Hydrothermal Synthesis and Characterization of Two Novel Lead(II) Frameworks: From 1D Infinite Helical Pb-(O-C-O)-Pb Linkage to 3D Infinite Pb- X-Pb Network ( X = O and Br).

Abstract . Two aliphatic dicarboxy1ic acid ligands, iminodiacetic acid (H2L1) and 3,3-thiodipropionic acid (H2L2), were used to construct two novel lead(II) frameworks, namely, [Pb(μ4-L1)Br] n ( 1) and [Pb3(μ9-L2)(μ2-Br)2Br2] n ( 2), under hydrothermal conditions. It has to be noted that for 1 the central PbII ions are bridged by L2- ligands resulting in infinite right- and left-handed helical Pb-(O-C-O)-Pb linkage. Compound 2 represents a novel 3D hybrid luminescent lead(II) framework with I3O0 type connectivity. For 2 infinite 2D Pb-O-Pb inorganic layers and trinuclear Pb3Br4 clusters are inter-linked forming a 3D inorganic connectivity. In 1 the five-coordinate central PbII ions adopt a hemi-directed coordination arrangement, whereas in 2 six-coordinate Pb1, six-coordinate Pb2, and four-coordinate Pb3 atoms adopt hemi-directed coordination arrangements. The variable lead(II) coordination environment and flexible coordination modes of carboxy1ic acid ligands such as H2L1 and H2L2 also reveal great potential for constructing novel inorganic-organic hybrid materials. Furthermore TGA, FT-IR, PXRD, elemental analysis, and photo-luminescent properties of 1 and 2 were investigated. [ABSTRACT FROM AUTHOR]