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1,4,7-Trithiacyclononane can be prepared within the coordination sphere of a metal, and then isolated by decomplexation.
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chemistry
Chemistry is the science, scientific study of the properties and behavior of matter. It is a natural science that covers the Chemical element, elements that make up matter to the chemical compound, compounds made of atoms, molecules and ions ...
, decomplexation refers to the removal of a ligand
In coordination chemistry, a ligand is an ion or molecule (functional group) that binds to a central metal atom to form a coordination complex. The bonding with the metal generally involves formal donation of one or more of the ligand's electr ...
from a coordination complex
A coordination complex consists of a central atom or ion, which is usually metallic and is called the ''coordination centre'', and a surrounding array of bound molecules or ions, that are in turn known as ''ligands'' or complexing agents. Many ...
. Decomplexation is of particular interest when the ligand has been synthesized within the coordination sphere of the metal, as is often the case in 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 so ...
.
Decomplexation by ligand displacement
Ligands can be decomplexed by displacement with another ligand, e.g., a highly basic ligand or the use of high pressures ofcarbon monoxide
Carbon monoxide (chemical formula CO) is a colorless, poisonous, odorless, tasteless, flammable gas that is slightly less dense than air. Carbon monoxide consists of one carbon atom and one oxygen atom connected by a triple bond. It is the simple ...
. Arene
Aromatic compounds, also known as "mono- and polycyclic aromatic hydrocarbons", are organic compounds containing one or more aromatic rings. The parent member of aromatic compounds is benzene. The word "aromatic" originates from the past grouping ...
s are liberated from (arene)Cr(CO)3 with pyridine
Pyridine is a basic heterocyclic organic compound with the chemical formula . It is structurally related to benzene, with one methine group replaced by a nitrogen atom. It is a highly flammable, weakly alkaline, water-miscible liquid with a d ...
:
:(arene)Cr(CO)3 + 3 C5H5N → Cr(CO)3(NC5H5)3 + arene
In this case Cr(CO)3(pyridine)3 can be recycled. Illustrative of this approach is the synthesis of (–)-steganone via a chromium haloarene complex. The synthesis is completed by decomplexation, liberating the natural product.
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1,4,7-Trithiacyclononane can be prepared within the coordination sphere of a metal, and then isolated by decomplexation.
:
Oxidative decomplexation
Another popular method for decomplexation involves oxidation of a low valent complex. Oxidants include air,dioxirane
In chemistry, dioxirane is a compound with formula , whose molecule consists of a ring with one carbon and two oxygen atoms, and two hydrogen atoms attached to the carbon. It is a heterocyclic compound, the smallest cyclic organic peroxide.
T ...
, ceric ammonium nitrate
Ceric ammonium nitrate (CAN) is the inorganic compound with the formula . This orange-red, water-soluble cerium salt is a specialised oxidizing agent in organic synthesis and a standard oxidant in quantitative analysis.
Preparation, properties, ...
(CAN), and halogens. Oxidants are selected to avoid reaction with the released organic ligand. Illustrative is the use of ferric chloride to release alkynes from Co2(C2R2)(CO)6. One drawback to this method is that the organometallic center is usually destroyed. One example of oxidative decomplexation involves the CAN-induced release and trapping of cyclobutadiene
Cyclobutadiene is an organic compound with the formula . It is very reactive owing to its tendency to dimerize. Although the parent compound has not been isolated, some substituted derivatives are robust and a single molecule of cyclobutadiene is ...
from cyclobutadieneiron tricarbonyl
Cyclobutadieneiron tricarbonyl is an organoiron compound with the formula Fe(C4H4)(CO)3. It is a yellow solid that is soluble in organic solvents. It has been used in organic chemistry as a precursor for cyclobutadiene, which is an elusive species ...
. {{cite journal, title=Cyclobutadiene In Synthesis: ''endo''-Tricyclo .4.0.02,5eca-3,8-diene-7,10-dione, authors=L. Brener, J. S. Mckennis, R. Pettit, journal=Org. Synth., year=1976, volume=55, page=43, doi=10.15227/orgsyn.055.0043
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