514-85-2Relevant articles and documents
Picosecond time-resolved multiplex coherent anti-Stokes Raman scattering spectroscopy by using a streak camera: Isomerization dynamics of all-trans and 9-cis retinal in the lowest excited triplet state
Tahara, Tahei,Toleutaev, Bulat N.,Hamaguchi, Hiro-o
, p. 786 - 796 (1994)
A picosecond time-resolved multiplex coherent anti-Stokes Raman scattering (CARS) measuring system using a streak camera was constructed.Picosecond uv laser pulses (50 ps) were used for the photoexcitation and nanosecond laser pulses (7 ns) were used as ω1 and ω2 for CARS probing.The multiplex CARS signals were spectrally analyzed by a spectrograph, and time-resolved and detected by a streak camera.This system enabled us two-dimensional (the time and frequency domain) detection of CARS signals with picosecond time resolution.The cis-trans photoisomerization dynamics of all-trans and 9-cis retinal was investigated.In the case of all-trans retinal, the CARS signals due to the "all-trans-like" T1 state appeared in accordance with the decay of the S1 fluorescence.In contrast, the appearance of the all-trans-like T1 signals was markedly delayed in the case of the 9-cis isomer.This indicates that there exists a T1 state having "9-cis-like" conformation in the picosecond time region.The lifetime of this 9-cis-like T1 state was obtained as 880 +/- 150 ps from the analysis of the rise of the all-trans-like T1 state.The mechanism of retinal photoisomerization is discussed on the basis of the obtained picosecond time-resolved data.It is concluded that the conformational change from the 9-cis to the all-trans form in the triplet manifold proceeds from the thermalized (not vibrationally excited) 9-cis-like T1 state.
Z -isomerization of retinoids through combination of monochromatic photoisomerization and metal catalysis
Kahremany, Shirin,Sander, Christopher Lane,Tochtrop, Gregory P.,Kubas, Adam,Palczewski, Krzysztof
supporting information, p. 8125 - 8139 (2019/09/19)
Catalytic Z-isomerization of retinoids to their thermodynamically less stable Z-isomer remains a challenge. In this report, we present a photochemical approach for the catalytic Z-isomerization of retinoids using monochromatic wavelength UV irradiation treatment. We have developed a straightforward approach for the synthesis of Z-retinoids in high yield, overcoming common obstacles normally associated with their synthesis. Calculations based on density functional theory (DFT) have allowed us to correlate the experimentally observed Z-isomer distribution of retinoids with the energies of chemically important intermediates, which include ground- and excited-state potential energy surfaces. We also demonstrate the application of the current method by synthesizing gram-scale quantities of 9-cis-retinyl acetate 9Z-a. Operational simplicity and gram-scale ability make this chemistry a very practical solution to the problem of Z-isomer retinoid synthesis.
Selective isomerization of retinal upon two-photon excitation
Sashima, Tokutake,Hashimoto, Hideki,Koshihara, Shin-ya
, p. 380 - 385 (2007/10/03)
The products of photo-isomerization when excited directly up to the two-photon-allowed 1Ag- excited state of alltrans and five cis isomers of retinal were determined. The composition of the isomers at the photo-stationary state was drastically changed as compared to one-photon excitation. The production of the 13-cis isomer was selectively increased, and the production of the dicis isomers was observed in the case of a direct excitation upon the 31Ag- state, although they were hard to be produced by one-photon excitation in n-hexane solution. These results clearly evidenced that there exist isomerization pathways via two-photon-allowed excited states.
