Structural Invariance in Silver(I) Coordination Networks Formed Using Flexible Four-Armed Thiopyridine Ligands

Two new isomeric, flexible four-armed thioether pyridine-containing ligands 1,2,4,5-tetrakis(3-pyridylmethylsulfanylmethyl)benzene (3tet) and 1,2,4,5-tetrakis(4-pyridylmethylsulfanylmethyl)benzene (4tet) were prepared and characterized. The ligand 3tet gave rise to three isomorphous 3-D networks when reacted with AgClO₄ (1), AgPF₆ (2), and AgCF₃CO₂ (3). The topology of the resulting networks was that of the pyrite net. The ligand 4tet gave rise to two isotopological 3-D networks when reacted with AgClO₄ (4·2MeCN·2CHCl₃) and AgPF₆ (5·6MeCN). The topology of these networks was that of the rutile net. A third type of 3-D network of previously unknown topology was formed on reaction with AgCF₃SO₃ (6·3H2O). The network showed nodes with short topological terms 4².6 and 4⁴.6².8⁷.10². All six networks were binodal and based on three-connected Ag(I) nodes and six-connected ligand-centered nodes. In all of the networks the flexible ligands 3tet and 4tet showed two categories of ligand geometry which in all but one case gave rise to an interligand three-layered π stack. The networks showed a remarkable lack of dependence on the nature of the counterion and solvent.