Structural diversity and fluorescence properties of lead (II) complexes based on a flexible tricarboxylate and two large conjugate N-donor ligands

Abstract Three novel structural diversiform lead(II) complexes, formulated as [Pb(HDBB)(dppz)] (1), [Pb(HDBB)(H2O)]·H2O(2), [Pb4Na(DBB)3(o-phen)3](3), have been synthesized under hydrothermal conditions based on 4-(3,5-dicarboxylatobenzyloxy) benzoic acid (H3DBB) and two N-donor ligands: dipyrido (3,2-a:2′,3′-c) phenazine (dppz) and 1,10-phenanthroline (o-phen). Structural analyses reveal complex 1 possesses 1D double-helical ladder-like chain sharing a common axis, and then the π···π interactions between adjacent dppz ligands give rise to supramolecular architecture. 2 features 2D (4,4) network based on 1D double-stranded slight helixes chains and the bridging of DBB ligands. For 3, a 3D framework arises from a hexagonal unit with the trinuclear central groups. The structural diversity from 1D to 3D of these complexes might be attributed to the coordination of auxiliary ligands. Solid-state fluorescence properties for these crystalline materials are also presented.