Hrvatska znanstvena bibliografija (CROSBI)



Pregled bibliografske jedinice broj: 781449

Časopis

Autori: Škalamera, Đani; Bohne, Cornelia; Landgraf, Stephan; Basarić, Nikola
Naslov: Photodeamination reaction mechanism in aminomethyl p-cresol derivatives: different reactivity of amines and ammonium salts
Izvornik: Journal of organic chemistry (0022-3263) 80 (2015); 10817-10828
Vrsta rada: članak
Ključne riječi: excited state proton transfer (ESPT) ; quinone methides ; laser flash photolysis ; photodeamination
Sažetak:
Derivatives of p-cresol 1-4 were synthesized and their photochemical reactivity, acid-base and photophysical properties were investigated. The photoreactivity of amines 1 and 3 is different from that for the corresponding ammonium salts 2 and 4. All compounds have low fluorescence quantum yields because the excited states undergo deamination reactions and for all cresols the formation of quinone methides (QMs) was observed by laser flash photolysis. The reactivity observed is a consequence of the higher acidity of the S1 states of these p-cresols and the ability for excited-state intramolecular proton transfer (ESIPT) to occur in the case of 1 and 3, but not for salts 2 and 4. In aqueous solvent deamination depends largely on the prototropic form of the molecule. The most efficient deamination takes place when monoamine is in the zwitterionic form (pH 9-11) or diamine is in the monocationic form (pH 7-9). QM1, QM3 and QM4 react with nucleophiles and QM1 exhibits shorter lifetime when formed from 1 (τ in CH3CN = 5 ms) then from 2 (τ in CH3CN = 200 ms) due to the reaction with eliminated dimethylamine, which acts as a nucleophile in the case of QM1. Bifunctional QM4 undergoes two types of reactions with nucleophiles, giving adducts or new QM species. The mechanistic diversity uncovered is of significance to biological systems, such as for the use of bifunctional QMs to achieve DNA cross-linking.
Projekt / tema: HRZZ-IP-2014-09-6312, NSERC, RGPIN-121389-2012
Izvorni jezik: ENG
Rad je indeksiran u
bazama podataka:
Current Contents Connect (CCC)
Scopus
SCI-EXP, SSCI i/ili A&HCI
Science Citation Index Expanded (SCI-EXP) (sastavni dio Web of Science Core Collectiona)
Kategorija: Znanstveni
URL Internet adrese: http://pubs.acs.org/doi/pdf/10.1021/acs.joc.5b01991
Broj citata:
Altmetric:
DOI: 10.1021/acs.joc.5b01991
URL cjelovitog teksta:
Google Scholar: Photodeamination reaction mechanism in aminomethyl p-cresol derivatives: different reactivity of amines and ammonium salts
Upisao u CROSBI: Enidija Lukša (Enidija.Luksa@irb.hr), 14. Lis. 2015. u 13:34 sati