Polymethiniove systemy

PhD thesis work describes synthesis and properties of polymethines, especially with pentamethinium and trimethinium salts. These compounds play an important role like building blocks (synthons) in the synthesis of heterocyclic compounds (e. g. 1-pyridinium salts, pyrimidines), organic dyes (cyanine dyes), there are also important due to their physical properties (photo-optical properties). In this work preparations of 2-substituted pentamethinium salts by the reactions of 3-substituted 1-(2,4-dinitrophenyl)pyridinium salts with dimethylamine (dimethylamonium-N,N-dimethylcarbamate) are described. Nucleophylic ring opening reactions of dinitrophenyl-pyridinium salts with secondary amine (dimethylamine) have been studied with attention to substitution of the starting pyridinium salts. This study provides the comparison of reactivity of OH nucleophile (aqueous K2CO3) towards starting pyridinium salt. Regioselectivity of these reactions (affording dinitroanilinopentadienals) is also described. Electron-withdrawing-group substituting pentamethinium salts were prepared by condensation reactions of 3-dimethylaminoacrylic acid derivatives (or analogues) with 3-dimethylaminoprop-2-enal. Synthesis of starting compounds and scope of these reactions is discussed. The new synthetic method of preparation of polymethinium tetrafluoroborates was discovered, using conversion of aminopolyenals in presence of BF3.Et2O and dimethylamine. 1- and 2- substituted trimethinium salts were prepared by Vilsmeyer-Haack-Arnold formylation reactions of substituted acetic acids and by reactions of 3-dimethylaminoprop-2-enones. Selected pentamethinium salts were studied in details by spectroscopic methods (NMR, UV, IR, Raman spectroscopy), results were correlated with quantum-chemical calculations. Selected pentamethinium and trimethinium salts are tested for their photo-conductivity behaviour and as potential ion-polymerisation initiatorsAvailable from STL Prague, CZ / NTK - National Technical LibrarySIGLECZCzech Republi