Coordination polymers and isomerism: a study using silver(I) and a #pi#-stacked ligand

摘要

The ligand 2,5-bis(2-pyridylmethylsulfanylmethyl)pyrazine (L) was prepared by the base coupling of 2-(sulfanylmethyl)pyridine and 2,5-bis(chloromethyl)pyrazine. This new ligand was treated with AgClO_4 in a 1:1 metal-to-ligand ratio and with AgNO_3 in a 2:1 metal-to-ligand ratio to give coordination polymers. The crystal structures of {[Ag(L)]ClO_4}_infinity (1) and {[Ag_2(L)](NO_3)_2}_infinity (2) were determined. The Ag(I) ions in the one-dimensional polymeric chains of 1 adopted square-pyramidal geometries with the pyridine and pyrazine N donors coordinated in an extremely bent fashion. The structure of 2 revealed two isomeric polymer chains in the one crystal forming a single supramolecular array. The isomeric polymers differed in the donor atoms about the Ag(I) ions and in the arangement of adjacent ligands aong the chain. A feature of both structures with that L adopted a three-layer #pi#-stacked arrangement.