Two new Pb coordination polymers derived from pyrimidine-2-thiolate: Synthesis, methyl substitution-induced effect and properties

Two new coordination compounds, {Pb(pymt)₂}_∞ (1) and {Pb(mpymt)₂}_∞ (2) (pymt = pyrimidine-2-thiolate and mpymt = 4-methyl-pyrimidine-2-thione) have been synthesized under solvothermal conditions and characterized by elemental analyses, IR spectroscopy, thermogravimetric analysis, powder X-ray diffraction and single-crystal X-ray diffraction. In compounds 1 and 2, pymt^- and mpymt^- adopt the same coordination modes (μ-1 κN, S and μ₂-1 κN, S: 2 κS, N) to interacted with Pb²⁺, however, different topology structures for compounds 1 and 2 are obtained. Compound 1 displays a one-dimensional (1D) ribbon with square cavity constructed from two double concentric chains of [Pb-S]_∞ and [Pb-Pyrimidine] _∞ sharing Pb1 ions. Compound 2 shows 1D polymeric single chain constructed by [Pb-S]_∞ and [Pb-methyl-pyrimidine]_∞ chains. The results revealed that the methyl groups don't influence the coordination modes of pyrimidine-2-thiolate but directed the structural variations. Moreover, the fluorescent properties of compounds 1 and 2 were investigated.