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