The lifetime and efficiency of triplet–triplet fluorescence from the excited state of a TMM biradical determined using transient emission spectroscopy by two-color two-laser flash photolysis

2013 ◽  
Vol 15 (19) ◽  
pp. 7064 ◽  
Author(s):  
Yasunori Matsui ◽  
Daisuke Kawahara ◽  
Eisuke Ohta ◽  
Hiroshi Ikeda
Keyword(s):  
Excited State ◽  
Emission Spectroscopy ◽  
Flash Photolysis ◽  
Laser Flash Photolysis ◽  
Laser Flash

Photophysics of Tungsten and Molybdenum Arylcarbyne Complexes. Observation of the Lowest Excited State by Laser Flash Photolysis

1996 ◽  
Vol 35 (26) ◽  
pp. 7769-7775 ◽  
Author(s):  
Thomas K. Schoch ◽  
Andrea D. Main ◽  
Richard D. Burton ◽  
Lucian A. Lucia ◽  
Edward A. Robinson ◽  
...  
Keyword(s):  
Excited State ◽  
Flash Photolysis ◽  
Laser Flash Photolysis ◽  
Laser Flash

Competing photodehydration and excited-state intramolecular proton transfer (ESIPT) in adamantyl derivatives of 2-phenylphenols

2011 ◽  
Vol 89 (2) ◽  
pp. 221-234 ◽  
Author(s):  
Nikola Basarić ◽  
Nikola Cindro ◽  
Yunyan Hou ◽  
Ivana Žabčić ◽  
Kata Mlinarić-Majerski ◽  
...  
Keyword(s):  
Excited State ◽  
Carbon Atom ◽  
Proton Transfer ◽  
Phenyl Ring ◽  
Flash Photolysis ◽  
Laser Flash Photolysis ◽  
Laser Flash ◽  
Intramolecular Proton Transfer ◽  
Hydroxyl Group ◽  
Quantum Yields

2-Phenylphenol derivatives strategically substituted with a hydroxyadamantyl substituent were synthesized and their photochemical reactivity was investigated. Derivatives 9 and 10 undergo competitive excited-state intramolecular proton transfer (ESIPT) from the phenol to the carbon atom of the adjacent phenyl ring and formal ESPT from the phenol to the hydroxyl group coupled with dehydration. These two processes (both via S1) give rise to two classes of quinone methides (QMs) that revert to starting material or react with nucleophiles, respectively. ESIPT to carbon atoms was studied by performing photolyses in the presence of D2O, whereupon deuterium incorporation to the adjacent phenyl ring was observed ([Formula: see text] = 0.1–0.2). The competing formal ESPT and dehydration takes place with quantum yields that are an order of magnitude lower and was studied by isolation of photomethanolysis products. Derivative 8 did not undergo ESIPT to carbon atom. Owing to the presence of an intramolecular H bond, an efficient ESIPT from the phenol to the hydroxyl group coupled with dehydration gives a QM that efficiently undergoes electrocyclization (overall [Formula: see text] = 0.33), to give chroman 16. In addition, spiro[adamantane-2,9′-(4′-hydroxy)fluorene] (12) undergoes ESIPT, unlike the previously reported unreactive parent 2-hydroxyfluorene. The reactive singlet excited states of the prepared biphenyl and fluorene molecules were characterized by fluorescence spectroscopy, whereas laser flash photolysis (LFP) was performed to characterize the longer lived QM intermediates.

Excited state and free radical properties of Rhodamine 123: a laser flash photolysis and radiolysis study

1999 ◽  
Vol 1 (2) ◽  
pp. 261-268 ◽  
Author(s):  
M W. Ferguson ◽  
P C. Beaumont ◽  
S E. Jones ◽  
S Navaratnam ◽  
B J. Parsons
Keyword(s):  
Excited State ◽  
Free Radical ◽  
Flash Photolysis ◽  
Laser Flash Photolysis ◽  
Laser Flash ◽  
Rhodamine 123
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