Photophysical characterization of pyrazino[2,3-c]-1,2,6-thiadiazine 2,2-dioxides in DMSO and acetonitrile solutions |
| |
Authors: | R. Weigand J. M. Guerra J. Dávila |
| |
Affiliation: | (1) Departamento de Optica, Facultad de Físicas, Universidad Compultense, Ciudad Universitaria, E-28040 Madrid, Spain;(2) Departamento de Químico-Física, Facultad de Químicas, Universidad Complutense, Ciudad Universitaria, E-28040 Madrid, Spain |
| |
Abstract: | Photophysical characterization of some pyrazino[2,3-c][1,2,6]thiadiazine 2,2-dioxides derivatives in DMSO and acetonitrile has been carried out. Acid-base processes have been found to occur in the ground and excited states. In DMSO and acetonitrile equilibrium between the neutral and deprotonated molecules is established in the ground state. In acetonitrile, a second equilibrium between the neutral and protonated form is also present at a lower pH, and can be treated independently of the first one. Absorption, emission, and excitation spectra of the species involved have been measured; data analysis allows us to calculate pKaand quantum efficiencies. The change of the decay lifetimes with pH, along with steady state fluorescence measurements show the existence of communication between the excited states and enable us to estimate the excited state kinetic rate constants.A discussion about their possible use as laser dyes based on the energy threshold condition is also given. |
| |
Keywords: | 82.50.m |
本文献已被 SpringerLink 等数据库收录! |
|