Adjusting the Frameworks of Silver(I) Complexes with New Pyridyl Thioethers by Varying the Chain Lengths of Ligand Spacers, Solvents, and Counteranions

In our efforts to systematically investigate the effects of the linker units of flexible ligands and other factors on the structures of AgI complexes with thioethers, five new flexible pyridyl thioether ligands, bis(2-pyridylthio)methane (L1), 1,3-bis(2-pyridylthio)propane (L3), 1,4-bis(2-pyridylthio)butane (L4), 1,5-bis(2-pyridylthio)pentane (L5), and 1,6-bis(2-pyridylthio)hexane (L6), have been designed and synthesized, and the reactions of these ligands with AgI salts under varied conditions (varying the solvents and counteranions) lead to the formation of eight novel metal−organic coordination architectures from di- and trinuclear species to two-dimensional networks:  [Ag3(L1)2(ClO4)2](ClO4) (1), {[AgL3](ClO4)} (2), {[Ag2(L4)2](ClO4)2(CHCl3)} (3), {[AgL4](ClO4)(C3H6O)} (4), {[Ag2L4](NO3)2} (5), [Ag2L4(CF3SO3)2] (6), {[AgL5](ClO4)(CHCl3)}2 (7), and {[AgL6](ClO4)} (8). All the structures were established by single-crystal X-ray diffraction analysis. The coordination modes of these ligands were found to vary from N,N-bidentate to N,N,S-tridentate to N,N,S,S-tetradentate modes, while the AgI centers adopt two-, three-, or four-coordination geometries with different coordination environments. The structural differences of 1, 2, 3, 7, and 8 indicate that the subtle variations on the spacer units can greatly affect the coordination modes of the terminal pyridylsulfanyl groups and the coordination geometries of AgI ions. The structural differences of 3 and 4 indicate that solvents also have great influence on the structures of AgI complexes, and the differences between 3, 5, and 6 show counteranion effects in polymerization of AgI complexes. The influences of counterions and solvents on the frameworks of these complexes are probably based upon the flexibility of ligands and the wide coordination geometries of AgI ions. The results of this study indicate that the frameworks of the AgI complexes with pyridyl dithioethers could be adjusted by ligand modifications and variations of the complex formation conditions.