Synthesis, Characterization, and Dielectric Properties of Phthalocyanines with Ester and Carboxylic Acid Functionalities

Autor:	Martin Molberg, Frank Nüesch, Matthias Nagel, Dorina M. Opris, Christiane Löwe
Rok vydání:	2008
Předmět:	chemistry.chemical_classification Materials science General Chemical Engineering Carboxylic acid Inorganic chemistry Pellets chemistry.chemical_element General Chemistry Dielectric Conductivity Oxygen chemistry.chemical_compound Hydrolysis Monomer chemistry Materials Chemistry Phthalocyanine
Zdroj:	Chemistry of Materials. 20:6889-6896
ISSN:	1520-5002 0897-4756
DOI:	10.1021/cm801871t
Popis:	Monomeric phthalocyanine pentylester derivatives containing Cu and Zn were synthesized via the cyclotetramerization of 4,5-dipentylphthalonitrile. Conversion of the pentylester derivatives by hydrolysis yielded the octacarboxylic acid phthalocyanine derivatives in high purity, without any contamination by oligomers. The dielectric properties of pressed pellets were investigated as a function of frequency. When exposing the phthalocyanine powders to water vapor, a high increase in the dielectric constant was found for the carboxylic acid derivatives, whereas the esters showed no effect. For Cu containing octacarboxylic acid phthalocyanine derivatives, the low-frequency dielectric constant of the pellets was raised from 12 to >1 × 105 when going from a water content of 6.4 to 14.7 wt %, respectively. The concomitant sharp rise in conductivity was attributed to the protons released from the acid groups after water uptake. The present work clearly demonstrates that water uptake and not oxygen is the major fac...
Databáze:	OpenAIRE
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