Thiazine dyes: evaluation of monomeric and aggregate forms.

CRISTINA ORTIZ; JIMENA VARA

SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY.

PERGAMON-ELSEVIER SCIENCE LTD

Lugar: Amsterdam; Año: 2016 vol. 166 p. 112 - 120

1386-1425

The aggregation phenomenon of Azure B, monobrominated Azure B, Thionine and Methylene Blue was studiedby UV-Visible spectrophotometry in different media as a function of dye concentration and temperature variations.The tests carried out in organic solvents allowed the identification of monomeric species of these compounds,which have not been reported in literature and have been wrongly assigned for years. The resultsobtained in water allowed demonstrating that different kinds of aggregates are present in this medium. In addition,the aggregation tendency of these dyes in organic solvent and aqueous media was established. Several parameterssuch as lipophilicity, effect of bulky substituents and interactions with media were considered tointerpret the aggregation behavior of thiazine dyes.