Mesomorphic silver( i ) complexes of 4-alkyloxy-2′-stilbazoles and 4-alkyloxy-3′-stilbazoles. Crystal and molecular structure of 4-methoxy-2′-stilbazole

Three new series of silver(I) complexes [AgL2][X] have been synthesised and their mesomorphism has been established. The new compounds were obtained by the complexation of 4-alkyloxy-3′-stilbazole and 4-alkyloxy-2′-stilbazole ligands, respectively, to silver(I) dodecyl sulfate (DOS), and to silver(I) triflate (OTf). Thus, they differ from previously reported 4-alkyloxy-4′-stilbazole silver complexes in that the new stilbazole ligands are isomers by virtue of having the 4-alkyloxystyryl group attached to the pyridine ring in the 2- or 3-position. The complexes are mesomorphic, displaying only a smectic A phase providing that a sufficient number of carbon atoms are present in the terminal aliphatic chain. The thermal behaviour observed for the new isomeric series is compared and discussed on the basis of simple structural arguments which account for the differences in mesomorphism and stability.