Supramolecular Assembly of Ag(I) Centers: Diverse Topologies Directed by Anionic Interactions

Ag(I)-Ag(I) interactions in supramolecular structures have been achieved through the use of structural support from the ligand frames. In structures involving simple ligands like pyridine, strong π-π interaction leads to spatial ordering of the individual [Ag(L)2]+ units. In such structures anions also play a crucial role in dictating the final arrangement of the [Ag(L)2]+ synthons. In order to determine whether the anions can solely dictate the arrangement of the [Ag(L)2]+ synthons in the supramolecular structure, four Ag(I) complexes of 4-pyridylcarbinol (PyOH), namely, [Ag(PyOH)2]X (X = NO3- (1), BF4- (2), CF3SO3- (3), and ClO4- (4)) have been synthesized and structurally characterized. Gradual transformation of the extended structures observed in 1-3 eventually merges into a unique linear alignment of the [Ag(PyOH)2]+ units in 4 along the c axis, a feature that results in strong argentophilic interactions. Complex 4 is sensitive to light and is inherently less stable than the other three analogues. The structural variations in this set of extended assemblies are solely dictated by the anions, since π-π interaction between the substituted pyridine ligands is significantly diminished due to disposition of the -CH2OH substituent at the 4 position and H-bonding throughout the structure.