Synthesis and investigation of polysubstituted triphenylenes with a predictable type of mesomorphism

This paper reports on synthesis and investigation of columnar mesophases of the new members of the homologous series of nitro and amino derivatives of hexaalkoxytriphenylenes, whose mesomorphism was predicted earlier. The for ecast is in good agreement with the experimental data. The effect of the in troduction of the donor and acceptor groups into the central fragment of tr iphenylene on the phase transition temperature, texture, and range of exist ence of columnar mesophases is examined. The predicting ability of the mole cular parameters suggested previously for the series under analysis is disc ussed. It is found that introduction of a nitro group, which is a strong el ectron acceptor, into the central fragment of triphenylene lowers the melti ng temperature of the compound versus its analog and does not promote colum nar mesomorphism in the lower nonmesomorphous homologs. At the same time, t his slightly expands the range of existence of the mesophase in higher homo logs.