Luminescent lead(ii) complexes: new three-dimensional mixed ligand MOFs

Abstract

Two new lead(II) butyrate-based compounds with formulae [Pb₂(but)₄(4,4′-bipy)(H₂O)]_n (1) and [Pb₂(but)₄(bpe)(H₂O)]_n (2) [with but = butyrate; 4,4′-bipy = 4,4′-bipyridine and bpe = 1,2-bis(4-pyridyl)ethene] have been synthesized and characterized, with the aim of obtaining different three-dimensional (3D) structures from the typical two-dimensional (2D) lamellar one of most of metal alkanoates, and enhancing the properties of the products synthesized, using these two different N bridging ligands (4,4′-bipy and bpe). Both new complexes show a similar 3D (4²6³8)-sra network in a monoclinic lattice (C2/c) and present interesting photophysical properties. The two compounds have been fully characterized by single crystal X-ray diffraction (synchrotron radiation), thermogravimetric analysis, differential scanning calorimetry, UV-Vis absorption spectroscopy, and steady-state fluorescence and lifetime measurements.