Hydrothermal syntheses and characterization of a series of lead(II) inorganic–organic hybrid frameworks tuned by reaction temperature and inclusion of halide anions

Based on a highly flexible H2L (2,2′-thiodiacetic acid) ligand and corresponding lead(II) salts, a series of novel lead(II) inorganic–organic hybrid frameworks {[Pb2(μ6-L)(μ7-L)]}n (1), [Pb(μ6-L)]n (2) and {Pb3(μ8-L)2(μ2-Cl)2}n (3) have been isolated under hydrothermal conditions. 1 and 2 represent a novel example of tuning the inorganic–organic hybrid frameworks from I1O1 type to I2O0 type and coordination geometries of lead(II) via changing the hydrothermal reaction temperature. When halide chloride anions were introduced into the reaction system, another novel hybrid framework 3 can be isolated. In 3, 1D infinite Pb–O–Pb and Pb–Cl–Pb connectivity can be observed, which are inter-linked forming another type of 2D inorganic–organic framework with I2O0 type. Four different coordination modes of full de-protonated L2 − ligand can be observed in 1–3. The variable lead(II) geometries and coordination numbers together with flexible coordination modes of de-protonated L2 − ligand also reveal great potential in the rational design and deliberate construction of those novel inorganic–organic hybrid materials.