A versatile gold synthon for acetylene C-H bond activation
George C Fortman1, Albert Poater, Jack W Levell
1EaStCHEM School of Chemistry, University of St Andrews, St Andrews, Scotland, UK. snolan@st-andrews.ac.uk.
Dalton Transactions (Cambridge, England : 2003)
|October 6, 2010
Summary
Gold hydroxide reacts with acetylene derivatives to form gold-acetylide bonds, yielding water or silanol. This efficient synthesis provides insights into gold chemistry and reaction mechanisms.
Area of Science:
- Organometallic Chemistry
- Gold Catalysis
- Synthetic Chemistry
Background:
- Gold complexes are increasingly utilized in catalysis and materials science.
- Understanding the reactivity of gold hydroxide precursors is crucial for developing new synthetic methodologies.
Purpose of the Study:
- To investigate the reaction of a gold hydroxide complex with terminal alkynes.
- To characterize the resulting gold-acetylide compounds and explore their properties.
- To elucidate the reaction mechanism using computational methods.
Main Methods:
- Reaction of N,N'-bis(2,6-diisopropylphenyl)imidazol-2-ylidene gold hydroxide ([Au(OH)(IPr)]) with acetylene and trimethylsilylacetylene.
- Isolation and characterization of products, including X-ray crystallography.
- UV-vis absorption and emission spectroscopy.
- Density Functional Theory (DFT) calculations.
Main Results:
- Clean formation of gold-acetylide bonds with high yields (>85%).
- Concomitant formation of water or trimethylsilanol as byproducts.
- Detailed structural analysis of gold acetylides and their photophysical properties.
- DFT calculations provided mechanistic insights into the reaction pathway.
Conclusions:
- The gold hydroxide precursor efficiently synthesizes gold acetylides.
- The study offers a facile route to functionalized gold acetylides with potential applications.
- Mechanistic understanding aids in designing future gold-mediated transformations.
Related Concept Videos
02:27Preparation of Alkynes: Alkylation Reaction
Introduction
Alkylation of terminal alkynes with primary alkyl halides in the presence of a strong base like sodium amide is one of the common methods for the synthesis of longer carbon-chain alkynes. For example, treatment of 1-propyne with sodium amide followed by reaction with ethyl bromide yields 2-pentyne.
Alkylation of terminal alkynes with primary alkyl halides in the presence of a strong base like sodium amide is one of the common methods for the synthesis of longer carbon-chain alkynes. For example, treatment of 1-propyne with sodium amide followed by reaction with ethyl bromide yields 2-pentyne.
02:34Preparation of Alkynes: Dehydrohalogenation
Introduction
Alkynes can be prepared by dehydrohalogenation of vicinal or geminal dihalides in the presence of a strong base like sodium amide in liquid ammonia. The reaction proceeds with the loss of two equivalents of hydrogen halide (HX) via two successive E2 elimination reactions.
Alkynes can be prepared by dehydrohalogenation of vicinal or geminal dihalides in the presence of a strong base like sodium amide in liquid ammonia. The reaction proceeds with the loss of two equivalents of hydrogen halide (HX) via two successive E2 elimination reactions.
02:24Reduction of Alkynes to cis-Alkenes: Catalytic Hydrogenation
Introduction
Like alkenes, alkynes can be reduced to alkanes in the presence of transition metal catalysts such as Pt, Pd, or Ni. The reaction involves two sequential syn additions of hydrogen via a cis-alkene intermediate.
Like alkenes, alkynes can be reduced to alkanes in the presence of transition metal catalysts such as Pt, Pd, or Ni. The reaction involves two sequential syn additions of hydrogen via a cis-alkene intermediate.
01:11Electrophilic Aromatic Substitution: Friedel–Crafts Acylation of Benzene
The Friedel–Crafts acylation reactions involve the addition of an acyl group to an aromatic ring. These reactions proceed via electrophilic aromatic substitution by employing an acyl chloride and a Lewis acid catalyst such as aluminum chloride to form aryl ketone.
02:37Structure and Physical Properties of Alkynes
Introduction:
In nature, compounds containing both carbon and hydrogen are known as "hydrocarbons". Aliphatic hydrocarbons are compounds whose molecules contain saturated single bonds (i.e., alkanes) or unsaturated double or triple bonds. Alkenes contain carbon–carbon double bonds and have a structural formula CnH2n. Unsaturated hydrocarbons containing carbon–carbon triple bonds are called "alkynes" and are structurally represented by the formula CnH2n-2.
The simplest alkyne is ethyne, or...
In nature, compounds containing both carbon and hydrogen are known as "hydrocarbons". Aliphatic hydrocarbons are compounds whose molecules contain saturated single bonds (i.e., alkanes) or unsaturated double or triple bonds. Alkenes contain carbon–carbon double bonds and have a structural formula CnH2n. Unsaturated hydrocarbons containing carbon–carbon triple bonds are called "alkynes" and are structurally represented by the formula CnH2n-2.
The simplest alkyne is ethyne, or...
01:12Cycloaddition Reactions: MO Requirements for Photochemical Activation
Some cycloaddition reactions are activated by heat, while others are initiated by light. For example, a [2 + 2] cycloaddition between two ethylene molecules occurs only in the presence of light. It is photochemically allowed but thermally forbidden.