5,5′-Dicyano-2,2′-bithiophene and 3,3′-dicyanobiphenyl: off-axis rod-like ligands for silver(I)

Abstract

The two ligands 3,3′-dicyanobiphenyl (3) and 5,5′-dicyano-2,2′-bithiophene (4) are geometrically similar but give rise to different coordination compounds when reacted with silver(I) salts. The crystal structures of 3·AgClO₄ and 3·AgBF₄ have 1 : 1 ligand : cation ratios, while 4₂·ClO₄ and 4₂·BF₄ have 2 : 1 ligand : cation ratios. These ratios for the solid-state materials were constant, even when different stoichiometric ratios were used in the reaction vessels. The structures of these four coordination compounds are presented and the reasons for the difference in the coordination environments discussed with reference to IR spectroscopic and DFT computational results.