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.