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Rybitví, Czech Republic

Rais D.,Czech Institute of Macromolecular Chemical | Toman P.,Czech Institute of Macromolecular Chemical | Cerny J.,Center for Organic Chemistry Ltd. | Mensik M.,Czech Institute of Macromolecular Chemical | Pfleger J.,Czech Institute of Macromolecular Chemical
Journal of Physical Chemistry A

Nickel phthalocyanine (NiPc) complexes are known to show a rapid nonradiative deactivation of the photoexcited state through the internal conversion. This could be exploited in practical applications, such as photoprotection and photodynamic therapy. The butoxy substitution of NiPc plays an important role for drug delivery but also greatly influences its photophysics. We prepared novel peripherally substituted 2,3,9,10,16,17,23,24- octabutoxy nickel(II) phthalocyanine and characterized the deactivation pathway of its photoexcited state in solution by femtosecond transient absorption spectroscopy and quantum chemical calculations. We bring experimental evidence for the kinetic model, in which the photoexcitation evolves in two independent branches. In the first branch, assigned to the monomer, it undergoes ultrafast intersystem crossing to a triplet state, which subsequently decays to the ground state through a pathway involving lower-lying triplet states, with a ground-state recovery lifetime of 814 ps. It is about three-times longer than the lifetime published for unsubstituted NiPc. In the second branch, the photoexcitation decayed to a triplet state with an orders of magnitude longer lifetime, with the quantum yield of about 4%. This state showed spectral features of J-aggregates. These findings are important for the applications that rely on singlet oxygen formation or fast nonradiative deactivation of the excited state. © 2014 American Chemical Society. Source

Pospisil P.,Czech Institute of Macromolecular Chemical | Tomsik E.,Czech Institute of Macromolecular Chemical | Nespurek S.,Czech Institute of Macromolecular Chemical | Kubac L.,Center for Organic Chemistry Ltd.
Journal of Nanostructured Polymers and Nanocomposites

Hydroxymethylated-3,4-ethylenedioxythiophene (EDOT-MeOH) was polymerized by chemical oxidation. The following oxidants were used: ammonium peroxydisulfate (APS) and iron(III) chloride hexahydrate.The polymerizations were carried out in 0.2 M hydrochloric aqueous solution or in tetrahydrofuran. Electrical conductivity, which is one of the most important parameters of conducting polymers, depends on the conditions of preparation. The highest conductivity was obtained in material polymerized in aqueous solution by APS oxidation; it was 1.8 S/cm. Thermogravimetric analysis and UV-Vis spectroscopy were used to characterize the polymers. Source

Freisleben J.,University of West Bohemia | Hamacek A.,University of West Bohemia | Vik R.,University of West Bohemia | Cerny J.,Center for Organic Chemistry Ltd. | And 2 more authors.
Proceedings of the International Spring Seminar on Electronics Technology

This article deals with the research of singlet oxygen generation using phthalocyanine photosensitizer. Singlet oxygen is extraordinary reactive and can be used in many applications such as photodynamic therapy, disinfection or chemical synthesis. For singlet oxygen generation, the photosensitized method in a new developed generator based on LED emitters was used. The amount of singlet oxygen generated by LED emitters was compared with laser excitation. The principle of measurement, design of a singlet oxygen generator and control unit are discussed in more detail. © 2012 IEEE. Source

Kubac L.,Center for Organic Chemistry Ltd. | Akrman J.,Center for Organic Chemistry Ltd. | Horalek J.,SYNPO A.s. | Martinkova L.,INOTEX Ltd | Wiener J.,Technical University of Liberec
NANOCON 2013 - Conference Proceedings, 5th International Conference

Long-term stable self-cleaning system for textile fabrics was developed and tested. The system consists of photoactive TiO2 nanoparticles and a carrier polymeric system, which is resistant against activity of free radicals coming from interactions of TiO2 nanoparticles and UV radiation. This newly developed system was tested separately or in combination with formulations determined for multifunctional effects (hydrophobic, self-cleaning, non-flammable). The system has a high self-cleaning efficiency under sun as well as artificial light. Source

Frebort S.,University of Pardubice | Frebort S.,Center for Organic Chemistry Ltd. | Elias Z.,University of Pardubice | Lycka A.,Center for Organic Chemistry Ltd. | And 6 more authors.
Tetrahedron Letters

The alkylation of 3-phenyl-6-(2-thienyl)pyrrolo[3,4-c]pyrrole-1,4-dione with 1-bromo-2-ethylhexane was performed. Besides the expected N,N0-dialkylated product, both possible N,O-dialkyl derivatives were isolated and identified for the first time. The position of the alkyl substituents in all three dialkylated isomers was determined by 2D 1H and 13C NMR spectroscopy. © 2011 Elsevier Ltd. All rights reserved. Source

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