Related Concept Videos
Lewis Acids and Bases
Diazonium Group Substitution: –OH and –H
Acidity of 1-Alkynes
The acidic strength of hydrocarbons follows the order: Alkynes > Alkenes > Alkanes. The strength of an acid is commonly expressed in units of pKa — the lower the pKa, the stronger the acid. Among the hydrocarbons, terminal alkynes have lower pKa values and are, therefore, more acidic. For example, the pKa values for ethane, ethene, and acetylene are 51, 44, and 25, respectively, as shown here.
Diazonium Group Substitution with Halogens and Cyanide: Sandmeyer and Schiemann Reactions
Ladder Diagrams: Complexation Equilibria
The formation constant, K1, for the formation of Cd(NH3)2+ complex from cadmium and ammonia is 3.55 × 102. Log K1 (i.e. pNH3) is 2.55, and...
Relative Reactivity of Carboxylic Acid Derivatives
A key factor in assessing the reactivity of the acid derivatives is the basicity of the substituent or the leaving group. The lower the basicity of the leaving group, the higher the reactivity of the derivative. The basicity of the leaving group follows this order:
Halide ions < Acyloxy ions < Alkoxy ions < Amine ions
You might also read
Related Articles
Articles linked to this work by shared authors, journal, and citation graph.
Assessing sexual health education in Canadian medical schools: a comprehensive curriculum review.
Oral hygiene agents at work: effects on <i>Streptococcus mutans</i> and caries risk.
Related Experiment Video
Updated: Sep 25, 2025

Efficient Synthesis of All-Carbon Quaternary Centers via the Conjugate Addition of Functionalized Monoorganozinc Bromides
Published on: May 26, 2019
Zinc Ammonio-dodecaborates: Synthesis, Lewis Acid Strength, and Reactivity.
Rudolf J Wehmschulte1, Brittany Bayliss1, Sydney Reed1
1Chemistry Program, Florida Institute of Technology, 150 West University Boulevard, Melbourne, Florida 32901, United States.
New zinc catalysts with chlorinated ammonio-closo-dodecaborate anions were synthesized. These catalysts showed low activity in 1-hexene hydrosilylation but moderate activity for benzophenone and acetophenone hydrosilylation.
More Related Videos
08:15Synthesis of Nine-atom Deltahedral Zintl Ions of Germanium and their Functionalization with Organic Groups
Published on: February 11, 2012
04:51Author Spotlight: Functionalizing Metal-Organic Frameworks: Advancements, Challenges, and the Power of Post-Synthetic Ligand Exchange
Published on: June 23, 2023
Area of Science:
- Organometallic Chemistry
- Catalysis
- Boron Chemistry
Background:
- Zinc salts with weakly coordinating anions are explored as catalysts.
- Ammonio-closo-dodecaborate anions offer alternatives to carborate anions.
- Understanding anion basicity and Lewis acidity is crucial for catalyst design.
Purpose of the Study:
- To synthesize and characterize zinc salts with novel chlorinated ammonio-closo-dodecaborate anions.
- To investigate the catalytic activity of these zinc complexes in hydrosilylation reactions.
- To correlate catalyst performance with anion properties like basicity and fluoride ion affinity.
Main Methods:
- Synthesis of zinc salts ([EtZn][A] and Zn[A]2) with various chlorinated ammonio-dodecaborate anions.
- Evaluation of catalytic activity in the hydrosilylation of 1-hexene, benzophenone, and acetophenone.
- Determination of anion basicity and fluoride ion affinities (FIAs) of the zinc complexes.
Main Results:
- Zinc salts with [Me3NB12Cl11]-, [Pr3NB12H5Cl6]-, [Bu3NB12H4Cl7]-, and [Hex3NB12H5Cl6]- anions were successfully prepared.
- Anion [Hex3NB12H5Cl6]- exhibits basicity similar to triflimide.
- Fluoride ion affinities of [EtZn][Pr3NB12H5Cl6] and Zn[Pr3NB12H5Cl6]2 are lower than established Lewis acids.
- Catalytic activity was low for 1-hexene hydrosilylation and moderate for benzophenone and acetophenone hydrosilylation.
Conclusions:
- Higher anion basicity and lower Lewis acidity of zinc centers correlate with reduced catalytic activity.
- Chlorinated ammonio-closo-dodecaborate anions present tunable properties for catalyst development.
- The investigated zinc catalysts show potential but require further optimization for efficient hydrosilylation.