Photoswitching Behavior of 5-Phenylazopyrimidines: In Situ Irradiation NMR and Optical Spectroscopy Combined with Theoretical Methods

0490912 - ÚOCHB 2019 RIV US eng J - Článek v odborném periodiku
Čechová, Lucie - Kind, J. - Dračínský, Martin - Filo, J. - Janeba, Zlatko - Thiele, C. M. - Cigáň, M. - Procházková, Eliška
Photoswitching Behavior of 5-Phenylazopyrimidines: In Situ Irradiation NMR and Optical Spectroscopy Combined with Theoretical Methods.
Journal of Organic Chemistry. Roč. 83, č. 11 (2018), s. 5986-5998. ISSN 0022-3263. E-ISSN 1520-6904
Grant CEP: GA ČR(CZ) GA18-11851S
Grant ostatní: AV ČR(CZ) L200551701
Institucionální podpora: RVO:61388963
Klíčová slova: intramolecular hydrogen bonds * visible light * single molecule
Obor OECD: Physical chemistry
Impakt faktor: 4.745, rok: 2018

The photoswitching behavior of 5-phenylazopyrimidines was investigated by optical methods and NMR spectroscopy with in situ irradiation sustained by mathematical modeling and DFT calculations. Irradiation of various compounds with electron-donating groups on the pyrimidine ring and substituents with electron-withdrawing as well as electron-donating substituent in the para-position of the phenyl ring were examined. All compounds could be successfully converted to the cis isomer, this isomerization and the subsequent thermal fading were studied. Switching cycles can be repeated without signs of photodegradation for most of the compounds, which makes them adept to molecular photoswitches. Interestingly, the chloro and cyano derivatives can be switched without UV light, which makes them vis(pi -> pi) vis(n -> pi*) photoswitches. Surprisingly equal trans-to-cis photoisomerization quantum yields for pi -> pi* and n -> pi* excitation indicate the blocking of the inversion pathway following pi -> pi* excitation. In contrast to that, DFT computations suggest the inversion mechanism for the reverse thermal cis-to-trans isomerization of 5-phenylazopyrimidines.
Trvalý link: http://hdl.handle.net/11104/0285026