Hydroxyphenyl benzothiazole

Chou PT, Martinez ML, Studer SL (1992) The role of the cw-keto triplet state in the proton transfer cycle of 2-(2 -hydroxyphenyl)benzothiazole. Chem Phys Lett 195 586-590... 

Ikegami M, Arai T (2000) Laser flash photolysis study on hydrogen atom transfer of 2-(2-hydn>xyphenyl)benzoxazole and 2-(2-hydroxyphenyl)benzothiazole in the triplet excited state. Chem Lett 9 996-997... 

Brewer WE, Martinez ML, Chou PT (1990) Mechanism of the ground-state reverse proton transfer of 2-(2-hydroxyphenyl)benzothiazole. J Phys Chem 94 1915-1918... 

Ikegami M, Arai T (2002) Photoinduced intramolecular hydrogen atom transfer in 2-(2-hydroxyphenyl)benzoxazole and 2-(2-hydroxyphenyl)-benzothiazole studied by laser flash photolysis. J Chem Soc Perkin Trans 2 1296-1301... 

Rate coefficients in the expected range have been observed in excited state intramolecular proton transfers involving 2-(2-hydroxyphenyl)benzothiazole (Barbara et al., 1980a) and salicylideneaniline (Barbara et al., 1980b). In the former, the observation of fluorescence was explained by Scheme 2 and the... 

Organic dye nanoparticles of DHIA and DHBIA (the chemical structures are shown in Fig. 1) have been synthesized in THF/water mixed solvent by a reprecipitation method [32]. These dye molecules possess a 2-(2-hydroxyphenyl) benzothiazole (HBT) unit, which is known to be more stable as an enol imine form in the ground state and as a keto amine form in the excited state [32, 33] (Fig. 6). The nanoparticles exhibited the AIEE phenomenon mainly due to a restricted intramolecular motion, that is, impediment to free rotation of two end-substituted HBT units around single bonds. It is interesting to note that the... 

Fig. 6 The 2-(2-hydroxyphenyl)benzothiazole (HBT) unit that represents the keto-enol equilibrium (tautomerism). Normally, the enol (keto) form is rather stable in the ground state (in the excited state), respectively...

Qian Y, Li S, Zhang G, Wang Q, Wang S, Xu H, Li C, Li Y, Yang G (2007) Aggregation-induced emission enhancement of 2-(2 -hydroxyphenyl)benzothiazole-based excited-state intramolecular proton-transfer compounds. J Phys Chem B 111 5861-5868... 

Nakagaki R, Kobayashi T, Nagakura S (1978) Luminescence properties and the primary process of photochromism of 2-(2-hydroxyphenyl)benzothiazole. Bull Chem Soc Jpn 51 1671-1675... 

F. Laermer, T. Elsaeser, and W. Kaiser, Femtosecond spectroscopy of excited-state proton-transfer in 2-(2 -hydroxyphenyl)benzothiazole, Chem, Phys. Lett. 148, 119(1988). 

Time-resolved electron paramagnetic resonance served to detected the short-lived triplet state of the keto tautomer (238) of 2-(2-hydroxyphenyl)benzothiazole (239) generated by excited state intramolecular proton transfer (92CC641). 

RISC has been observed by two-color irradiation for a series of photo-tautomers generated by photoinduced proton transfer [40-46]. [The parent molecules, 3-hydroxyflavone (63), 2, 3, 4, 5, 6 -pentamethylphenyl-3-hydroxyflavone (64), 7-hydroxy indanone (65), 2-(2 -hydroxyphenyl)benzothiazole (66), and 2,2 -bipyridine-3,3 -diol (67), are shown in Chart 3.] Following proton transfer in the... 

Several molecules which can undergo intramolecular proton transfer in the excited state have been found to be unusually photostable. Thus, for example, 2-hydroxybenzophenone is used as a photostabilizer in polymers while benzophenone itself is photoactive (Kysel, 1969). In crystalline 2-(2 -hydroxyphenyl)benzothiazole and its derivatives [3] a proton is transferred in the excited state from an... 

Semi-empirical AMI-SCI calculations have been performed to rationalize the photophysical behavior of two series of compounds one comprising of 2-(2 -hydroxyphenyl)benzoxazole, 2-(2 -hydroxyphenyl)benzimidazole (HBI), and 2-(2 -hydroxyphenyl)benzothiazole, and the other of 2-(2 -hydroxyphenyl)oxazole (HPO), 2-(2 -hydroxyphenyl)imi-dazole (HPI), and 2-(2 -hydroxyphenyl)thiazole (HPT). These compounds exhibit intramolecular rotation as well as excited state intramolecular proton transfer (ESIPT). The results suggested that for the first series of compounds two rotational isomers are present in the ground state of HBO and HBI while HBT has a single conformer under similar circumstances. For the other series, existence of rotamers depends very much on the polarity of the environment <2003IMS335, 2002JST(604)87>. 

AMI semi-empirical MO calculations in both gaseous and condensed phases were employed to study excited-state intramolecular proton transfer from 2-(2 -hydroxyphenyl) benzothiazole <2000CPL(327)23, 2000PCP203>. 

The dependence of intramolecular proton transfer on solvent friction has been established for 2-(2 -hydroxy-5-methylphenyl) benzotriazole in alcohol and other solvents. Excited-state proton transfer in 2-(2 -hydroxyphenyl) benzothiazole has also been studied 2 Photophysical properties and laser performance of w, w -bis ( oxazol-2-yl)- -oligophenylenes in dioxane have been measured at room temperature. +p increases with the number of phenyl rings between terminally positioned oxazoyl groups. 

Syntheses and crystal structures of tetraphenylarsonium oxotrichloro[2-(2-hydroxyphenyl)benzothiazolate]technetate(V) and rhenate... 

R. S. Becker, C. Lenoble, and A. Zein, Photophysics and photochemistry ofthe nitro derivatives of salicylideneaniline and 2-(2 -hydroxyphenyl)benzothiazole and solvent effects, J. Phys. Chem. 91, 3517-3524(1987). 

---