Organoantimony chemistry is the chemistry of compounds containing a

carbon Carbon () is a chemical element with the symbol C and atomic number 6. It is nonmetallic and tetravalent—its atom making four electrons available to form covalent chemical bonds. It belongs to group 14 of the periodic table. Carbon mak ...

antimony Antimony is a chemical element with the symbol Sb (from la, stibium) and atomic number 51. A lustrous gray metalloid, it is found in nature mainly as the sulfide mineral stibnite (Sb2S3). Antimony compounds have been known since ancient t ...

(Sb)

chemical bond A chemical bond is a lasting attraction between atoms or ions that enables the formation of molecules and crystals. The bond may result from the electrostatic force between oppositely charged ions as in ionic bonds, or through the sharing of ...

. Relevant

oxidation states In chemistry, the oxidation state, or oxidation number, is the hypothetical charge of an atom if all of its bonds to different atoms were fully ionic. It describes the degree of oxidation (loss of electrons) of an atom in a chemical compound. C ...

are Sb(V) and Sb(III). The toxicity of antimony limits practical application in

organic chemistry Organic chemistry is a subdiscipline within chemistry involving the scientific study of the structure, properties, and reactions of organic compounds and organic materials, i.e., matter in its various forms that contain carbon atoms.Clayden, ...

Organoantimony(V) chemistry

Antimony compounds of the type R₅Sb (stiboranes) can be synthesised from trivalent Sb precursors: :Ph₃Sb + Cl₂ → Ph₃SbCl₂ :Ph₃SbCl₂ + 2 PhLi → Ph₅Sb Asymmetric compounds can also be obtained through the stibonium ion: :R₅Sb + X₂ → ₄Sbsup>+ : ₄Sbsup>+ + R'MgX → R₄R'Sb Just as in the related organobismuth compounds (same

group 15 A pnictogen ( or ; from grc, πνῑ́γω "to choke" and -gen, "generator") is any of the chemical elements in group 15 of the periodic table. Group 15 is also known as the nitrogen group or nitrogen family. Group 15 consists of the ...

), organoantimony(V) compounds form

onium An onium (plural: onia) is a bound state of a particle and its antiparticle. These states are usually named by adding the suffix ''-onium'' to the name of one of the constituent particles (replacing an ''-on'' suffix when present), with one excep ...

compounds and

ate complex In chemistry, an ate complex is a salt formed by the reaction of a Lewis acid with a Lewis base whereby the central atom (from the Lewis acid) increases its valence and gains a negative formal charge. (In this definition, the meaning of valence i ...

es. Pentaphenylantimony decomposes at 200 °C to

triphenylstibine Triphenylstibine is the chemical compound with the formula Sb(C6H5)3. Abbreviated SbPh3, this colourless solid is often considered the prototypical organoantimony compound. It is used as a ligand in coordination chemistry and as a reagent in o ...

and

biphenyl Biphenyl (also known as diphenyl, phenylbenzene, 1,1′-biphenyl, lemonene or BP) is an organic compound that forms colorless crystals. Particularly in older literature, compounds containing the functional group consisting of biphenyl less one ...

. It forms a

trigonal bipyramidal molecular geometry In chemistry, a trigonal bipyramid formation is a molecular geometry with one atom at the center and 5 more atoms at the corners of a triangular bipyramid. This is one geometry for which the bond angles surrounding the central atom are not iden ...

. In the related Me₅Sb all methyl protons are equivalent at -100 °C in

proton NMR Proton nuclear magnetic resonance (proton NMR, hydrogen-1 NMR, or 1H NMR) is the application of nuclear magnetic resonance in NMR spectroscopy with respect to hydrogen-1 nuclei within the molecules of a substance, in order to determine the struct ...

. Compounds of the type R₄SbX tend to form dimers.

Organoantimony(III) chemistry

Compounds of the type R₃Sb (stibines) can be accessed by reaction of

antimony trichloride Antimony trichloride is the chemical compound with the formula SbCl3. It is a soft colorless solid with a pungent odor and was known to alchemists as butter of antimony. Preparation Antimony trichloride is prepared by reaction of chlorine with an ...

with

organolithium In organometallic chemistry, organolithium reagents are chemical compounds that contain carbon–lithium (C–Li) bonds. These reagents are important in organic synthesis, and are frequently used to transfer the organic group or the lithium atom ...

or Grignard reagents. :SbCl₃ + 3 RLi (or RMgCl) → R₃Sb Typical reactions are: :R₃Sb + Br₂ → R₃SbBr₂ :R₃Sb + O₂ → R₃SbO :R₃Sb + Na + NH₃ → R₂SbNa :R₃Sb + B₂H₆ → R₃Sb·BH₃ Stibanes are weak Lewis acids and therefore ate complexes are not encountered. On the other hand, they have good donor properties and are therefore widely used in coordination chemistry. R₃Sb compounds are more air-sensitive than the R₅Sb counterparts. Antimony

Metallocene A metallocene is a compound typically consisting of two cyclopentadienyl anions (, abbreviated Cp) bound to a metal center (M) in the oxidation state II, with the resulting general formula Closely related to the metallocenes are the metallocene d ...

s are known as well: :14SbI₃ + 3 ( Cp*Al)₄ → Cp*Sbsup>+ lI₄sup>− + 8Sb + 6 AlI₃ The Cp*-Sb-Cp* angle is 154°. The cyclic compound

stibole Stibole is a theoretical heterocyclic organic compound, a five-membered ring with the formula C4 H4 SbH. It is classified as a metallole. It can be viewed as a structural analog of pyrrole, with antimony replacing the nitrogen atom of pyrrole. Su ...

, a

structural analog A structural analog (analogue in modern traditional English; Commonwealth English), also known as a chemical analog or simply an analog, is a compound having a structure similar to that of another compound, but differing from it in respect to a c ...

of pyrrole, has not been isolated, but substituted derivatives known as stiboles are known.

Organoantimony(II) chemistry

Distibines have a Sb-Sb single bond and are of some interest as

thermochromic Thermochromism is the property of substances to change color due to a change in temperature. A mood ring is an excellent example of this phenomenon, but thermochromism also has more practical uses, such as baby bottles which change to a differen ...

materials. For example, tetramethyldistibine is colorless as a gas, yellow as a liquid, red as solid just below the melting point of 18.5 °C and again yellow well below the melting point.''Organoantimony compounds with element-element bonds'' H.J. Breunig, R. Rosler Coordination Chemistry Reviews 163 (1997) 33-53

References

{{ChemicalBondsToCarbon *

Organoantimony(V) chemistry

Organoantimony(III) chemistry

Organoantimony(II) chemistry

See also

References