Organometallic chemistry
Organometallic chemistry is the study of organometallic compounds, chemical compounds containing at least one chemical bond between a carbon atom of an organic molecule and a metal, including alkali, alkaline earth, and transition metals, and sometimes broadened to include metalloids like boron, silicon, and selenium, as well.
Complexes where the organic ligands bind the metal through a heteroatom such as oxygen or nitrogen are considered coordination compounds (e.g., heme A and Fe(acac)3).
[1] For highly electropositive elements, such as lithium and sodium, the carbon ligand exhibits carbanionic character, but free carbon-based anions are extremely rare, an example being cyanide.
[7] Hapticity (η, lowercase Greek eta), describes the number of contiguous ligands coordinated to a metal.
The metal atoms in organometallic compounds are frequently described by their d electron count and oxidation state.
A wide variety of physical techniques are used to determine the structure, composition, and properties of organometallic compounds.
X-ray diffraction is a particularly important technique that can locate the positions of atoms within a solid compound, providing a detailed description of its structure.
[1][8] Ultraviolet-visible spectroscopy is a common technique used to obtain information on the electronic structure of organometallic compounds.
[1][8] Due to their high reactivity towards oxygen and moisture, organometallic compounds often must be handled using air-free techniques.
Air-free handling of organometallic compounds typically requires the use of laboratory apparatuses such as a glovebox or Schlenk line.
[1] Early developments in organometallic chemistry include Louis Claude Cadet's synthesis of methyl arsenic compounds related to cacodyl, William Christopher Zeise's[10] platinum-ethylene complex,[11] Edward Frankland's discovery of diethyl- and dimethylzinc, Ludwig Mond's discovery of Ni(CO)4,[1] and Victor Grignard's organomagnesium compounds.
(Although not always acknowledged as an organometallic compound, Prussian blue, a mixed-valence iron-cyanide complex, was first prepared in 1706 by paint maker Johann Jacob Diesbach as the first coordination polymer and synthetic material containing a metal-carbon bond.
[12]) The abundant and diverse products from coal and petroleum led to Ziegler–Natta, Fischer–Tropsch, hydroformylation catalysis which employ CO, H2, and alkenes as feedstocks and ligands.
Recognition of organometallic chemistry as a distinct subfield culminated in the Nobel Prizes to Ernst Fischer and Geoffrey Wilkinson for work on metallocenes.
In 2005, Yves Chauvin, Robert H. Grubbs and Richard R. Schrock shared the Nobel Prize for metal-catalyzed olefin metathesis.
[14] Almost all processes involving carbon monoxide rely on catalysts, notable examples being described as carbonylations.
These volatile compounds are decomposed along with ammonia, arsine, phosphine and related hydrides on a heated substrate via metalorganic vapor phase epitaxy (MOVPE) process in the production of light-emitting diodes (LEDs).
