Synthesis and characterization of silver(I) coordination networks bearing flexible thioethers: Anion versus ligand dominated structures

This report describes the synthesis and X-ray characterization of a series of (LAgX)-Ag-n complexes wherein L-n = PhS(CH2)(n)SPh (n = 2, 4, 6, 10) and X = CF3SO3-, CF3COO-, CF3CF2COO-, CF3CF2CF2COO-, NO3-, and ClO4-. This study was undertaken in order to rationalize the structure of the coordination networks formed as a function of the anion coordinating strength and the ligand structure. The following complexes were examined: with L-2, CF3SO3- (1), CF3COO- (2), ClO4- (3); L-4, CF3SO3- (4), CF3COO- (5), CF3CF2COO- (6), CF3CF2CF2COO-(7); L-6, CF3COO-center dot H2O (8), CF3CF2COO- (9), CF3CF2CF2COO- (10); and L-10, NO3- (11). The anions selected are classified in three groups of increasing coordinating strength: perchlorates, fluorosulfonates, and perfluorocarboxylates. Except in two cases, all complexes form 2D-coordination networks. The 2D-network in 1 (L-2, CF3SO3-) is made up of Ag(I) and L-2, while the anion is only a terminal co-ligand that completes the trigonal coordination around Ag(I). In 4 (L-4, CF3SO3-), a 1D-coordination polymer, [Ag-L-4-](infinity), is observed where the anions are coordinated to Ag(I) in a trigonal fashion. The perfluorocarboxylates form tetrameric units in a zigzag shape, but only with the L4 ligand. In these (6 and 7), the silver-silver distances are very short, especially those of the central bond, indicating the presence of weak Ag-Ag interactions. Dimers, with short silver-silver distances, are observed with ligands L2 and L-6 and perfluorocarboxylates. In 8 (L-6, CF3COO-H2O), a 3D channel-like structure is built through water molecules that connect adjacent layers. An unusual stoichiometry is noted in 3 (L-2, ClO4-, acetone); Ag:L is 4:2.5. In 11 (L-10 and NO3), the nitrate acts as a bidentate ligand and an [Ag-NO3-](infinity) chain is formed. Adjacent chains are linked by the L-10 ligands into a 2D-coordination network.