ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Properties of singlet- and triplet-excited states of hemicyanine dyes

Daniel O. Mártire, Walter Massad, Hernán Montejano, Mónica C. Gonzalez, Paula Caregnato, Laura S. Villata, and Norman A. García

Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA), CCT-La Plata-CONICET, Universidad Nacional de La Plata, Diag 113 y 64, 1900, La Plata, Argentina

E-mail: dmartire@inifta.unlp.edu.ar

Abstract: The fluorescence emission spectra and fluorescence quantum yields of hemicyanine dyes LDS 698, LDS 722, and LDS 730 were measured in different media. No transient species was detected in the laser flash-photolysis experiments performed with Ar-saturated solutions of the dyes in methanol. However, in the presence of 0.08 M potassium iodide, the absorption of the triplet states was clearly observed. Oxygen consumption measurements in the absence and presence of a chemical trap (furfuryl alcohol) in MeOH: H₂O (φ_r = 1: 1) solutions of the dyes containing KI confirmed the generation of singlet molecular oxygen.

Keywords: triplet states – singlet oxygen – hemicyanine dyes – flash-photolysis

Full paper is available at www.springerlink.com.

DOI: 10.2478/s11696-014-0547-5

Chemical Papers 68 (8) 1137–1140 (2014)