Construction of a Pb II coordination polymer from a semi-rigid ditopic 2,2-biimidazole derivative: synthesis, crystal structure and characterization

A new Pb coordination polymer, poly[0.75(aqua)[μ -4,4'-(1H,1'H-[2,2'-biimidazole]-1,1'-diyl)dibenzoato-κ O,O';N;O'',O''']]lead(II)] 1.25-hydrate], {[Pb(C H N O )(H O) ]·1.25H O} or {[Pb(L)(H O) ]·1.25H O} (1) [H L = 4,4'-(1H,1'H-[2,2'-biimidazole]-1,1'-diyl)dibenzoic acid], was synthesized under solvothermal reaction conditions and characterized using microanalysis, IR spectroscopy and thermogravimetric analysis. Single-crystal structure analysis reveals that a two-dimensional corrugated layer structure is formed in 1 and that neighbouring layers are further extended into a three-dimensional structure by hydrogen-bonding interactions. In addition, a fluorescence sensing experiment towards Cu based on the polymeric Pb complex was carried out.