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, <b>1</b>) 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 <i>cisoid</i> and planar <i>transoid</i>. With silver(I) triflate (AgCF<sub>3</sub>SO<sub>3</sub>) in benzene, a sheet structure of composition [Ag(<b>1</b>)CF<sub>3</sub>SO<sub>3</sub>]C<sub>6</sub>H<sub>6</sub> (<b>2</b>) 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 [Ag<sub>2</sub>(<b>1</b>)(CF<sub>3</sub>SO<sub>3</sub>)<sub>2</sub>] (<b>3</b>) 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 <i>transoid</i> conformation with respect to the positioning of the nitrile groups. With silver(I) hexafluorophosphate (AgPF<sub>6</sub>), silver(I) hexafluoroarsenate (AgAsF<sub>6</sub>), or silver(I) hexafluoroantimonate (AgSbF<sub>6</sub>), 2-fold interpenetrated sheet structures [Ag(<b>1</b>)<sub>2</sub>]<i>X</i>F<sub>6</sub> (<i>X</i> = P (<b>4</b>), As (<b>5</b>), or Sb (<b>6</b>)) are obtained in which 3,3‘-DCPA coordinates to tetrahedral silver(I) ions in a <i>cisoid</i> conformation. In spite of the large difference in counterion size, minimal network deformation is observed among these systems. Interestingly, with silver(I) perchlorate hydrate (AgClO<sub>4</sub>·<i>x</i>H<sub>2</sub>O, <i>x</i> ∼ 1), 3,3‘-DCPA coordinates in a <i>transoid</i> conformation to tetrahedral silver(I) ions to form the 8-fold interpenetrated diamondoid network [Ag(<b>1</b>)<sub>2</sub>]ClO<sub>4</sub>·H<sub>2</sub>O (<b>7</b>). 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.