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

Abstract

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.

Silver complexes of ligands derived from adamantylamines: Water-soluble silver-donating compounds with antibacterial properties

“…Distorted tetrahedron coordination geometry is not uncommon for Ag complexes with N donor ligands. A similar Ag complex with N donor namely, [Ag(bpy-OH) 2 ]+ (where bpy-OH = bis(hydroxymethyl)-2,2′-bipyridne) exhibits distorted tetrahedral geometry with average Ag–N distance of 2.320 Å [28] comparable to that observed for the present complexes. No noticeable π-π stacking or other intermolecular interactions are realized upon careful examination of the crystal packing for both the structures.…”

“…Such precipitation renders the bioactive Ag + ions unavailable at the wound bed. Because effective treatment of infections requires sustained release of Ag + , researchers have attempted use of different silver complexes to resist the rapid exit of the bioactive “drug” from the interaction zone [19, 28,29]. In the present study only 2 exhibits solubility in water (1 mg/mL) and we have carefully measured the stability of 2 in water at 37° C. As shown in Fig.…”

Exchange Capability of Cationic Silver 4,4′-Bipyrdine Materials for Potential Water Remediation: Structure, Stability, and Anion Exchange Properties

“…22 An additional driving force could be the relatively strong interaction perchlorate seems to have with silver. 3,17,22,28 The long-range linear Ag−Ag interactions (both direct Ag−Ag and through-space Ag ••• Ag long contact) when perchlorate is present is in contrast to that observed in complexes with NO 3…”

“…11,17,18,22,27,28 Of these anions, the PF 6 − was the only one that supported a 3D-type network due to bridging Ag ••• F and C−H ••• F interactions and will not be considered in this discussion. 27,28 Of the remaining anions, there seemed to be a relationship between anion shape and the resultant extended network conformations. For instance, ClO 4…”

Five- and Six-Coordinated Silver(I) Complexes Derived from 2,6-(Pyridyl)iminodiadamantanes: Sustained Release of Bioactive Silver toward Bacterial Eradication

“…The 269 structures that crystallized with I 3 m symmetry are mostly dominated by zinc and copper complexes, while only two examples of silver-bearing complexes have been found with the I 3 m space group. 7–9 It is worth mentioning that neither of those systems represents a discrete silver complex (such as complex 1 ).…”