Photophysical and photochemical studies of phenothiazine and some derivatives: exploratory studies of novel photosensitizers for photoresist technology

Bioactive Phenothiazines and Benzo[a]phenothiazines: Spectroscopic Studies, and Biological and Biomedical Properties and Applications

“…This red-shift behaviour was explained by Garcia et al [4] in terms of the involved molecular orbitals, which are located on the phenothiazine moiety. It can be concluded that there is no contribution of the N-alkyl chain to the emission properties of the phenothiazine derivatives, which is in agreement with the fact that the emission maxima of the parent phenothiazines are exactly the same as those of the corresponding 10-alkylated derivatives [30]. The fluorescence quantum yield values were found to be very low for these phenothiazine derivatives, ranging between about 2 × 10 -2 and 10 -3 , according to the compound [4,29] (Table 2).…”

“…It was found that the nature of the 10-alkyl chain had practically no significant effect on the τ F values, as shown by the fact that these lifetimes had the same values, within experimental error, as those reported for the corresponding non-alkylated phenothiazines: PH (τ F ≤ 1 ns), CPH (τ F ≤ 1 ns) and TFZF (τ F = 2.5 ns) [30]. Garcia et al [4] noted that the 2-CF 3 -substituted derivatives gave similar τ F values and presented the same solvent dependency, a τ F value of 2.4-2.7 ns being measured in acetonitrile and methanol, whereas in a more polar medium, such as the phosphate buffer solution, a 3.1-ns value was obtained.…”

Two-Laser Photochemistry of Phenothiazine in Solution: Ionization and Bond Cleavage from Upper States

“…The spcctra were obtained 1.5 p after the UV pulse in each case. In the two-laser experiment, the dye laser pulse followed the UV pulse by 1 production. The insets in Figure 6 show the two-laser decay kinetics at 460 and 380 nm as well as a comparison of the one and two-laser transient absorption spectra.…”

Nanosecond transient absorption spectroscopy of a Ru polypyridine phenothiazine dyad

“…The broad bleach feature actually appears as two negative peaks. In this case, we suspect that the appearance of two negative peaks in the transient absorption signal is the superposition of the excited state absorption of triplet phenothiazine ( 3 PTZ), which often appears near 470 nm [22], and the ground state bleach with oxidized Ru III associated with the MLCT excited state. This feature is not likely due to oxidized phenothiazine (PTZ +Å ) as that typically appears near 510 nm [22].…”

“…In this case, we suspect that the appearance of two negative peaks in the transient absorption signal is the superposition of the excited state absorption of triplet phenothiazine ( 3 PTZ), which often appears near 470 nm [22], and the ground state bleach with oxidized Ru III associated with the MLCT excited state. This feature is not likely due to oxidized phenothiazine (PTZ +Å ) as that typically appears near 510 nm [22]. Indeed, nanosecond transient absorption spectra of [Ru(Ph 2 bpy) 3 ] 2+ , where Ph 2 bpy is 4,4 0 -diphenyl-2,2 0 -bipyridine, show only a single broad bleach in this region of the spectrum [23].…”