Organoantimony chemistry is the chemistry of compounds containing a carbon to antimony (Sb) chemical bond. Relevant oxidation states are SbV and SbIII. The toxicity of antimony [1] limits practical application in organic chemistry. [2]
An organoantimony synthesis typically begins with tricoordinate antimony compounds, called stibines. Antimony trichloride reacts with organolithium or Grignard reagents to give compounds of the form R3Sb:
Stibines are weak Lewis acids and do not form ate complexes. As soft Lewis donors, they see wide use in coordination chemistry [3] : 348 and typically react through oxidative addition:
This property also sensitizes them to air.
If reduced instead, stibanes typically release substituents (ligands): [3] : 443
The cyclic compound stibole, a structural analog of pyrrole, has not been isolated, but substituted derivatives have. Antimony metallocenes are known as well:
The Cp*-Sb-Cp* angle is 154°.
Pentacoordinate antimony compounds are called stiboranes, and can be synthesised from stibines and halogens:
Like their heavier congeners, the organobismuth compounds, stiboranes form onium compounds and ate complexes. Asymmetric compounds can also be obtained through the stibonium ion:
Stibonium halides (R4SbX) tend to dimerize.
Trigonal-bipyramidal molecule pentaphenylantimony decomposes at 200 °C to triphenylstibine and biphenyl. In the related Me5Sb, proton NMR at -100 °C cannot resolve different methyl protons.
Distibines are formally SbII compounds, but feature tricoordinate Sb atoms with a single Sb-Sb bond. They may have interest as thermochromes. For example, tetramethyldistibine is colorless when gas, yellow when liquid, red when solid just below the melting point of 18.5 °C, shiny-blue when cooler, and again yellow at cryogenic temperatures. [5] [3] : 442 A typical synthesis first displaces an SbIII halide with an alkali metal and then reduces the resulting anion with ethylene dichloride. [3] : 781–783
Like its lighter congener, arsenic, organoantimony compounds can be reduced to cyclic oligomers that are formally antimony(I) compounds. [3] : 563–577
SbV-N bonds are unstable, except where the N is also bonded to other electron-withdrawing substituents. [6]
Stibine oxides undergo a sort of polarized-olefin metathesis. For example, they mediate a carbonyl-imine exchange (Ar is any activated arene): [7] : 399
Ph3Sb=NSO2Ar + PhC=O → Ph3Sb=O + PhC=NSO2Ar
The effect may extend vinylically: [8] In contrast, unstabilized ylides (R3Sb=CR'2; R' not electron-withdrawing) form only with difficulty (e.g. diazo reagents). [7] : 399–400
Like other metals, stibanes vicinal to a leaving group can eliminate before a proton. For example, diphenyl(β-hydroxyphenethyl)stibine decomposes in heat or acid to styrene: [7] : 400–402
As tertiary stibines also insert into haloalkyl bonds, tertiary stibines are powerful dehalogenating agents. [7] : 403 However, stibanes poorly imitate active metal organometallics: only with difficulty do their ligands add to carbonyls or they power noble-metal cross couplings. [7] : 403–405
Stiboranes are gentle oxidants, converting acyloins to diketones and thiols to disulfides. [7] : 406–408 In air, tris(thiophenyl)stibine catalyzes a Hunsdiecker-like decarboxylative oxidation of anhydrides to alcohols. [7] : 411
In ultraviolet light, distibines radicalize; the resulting radicals can displace iodide. [3] : 766
Zinc chloride is an inorganic chemical compound with the formula ZnCl2·nH2O, with n ranging from 0 to 4.5, forming hydrates. Zinc chloride, anhydrous and its hydrates, are colorless or white crystalline solids, and are highly soluble in water. Five hydrates of zinc chloride are known, as well as four forms of anhydrous zinc chloride.
Stibine (IUPAC name: stibane) is a chemical compound with the formula SbH3. A pnictogen hydride, this colourless, highly toxic gas is the principal covalent hydride of antimony, and a heavy analogue of ammonia. The molecule is pyramidal with H–Sb–H angles of 91.7° and Sb–H distances of 170.7 pm (1.707 Å). The smell of this compound from usual sources (like from reduction of antimony compounds) is reminiscent of arsine, i.e. garlic-like.
Hydroperoxides or peroxols are compounds of the form ROOH, where R stands for any group, typically organic, which contain the hydroperoxy functional group. Hydroperoxide also refers to the hydroperoxide anion and its salts, and the neutral hydroperoxyl radical (•OOH) consist of an unbond hydroperoxy group. When R is organic, the compounds are called organic hydroperoxides. Such compounds are a subset of organic peroxides, which have the formula ROOR. Organic hydroperoxides can either intentionally or unintentionally initiate explosive polymerisation in materials with unsaturated chemical bonds.
Zeise's salt, potassium trichloro(ethylene)platinate(II) hydrate, is the chemical compound with the formula K[PtCl3(C2H4)]·H2O. The anion of this air-stable, yellow, coordination complex contains an η2-ethylene ligand. The anion features a platinum atom with a square planar geometry. The salt is of historical importance in the area of organometallic chemistry as one of the first examples of a transition metal alkene complex and is named for its discoverer, William Christopher Zeise.
Technetium compounds are chemical compounds containing the chemical element technetium. Technetium can form multiple oxidation states, but often forms in the +4 and +7 oxidation states. Because technetium is radioactive, technetium compounds are extremely rare on Earth.
