Synthesis and Liquid-Crystal Behavior of Triazolephthalocyanines

Abstract

The synthesis, characterization, and mesomorphic properties of new discotic molecules based on the triazolephthalocyanine macrocycle are described. This core has been attached to six lipophilic chains, and metallic complexes (Ni, Cu) have been prepared. The mesogenic behavior has been studied using optical microscopy, DSC, and X-ray diffraction techniques. The hexaalkoxy-substituted triazolephthalocyanines exhibited hexagonal columnar mesophases with a high viscosity from room temperature up to decomposition temperature. Progressive formal replacement of alkoxy chains with alkylamide groups induces the lowering of the clearing point but gradually hinders mesomorphism. Mesomorphism is also suppressed when the compound is ionic.

Synthesis of Crowned Triazolephthalocyanines

“…[15,17,19] One reason of this behaviour could be the ease with which crown ethers form aggregates, thereby reducing the reactivity of the 1,3-diiminoisoindoline precursors and also resulting in the difficulties in the purification process. [15,17,19] One reason of this behaviour could be the ease with which crown ethers form aggregates, thereby reducing the reactivity of the 1,3-diiminoisoindoline precursors and also resulting in the difficulties in the purification process.…”

“…[17] Moreover, these compounds can be self-assembled by the LangmuirϪBlodgett technique, to afford in-plane organised films [18,19] with semiconducting properties, and can be applied as gassensor devices. [17] Moreover, these compounds can be self-assembled by the LangmuirϪBlodgett technique, to afford in-plane organised films [18,19] with semiconducting properties, and can be applied as gassensor devices.…”

Synthesis of Crowned Triazolephthalocyanines

“…[15,17,19] One reason of this behaviour could be the ease with which crown ethers form aggregates, thereby reducing the reactivity of the 1,3-diiminoisoindoline precursors and also resulting in the difficulties in the purification process. This trend is justified, since the lowest isolated yield corresponds to the triazolephthalocyanine 29 bearing three crown ethers.…”

“…Synthesis: Compounds 1, [36,37] 4, [38] 5, [37] 8, [33] 18, [41] and 22, [17,46] have been previously described. Starting materials were purchased from Aldrich Chemical Co. and used as received without further purification.…”

“…[17] Moreover, these compounds can be self-assembled by the LangmuirϪBlodgett technique, to afford in-plane organised films [18,19] with semiconducting properties, and can be applied as gassensor devices. [20] Two synthetic methodologies have been developed for obtaining Tpcs: a single-step metal template method, and a two-step method.…”