Agnieszka Lipke

Thermal and photoluminescence analysis of a methacrylic diester derivative of naphthalene-2,7-diol

The synthesis and thermal and optical properties of a new type of photoluminescent monomer of 2,7-bis[2-(2-hydroxy-3-methacryloyloxypropoxy)propoxy]naphthalene (2,7-NAF.PMEM) are presented. The chemical structure of 2,7-NAF.PMEM was confirmed by 1H and 13C NMR analysis and ATR-FTIR spectroscopy. Next, bulk copolymers were synthesized using two comonomers, methyl methacrylate and styrene. These monomers were chosen because of their good optical properties (high visible light transparency). The thermal properties of the new copolymers were studied by the TG/DSC/QMS-coupled method in an inert atmosphere. The UV–Vis absorption and luminescence spectra of the obtained polymers were registered and evaluated. The 510-nm luminescence band was observed independently of the kind of monomer and its concentration.

Non-covalent interactions between thio-caffeine derivatives and water-soluble porphyrin in ethanol-water environment

To determine the binding interactions and ability to form the non-covalent systems, the association process between 5,10,15,20-tetrakis[4-(trimethylammonio)phenyl]-21H,23H-porphine tetra-p-tosylate (H2TTMePP) and a series of five structurally diverse thio-caffeine analogues has been studied in ethanol and ethanol-water solutions, analyzing its absorption and steady-state fluorescence spectra. The porphyrin fluorescence lifetimes in the systems studied were established as well. During the titration with thio-caffeine compounds the slight bathochromic effect and considerable hypochromicity of the porphyrin Soret band maximum can be noted. The fluorescence quenching effect observed for interactions in H2TTMePP - thio-caffeine derivative systems, as well as the order of binding and fluorescence quenching constants (of 105-103mol-1) suggest the existence of the mechanism of static quenching due to the formation of non-covalent and non-fluorescent stacking complexes. In all the systems studied the phenomenon of the fractional accessibility of the fluorophore for the quencher was observed as well. Additionally, the specific binding interactions, due to the changes in reaction environment polarity, can be observed. It was found that thio-caffeine compounds can quench the porphyrin fluorescence according to the structure of thio-substituent in caffeine molecule. The obtained results can be potentially useful from scientific, therapeutic or environmental points of view.

Synthesis of chiral porphyrins and their use in photochemical oxidation of carbonyl compounds

A series of chiral A4, A2B2, and AB3 porphyrins bearing proline moieties at the meso-phenyl group has been synthesized. Photostability studies revealed that the number of L-proline units and their position on meso-phenyl rings strongly influence the decomposition rate of the catalyst. 5,10,15-Tris(mesityl)-20-(3-prolinanilidylphenyl)-21,23H-porphyrin is the most stable while porphyrin bearing four 3-prolinanilidylphenyl substituents completely decomposes in CHCl3 within 3 h. Singlet oxygen quantum yields of the conjugates were determined by measuring the peak areas of the NIR emission of 1O2 (1280 nm) generated by these compounds and compared to that generated by the reference standard TPP. Selected porphyrins were tested as catalysts in the photooxidation of carbonyl compounds at the α-position.

Naphthalene sorption on red clay and halloysite modified by quaternary ammonium salts

Sorption of naphthalene on modified red clay and halloysite was carried out successfully. It was established that the process was of pseudo-second-order mechanism. The maximum sorption capacities were 9.23 mg/g and 112.79 mg/g for red clay and halloysite, respectively.

Immobilization of Polymeric Luminophor on Nanoparticles Surface.

Polymeric luminophors with reduced toxicity are of the priorities in the production of lighting devices, sensors, detectors, bioassays or diagnostic systems. The aim of this study was to develop a method of immobilization of the new luminophor on a surface of nanoparticles and investigation of the structure of the grafted layer. Monomer 2,7-(2-hydroxy-3-methacryloyloxypropoxy)naphthalene (2,7-NAF.DM) with luminophoric properties was immobilized on silica and carbon nanotubes in two ways: mechanical mixing with previously obtained polymer and by in situ oligomerization with chemisorption after carrier’s modification with vinyl groups. The attached polymeric (or oligomeric) surface layer was studied using thermal and spectral techniques. Obtained results confirm the chemisorption of luminophor on the nanotubes and silica nanoparticles at the elaborated synthesis techniques. The microstructure of 2,7-NAF.DM molecules after chemisorption was found to be not changed. The elaborated modification approach allows one to obtain nanoparticles uniformly covered with polymeric luminophor.