Mesomorphic stilbazole complexes of silver octyl sulfate. Crystal and molecular structure of bis[4-(4-methoxystyryl)pyridinato]silver(I) octyl sulfate hemihydrate

Reaction of the salts bis[4-(4-alkoxystyryl)pyridinato]silver(I) trifluoromethanesulfonate {[Ag(n-OPhVPy)2][CF3SO3]} with sodium octyl sulfate (NaOS) in acetone leads to the metathesised product [Ag(n-OPhVPy)2][OS] in good yield. These octylsulfate salts are mesomorphic showing a nematic phase at short chain lengths and SC and SA phases at longer chain lengths. The single-crystal X-ray structure of the methoxy homologue has four molecules in the unit cell which are arranged as two crystallographically independent, centrosymmetric pairs linked by a hydrogen-bonded water molecule. Each pair of silver atoms is bridged by two sulfate groups with Ag — O distances longer than those normally associated with covalent bonds.