Halide assisted formation of polymeric ethylenediaminetetraacetato lead( ii ) complexes

Insoluble lead( ii ) ethylenediaminetetraacetate isomers [Pb 2 (EDTA)(H 2 O)] 2n ( 1 ) and [Pb 4 (EDTA) 2 ] n ·2 n H 2 O ( 2 ) and allomers Pb n [Pb(EDTA)Pb(H 2 O)X] 2n ·2 n H 2 O (X = Cl, 3 and Br, 4 ) are isolated from the reactions of lead nitrate with ethylenediaminetetraacetic acid in acidic solution (H 4 EDTA = ethylenediaminetetraacetic acid). The four complexes are fully characterized via elemental analysis, FT-IR spectroscopy, thermogravimetric analyses, solid state 13 C NMR spectroscopy and X-ray crystal structure analyses. Topological analyses of complexes 2 and 3 ( 4 ) show unusual (6,8)-connected 2-nodal and (4,5,6)-connected 3-nodal network topologies, respectively. The insertions of chloride and bromide in 3 and 4 , respectively, give new polymeric lead–EDTA complexes. Products 3 and 4 , which are obtained at room temperature, show a significant halide-assisted formation effect of insoluble ethylenediaminetetraacetato lead( ii ) complexes, which is supported by solid state NMR and X-ray crystal structure analyses.