Substitution effects on the absorption spectra of nitrophenolate isomers
| Autor: | Angel Rubio, Marius Wanko, Steen Brøndsted Nielsen, Jørgen Houmøller, Maj-Britt Suhr Kirketerp, Kristian Støchkel, Mogens Brøndsted Nielsen, Michael Åxman Petersen |
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| Přispěvatelé: | Ministerio de Ciencia e Innovación (España), European Commission, Eusko Jaurlaritza, Lundbeck Foundation |
| Rok vydání: | 2012 |
| Předmět: |
Absorption spectroscopy
010405 organic chemistry Oscillator strength Chemistry General Physics and Astronomy 010402 general chemistry Photochemistry 01 natural sciences Acceptor 0104 chemical sciences Isomerism Models Chemical Spectrophotometry Bathochromic shift Hydroxybenzoates Solvents Physics::Atomic and Molecular Clusters Quantum Theory Hypsochromic shift Gases Physics::Chemical Physics Physical and Theoretical Chemistry Absorption (chemistry) Solvent effects Ground state |
| Zdroj: | Digital.CSIC. Repositorio Institucional del CSIC instname Wanko, M, Houmøller, J, Støchkel, K, Suhr Kirketerp, M-B, Petersen, M Å, Nielsen, M B, Nielsen, S B & Rubio, A 2012, ' Substitution effects on the absorption spectra of nitrophenolate isomers ', Physical Chemistry Chemical Physics, vol. 14, no. 37, pp. 12905-11 . https://doi.org/10.1039/c2cp41636k Physical Chemistry Chemical Physics |
| DOI: | 10.1039/c2cp41636k |
| Popis: | Charge-transfer excitations highly depend on the electronic coupling between the donor and acceptor groups. Nitrophenolates are simple examples of charge-transfer systems where the degree of coupling differs between ortho, meta and para isomers. Here we report the absorption spectra of the isolated anions in vacuo to avoid the complications of solvent effects. Gas-phase action spectroscopy was done with two different setups, an electrostatic ion storage ring and an accelerator mass spectrometer. The results are interpreted on the basis of CC2 quantum chemical calculations. We identified absorption maxima at 393, 532, and 399 nm for the para, meta, and ortho isomer, respectively, with the charge-transfer transition into the lowest excited singlet state. In the meta isomer, this π–π* transition is strongly redshifted and its oscillator strength reduced, which is related to the pronounced charge-transfer character, as a consequence of the topology of the conjugated π-system. Each isomer's different charge distribution in the ground state leads to a very different solvent shift, which in acetonitrile is bathochromic for the para and ortho, but hypsochromic for the meta isomer. MW and AR acknowledge funding by the Spanish MICINN (‘‘Juan de la Cierva’’, FIS2010-65702-C02-01, PIB2010US-00652 and /CSD2010-00044/), ‘‘Grupos Consolidados UPV/EHU del Gobierno Vasco’’ (IT-319-07), European Research Council Advanced Grant DYNamo (ERC-2010-AdG No. 267374), and SGIker ARINA UPV/EHU). SBN acknowledges support from Lundbeckfonden and FNU. |
| Databáze: | OpenAIRE |
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