| People | Locations | Statistics |
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| Naji, M. |
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| Motta, Antonella |
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| Aletan, Dirar |
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| Mohamed, Tarek |
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| Ertürk, Emre |
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| Taccardi, Nicola |
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| Kononenko, Denys |
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| Petrov, R. H. | Madrid |
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| Alshaaer, Mazen | Brussels |
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| Bih, L. |
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| Casati, R. |
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| Muller, Hermance |
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| Kočí, Jan | Prague |
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| Šuljagić, Marija |
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| Kalteremidou, Kalliopi-Artemi | Brussels |
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| Azam, Siraj |
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| Ospanova, Alyiya |
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| Blanpain, Bart |
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| Ali, M. A. |
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| Popa, V. |
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| Rančić, M. |
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| Ollier, Nadège |
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| Azevedo, Nuno Monteiro |
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| Landes, Michael |
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| Rignanese, Gian-Marco |
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Mckee, Vickie
in Cooperation with on an Cooperation-Score of 37%
Topics
Publications (9/9 displayed)
- 2022Single source precursor derived ZnO–PbO composite thin films for enhanced photocatalytic activitycitations
- 2022Synthesis and structural studies of quinolone-based Zn(II), Mn(II) and Ca(II) complexes involving supramolecular interactionscitations
- 2021Anion and solvent controlled growth of crystalline and amorphous zinc( ii ) coordination polymers and a molecular complexcitations
- 2021Anion and solvent controlled growth of crystalline and amorphous zinc(ii) coordination polymers and a molecular complexcitations
- 2020On the synthesis and structure of the copper-molybdenum oxide bronzes
- 2020Cubes on a string:a series of linear coordination polymers with cubane-like nodes and dicarboxylate linkerscitations
- 2020Optical and photocatalytic properties of biomimetic cauliflowered Ca 2 Mn 3 O 8 –CaO composite thin filmscitations
- 2020Remarkable reversal of 13 C-NMR assignment in d 1 , d 2 compared to d 8 , d 9 acetylacetonate complexes:Analysis and explanation based on solid-state MAS NMR and computationscitations
- 2020Remarkable reversal of 13C-NMR assignment in d1, d2 compared to d8, d9 acetylacetonate complexescitations
Places of action
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article
Remarkable reversal of 13C-NMR assignment in d1, d2 compared to d8, d9 acetylacetonate complexes
Abstract
<p><sup>13</sup>C solid-state MAS NMR spectra of a series of paramagnetic metal acetylacetonate complexes; [VO(acac)<sub>2</sub>] (d<sup>1</sup>, S = ½), [V(acac)<sub>3</sub>] (d<sup>2</sup>, S = 1), [Ni(acac)<sub>2</sub>(H<sub>2</sub>O)<sub>2</sub>] (d<sup>8</sup>, S = 1), and [Cu(acac)<sub>2</sub>] (d<sup>9</sup>, S = ½), were assigned using modern NMR shielding calculations. This provided a reliable assignment of the chemical shifts and a qualitative insight into the hyperfine couplings. Our results show a reversal of the isotropic <sup>13</sup>C shifts, δ<sub>iso</sub>(<sup>13</sup>C), for CH<sub>3</sub> and CO between the d<sup>1</sup> and d<sup>2</sup>versus the d<sup>8</sup> and d<sup>9</sup> acetylacetonate complexes. The CH<sub>3</sub> shifts change from about -150 ppm (d<sup>1,2</sup>) to roughly 1000 ppm (d<sup>8,9</sup>), whereas the CO shifts decrease from 800 ppm to about 150 ppm for d<sup>1,2</sup> and d<sup>8,9</sup>, respectively. This was rationalized by comparison of total spin-density plots and computed contact couplings to those corresponding to singly occupied molecular orbitals (SOMOs). This revealed the interplay between spin delocalization of the SOMOs and spin polarization of the lower-energy MOs, influenced by both the molecular symmetry and the d-electron configuration. A large positive chemical shift results from spin delocalization and spin polarization acting in the same direction, whereas their cancellation corresponds to a small shift. The SOMO(s) for the d<sup>8</sup> and d<sup>9</sup> complexes are σ-like, implying spin-delocalization on the CH<sub>3</sub> and CO groups of the acac ligand, cancelled only for CO by spin polarization. In contrast, the SOMOs of the d<sup>1</sup> and d<sup>2</sup> systems are π-like and a large CO-shift results from spin polarization, which accounts for the reversed assignment of δ<sub>iso</sub>(<sup>13</sup>C) for CH<sub>3</sub> and CO.</p>