An eight-connected 3D lead(II) metal-organic framework with octanuclear lead(II) as a secondary building unit: synthesis, characterization and luminescent property

A novel 3D lead(II) metal-organic framework {Pb-4(Bdc)(3)-(mu(4)-O)(H2O)}(n) (1) (H(2)Bdc = isophthalic acid) with octanuclear [Pb-8(Bdc)(6)(mu(4)-O)(2)(H2O)(2)] as secondary building units (SBUs) has been obtained and fully characterized by single crystal X-ray diffraction, IR, elemental analysis, TG-DTA and fluorescent spectra. XRD results indicate octanuclear lead(II) SBU contains two inversely related [Pb-4(mu(4)-O)] cores and is extended topologically into an infinite eight-connected bcu-type network via twelve Bdc ligands linking eight neighboring SBUs. At room temperature, 1 in the solid-state exhibits strong emission peak at 424 nm originated from the LMCT between delocalized pi bonds of Bdc carboxylate groups and p orbitals of lead(II) centers.