Nanosecond laser photolysis techniques were incorporated to obtain (1) the absorption spectra and coefficients of triplet vitamin K3 (2-methyl-1,4-naphthoquinone, MNQ) and its ketyl radical (2-methylnaphthosemiquinone, 2MNQH*) in acetonitrile (ACN) as well as to reveal (2) the mechanisms for hydrogen atom abstraction of triplet MNQ (3MNQ*) from phenol which proceeded in a diffusion process with an efficiency of unity. On the other hand, the hydroxymethylnaphthoxy radical was produced with the benzophenone ketyl radical (BPK) by the hydrogen atom transfer from triplet 2-methyl-1,4-dihydroxynaphthalene (MDHNp) sensitized by triplet benzophenone to benzophenone (BP) via the triplet exciplex. The question to be addressed was, which was produced in the MDHNp-BP system, the 2-methyl or 3-methylnaphthosemiquinone radical? Comparing the absorption spectrum and coefficient of the radical produced via the triplet exciplex with those of the 2MNQH* obtained by H-atom abstraction of 3MNQ*, the radical formed with BPK was revealed to be 2MNQH*. The reasons for the preferable formation of 2MNQH* are discussed for H-atom abstraction as well as the transfer reactions.
Research on Chemical Intermediates – Springer Journals
Published: Apr 14, 2009
It’s your single place to instantly
discover and read the research
that matters to you.
Enjoy affordable access to
over 18 million articles from more than
15,000 peer-reviewed journals.
All for just $49/month
Query the DeepDyve database, plus search all of PubMed and Google Scholar seamlessly
Save any article or search result from DeepDyve, PubMed, and Google Scholar... all in one place.
All the latest content is available, no embargo periods.
“Whoa! It’s like Spotify but for academic articles.”@Phil_Robichaud