Blood Pressure and Age Are the Main Determinants of Aortic Stiffness

WOS: 000418303200017PubMed ID: 28982100

Synthesis and spectroscopic properties of a novel perylenediimide derivative

A novel symmetric 3,4,9,10-perylenetetracarboxylic acid derivative (PDI1) dye based on thiophene donor group was synthesized and characterized by FT-IR and 1H NMR. Cyclic Voltammetry analysis is performed to determine the energy levels of the perylene derivative. Optical characteristics were determined by visible absorption and fluorescence emission spectra. Spectral behavior and fluorescence quantum yield of PDI1 have been measured in different solvents. The dye exhibits high fluorescence quantum yield ( Φf: 0.94-0.99). But the quantum yield PDI1 is very low in the n-butanol solution ( Φf: 0.12). The photophysical properties have important implications for use in a variety of electroactive and photovoltaic applications. A photovoltaic device was fabricated with PDI1 as transporting material. The conversion efficiency for DSSC sensitized by PDI1 is 0.0065%. PDI1 exhibits electrochromic behavior by switching between neutral (red) and oxidized (blue) states. Electron transfer capacity of PDI to the TiO2 was investigated by incorporation of dye as sensitizer in dye sensitized solar cell (DSSC). Soluble dye molecules are very important to prepare dye sensitized solar cell. Solubility was increased with thiophene group

Fluorescence quantum yields of perylene 3,4,9,10-tetracarboxylic acid-bis-n,n’ aryl(alkyl)diimides

The synthesized perylenes 3,4,9,10-tetracarboxylic acid N,N'-ethyl, phenyl, ?-anisyl, ?-naphthyl and acetyl diimides have shown great variations in absorption and emission spectra. The variation in molar extinction coefficients and fluorescence quantum yields have indicated that steric and electronic effects, caused by N-substitution, alters emission characteristics of perylene diimides significandy. © 1994, Taylor & Francis Group, LLC. All rights reserved

Synthesis and properties of alkyl chain substituted naphthalenetetracarboxylic monoanhydride monoimides and unsymmetrically substituted naphthalene derivatives

1,4,5,8-Naphthalenedianhydride is converted to N-(2-ethylhexyl)-1,4,5,8-naphthalenetetracarboxylic monoanhydride monoimide (2a) and N-(2-hydroxyethyl)-1,4,5,8-naphthalenetetracarboxylic monoanhydride monoimide (2c) through the potassium salt prepared from a reaction with potassium hydroxide. N-Dodecyl-1,4,5,8-naphthalenetetracarboxylic monoanhydride monoimide (2b) was prepared by the condensation reaction of 1,4,5,8-naphthalenedianhydride with dodecylamine. Naphthalene-1,4-N-(2-ethylhexyl)-imide-N-ethyl-1H-benzo[d]imidazol-5-carboxylate and naphthalene-1,4-N-dodecyl-imide-N-ethyl-1H-benzo[d]imidazol-5-carboxylate were prepared by the condensation reaction of N-alkyl-1,4,5,8-naphthalenetetracarboxylic monoanhydride monoimide (alkyl = 2-ethylhexyl and dodecyl) with ethyl 3,4-diaminobenzoate. Molecular structures and electrochemical properties of all naphthalene derivatives were determined. Their thermal properties were also studied by thermal gravimetric analysis. © 2016, Chemical Publishing Co. All rights reserved

High rates of fluorescence quenching between perylene dodecyldiimide and certain ?-electron donors

Perylene bis-n-dodecyl diimide is found to quench fluorescenc emissions of naphthalene, phenanthrene and dihydrocarbazolocarbazole molecules at rates of 4.4×1011 , 2.8×1012 and 2.5×104 M-1 sec-1 , in respective order of aromaticity. These unusulally high rates of fluorecence quenchings are attributed to Perrin model static quenching and presence of electron transfer through singlet excited state of perylene diimide. Calculated free energy of electron transfer, ? G ET=-120.5 kJ/mol, between perylene diimide and dihydrocarbazolocarbazole is taken as evidence for observation of high fluorescence quenching rate for carbazolocarbazole molecule

