Anion effects on the formation of cross-linked argentophilic interaction. synthesis and structural properties of AgX bearing bis(3-pyridyl)dimethylsilane (X- = CF3SO3-, PF6-, and NO3-)

Anion effects on the formation of a cross-linked Ag-Ag interaction in the molecular construction of a series of AgX complexes with bis(3-pyridyl)dimethylsilane (L) (X- = CF3SO3-, PF6-, and NO3-) have been carried out. The slow diffusion of an organic solution of L into an aqueous solution of AgX afforded [Ag(L)]X or [Ag(X)(L)]. Each L connected two Ag(I) ions [Ag-N = 2.110(5)-2.16](4) angstrom to form a wave strand. For CF3SO3- and PF6- anions, each single strand cross-linked the adjacent single strands via an argentophilic interaction (Ag-Ag = 3.0551(7) angstrom for CF3SO3- 3.279(1) angstrom) for PF6- to produce unique 2D sheets. In contrast, for the NO3- anion, the anion acts as a ligand (Ag-O3N = 2.61-2.79 angstrom) instead of the argentophilic interaction (Ag...Ag = 3.351(1) angstrom). That is, a small coordinating anion is an obstacle to form the argentophilic interaction, whereas a big non-coordinating anion favors the argentophilic interaction in the present molecular construction. For all complexes, the geometry around the Ag(I) ion is a typical T-shaped arrangement. The thermal stability can be explained in terms of the structural properties, including the argentophilic interaction.