Triflate anion and ligand influences in silver(i) coordination polymers of four isomeric dipyridyl ketone oximes

Abstract

The synthesis and X-ray characterisation of four isomeric dipyridyl ketone oxime ligands, 4,4′-dipyridyl ketone oxime, L44, 3,3′-dipyridyl ketone oxime, L33, 2,4-dipyridyl ketone oxime, L24 and 2,3-dipyridyl ketone oxime, L23 is described. X-ray structural characterisation of the precursor ketones 3,3′-dipyridyl ketone, L1, and 2,4-dipyridyl ketone, L2, is also reported for comparison. Four AgCF3SO3 complexes of the dipyridyl ketone oxime ligands were prepared and structurally characterised, [Ag(L44)2](CF3SO3), 1, {[AgL33](CF3SO3)}∞, 2, [AgL24(CF3SO3)]∞, 3, and [Ag2L23(CF3SO3)2]∞, 4. The structural role of the CF3SO3− anion in the formation of Ag(I) coordination polymer networks, together with the effect of the varying pyridyl substitution patterns of L44, L33, L24 and L23 was investigated. In 1 the CF3SO3− anion was unbound and disordered. It was encapsulated in the channels of a honeycomb 3D H-bonded structure. In 2 the CF3SO3− anion remained unbound, being encapsulated within the centre of a helical polymer chain. In 3 the CF3SO3− anion was weakly bound to the Ag(I) ion and as such decorated the side of a bowed 1-D chain. The two different CF3SO3− anions in 4 adopted a range of binding modes from monodentate, bis-monodentate to tris-monodentate with the Ag(I) ions and gave rise to the formation of an unusual CF3SO3− bridged 2-D network.