Springer Online Journal Archives 1860-2000
Electrical Engineering, Measurement and Control Technology
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Abstract The introduction of eight alkoxy or eight alkyl substituents onto the phthalocyanine (Pc) nucleus at the non-peripheral (1,4,8,11,15,18,22,25) positions produces derivatives which are soluble in a variety of organic solvents. However, other physico-chemical properties of the two series differ. Octa-alkyl derivatives, R8 Pcs, pack as more ordered molecular assemblies in the solid state and show thermotropic liquid crystal behaviour with transition temperatures dependent upon substituent chain length and the central metal atom. In contrast, octa-alkoxy materials, (RO)8 Pcs, melt directly into the isotropic liquid. The latter can be deposited as Langmuir-Blodgett films whereas the former cannot. Experiments with examples of the two series in which one or two of the chains are functionalized at the terminal positions with a hydrophilic moiety show that these amphiphilic analogues deposit well by the Langmuir-Blodgett method. A number of the films show a high degree of molecular ordering, as judged by X-ray reflectivity methods, transmission infrared, RAIRS and polarized optical spectroscopy. Results indicate that the type of ordering is controlled by the type of substituent and the length of the chain.
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