6005-15-8Relevant articles and documents
Photophysical triplet state processes of 4-H-1-benzopyrane-4-thione in a perfluoroalkane: Part 1. - Temperature dependence of unimolecular triplet decay
Eisenberger, Heike,Nickel, Bernhard
, p. 733 - 740 (1996)
The rate constant kTO for the unimolecular decay of the lowest triplet state, T1, of 4-H-1-benzopyrane-4-thione (BPT) in perfluoro1,3-dimethylcyclohexane was determined between 230 and 300 K. By assuming a very fast and virtually complete thermal equilibration T1 ? S1 of the relative population of T1 and the lowest excited singlet state S1, three parameters can be calculated from the temperature dependence of kTO: the individual rate constants βS = (4.0 ± 0.2) × 106 s-1 for the decay of S1 to S0 and βTz = (8.2 ± 2) × 104 s-1 for the decay of the strongly phosphorescent triplet substate T1z to S0, and the energy difference ΔE(S1,T1z) = hc × (757 ± 13) cm-1l between T1z and S1. The value of ΔE(S1,T1z) is in agreement with the positions of T1,0 and S1,0 in the absorption spectrum. The spectrum of the S0 → S1 transition is estimated. The assignment of the hot-band range of the delayed luminescence above the energy hcν0,0 of T1,0 is facilitated by an inverse Boltzmann weighting (multiplication with exp[hc(ν - ν0,0)/kBT]). At the position of S1,0, a contribution of E-type delayed S1 → S0 fluorescence can be discerned. The contribution of diffusion-controlled concentration-quenching (rate constant kQ) to the triplet decay was eliminated by extrapolation to infinite dilution; kQ is proportional to the ratio T/η of temperature T and viscosity η. The temperature dependence of the viscosity and density of perfluoro-1,3-dimethylcyclohexane were measured.
α1-Adrenoceptor agonists: The identification of novel α1A subtype selective 2′-heteroaryl-2-(phenoxymethyl)imidazolines
Bishop, Michael J.,Barvian, Kevin A.,Berman, Judd,Bigham, Eric C.,Garrison, Deanna T.,Gobel, Michael J.,Hodson, Stephen J.,Irving, Paul E.,Liacos, James A.,Navas, Iii, Frank,Saussy Jr., David L.,Speake, Jason D.
, p. 471 - 475 (2007/10/03)
Novel 2′-heteroaryl-2-(phenoxymethyl)imidazolines have been identified as potent agonists of the cloned human α1-adrenoceptors in vitro. The nature of the 2′-heteroaryl group can have significant effects on the potency, efficacy, and subtype selectivity in this series. α1A Subtype selective agonists have been identified.
Photosensitizers: Comprehensive Photophysics/Photochemistry and Theory of Coumarins, Chromones, their Homologues and Thione Analogues
Becker, Ralph S.,Chakravorti, Sankar,Gartner, Carlos A.,Miguel, Maria de Graca
, p. 1007 - 1020 (2007/10/02)
The photophysical-photochemical behaviour, including absorption spectra, flourescence spectra and lifetimes, phosphorescence spectra, triplet-triplet transient spectra, triplet lifetimes and quantum yields and sensitized singlet oxygen formation and yields, has been determined for many of a group of 22 carbonyl and thione compounds.These includes coumarins, psoralens, chromones and furochromone and their thiones.Many of the thiones were synthesized for the first time.Two types of theoretical calculations were carried out on the majority of the compounds.The principal goals of the research for the thiones, were (1) to produce or improve the photosensitizer capability of the compounds in vivo, (2) to shift the spectra of the compounds to significantly longer wavelength and (3) to increase the triplet and singlet oxygen quantum yields.Most of these have been largely achieved.The photosensitizing abilities of the two thiones have been evaluated using a unique testing technique employing a series of genitically engineered bacteria.
