SYNTHESIS AND SUPRAMOLECULAR CHEMISTRY OF NOVEL LIQUID-CRYSTALLINE CROWN ETHER-SUBSTITUTED PHTHALOCYANINES - TOWARD MOLECULAR WIRES AND MOLECULAR IONOELECTRONICS

The synthesis of the metal-free and the dihydroxysilicon derivatives o f s[4',5'-bis(decoxy)benzo-18-crown-6]phthalocyanine is described. The metal-free phthalocyanine is liquid crystalline and exhibits a crysta lline phase to mesophase transition at 148 degrees C. The structures o f the crystalline phase and the mesophase are determined by X-ray meas urements. The metal-free compound strongly aggregates in chloroform so lution to form a gel. Electron micrographs show that this gel contains a network of fibers, each of which is built up of parallel strands of supermolecules having the thickness of one molecule and a length of s everal micrometers. The strands are formed by a process of self-assemb ly involving up to 10(4) molecules. They can be considered as being mo lecular cables, containing a central electron wire, four ion channels, and a surrounding insulating hydrocarbon mantle. The silicon derivati ve contains two axial hydroxy groups which prevent the molecule from a ggregating. This compound is not liquid crystalline. It forms a stable monolayer at the air-water interface. In this layer, the phthalocyani ne planes are oriented parallel to the water surface. The monolayers c an be transferred onto glass substrates by a Y-type deposition. The re sulting Langmuir-Blodgett film is built up of bilayers containing slip ped face-to-face phthalocyanine dimers. The monolayer is capable of bi nding alkali metal ions from the subphase, as is concluded from surfac e area-surface pressure isotherms. The binding constant for potassium ions has been determined by analyzing the isotherms as a function of t he concentration of this metal ion. The dihydroxysilicon phthalocyanin e can be polymerized to form a polysiloxane.