Silver(I) Coordination Polymers Containing Heteroditopic Ureidopyridine Ligands: The Role of Ligand Isomerism, Hydrogen Bonding, and Stacking Interactions

New silver (I) coordination polymers has been successfully designed and synthesized using heteroditopic
ureidopyridine ligands 1 and 2 via a combination of coordinations bonds, hydrogen bonding, and π−π stacking
interactions. This study shows an example of the orientation of the pyridine nitrogen relative to the urea moiety
(4-substituted, 1, or 3-substituted, 2), used to control the packing of resulting crystalline coordination polymers. The
ureidopyridine ligands present some flexibility because of the conformational rotation around the central urea moiety.
The co-complexation of the silver(I) cation by two pyridine moieties and of the PF6- counteranion by the urea
moiety results in the formation of discrete [12Ag]+PF6-, (3) and [22Ag]+PF6-, (4) complexes presenting restricted
rotation around the central urea functionality. The geometrical information contained in the structures of ligands 1
and 2 and the heteroditopic complexation of silver hexafluorophosphate are fully exploited in an independent manner
resulting in the emergence of quasi-rigidly preorganized linear and angular building blocks of 3 and 4, respectively.
Additional π−π stacking contacts involving interactions between the π-donor benzene and the π-acceptor pyridine
systems reinforce and direct the self-assembly of the above-described combined structural motifs in the solid state.
Accordingly, linear and tubular arrays of π−π stacked architectures are generated in the solid state by synergistic
and sequential metal ion complexation, hydrogen bonding, and π−π stacking interactions