Anionic and neutral metal-4,4'-bipyridine networks. Synthesis, structures and thermal properties of one- and three-dimensional coordination polymers constructed by metal salts and 4,4'-bipyridine

Abstract

Two compounds, [Zn₃(4,4'-bipy)₃(H₂O)₆(SO₄)₄]((4,4'-H₂bipy)(10H₂O (1) and [Cu(4,4'-bipy)(H₂O)₃(SO₄)](2H₂O (2) (4,4'-bipy = 4,4'-bipyridine), were obtained from the reactions of different metal salts and 4,4'-bipy under weak acidic conditions. 1 is the first anionic 3D coordination network constructed by 4,4'-bipy in which each structural unit consists of three Zn(II) atoms with the formula [Zn₃(4,4'-bipy)₃(H₂O)₆(SO₄)₄]^2?. Two Zn(II) atoms are linked by 4,4'-bipy units to form linear [4,4'-bipy-Zn(1)-4,4'-bipy-Zn(2)]₍ chains, the third Zn(II) atom is also connected by 4,4'-bipy unit and form another type of linear [Zn(3)-4,4'-bipy]₍ chains; both types of chains are interlinked covalently by µ₂-sulfate bridges, resulting in a 3D coordination network of novel topology. The large cationic [4,4'-H₂bipy]²⁺ molecules as well as lattice water molecules occupy the channels. 2 comprises 1D linear coordination chains. The adjacent chains are each arranged in a cross-like fashion at the midpoints of the 4,4'-bipy ligands, resulting in a 3D supramolecular arrays