Synthesis and characterization of binuclear and unsymmetrical phthalocyanines
"The metal free planar binuclear phthalocyanines sharing a benzene or naphthalene ring have been synthesized and characterized. The position of Q band of binuclear phthalocyanine sharing a naphthalene ring is red shifted compared to binuclear phthalocyanine sharing a benzene ring. The compounds are shown to form the liquid crystal mesophases at room temperature. The unique unsymmetrical phthalocyanines with steric hindrance tetraphenyl or “opposite” octaphenyl substitution have been synthesized with the aid of computer modeling. The compounds are characterized by UV-visible near IR absorption and NMR spectroscopy. Mesophase is observed by optical microscopy and differential scanning calorimetry. The aggregation behavior has been studied as a function of solvent polarity by absorption and emission spectra. The aggregation is decreased in order of symmetrical octakis (dodecyloxy) phthalocyanine, unsymmetrical tetraphenyl substituted phthalocyanine and “opposite” octa phenyl substituted phthalocyanine with increasing solvent polarity. Proton magnetic resonance spectra have been used to examine the aggregation processes of phthalocyanines in non-aqueous solution. Depending on the different molecular structure and specific solvent used, the positions of cavity protons are shifted to upper or lower field as the concentration increases. The most favored geometry of the aggregation in solution has been qualitatively postulated based on these observations"--Abstract, p. iii
Missouri University of Science and Technology
Networked Digital Library of Theses and Dissertations