Theoretical Modelling of Photoswitching of Hyperpolarisabilities in Ruthenium Complexes
| Autor: | Kristine Pierloot, Steven Vancoillie, Manthos G. Papadopoulos, Heribert Reis, Benjamin J. Coe, Aggelos Avramopoulos |
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| Jazyk: | angličtina |
| Rok vydání: | 2013 |
| Předmět: |
Ab initio
02 engineering and technology 010402 general chemistry Ligands 01 natural sciences Molecular physics Catalysis Ruthenium Computational chemistry Coordination Complexes ruthenium complexes Perturbation theory molecular switches Basis set Chemistry Organic Chemistry nonlinear optics General Chemistry Full Papers Models Theoretical 021001 nanoscience & nanotechnology 0104 chemical sciences Hybrid functional Dipole Excited state Quantum Theory Density functional theory Gases density functional caclulations 0210 nano-technology Ground state |
| Zdroj: | Chemistry (Weinheim an Der Bergstrasse, Germany) |
| ISSN: | 1521-3765 0947-6539 |
| Popis: | Static excited-state polarisabilities and hyperpolarisabilities of three Ru(II) ammine complexes are computed at the density functional theory (DFT) and several correlated ab initio levels. Most accurate modelling of the low energy electronic absorption spectrum is obtained with the hybrid functionals B3LYP, B3P86 or M06 for the complex [Ru(II)(NH3)5(MeQ(+))](3+) (MeQ(+)=N-methyl-4,4'-bipyridinium, 3) in acetonitrile. The match with experimental data is less good for [Ru(II)(NH3)5L](3+) (L=N-methylpyrazinium, 2; N-methyl-4-{E,E-4-(4-pyridyl)buta-1,3-dienyl}pyridinium, 4). These calculations confirm that the first dipole- allowed excited state (FDAES) has metal-to-ligand charge-transfer (MLCT) character. Both the solution and gas-phase results obtained for 3 by using B3LYP, B3P86 or M06 are very similar to those from restricted active-space SCF second-order perturbation theory (RASPT2) with a very large basis set and large active space. However, the time-dependent DFT λ(max) predictions from the long-range corrected functionals CAM-B3LYP, LC-ωPBE and wB97XB and also the fully ab initio resolution of identity approximate coupled-cluster method (gas-phase only) are less accurate for all three complexes. The ground state (GS) two-state approximation first hyperpolarisability β(2SA) for 3 from RASPT2 is very close to that derived experimentally via hyper-Rayleigh scattering, whereas the corresponding DFT-based values are considerably larger. The β responses calculated by using B3LYP, B3P86 or M06 increase markedly as the π-conjugation extends on moving along the series 2→4, for both the GS and FDAES species. All three functionals predict substantial FDAES β enhancements for each complex, increasing with the π-conjugation, up to about sevenfold for 4. Also, the computed second hyperpolarisabilities γ generally increase in the FDAES, but the results vary between the different functionals. |
| Databáze: | OpenAIRE |
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