Matrix-isolation studies of 7-hydroxyquinoline. 3. Deuterium-isotope and xenon matrix effects

Abstract

Previously, we have observed the stabilization of the ground-state keto tautomer of 7-hydroxyquinoline (7HQ) in methanol/argon mixed matrices at 10 K. We ascribed the stabilized tautomer to the isolated 7HQ-(MeOH) 2 bridged complex on the basis of the observation that the open-chain methanol dimer concentration reaches a maximum concomitantly with the fluorescence excitation spectrum of the keto tautomer centered at 420 nm. Here, we report an increased stabilization of the ground-state keto tautomer when the open-chain CD 3 OD dimer is used and an additional increase upon photolysis. We also find that the use of the xenon matrix instead of argon inhibits the formation of the keto tautomer