Coordination polymers and supramolecular structures in Ag(I)triflate-dppf systems (dppf=1,1′-bis(diphenylphosphino) ferrocene)

The interaction of silver triflate (OTf^-=SO₃ (CF₃)^-) and dppf [(C₅H₄ PPh₂)₂Fe)] gave different complexes, depending on the stoichiometric proportions and reaction conditions. Under limiting dppf conditions, three different forms (1-3) of [Ag₂(OTf)₂(dppf)]_x were isolated. Single crystal X-ray diffraction analyses showed that the structure of 1 (x=2n) consists of a 2-D polymer comprising a tetra-silver basic unit, while that of 2 (x=2) possesses a discrete tetra-silver framework and that of 3 (x=n) is a linear polymer based on a di-silver repeating unit. The structures are supported by bridging dppf ligands and triflate groups. The crystal lattices of the compounds are stabilized by extensive intermolecular C-H⋯X hydrogen bonding (H=ring proton of Cp or Ph of dpppf; X=O or F of OTf). [Ag(dppf)(OTf)] (4) and the structurally characterized mononuclear [Ag(dppf)₂](OTf) (5) were the sole products obtained from treatment of AgOTf with dppf in molar ratios of 1:1 and 1:2, respectively.