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

Abstract

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.