Five new luminescent Pb(II) and Ag(I) coordination polymers based on 1-(4-carboxybenzyl)-1H-pyrazole-3,5-dicarboxylic acid and different neutral ligands

Five new coordination polymers (CPs), namely {Pb1.5(L)} (1), {Pb3(L)2(2,2′-bpy)·2·5H2O} (2), {[Pb(HL)(phen)]·H2O} (3), {Ag2(HL)} (4) and {Ag(H2L)(phen)} (5), have been constructed by using 1-(4-carboxybenzyl)-1H-pyrazole-3,5-dicarboxylic acid (H3L) as an organic ligand. Compound 1 reveals a three-dimensional (3D) (4,6,7)-connected framework with the point symbol of {410·65}{46}2{48·613}2. Compound 2 exhibits a novel (3,6)-connected 3D framework based on a trinuclear Pb(II) cluster with point symbol {42.6}2{44.62.88.10}. Compound 3 is a 1D chain that is further assembled into a 3D supramolecular framework by hydrogen-bonds. Compound 4 shows a (3,6)-connected 3D structure based on a tetranuclear Ag(I) cluster with {4·62}2{42·610·83} topology. Compound 5 is a 0D structure, and can be further expanded into a 3D supramolecular network by various weak interactions. The solid-state luminescent spectra have been measured at room temperature. The results show that compounds 1–5 exhibit strong luminescent emission in the visible region, and can be tunable by varying excitation wavelengths.