Studies on photophysical and electrochemical properties of synthesized hydroxy perylenediimides in nanostructured titania thin films

Four new bis-N-hydroxyalkyl perylenediimide derivatives (PDIs) have been synthesized and were characterized by UV-vis, IR, 1H and 13C NMR, FAB Mass, DTA/TGA and CV measurements. Their photophysical properties were determined in solution phase and in sol-gel matrix. The fluorescence life times were measured to be in the range of 2.2-4.7ns. Both electron acceptor (Co2+) and donor (anthracence) were used for solution phase fluorescence emission quenching experiments. The calculated quenching rate constants (kqs) for fluorescence quenching between Co2+, anthracence, iodide and synthesized hydroxy PDI derivatives were around 1010 and 109M-1s-1 in solutions. Quenching experiment of PDI on titania thin film with the aqueous solution of Co2+ and iodide ion gave the similar quenching rates. The free energies of exothermic photo-electron transfer (ET) processes between PDI and Co2+ ions [-22.1-(-27.2) kcalmol-1] were approximately two fold of the corresponding value between anthracene and PDI derivatives [-10.9-(-16.4) kcalmol-1] and half of the value between PDI and KI [-44.0-(-46.5) kcalmol-1]. The LUMO energy values, determined by cyclic voltammetry were between -3.5 and -3.7, which have shown two reversible reduction steps (versus Fc) in solution. The precursors used for sol-gel matrix preparation were tetraisopropyl-orthotitanate in TP, and a mixture of GLYMO (30%) and tetraisopropyl-orthotitanate (70%) in TG. In TP type of coatings, the maximum single film thickness was 0.3µm. TG type of coatings have no such limitation and more advantageous. An efficient ET is being observed between the PDI derivatives immobilised in TG and Co2+ and KI in water with kq values of around 1010 and 109M -1s-1, respectively. The substituted hydroxyl groups in synthesized PDI derivatives are found to increase the solubilities in sol-gel matrix. Overall results prove that bis-N-hydroxyalkyl substituted perylene diimides are suitable for applications in Graetzel type dye sensitized solar cells. © 2004 Elsevier B.V. All rights reserved.Devlet Planlama Örgütü Alexander von Humboldt-Stiftung National Council for Scientific ResearchWe thank Professor Christopher S. Foote for providing some of the spectroscopic measurements at their laboratory and Dr. Tanju Varlikli for the proof reading. We acknowledge NATO A-2 support funds of the Scientific Research Council of Turkey (TUBITAK) and Alexander von Humboldt Foundation of Germany. We appreciate the project support funds of Research Center of Ege University (EBILTEM), the State Planning Organization of Turkey (DPT). -

Photochemical reactions of ?-terpinene and acenaphthene under concentrated sunlight

?-Terpinene was successfully dehydrogenated to p-cymene in photocatalytic reaction with benzophenone and cupric ions under 40 suns concentrated sunlight irradiation, proving that photodehydrogenation reactions may be employed for the synthesis of fine chemicals under sunlight. Acenaphthene dehydrogenation under concentrated sunlight resulted in the minor formation of acenaphthylene and the quantitative formation of acenaphthenone when the solution was aerated. Stable benzylic-type radical intermediates are thought to lower the yield of dehydrogenation reactions

The study of the solubility of naphthalene diimides with various bulky flanking substituents in different solvents by UV-vis spectroscopy

A systematic quantitative study of the solubility of various naphthalene diimides in apolar and polar solvents with different lipophilicity has been done by means of UV-vis spectroscopy. It has been found that the most soluble naphthalene diimide derivative is N,N'-bis(dehydroabietyl)-1,4,5,8-naphthalene diimide. The conclusion that the introduction of bulky aliphatic substituents is the most appropriate way to improve the solubility of naphthalene diimides has been made. It has been estimated that, in contrast to the case of bulky alkyl substituents, the introduction of bulky aryl substituents does not increase the naphthalene diimide solubility considerably. © 2004 Elsevier Ltd. All rights reserved.Alexander von Humboldt-StiftungWe thank the Scientific and Technical Research Council of Turkey (TUBITAK) and the Alexander von Humboldt Foundation of Germany for research supports. -