Discotic Liquid Crystals of Organic Metal Complexes (51) : Synthesis and Mesophase Structures of Octakis(3,4-dialkoxyphenyl)tetrapyrazinoporphyrazinato metal(II) Complexes and Their Ring-closed Complexes

Abstract

Liquid crystals of phthalocyanines and their analogues have been demonstrated to be particularly attractive materials due to their extended two-dimensional π-conjugated electron system and their ali9nment in one-dimensional columnar stacks. We report here the synthesis and mesophase structures of octakis(3,4-dialkoxyphenyl)-tetrapyrazinoporphyrazinato metal(II) complexes, 1, and their corresponding ring-closed complexes, 2, with a widely extended core peripherally bearing sixteen n-alkoxy chains. All of them exhibit columnar mesophases. Interestingly, the mesophase structures of Complexes, 1, are strongly related to the structures of the aggregates in solvents. Complexes, 1, have a very rare structure of "slipped-roof-top-shaped dimer" in both the n-hexane solution and the D_hd columnar mesophase, whereas Complexes, 2, do not have such a unique structure.