One-Dimensional Coordination Polymer And Its Hydrogen Bonded 2D Network Generated From Dimeric Ag(I) Building Units

Most of synthetic polymers and supramolecules have been constructed based upon mononuclear metal centres and organic ligands with specific geometries. Recently the employment of pre-designed and functional bi- or polynuclear units as building blocks to construct coordination polymers, especially low-dimensional polymers, is an attractive road to functional materials, in which way the reaction condition is quite mild and the control of product is easy to achieve, and also synthetic materials may posses some novel properties due to metal-metal bonding and rigidity of dimeric or cluster units. Design and synthesis of coordination polymers are of great interest due to their intriguing topologies and potential applications in catalysis, magnetism, luminescence and electrical conductivity.In an early work, a replacement of axially bonded acetonotrile molecules in [[Cu₂(μ-PhPPy₂)₂(CH₃CN)₂](ClO₄)₂ with sulfate anions successfully led to a neutral and strongly blue-emissive coordination polymer [Cu₂(μ-PhPPy₂)₂(μ-SO₄)]_∞with a zigzag chain. Based upon the difference in photoluminescent properties of silver(I) complex and copper(I) complex, a new dinuclear silver(Ι) complex, which has linear and rigid structures, was designed and synthesized.The new dimeric silver(I) complex [Ag(PhPPy₂)(CH₃CN)]₂(ClO₄)₂ (PhPPy₂ = bis(2-pyridyl) phenylphosphine) was synthesized by a direct reaction of [Ag(CH₃CN)₄]ClO₄ with ligand PhPPy2. X-ray crystallographical studies revealed that in [Ag(PhPPy₂)(CH₃CN)]₂(ClO₄)₂, two silver atoms are bridged by two PhPPy2 ligands and bonded to each other. Each Ag(I) adopts a distorted trigonally bi-pyramidal geometry, and axial coordinated acetonitrile molecules are collinear with two silver atoms.By using [Ag(PhPPy₂)(CH₃CN)]₂(ClO₄)₂ as a building block precursor, a 1D coordination polymer [Ag₂(PhPPy₂)₂(1,3,5-C₆H₃(CO₂)₂(CO₂H))]_∞was prepared by replacing axially coordinated acetonitrile molecules in[Ag(PhPPy₂)(CH₃CN)]₂-(ClO₄)₂ with two carboxylate groups of a bridging ligand, 1,3,5-benzenetricarboxylate. In solid state, linear polymeric chains are oriented parallel to each other and interestingly interact by hydrogen bonding through their carboxylic/carboxylate groups to construct a novel wave-shaped 2D network. Both [Ag(PhPPy₂)(CH₃CN)]₂(ClO₄)₂ and [Ag₂(PhPPy₂)₂(1,3,5-C₆H₃(CO₂)₎2(CO₂H))]_∞exhibit similar photoluminescent properties in solid state at room temperature.