Experimental and theoretical UV characterizations of acetylacetone and its isomers
| Autor: | Roubin P, Manca C, Stéphane Coussan, Yves Ferro, Marta Włoch, Monika Musiał, Aurélien Trivella, Karol Kowalski, Robert Wieczorek, Piotr Piecuch, Stanisław A. Kucharski, Rajzmann M |
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| Rok vydání: | 2006 |
| Předmět: |
Molecular Structure
Chemistry Ultraviolet Rays Acetylacetone Matrix isolation Infrared spectroscopy Stereoisomerism Sensitivity and Specificity Spectral line chemistry.chemical_compound Dipole Models Chemical Computational chemistry Molecular vibration Pentanones Physical chemistry Density functional theory Spectrophotometry Ultraviolet Physical and Theoretical Chemistry Isomerization |
| Zdroj: | The journal of physical chemistry. A. 110(11) |
| ISSN: | 1089-5639 |
| Popis: | Cryogenic matrix isolation experiments have allowed the measurement of the UV absorption spectra of the high-energy non-chelated isomers of acetylacetone, these isomers being produced by UV irradiation of the stable chelated form. Their identification has been done by coupling selective UV-induced isomerization, infrared spectroscopy, and harmonic vibrational frequency calculations using density functional theory. The relative energies of the chelated and non-chelated forms of acetylacetone in the S0 state have been obtained using density functional theory and coupled-cluster methods. For each isomer of acetylacetone, we have calculated the UV transition energies and dipole oscillator strengths using the excited-state coupled-cluster methods, including EOMCCSD (equation-of-motion coupled-cluster method with singles and doubles) and CR-EOMCCSD(T) (the completely renormalized EOMCC approach with singles, doubles, and non-iterative triples). For dipole-allowed transition energies, there is a very good agreement between experiment and theory. In particular, the CR-EOMCCSD(T) approach explains the blue shift in the electronic spectrum due to the formation of the non-chelated species after the UV irradiation of the chelated form of acetylacetone. Both experiment and CR-EOMCCSD(T) theory identify two among the seven non-chelated forms to be characterized by red-shifted UV transitions relative to the remaining five non-chelated isomers. |
| Databáze: | OpenAIRE |
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