# name
Assessement of the σ-donation of phosphorus ligands through the study of the published 1JPSe

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Treballs Finals de Grau de Química, Facultat de Química, Universitat de Barcelona, Any: 2026, Tutor: Arnald Grabulosa Rodríguez

# metadata.dc.description.abstract[].value
Phosphorus(III) ligands (PR3) are central to homogeneous catalysis, to the point of underpinning several Nobel Prizes in Chemistry.
Their importance lies in the fact that, upon coordination to the metal, they control the electron density and the steric environment of the metal centre and thereby govern the key steps of the catalytic cycle, giving rise to levels of activity and selectivity unattainable by other means. This control is possible thanks to their dual σ-donor and π-acceptor character, a delicate balance that can be finely tuned by modifying the groups bonded to the phosphorus. Such tunability is at their greatest advantage and the reason why measuring their σ-donor strength is worth to understand their electronic properties.
One of the most practical tools for assessing this property is Nuclear Magnetic Resonance (NMR) spectroscopy. When a phosphane (PR3) is converted into its selenide (Se=PR3), the one-bond coupling constant ¹JPSe reflects the s-character of the phosphorus lone pair through the Fermi-contact term. In accordance with Bent's rule, this value decreases when the substituents are good electron donors and increases when they are electron-withdrawing.
Although ¹JPSe values have been determined for several thousands of compounds, these data had never been compiled or analysed collectively. The present work addresses this gap through a systematic literature search in SciFinder and Reaxys, complemented by cited reference searching of the seminal papers on the topic. As a result, in this TFG 1250 publications reporting ¹JPSe values have been identified and collected. All the documentation was managed with EndNote, and, from a representative sample of 250 articles, the relevant information was organised in an Excel workbook structured into separate sheets according to ligand type. For each compound, the SMILES code, the ³¹P chemical shift, the ¹JPSe value and the experimental measurement conditions were recorded, which made it possible to classify the ligands according to the atoms directly bonded to phosphorus and to compare them across different families.
The analysis of the data reveals two important facts. Firstly, the solvent appreciably influences the value of the coupling constant, so comparisons were restricted to data in similar solvents. Secondly, the nature of the atoms bonded to phosphorus determines a clear trend in the ¹JPSe values, consistent with the differences in electronegativity between the substituents.
These findings confirm the value of phosphane selenides as simple model systems and of the ¹JPSe constant as a reliable NMR descriptor for ranking σ-donor ability within structurally related ligand families. The work also delivers an expandable database that may prove useful for the study, parametrisation and rational design of new phosphorus ligands

# metadata.dc.rights[].value
cc-by-nc-nd (c) Ríos García, Dakota, 2026

# metadata.dc.title[].value
Assessement of the σ-donation of phosphorus ligands through the study of the published 1JPSe

# metadata.dc.title.alternative[].value
Avaluació de la donació σ del lligands fosforats mitjançant l’estudi de les 1JPSe publicades