2D Holodirected lead(II) bromide coordination polymers constructed of rigid and flexible ligands

Three new 2D PbII coordination polymers containing 4,4′-bipyridine (4,4′-bipy), 1,2-bis(4-pyridyl)ethane (bpa) and 1,2-bis(4-pyridyl)ethene (bpe) with bromide anions, [Pb(μ-4,4′-bipy)(μ-Br)2]n (1), [Pb(μ-bpa)(μ-Br)2]n (2) and [Pb(μ-bpe)(μ-Br)2]n (3) have been synthesized and characterized by elemental analysis, IR spectroscopy and their structures studied by X-ray crystallography. The thermal stability of compounds 1–3 was studied by thermal gravimetric (TG) and differential thermal analyses (DTA). The single-crystal X-ray data shows that the Pb2+-ions have coordination numbers of six and contain the rarely holodirected geometries.