Determination of the orbital and paramagnetic contributions to the 1H and 13C NMR chemical shifts of ruthenium(III) complexes
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| Year of publication | 2017 |
| Type | Appeared in Conference without Proceedings |
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| Description | The paramagnetic NMR (pNMR) spectroscopy is becoming crucially important in many areas of research despite the fact that unpaired electrons affect the NMR chemical-shift tensors, the isotropic NMR chemical shifts, and indirect nuclear spin-spin coupling constants [1]. Therefore the resonance frequencies for paramagnetic species lie typically out of the standard chemical-shift ranges for their diamagnetic analogs and the NMR signals are significantly broadened. The observed total NMR chemical shift can be decomposed into temperature-independent orbital term and temperature-dependent paramagnetic term [2]. In this study, the orbital and paramagnetic contributions to the NMR chemical shifts were determined experimentally from the 1H and 13C NMR measurements at various temperatures for a series of ruthenium(III) complexes - Ru(X-acac)3 and Ru(dbm)3 (X = H, Br, Me, NO2; acac = acetylacetonate; dbmH = dibenzoylmethane). The relativistic DFT calculations (two-component SO-ZORA and four-component DKS) were performed to assist with the resonance assignments. [1] J. Autschbach, In D. A. Dixon, Annual Reports in Computational Chemistry, Elsevier, 2015, 11, 3–36. [2] J. Novotný, M. Sojka, S. Komorovsky, M. Nečas, R. Marek, J. Am. Chem. Soc., 2016, 138, 8432–8445. |
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