Abstract
The work described in this thesis is concerned with condensation reactions between phthalonitrile and biscyanomethylene substituted compounds with a view to synthesising methine linked macrocycles analogous to the series of well known aza-linked macrocycles which have been well characterized and extensively investigated. Another objective was to prepare condensation products which might serve as monomers for possible polymeric materials. Model condensation reactions were carried out, using phthalo-nitrile and benzyl cyanide as reactants, in order to establish the necessary conditions for condensation to take place. Two and 'three-unit' condensation products were obtained and their structure was investigated. Using the established reaction conditions,phthalonitrile was reacted with p-dicyanoxylylene, m-dicyanoxylylene, 2,6-biscyanomethylpyridine and 4,4-di(cyanomethyl)phenyl ether. In each case only the 'two-unit' and 'three-unit' condensation products were obtained. No evidence of macrocycle formation was found even when very stringent reaction conditions were employed. Attempts to synthesise macrocycles by 'ring-closure' of the 'three-unit'' bis-isoindoline compounds, by reacting them with the appropriate dicyanomethylene compound or aromatic diamines were also unsuccessful. However, m-di [cyano-(3-imino-l-isoindoleninyl) methyl] benzene reacted with 1,3-diiminoisoindoline to give the di-methine linked macrocycle. Among the model compounds prepared were the 'two-unit' and 'three-unit' condensation products from the reaction of phthalonitrile with 3-cyanomethyl-5-pheny1-1-2,4-triazole and 2-cyanomethylthiophene. These products had the expected characteristics. Attempted synthesis of 3,5-biscyanomethy1-1-2,4-triazole gave an anomalous product which spectroscopic analysis proved to be 2-cyanomethyl-4,6-diaminopyrimidine. This compound failed to condense with phthalonitrile. The reaction of 2,5-biscyanomethyl-thiophene with phthalo-nitrile in 2-ethoxyethanol containing sodium as catalyst gave a mixture of polycondensation products.