Silver(I) 3-aminomethylpyridine complexes, part 2: effect of ligand ratio, hydrogen bonding, and pi-stacking with an interacting anion.

Reaction of 3-aminomethylpyridine (3-amp) with silver(I) salts of triflate (OTf-) and trifluoroacetate (tfa-) produce a variety of multidimensional coordination networks whose structures depend on the stoichiometry of the components present. A 1:1 ratio of 3-amp to AgX produces a linear polymer, 1, when X = tfa- and a planar sheet, 2, when X = OTf-. Addition of a second equivalent of ligand increases the dimensionality of both structures by one to form a two-dimensional sheet, 3, and a three-dimensional system, 4, for their respective anions. Addition of 2,2'-bipyridine (bipy) to solutions of any of the previous compounds produces the fixed-ratio complexes 5 (tfa- salt) and 6 (OTf- salt). The bipyridyl ligand halts the polymerization of compounds 1-4 by cutting the chain after each silver(I) link and forcing a 1:2:2 ratio of 3-amp to AgX to bipy. Compound 5, however, remains polymeric in nature due to the closed-shell Ag-Ag interactions of the planar metals holding the monomers together. Differences between structures of each ratio stem from the differences in basicity and in the extra degree of H-bonding ability that the OTf- anion has over tfa-.