Related Experiment Video
Updated: May 14, 2026
08:46
Preparation and Reactivity of a Triphosphenium Bromide Salt: A Convenient and Stable Source of Phosphorus(I)
Published on: November 22, 2016
Bis(phosphazenyl)phosphines: From Superbases to Superhydrides
Mario Damjanović1,2, Borislav Kovačević1,3
1Division of Physical Chemistry, Ruđer Bošković Institute, 10000 Zagreb, Croatia.
Molecules (Basel, Switzerland)
|May 13, 2026
Summary
New proton-sponge-like bisphosphines act as potent hydride donors, surpassing commercial options. Their design leverages phosphazene substituents and rigid scaffolds for enhanced reactivity in chemical reductions.
Area of Science:
- Organometallic Chemistry
- Computational Chemistry
- Organic Synthesis
Background:
- Phosphines are versatile ligands and reagents in organic chemistry.
- Superhydrides are powerful hydride donors, but their applications can be limited.
- Developing novel strong hydride donors is crucial for advancing synthetic methodologies.
Purpose of the Study:
- To design and computationally investigate novel bisphosphines with enhanced hydride-donating capabilities.
- To explore the potential of phosphazene substituents and rigid scaffolds in modulating electronic properties.
- To compare the hydricity of the designed bisphosphines with established superhydrides.
Main Methods:
- Computational investigation using density functional theory (DFT).
- Design of bisphosphine structures incorporating phosphazene substituents and rigid cage-like frameworks (pentacycloundecane, pentacyclododecane, seco-dodecahedradiene).
- Analysis of electronic structure and bonding to understand hydride-donating mechanisms.
Main Results:
- Designed bisphosphines exhibit significantly higher hydricities than LiEt3BH in their monoprotonated forms.
- Electron-donating phosphazenyl groups and intramolecular P→P dative interactions stabilize the dication intermediate, enhancing hydride release.
- Neutral bisphosphine forms display superbasic properties.
Conclusions:
- Proton-sponge-like bisphosphines represent a new class of exceptionally strong hydride donors.
- The combination of phosphazene substituents and rigid scaffolds is effective for tuning hydride-donating ability.
- These findings open avenues for developing advanced reagents in organic synthesis and catalysis.
Related Concept Videos
03:35Hybridization of Atomic Orbitals II
sp3d and sp3d 2 Hybridization
01:15α-Bromination of Carboxylic Acids: Hell–Volhard–Zelinski Reaction
The method to achieve α-brominated carboxylic acids using a mixture of phosphorus tribromide and bromine is known as the Hell–Volhard–Zelinski reaction. The reaction is catalyzed by phosphorus tribromide, which can be used directly or produced in situ from red phosphorus and bromine. The mechanism comprises PBr3 catalyzed conversion of acid to acid bromide and hydrogen bromide. The acid bromide enolizes to its enol form in the presence of HBr. The nucleophilic enol attacks the bromine molecule...
02:26Preparation and Reactions of Sulfides
Sulfides are the sulfur analog of ethers, just as thiols are the sulfur analog of alcohol. Like ethers, sulfides also consist of two hydrocarbon groups bonded to the central sulfur atom. Depending upon the type of groups present, sulfides can be symmetrical or asymmetrical. Symmetrical sulfides can be prepared via an SN2 reaction between 2 equivalents of an alkyl halide and one equivalent of sodium sulfide.
02:47Alkynes to Aldehydes and Ketones: Hydroboration-Oxidation
Introduction
One of the convenient methods for the preparation of aldehydes and ketones is via hydration of alkynes. Hydroboration-oxidation of alkynes is an indirect hydration reaction in which an alkyne is treated with borane followed by oxidation with alkaline peroxide to form an enol that rapidly converts into an aldehyde or a ketone. Terminal alkynes form aldehydes, whereas internal alkynes give ketones as the final product.
One of the convenient methods for the preparation of aldehydes and ketones is via hydration of alkynes. Hydroboration-oxidation of alkynes is an indirect hydration reaction in which an alkyne is treated with borane followed by oxidation with alkaline peroxide to form an enol that rapidly converts into an aldehyde or a ketone. Terminal alkynes form aldehydes, whereas internal alkynes give ketones as the final product.
01:01Acid Halides to Carboxylic Acids: Hydrolysis
Hydrolysis of acid halides is a nucleophilic acyl substitution reaction in which acid halides react with water to give carboxylic acids. The reaction occurs readily and does not require acid or a base catalyst.
As shown below, the mechanism involves a nucleophilic attack by water at the carbonyl carbon to form a tetrahedral intermediate. This is followed by the reformation of the carbon–oxygen π bond along with the departure of a halide ion. A final proton transfer step yields carboxylic acid...
As shown below, the mechanism involves a nucleophilic attack by water at the carbonyl carbon to form a tetrahedral intermediate. This is followed by the reformation of the carbon–oxygen π bond along with the departure of a halide ion. A final proton transfer step yields carboxylic acid...
01:26Radical Substitution: Hydrogenolysis of Alkyl Halides with Tributyltin Hydride
Radical substitution reactions can be used to remove functional groups from molecules. The hydrogenolysis of alkyl halides is one such reaction, where the weak Sn–H bond in tributyltin hydride reacts with alkyl halides to form alkanes. Here, the reagent Bu3SnH yields tributyltin halide as a byproduct.
The bonds formed in this reaction are stronger than the bonds broken, making it energetically favorable. The reaction follows a radical chain mechanism similar to radical halogenation reactions,...
The bonds formed in this reaction are stronger than the bonds broken, making it energetically favorable. The reaction follows a radical chain mechanism similar to radical halogenation reactions,...