Seven novel SrII–SmIII and SrII–DyIII coordination polymers: construction of five classes of structural topologies using different amounts of imidazole

The employment of pyridine-2,6-dicarboxylic acid (H2pda) and imidazole (im) in the synthesis of SrII–SmIII and SrII–DyIII coordination polymers has been reported. Seven novel heterometallic coordination polymers of compositions, [Dy3Sr3(pda)7(Hpda)(H2O)9]·6H2O (1), [LnSr(pda)3(H2O)5]·Him·H2O (Ln = Sm(2), Dy(3)), [Ln2Sr(pda)6(H2O)5]·4Him·C2H5OH·nH2O (Ln = Sm(4), n = 4; Dy(5), n = 5), [Sm2Sr2(pda)5(H2O)9]·2H2O (6) and [DySr(pda)3(H2O)4]·Him·3H2O (7), have been prepared and characterized. Complexes 1, 2–3, and 6 display three varieties of 2-D structures. 4–5 and 7 exhibit two types of 1-D chain structures. The structures of the complexes could be controlled via choosing appropriate starting materials and tuning the amount of imidazole. The photo-luminescent properties of these complexes have been investigated. The results show the exclusive luminescence emission bands being characteristic of SmIII and DyIII.