbium (Er, 3), poly[bis(µ2-benzene-1,3-dicarboxylato)bis[µ2-2-(2,2':6',2''-terpyridin-4'-yl)benzoato]dilanthanide(III)], [Ln2(C8H4O4)2(C22H14N3O2)2]n or [Ln2(1,3-bdc)2(L)2]n, with Ln = gadolinium (Gd, 4), Ho (5) and Er (6), and poly[(µ2-benzene-1,4-dicarboxylato)[µ2-2-(2,2':6',2''-terpyridin-4'-yl)benzoato]lanthanide(III)], [Ln(C8H4O4)(C22H14N3O2)]n or [Ln(1,4-bdc)(L)]n, 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 Ln2(COO)2 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 Ln2(COO)2 units. Compounds 7-10 display 8-connected 3D frameworks with the topological type rob, consisting of Ln2(COO)2 units. The influence of the coordination orientations of the aromatic dicarboxylate groups on the crystal structures is discussed.

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.