title: Gas-phase tautomerism in hydroxy azo dyes - from 4-phenylazo-1-phenol to 4-phenylazo-anthracen-1-ol.
abstract: The tautomeric constants of a series of azo dyes were estimated in the gas phase by using electron ionization mass spectrometry. It was shown that the relative amount of the keto tautomer increases from 4-phenylazo-1-phenol to 4-phenylazo-anthracen-1-ol, thus confirming the quantum-chemical predictions. The existence of the enol tautomer of 4-phenylazo-anthracen-1-ol is shown for the first time by mass spectrometry in the gas phase. This finding is supported by flash photolysis measurements in solution.
authors.affiliation: Institute of Organic Chemistry with Centre of Phytochemistry, Acad. G.Bonchev str., bl.9, Sofia 1113, Bulgaria. dantonova@orgchm.bas.bg
authors.forename: Daniela
authors.initials: D
authors.lastname: Nedeltcheva
authors.forename: Vanya
authors.initials: V
authors.lastname: Kurteva
authors.forename: Ivanka
authors.initials: I
authors.lastname: Topalova