Photoswitching Behavior of 5-Phenylazopyrimidines: In Situ Irradiation NMR and Optical Spectroscopy Combined with Theoretical Methods.
Lucie ČechováJonas KindMartin DračínskýJuraj FiloZlatko JanebaChristina Marie ThieleMarek CigáňEliška ProcházkováPublished in: The Journal of organic chemistry (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(π → π*)-vis(n → π*) photoswitches. Surprisingly equal trans-to- cis photoisomerization quantum yields for π → π* and n → π* excitation indicate the blocking of the inversion pathway following π → π* excitation. In contrast to that, DFT computations suggest the inversion mechanism for the reverse thermal cis-to- trans isomerization of 5-phenylazopyrimidines.
Keyphrases
- high resolution
- density functional theory
- molecular dynamics
- magnetic resonance
- contrast enhanced
- solid state
- energy transfer
- solar cells
- high speed
- molecular docking
- single molecule
- electron transfer
- magnetic resonance imaging
- atomic force microscopy
- molecular dynamics simulations
- computed tomography
- quantum dots
- transition metal