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Measurement of rate constants for quenching singlet oxygen with aCypridina luciferin analog (2-methyl-6-[p-methoxyphenyl]-3,7-dihydroimidazo[1,2-a]pyrazin-3-one) and sodium azide

✍ Scribed by Mashiko, Shinro ;Suzuki, Nobutaka ;Koga, Satoshi ;Nakano, Minoru ;Goto, Toshio ;Ashino, Toshihiko ;Mizumoto, Iwao ;Inaba, Humio


Publisher
John Wiley and Sons
Year
1991
Weight
347 KB
Volume
6
Category
Article
ISSN
0884-3996

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✦ Synopsis


Abstract

The rate constants for [^1^O~2~] [MCLA] and [^1^O~2~][NaN~3~] were measured by quenching the near‐infrared emission (^1^Δ~g~→^3^∑~g~) in steady state with MCLA and NaN~3~, respectively. ^1^O~2~ was constantly generated by energy transfer to O~2~ from Ar laser‐excited Rose Bengal. The Stern—Volmer plots yielded the second‐order rate constants of 2.94 × 10^9^ M^−1^ S^−1^ and 3.83 × 10^8^ M^−1^ S^−1^ for quenching ^1^O~2~ with MCLA and NaN~3~ in water at pH 5.4, respectively. The ^1^O~2~ + MCLA reaction emitted light with maximum at 465 nm at pD 4.5 identical to the O~2~^−^ + MCLA reaction.