4-Bromo- and 4,5-dibromo-3,6-dibutoxyphthalonitrile have been prepared and treated with 3,6-didecylphthalonitrile in cross tetramerisation reactions in the presence of nickel acetate to afford monobromo- and dibromo-dibutoxyhexadecylphthalocyaninato nickel(II) complexes. Sonogashira and Stille coupling reactions on these compounds displaced the bromine substituents by ethynyl groups. Oxidative coupling of the monoethynyl derivatised nickel phthalocyanine afforded a butadiynyl-linked dinuclear phthalocyanine. The corresponding coupling reaction of the diethynylated phthalocyanine gave a mixture of phthalocyaninodehydroannulenes. Separation of the mixture yielded the diphthalocyaninodehydroannulene as the major product. Electrospray mass spectrometry provides evidence for its aggregation in solution. The corresponding cyclic trimer, the triphthalocyaninodehydroannulene. has been identified as a minor product. Both compounds show a large splitting of the Q-band absorption in the visible region spectrum, Most of the mononuclear phthalocyanine precursors exhibit discotic liquid crystal behaviour. The diphthalocyaninodehydroannulene also enters a mobile phase on heating, hut undergoes an irreversible change at 220 degreesC. MALDI-TOF mass spectrometry of the product reveals that the compound undergoes oligomerisation at this temperature.
|Number of pages||10|
|Journal||Chemistry - A European Journal|
|Publication status||Published - 2000|