Spectroscopic, thermal, fluorescence and structural studies of new TlI pyridine dicarboxylate complexes, [Tl2(py-2,5-dc)] and [Tl2(py-3,5-dc)]

[Tl2(py-2,5-dc)] (1) and [Tl2(py-3,5-dc)] (2) (py-2,5-dc = pyridine-2,5-dicarboxylate and py-3,5-dc = pyridine-3,5-dicarboxylate), two new TlI coordination polymers have been synthesized, characterized by elemental analysis, IR spectroscopy and the crystal structure of compound 2 determined by single-crystal X-ray diffraction. The thermal stability of compounds 1 and 2 was studied by thermal gravimetric (TG) and differential thermal analyses (DTA). Determination of the structure of the compound 2 by X-ray crystallography shows that there are six (TlO5N) coordinate Tl atoms. The complex is a two-dimensional coordination polymer. Solid-state luminescent spectra of the ligands H2py-2,5-dc and H2py-3,5-dc as well as compounds 1–2 indicate an emission band with a maximum intensity at 465 nm upon excitation at 300 nm, respectively.