Novel lead(II) coordination polymers based on p-sulfophenylarsonic acid

Hydrothermal reactions of lead(II) salts with p-sulfophenylarsonic acid (p-HO3S-C6H4-AsO3H2, H3L) afforded two novel lead(II) p-sulfonate-arsonates, namely, Pb3(L)2(H2O)·H2O (1) and Pb3(L)2·6.5H2O (2). Their structures feature two different types of three-dimensional structures. In compound 1, the interconnection of Pb(II) ions by bridging arsonate and sulfonate groups results into a 2D layer parallel to the bc plane. These layers are further cross-linked by phenyl groups into a pillared-layered architecture with small voids occupied by the lattice water. Compound 2 features a 3D open framework based on 1D lead sulfonate-arsonate chains of Pb3O4 clusters along c-axis that are further cross-linked by phenyl groups, forming large tunnels along c-axis which are occupied by a number of lattice water molecules. Introduction of 2,2′-bipyridine (bipy) or 1,10-phenanthroline (phen) as the auxiliary chelating ligand into the above system led to two new mixed-ligand lead(II) sulfonate-arsonates, namely, Pb(HL)(bipy)·2H2O (3) and Pb(HL)(phen)·2H2O (4). Compounds 3 and 4 display a similar one-dimensional chain in which neighboring Pb2O2 units are bridged by a pair of HL2− anions. There also exists a 1D water chain in compound 3. All four compounds display strong fluorescent emission bands in the green or red light region.