Naslov
Competing photodehydration and ESIPT in adamantyl derivatives of 2-phenylphenols

Autori
Basarić, Nikola ; Cindro, Nikola ; Hou, Yunyan ; Žabčić, Ivana ; Mlinarić-Majerski, Kata ; Wan, Peter

Izvornik
Canadian journal of chemistry (0008-4042) 89 (2011), 2; 221-234

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
adamantanes; ESIPT; proton transfer; photochemistry; quinone methides; photosolvolysis

Sažetak
2-Phenylphenol derivatives strategically substituted with a hydroxyadamantyl substituent were synthesized and their photochemical reactivity investigated. Derivatives 9 and 10 undergo competitive 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 (Φ = 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. Due to the presence of an intramolecular H-bond, an efficient ESIPT from the phenol to the hydroxyl group coupled with dehydration gives an QM that efficiently undergoes electrocyclization (overall Φ = 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 LFP was performed to characterize the longer lived QM intermediates.

Izvorni jezik
Engleski

Znanstvena područja
Kemija

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