THE GROUND-STATE STABILIZATION OF THE KETO TAUTOMER OF THE 7-HYDROXYQUINOLINE DIMER IN ARGON MATRICES AT 10-K

The stabilization of the ground-state keto tautomer of the 7-hydroxyquinoline dimer (7HQ)2 has been observed in argon matrices at 10 K. The stabilized tautomer has been ascribed to the isolated dimer complex based on the similarity of the fluorescence excitation and emission spectra to those of the ground-state keto tautomer of the isolated 7-hydroxyquinoline/methanol dimer complex, 7HQ-(MeOH)2. Our studies indicate that 7HQ dimer concentration can be increased by photolysis or by an increase in the deposition temperature. Also discussed are the fluorescence spectrum arising from the non-cyclic hydrogen-bonded 7HQ and the phosphorescence spectrum arising from the isolated 7HQ monomer.