Assembly via H-bonds and AgAg attractions of one-dimensional silver(I) complexes of nicotinamide and nicotinic acid with sulfonate counter-anions

Abstract

Three silver(I) complexes containing pyridine derivatives have been synthesized and structurally characterized by X-ray single crystal diffraction, in order to evaluate the effect of counter anions upon the assembly process of complex cations via intermolecular hydrogen bonds. [Ag(nia) 2] 2(bpds)·2H 2O ( 1) and [Ag(nia) 2](asa) ( 2) (nia=nicotinamide, bpds=4,4′-biphenyldisulfonate, asa=aminosulfonate) contain cationic complexes comprised of two nicotinamide ligands coordinated with the pyridine nitrogen atoms to a silver(I) ion in a linear fashion. The linear unit is connected to another one by a weak AgAg interaction leading to an H-shaped dimeric unit. The dimeric units are linked through hydrogen bonds formed between amide groups in a head-to-head mode, creating one-dimensional cationic ribbons. In 1, the ribbons are extended into two-dimensional network via hydrogen bonds formed by the amide groups. The cationic complex cations in [Ag(niac) 2] 2(1,5nds)·2H 2O ( 3) (niac=nicotinic acid, 1,5nds=1,5-disulfonate) are also connected to each other through AgAg interactions, leading to H-shaped dimeric units. The dimeric units are propagated via CH⋯O hydrogen bonds between the aromatic hydrogen atom and the carbonyl oxygen. A database search shows that the unique AgAg interaction between the discrete silver(I) coordinated linearly just by two pyridine nitrogen atoms is only observed in salts containing sulfonate or sulfate as counter anions.