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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
Dátum:	2022
ISSN:	1422-0067
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 folyóiratcikk
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 Csilla Kuki Ákos (1966-) (villamosmérnök) Nagy Lajos (1979-) (vegyész) Zsuga Miklós (1944-) (polimer kémikus) Kéki Sándor (1964-) (polimer kémikus)
Pályázati támogatás:	K-132685 OTKA K-132236 OTKA
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001-es BibID:	BIBFORM089662
035-os BibID:	(cikkazonosító)5588 (scopus)85089170694 (wos)000558993700001
Első szerző:	Dékány-Adamoczky Anita (anyagmérnök)
Cím:	Conversion of Isocyanide to Amine in The Presence of Water and Hg(II) Ions: Kinetics and Mechanism as Detected by Fluorescence Spectroscopy and Mass Spectrometry / Anita Adamoczky, Lajos Nagy, Miklós Nagy, Miklós Zsuga, Sándor Kéki
Dátum:	2020
ISSN:	1661-6596 1422-0067
Megjegyzések:	Aromatic isocyanides including isocyanonaphthalene derivatives have been proven to be very effective fluorescent sensors for the quantification of Hg(II) ions in water. Thus, the reaction of 1,5-isocyanoaminonaphthalene (1,5-ICAN), which is one of the most important members of this family, with water and HgCl2 as the oxidation agents, was studied by fluorescence spectroscopy and mass spectrometry in order to get deeper insight into the kinetics and mechanistic details of this complex reaction. The reactions of 1,5-ICAN with water and HgCl2 were performed in various water/co-solvent mixtures of different compositions. The co-solvents used in this study were both aprotic solvents including tetrahydrofuran, acetonitrile and N,N-dimethylformamide and protic solvents, such as ethanol and 2-propanol. It was found that in aprotic solvents the conversion of the isocyano group to amino moiety takes place, while in protic solvents the corresponding carbamate (urethane) group is formed in addition to the amino moiety. The variation of the resulting fluorescence intensities versus time curves were described using an irreversible, consecutive reaction model, in which the formation of isocyanate and carbamic acid intermediates, as well as diamino and carbamate (in the case of protic solvents) products were assumed. The formation of these intermediates and products was unambiguously confirmed by mass spectrometric measurements. Furthermore, by fitting the model to the experimental fluorescence versus time curves, the corresponding rate coefficients were determined. It was observed that the overall rate of transformation of the isocyano group to amino moiety increased with the water concentration and the polarity of the co-solvent. It was also supported that formation of diamino and carbamate derivatives in protic solvents takes place simultaneously and that the ratio of the amino to the carbamate function increased with the increasing water concentration. In addition, with an extension, the model presented herein proved to be capable of describing the kinetics of the transformation of 1,5-diisocyanonaphthalene (1,5-DIN) into 1,5-diaminonaphthalene (1,5-DAN) in the mixtures of water/aprotic solvents.
Tárgyszavak:	Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban folyóiratcikk steady-state fluorescence kinetics isocyanoaminonaphthalenes HgCl2 carbamic acid carbamate isocyanate
Megjelenés:	International Journal of Molecular Sciences. - 21 : 15 (2020), p. 1-14. -
További szerzők:	Nagy Lajos (1979-) (vegyész) Nagy Miklós (1976-) (vegyész) Zsuga Miklós (1944-) (polimer kémikus) Kéki Sándor (1964-) (polimer kémikus)
Pályázati támogatás:	NKFIH K-132685 egyéb GINOP-2.3.2-15-2016-00041 GINOP
Internet cím:	Szerző által megadott URL DOI Intézményi repozitóriumban (DEA) tárolt változat
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