Molecular and Multidimensional Organic−Inorganic Hybrids Based on Polyoxometalates and Copper Coordination Polymer with Mixed 4,4‘-Bipyridine and 2,2‘-Bipyridine Ligands

Three novel organic−inorganic hybrid materials with mixed 4,4‘-bipyridine and 2,2‘-bipyridine ligands, K[{Cu^I(2,2‘-bipy)}(4,4‘-bipy){Cu^I(2,2‘-bipy)}_0.5]₂[Mo₈O₂₆] (<b>1</b>), [Cu^I(4,4‘-bipy)]₃[PMo₁₀^VIMo₂^VO₄₀{Cu^II(2,2‘-bipy)}] (<b>2</b>), and [Cu^I(2,2‘-bipy)(4,4‘-bipy)_0.5]₂[Cu^I(4,4‘-bipy)]₂[SiW₁₂O₄₀] (<b>3</b>) (2,2‘-bipy = 2,2‘-bipyridine, 4,4‘-bipy = 4,4‘-bipyridine), have been hydrothermally synthesized. Compound <b>1</b> is a novel β-[Mo₈O₂₆]^4- polyoxoanion bisupported by copper(I) coordination cations with mixed 4,4‘-bipy and 2,2‘-bipy ligands. Compound <b>2</b> consists of the divalent copper {Cu^II(2,2‘-bipy)}²⁺ capped [PMo₁₀^VIMo₂^VO₄₀]^5- building blocks linked by {Cu(4,4‘-bipy)}<i>_n</i><i>ⁿ</i>⁺ linear cationic chains into a novel two-dimensional (2D) network. To the best of our knowledge, compound <b>2</b> exhibits an unprecedented 2D structure containing the divalent copper capped polyoxometalate as building blocks. The novel structure of <b>3</b> is composed of one-dimensional hybrid zigzag chains linked by {Cu(4,4‘-bipy)}<i>_n</i><i>ⁿ</i>⁺ chains into a three-dimensional (3D) framework via weak Cu−O interactions. The novelty of compound <b>3</b> is that it is the first time that a novel 3D framework has been formed by polyoxometalate and transition metal coordination polymer chains with mixed 4,4‘-bipy and 2,2‘-bipy.