Related Experiment Video
Updated: Jul 17, 2025
08:46
Preparation and Reactivity of a Triphosphenium Bromide Salt: A Convenient and Stable Source of PhosphorusI
Published on: November 22, 2016
7.8K
Exploring phosphoryl oxygen basicity in U(VI) complexation: A comparative study from trialkyl phosphate to phosphine
Aditya Ramesh Sachin1,2, Gopinadhanpillai Gopakumar1,2, Cherukuri Venkata Siva Brahmananda Rao1,2
1Indira Gandhi Centre for Atomic Research, Kalpakkam, India.
Journal of Computational Chemistry
|September 2, 2023
Summary
Ligand structure significantly impacts uranium extraction efficiency. Longer alkyl chains on ligands enhance stability through dispersion interactions, favoring uranyl ions (U(VI)).
Area of Science:
- Inorganic Chemistry
- Materials Science
- Nuclear Chemistry
Background:
- The "basicity of the phosphoryl oxygen" is a traditional factor considered for extraction efficiency.
- Understanding ligand-metal interactions is crucial for optimizing solvent extraction processes.
Purpose of the Study:
- To thoroughly examine the conventional argument of extraction efficiency dependence on phosphoryl oxygen basicity.
- To investigate the role of ligand electronic structure, alkyl chain length, and steric effects in uranium complexation.
- To elucidate the contributions of orbital and dispersion interactions in ligand selectivity for uranyl ions.
Main Methods:
- Computational studies of electronic structures for various ligands (phosphate, phosphonate, phosphinate, phosphine oxide) and their uranium complexes.
- Analysis of steric repulsion and stabilizing interactions (orbital, dispersion) upon complexation.
- Evaluation of ligand properties like electronegative environment around phosphorus and dipole moment.
Main Results:
- Longer alkyl chains on ligands induce destabilizing strain and steric repulsion during complexation.
- Stabilizing orbital and dispersion interactions compensate for repulsions, forming stable uranium complexes.
- Dispersion interactions become more significant with increased chain length, driving preference for U(VI) ions.
- Phosphine oxide ligands show preference for U(VI) due to enhanced orbital interactions and significant dispersion forces.
Conclusions:
- Extraction efficiency is influenced by a combination of electronic, steric, and dispersion interactions, not solely basicity.
- Ligand design with longer alkyl chains can enhance selectivity for uranyl species through significant dispersion interactions.
- Understanding these complex interactions is key to developing advanced ligands for efficient uranium solvent extraction.
Related Concept Videos
01:23Titration of Polyprotic Acids with a Strong Base
1.8K
Titration of a polyprotic acid, which contains multiple ionizable protons, involves distinct dissociation steps, each with its own dissociation constant (Ka). Each successive Ka is weaker than the previous one. In the titration of a polyprotic acid like sulfurous acid with a strong base such as sodium hydroxide, the base first neutralizes the initial ionizable proton, forming an intermediate species (e.g., hydrogen sulfite ions). This step's titration curve resembles that of a weak...
1.8K
02:36Acidity and Basicity of Alcohols and Phenols
19.2K
Like water, alcohols are weak acids and bases. This is attributed to the polarization of the O–H bond making the hydrogen partially positive. Moreover, the electron pairs on the oxygen atom of alcohol make it both basic and nucleophilic. Protonation of an alcohol converts hydroxide, a poor leaving group, into water—a good one. The two acid–base equilibria corresponding to ethanol are depicted below.
19.2K
03:08Hydroboration-Oxidation of Alkenes
8.4K
In addition to the oxymercuration–demercuration method, which converts the alkenes to alcohols with Markovnikov orientation, a complementary hydroboration-oxidation method yields the anti-Markovnikov product. The hydroboration reaction, discovered in 1959 by H.C. Brown, involves the addition of a B–H bond of borane to an alkene giving an organoborane intermediate. The oxidation of this intermediate with basic hydrogen peroxide forms an alcohol.
8.4K
02:08Titration of a Polyprotic Acid
96.7K
A polyprotic acid contains more than one ionizable hydrogen and undergoes a stepwise ionization process. If the acid dissociation constants of the ionizable protons differ sufficiently from each other, then the titration curve for such polyprotic acid generates a distinct equivalence point for each of its ionizable hydrogens. Therefore, titration of a diprotic acid results in the formation of two equivalence points, whereas the titration of a triprotic acid results in the formation of three...
96.7K
01:14Aldehydes and Ketones to Alkenes: Wittig Reaction Mechanism
3.6K
The Wittig reaction, which converts aldehydes or ketones to alkenes using phosphorus ylides, proceeds through a nucleophilic addition‒elimination process.
The reaction begins with the nucleophilic addition between a phosphorus ylide and the carbonyl compound. Due to its carbanionic character, phosphorus ylide acts as a strong nucleophile and attacks the electrophilic carbonyl group. This generates a charge-separated dipolar intermediate called betaine. The negatively charged oxygen atom and...
The reaction begins with the nucleophilic addition between a phosphorus ylide and the carbonyl compound. Due to its carbanionic character, phosphorus ylide acts as a strong nucleophile and attacks the electrophilic carbonyl group. This generates a charge-separated dipolar intermediate called betaine. The negatively charged oxygen atom and...
3.6K
01:11ortho–para-Directing Activators: –CH3, –OH, –NH2, –OCH3
6.1K
All ortho–para directors, excluding halogens, are activating groups. These groups donate electrons to the ring, making the ring carbons electron-rich. Consequently, the reactivity of the aromatic ring towards electrophilic substitution increases. For instance, the nitration of anisole is about 10,000 times faster than the nitration of benzene. The electron-donating effect of the methoxy group in anisole activates the ortho and para positions on the ring and stabilizes the corresponding...
6.1K