Coordination Networks of 3,3′-Dicyanodiphenylacetylene and Silver (I) Salts: Structural Diversity through Changes in Ligand Conformation and Counterion

Coordination networks of 3,3′-dicyanodiphenylacetylene (3,3′-DCPA, 1) with silver (I) salts characterized by single-crystal X-ray analysis are described. Network topology is found to depend on both the counterion and solvent employed during crystallization. The conformation adopted by the ligand varies between planar cisoid and planar transoid. With silver (I) triflate (AgCF₃SO₃) in benzene, a sheet structure of composition [Ag(1)CF₃SO₃]C₆H₆ (2) forms in which silver (I) is five-coordinate and bonds to two nitrogen atoms of distinct 3.3′-DCPA molecules, another silver (I) ion, and two oxygen atoms of the triflate ions. Changing the solvent to toluene produces an undulating sheet structure of composition [Ag₂(1)(CF₃SO₃)₂] (3) in which silver (I) is six-coordinate, bonding to a ligand nitrogen atom, to four oxygen atoms of bridging triflate ions, and to a neighboring silver (I) ion. In both triflate structures, 3,3′-DCPA adopts a transoid conformation with respect to the positioning of the nitrile groups. With silver (I) hexafluorophosphate (AgPF₆), silver (I) hexafluoroarsenate (AgAsF₆), or silver (I) hexafluoroantimonate (AgSbF₆), 2-fold interpenetrated sheet structures [Ag(1)₂]XF₆ (X = P (4), As (5), or Sb (6)) are obtained in which 3,3′-DCPA coordinates to tetrahedral silver (I) ions in a cisoid conformation. In spite of the large difference in counterion size, minimal network deformation is observed among these systems. Interestingly, with silver (I) perchlorate hydrate (AgCIO₄·xH₂O, x ∼ 1), 3,3′-DCPA coordinates in a transoid conformation to tetrahedral silver (I) ions to form the 8-fold interpenetrated diamondoid network [Ag(1)₂]CIO₄·H₂O (7). An analysis of the packing of these networks is provided, and the results are compared to complementary systems previously reported from our study of coordination networks of dinitriles and silver (I) salts.