Acetic acid as a proton shuttle in gold chemistry

July 24, 2015

Being found mostly in the native state, gold is one of the oldest elements known to man. The affection to gold was determined by it's unusual properties - heft, shine and ability to withstand oxidation and corrosion. The combination of properties determined gold use in the jewelry and as a coinage metal. The ancient alchemists working with gold were struggled by utmost chemical resistance of this element - it did not react with concentrated acids or alkali solutions even at high temperatures. Actually, it is the chemical inertness that makes gold to appear in a native form and not as a part of a mineral.

Later analysis established that gold compounds can not only compete with traditional nickel and palladium-based catalysts in the common reactions, but to surpass them. Besides that, gold compounds often demonstrated principally novel types of reactivity compared to well-established catalysts. This allowed chemists to discover a bunch of new chemical reactions and predetermined a fascinating boom in gold catalysis that we have observed in the recent years.

Professor Ananikov and co-workers introduced gold into well-known catalytic system which led to dramatic change of the reactivity and furnished the formation of novel gold-containing complexes. The complexes appeared to be air stable and were isolated in the individual state. A single crystal X-Ray diffraction study ascertained the existence of unique structural motif in the molecule, which can not be explained within conventional mechanistic framework.

The study was carried out using both theoretical and experimental approaches. Dedicated labeling of the reagents allowed observation of molecular re-organizations. Variation of reaction conditions helped to estimate key factors governing the discovered transformation. In addition, computational study of the reaction provided the models of certain intermediate steps, which were invisible for experimental investigation. The theoretical data obtained was in excellent agreement with experiment, proposing the reaction mechanism, where a molecule of acetic acid serves as a proton shuttle, transferring the hydrogen atom between the reaction centers.

The belief of gold inactivity towards chemical transformations resulted in the fact, that organometallic chemistry of gold was developed significantly later compared to other coinage metals (like silver, nickel or copper). Today, our goal is to "introduce gold catalysis as a valuable practical tool in fine organic chemistry, competitive with other transition metal catalysts", says Prof. Ananikov.
-end-
http://pubs.acs.org/doi/abs/10.1021/acs.organomet.5b00210

Institute of Organic Chemistry, Russian Academy of Sciences

Related Gold Articles from Brightsurf:

The "gold" in breast milk
Breast milk strengthens a child's immune system, supporting the intestinal flora.

From nanocellulose to gold
When nanocellulose is combined with various types of metal nanoparticles, materials are formed with many new and exciting properties.

Research brief: 'Fool's gold' may be valuable after all
In a breakthrough new study, scientists and engineers at the University of Minnesota have electrically transformed the abundant and low-cost non-magnetic material iron sulfide, also known as 'fool's gold' or pyrite, into a magnetic material.

Water molecules are gold for nanocatalysis
Nanocatalysts made of gold nanoparticles dispersed on metal oxides are very promising for the industrial, selective oxidation of compounds, including alcohols, into valuable chemicals.

As electronics shrink to nanoscale, will they still be good as gold?
As circuit interconnects shrink to nanoscale, will the pressure caused by thermal expansion when current flows through wires cause gold to behave more like a liquid than a solid -- making nanoelectronics unreliable?

Peppered with gold
Terahertz waves are becoming more important in science and technology.

No need to dig too deep to find gold!
Why are some porphyry deposits rich in copper while others contain gold?

An 18-carat gold nugget made of plastic
ETH researchers have created an incredibly lightweight 18-carat gold, using a matrix of plastic in place of metallic alloy elements.

What happens to gold nanoparticles in cells?
Gold nanoparticles, which are supposed to be stable in biological environments, can be degraded inside cells.

Turning 'junk' DNA into gold
Mining the rich uncharted territory of the genome or genetic material of a cancer cell has yielded gold for Princess Margaret scientists: new protein targets for drug development against prostate cancer.

Read More: Gold News and Gold Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.