Bromine compounds are compounds containing the element bromine (Br). These compounds usually form the -1, +1, +3 and +5 oxidation states. Bromine is intermediate in reactivity between chlorine and iodine, and is one of the most reactive elements. Bond energies to bromine tend to be lower than those to chlorine but higher than those to iodine, and bromine is a weaker oxidising agent than chlorine but a stronger one than iodine. This can be seen from the standard electrode potentials of the X2/X− couples (F, +2.866 V; Cl, +1.395 V; Br, +1.087 V; I, +0.615 V; At, approximately +0.3 V). Bromination often leads to higher oxidation states than iodination but lower or equal oxidation states to chlorination. Bromine tends to react with compounds including M–M, M–H, or M–C bonds to form M–Br bonds.
Organotitanium chemistry is the science of organotitanium compounds describing their physical properties, synthesis, and reactions. Organotitanium compounds in organometallic chemistry contain carbon-titanium chemical bonds. They are reagents in organic chemistry and are involved in major industrial processes.
Bismuth chloride (or butter of bismuth) is an inorganic compound with the chemical formula BiCl3. It is a covalent compound and is the common source of the Bi3+ ion. In the gas phase and in the crystal, the species adopts a pyramidal structure, in accord with VSEPR theory.
The thallium halides include monohalides, where thallium has oxidation state +1, trihalides in which thallium generally has oxidation state +3, and some intermediate halides containing thallium with mixed +1 and +3 oxidation states. These salts find use in specialized optical settings, such as focusing elements in research spectrophotometers. Compared to the more common zinc selenide-based optics, materials such as thallium bromoiodide enable transmission at longer wavelengths. In the infrared, this allows for measurements as low as 350 cm−1 (28 μm), whereas zinc selenide is opaque by 21.5 μm, and ZnSe optics are generally only usable to 650 cm−1 (15 μm).
Organoarsenic chemistry is the chemistry of compounds containing a chemical bond between arsenic and carbon. A few organoarsenic compounds, also called "organoarsenicals," are produced industrially with uses as insecticides, herbicides, and fungicides. In general these applications are declining in step with growing concerns about their impact on the environment and human health. The parent compounds are arsane and arsenic acid. Despite their toxicity, organoarsenic biomolecules are well known.
Organobismuth chemistry is the chemistry of organometallic compounds containing a carbon to bismuth chemical bond. Applications are few. The main bismuth oxidation states are Bi(III) and Bi(V) as in all higher group 15 elements. The energy of a bond to carbon in this group decreases in the order P > As > Sb > Bi. The first reported use of bismuth in organic chemistry was in oxidation of alcohols by Frederick Challenger in 1934 (using Ph3Bi(OH)2). Knowledge about methylated species of bismuth in environmental and biological media is limited.
Polyhalogen ions are a group of polyatomic cations and anions containing halogens only. The ions can be classified into two classes, isopolyhalogen ions which contain one type of halogen only, and heteropolyhalogen ions with more than one type of halogen.
Pentamethylcyclopentadienyl rhodium dichloride dimer is an organometallic compound with the formula [(C5(CH3)5RhCl2)]2, commonly abbreviated [Cp*RhCl2]2 This dark red air-stable diamagnetic solid is a reagent in organometallic chemistry.
Nontrigonal pnictogen compounds refer to tricoordinate trivalent pnictogen compounds that are not of typical trigonal pyramidal molecular geometry. By virtue of their geometric constraint, these compounds exhibit distinct electronic structures and reactivities, which bestow on them potential to provide unique nonmetal platforms for bond cleavage reactions.
Among pnictogen group Lewis acidic compounds, unusual lewis acidity of Lewis acidic antimony compounds have long been exploited as both stable conjugate acids of non-coordinating anions, and strong Lewis acid counterparts of well-known superacids. Also, Lewis-acidic antimony compounds have recently been investigated to extend the chemistry of boron because of the isolobal analogy between the vacant p orbital of borane and σ*(Sb–X) orbitals of stiborane, and the similar electronegativities of antimony (2.05) and boron (2.04).
Americium compounds are compounds containing the element americium (Am). These compounds can form in the +2, +3, and +4, although the +3 oxidation state is the most common. The +5, +6 and +7 oxidation states have also been reported.
The stabilization of bismuth's +3 oxidation state due to the inert pair effect yields a plethora of organometallic bismuth-transition metal compounds and clusters with interesting electronics and 3D structures.
Stibinidenes are a class of organoantimony compounds in which the antimony center exhibits a formal oxidation state of +1. The parent stibinidenes have the formula R–Sb, with the antimony center possessing two lone pairs of electrons and a vacant 5p orbital. Reflecting their unusual low coordination number]] at [antimony]], stibinidines cannot be isolated. Instead, their oligomers or their adducts are often robust.
Organobismuth radical is a chemical species that has unpaired electrons on bismuth centers within organic frameworks. These radicals are part of the broader family of pnictogen-centered radicals, which include nitrogen, phosphorus, arsenic, antimony, and bismuth. Bismuth radicals, with a +2 oxidation state, are highly reactive and prone to degradation. They are sensitive to air and moisture, often undergoing disproportionation to form more stable bismuth species with different oxidation state: Bi(III) and Bi(0). This instability makes Bi(II) compounds challenging to isolate and handle. Despite these restrictions, significant progress has been made in recent years with the isolation and characterization of Bi(II) radicals. These species exhibit diverse reactivity, particularly in bond activation, radical polymerization, and cross-coupling reactions.
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