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RESEARCH PRODUCT
On the Low-Lying Excited States ofsym-Triazine-Based Herbicides
Rita CoimbraLuis Serrano-andrésM. Isabel FernándezJosep M. OlivaM. Emília AzenhaJ. Arturo SantaballaHugh D. BurrowsJ. Serxio Seixas De MeloL Moisés Canlesubject
Absorption spectroscopyQuantum yieldPhotochemistryMolecular physicsAbsorptionAb initio quantum chemistry methodsOscillometryPressureRadiative transferEmission spectrumPhysical and Theoretical ChemistryMolecular StructureChemistry PhysicalHerbicidesTriazinesChemistryTemperatureHydrogen-Ion ConcentrationModels TheoreticalAtomic and Molecular Physics and OpticsSpectrometry FluorescenceModels ChemicalSpectrophotometryExcited stateAtrazineIndicators and ReagentsPhosphorescenceLuminescenceSoftwaredescription
We report a joint computational and luminescence study on the low-lying excited states of sym-triazines, namely, 1,3,5-triazine (1) and the ubiquitous herbicides atrazine [6-chloro-N2-ethyl-N4-isopropyl-1,3,5-triazine-2,4-diamine (2)] and ametryn [6-methylthio-N2-ethyl-N4-isopropyl-1,3,5-triazine-2,4-diamine (3)]. Geometrical structures, energetics, and transition and state properties of I and 2 were computed at the TD-DFT, CASSCF, and CASPT2 levels of theory. The fluorescence and phosphorescence emission spectra, lifetimes, and fluorescence quantum yields were measured for the three compounds, and from these, the energies of the lowest excited states and their corresponding radiative rates were determined. The predictions from CASPT2 calculations are in good agreement with the experimental results obtained from the luminescence studies and allow the interpretation of different absorption and emission features.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2005-01-01 | ChemPhysChem |