Mesomorphic Transition Metal N₂O₂ Chelates

Abstract

The first class of transition metal N₂O₂ liquid crystals are reported. They are synthesized as the alkyl ethers of N,N'-bis(5-hydroxysalicylidene) ethylene diamine Mt^|| complexes (Salen-Mt-n) containing either Cu^|| or Ni^||. Both series were prepared with pentyl through nonyl alkane units. All complexes except Salen-Cu-5 exhibit liquid crystallinity. Decomposition controls the thermal behavior in the Salen-Cu-n complex series with degradation occurring several degrees above the clearing point. Smectic mesomorphism is found in all liquid crystalline chelates. The differences in the thermal characteristics between Salen-Cu-n and Salen-Ni-n chelates is attributed to the different electronic structures of the chelated metals. This behavior exemplifies the influence of the metal upon mesomorphic properties.