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001-es BibID:BIBFORM106867
035-os BibID:(Wos)000825749700001 (Scopus)85133129093
Első szerző:Dékány-Adamoczky Anita (anyagmérnök)
Cím:Isocyanonaphthol Derivatives: Excited-State Proton Transfer and Solvatochromic Properties / Anita Adamoczky, Tibor Nagy, Péter Pál Fehér, Veronika Pardi-Tóth, Ákos Kuki, Lajos Nagy, Miklos Zsuga, Sándor Kéki
Megjegyzések:Fluorescent probes that exhibit solvatochromic or excited-state proton-transfer (ESPT) prop- erties are essential tools for the study of complex biological or chemical systems. Herein, the synthesis and characterization of a novel fluorophore that reveals both features, 5-isocyanonaphthalene-1-ol (ICOL), are reported. Various solvatochromic methods, such as Lippert?Mataga and Bilot?Kawski, together with time-dependent density functional theory (TD-DFT) and time-resolved emission spec- troscopy (TRES), were applied to gain insights into its excited-state behavior. To make comparisons, the octyloxy derivative of ICOL, 5-isocyano-1-(octyloxy)naphthalene (ICON), was also prepared. We found that internal charge transfer (ICT) takes place between the isocyano and ?OH groups of ICOL, and we determined the values of the dipole moments for the ground and excited states of both ICOL and ICON. Furthermore, in the emission spectra of ICOL, a second band at higher wavelengths (green emission) in solvents of higher polarities (dual emission), in addition to the band present at lower wavelengths (blue emission), were observed. The extent of this dual emission increases in the order of 2-propanol < methanol < N,N-dimethylformamide (DMF) < dimethyl sulfoxide (DMSO). The presence of the dual fluorescence of ICOL in these solvents can be ascribed to ESPT. For ICOL, we also determined ground- and excited-state pKa values of 8.4 ? 0.3 and 0.9 ? 0.7, respectively, which indicates a considerable increase in acidity upon excitation. The TRES experiments showed that the excited-state lifetimes of the ICOL and ICON spanned from 10.1 ns to 5.0 ns and from 5.7 ns to 3.8 ns, respectively. In addition, we demonstrated that ICOL can be used as an effective indicator of not only the critical micelle concentration (cmc) of ionic (sodium lauryl sulfate (SLS)) and nonionic surfactants (Tween 80), but also other micellar parameters, such as partition coefficients, as well as to map the microenvironments in the cavities of biomacromolecules (e.g., BSA). It is also pointed out that fluorescence quenching by pyridine can effectively be utilized for the determination of the fractions of ICOL molecules that reside at the water?micelle interface and in the interior spaces of micelles.
Tárgyszavak:Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:International Journal Of Molecular Sciences. - 23 : 13 (2022), p. 7250-7272. -
További szerzők:Nagy Tibor (1988-) (vegyész) Fehér Péter Pál (1991-) (vegyész) Pardi-Tóth Veronika Cs. Kuki Ákos (1966-) (villamosmérnök) Nagy Lajos (1979-) (vegyész) Zsuga Miklós (1944-) (polimer kémikus) Kéki Sándor (1964-) (polimer kémikus)
Pályázati támogatás:K-132685
Internet cím:Szerző által megadott URL
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001-es BibID:BIBFORM064106
Első szerző:Nagy Tibor (vegyész)
Cím:Uncatalyzed reactions of 4,4·-diphenylmethane-diisocyanate with polymer polyols as revealed by matrix-assisted laser desorption/ionization mass spectrometry / Tibor Nagy, Borbala Antal, Anita Dekány-Adamoczky, Jozsef Karger-Kocsis, Miklos Zsuga, Sandor Kéki
Megjegyzések:The uncatalyzed reactions of polyols including polypropylene glycol (PPG, Mn = 2000 g/mol), polytetrahydrofuran (PTHF, Mn = 1000 g/mol), poly(?-caprolactone)-diol (PCLD, Mn = 2000 g/mol) and polypropylene glycol glycerol triether (PPG_GL, Mn = 1000 g/mol) with 4,4`-diphenylmethane-diisocyanate (MDI) were studied using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). The reactions between these polyols and MDI were monitored in time and first-order consecutive reaction kinetics for the formations of polyols end-capped with MDI units were established. The fractional MALDI-TOF MS intensities obtained for the different polymer series at various reaction times were converted into molar fractions versus time data by means of the estimated relative MALDI-TOF MS response factors from which the corresponding rate constants and the relative reactivities of the hydroxyl groups of polyols were determined. It was found that the pseudo first-order rate constants for the polyol-MDI reaction decreased in the order of PCLD > PTHF > PPG ? PPG_GL. It was also ascertained that the reactivity of the unreacted hydroxyl groups of the diols does not change significantly after the first one has been reacted. On the contrary, in the case of PPG_GL it was found that the reactions of the hydroxyl groups with MDI proceed faster after either of the three hydroxyl groups has been reacted, suggesting positive substitution effect for this system.
Tárgyszavak:Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:RSC Advances. - 6 : 52 (2016), p. 47023-47032. -
További szerzők:Antal Borbála (1988-) (vegyész) Dékány-Adamoczky Anita (1985-) (anyagmérnök) Karger-Kocsis József (1950-) (vegyészmérnök) Zsuga Miklós (1944-) (polimer kémikus) Kéki Sándor (1964-) (polimer kémikus)
Pályázati támogatás:K-101850
Internet cím:Szerző által megadott URL
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