Dependence of photochemical reactivity of the all-trans retinal protonated Schiff base on the solvent and the excitation wavelength.
An all-optical experimental technique aimed at measuring photoisomerization quantum yield (phi) of the all-trans protonated Schiff base of retinal in solution has been implemented. Upon the increase in the excitation wavelength from 400 to 540 nm a slight increase in phi from 0.16 +/- 0.03 to 0.20 +/- 0.02 is observed in the chromophore dissolved in methanol, whereas the phi value of the one dissolved in acetonitrile varies only from 0.22 +/- 0.03 (400 nm) to 0.23 +/- 0.04 (540 nm). The results suggest that dissipation of the excited-state vibrational energy excess, along with environment-induced modifications of the potential energy surfaces are necessary for an efficient retinal photoisomerization in both solvent and protein environment.
T-ReX Laboratory, Sincrotrone Trieste, Basovizza Trieste, Italy. goran.zgrablic@elettra.trieste.it
Goran
G
Zgrablić
Maria
M
Ricci
Anna Maria
AM
Novello
Fulvio
F
Parmigiani
D000097:Acetonitriles; D007536:Isomerism; D008027:Light; D000432:Methanol; D055668:Photochemical Processes / Q000528:radiation effects*; D012172:Retinaldehyde / Q000737:chemistry* / Q000528:radiation effects; D012545:Schiff Bases / Q000737:chemistry* / Q000528:radiation effects; D012997:Solvents / Q000737:chemistry
D000097:Acetonitriles; D012545:Schiff Bases; D012997:Solvents; D012172:Retinaldehyde; D000432:Methanol; C032159:acetonitrile