Phosphole

Last updated
Phosphole
UnsubstitutedPhosphole.png
Phosphole B3LYP 6-31G.png
Names
Preferred IUPAC name
1H-Phosphole [1]
Identifiers
3D model (JSmol)
ChemSpider
PubChem CID
  • InChI=1S/C4H5P/c1-2-4-5-3-1/h1-5H
  • P1C=CC=C1
Properties
C4H5P
Molar mass 84.058 g·mol−1
Related compounds
Related compounds
 Pyrrole, bismole, arsole, stibole; phosphorine
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Phosphole is the organic compound with the chemical formula C
4H
4PH; it is the phosphorus analog of pyrrole. The term phosphole also refers to substituted derivatives of the parent heterocycle. These compounds are of theoretical interest but also serve as ligands for transition metals and as precursors to more complex organophosphorus compounds.

Contents

Triphosphole, C
2H
3P
3, is a heterocycle with 3 phosphorus atoms.

Pentaphosphole, P
5H, is a cyclic compound with 5 phosphorus atoms.

Structure and bonding

Unlike the related 5-membered heterocycles pyrrole, thiophene, and furan, the aromaticity of phospholes is diminished, reflecting the reluctance of phosphorus to delocalize its lone pair. [2] The main indication of this difference is the pyramidalization of phosphorus. The absence of aromaticity is also indicated by the reactivity of phospholes. [3] Phospholes undergo different cycloaddition reactions; coordination properties of phospholes are also well studied. [4]

Preparation

The parent phosphole was first described in 1983. It was prepared by low-temperature protonation of lithium phospholide. [5] Pentaphenylphosphole was reported in 1953. [6] One route to phospholes is via the McCormack reaction, involving the addition of a 1,3-diene to a phosphonous chloride (RPCl2) followed by dehydrohalogenation. [7] Phenylphospholes can be prepared via zirconacyclopentadienes by reaction with PhPCl2. [8]

Phospholes.png

Reactivity

The behavior of the secondary phospholes, those with P−H bond, is dominated by the reactivity of this group. [5] The parent phosphole readily rearranges by migration of H from P to carbon-2, followed by dimerization.

Most phospholes are tertiary, typically P-methyl or P-phenyl. The nonaromaticity of these phospholes is manifested in their reactivity but the P−C bonds remain intact. For example, they undergo Diels–Alder reactions with electrophilic alkynes. They are basic at P, serving as ligands. [5]

2,5-Diphenyl phospholes can be functionalised by deprotonation followed by P-acylation then a 1H, 2H, 3H phospholide equilibrium resulting in a 1:3 shift of the acyl group. [9]

Phospholes can also be turned into β-functional phosphabenzenes (phosphinines, or phosphorine) via functionalisation by imidoyl chloride and insertion. [10]

See also

Related Research Articles

Pyrrole is a heterocyclic aromatic organic compound, a five-membered ring with the formula C4H4NH. It is a colorless volatile liquid that darkens readily upon exposure to air. Substituted derivatives are also called pyrroles, e.g., N-methylpyrrole, C4H4NCH3. Porphobilinogen, a trisubstituted pyrrole, is the biosynthetic precursor to many natural products such as heme.

Oxime

An oxime is a chemical compound belonging to the imines, with the general formula RR'C=NOH, where R is an organic side-chain and R' may be hydrogen, forming an aldoxime, or another organic group, forming a ketoxime. O-substituted oximes form a closely related family of compounds. Amidoximes are oximes of amides with general structure R1C(=NOH)NR2R3.

In organic chemistry, nitration is a general class of chemical processes for the introduction of a nitro group into an organic compound. The term also is applied incorrectly to the different process of forming nitrate esters between alcohols and nitric acid. The difference between the resulting molecular structures of nitro compounds and nitrates is that the nitrogen atom in nitro compounds is directly bonded to a non-oxygen atom, whereas in nitrate esters, the nitrogen is bonded to an oxygen atom that in turn usually is bonded to a carbon atom.

Phosphorine Chemical compound

Phosphorine is a heavier element analog of pyridine, containing a phosphorus atom instead of an aza- moiety. It is also called phosphabenzene and belongs to the phosphaalkene class. It is a colorless liquid that is mainly of interest in research.

Thiazole, or 1,3-thiazole, is a heterocyclic compound that contains both sulfur and nitrogen; the term 'thiazole' also refers to a large family of derivatives. Thiazole itself is a pale yellow liquid with a pyridine-like odor and the molecular formula C3H3NS. The thiazole ring is notable as a component of the vitamin thiamine (B1).

Arsole Chemical compound

Arsole, also called arsenole or arsacyclopentadiene, is an organoarsenic compound with the formula C4H4AsH. It is classified as a metallole and is isoelectronic to and related to pyrrole except that an arsenic atom is substituted for the nitrogen atom. Whereas the pyrrole molecule is planar, the arsole molecule is not, and the hydrogen atom bonded to arsenic extends out of the molecular plane. Arsole is only moderately aromatic, with about 40% the aromaticity of pyrrole. Arsole itself has not been reported in pure form, but several substituted analogs called arsoles exist. Arsoles and more complex arsole derivatives have similar structure and chemical properties to those of phosphole derivatives. When arsole is fused to a benzene ring, this molecule is called arsindole, or benzarsole.

Benzoyl chloride Chemical compound

Benzoyl chloride, also known as benzenecarbonyl chloride, is an organochlorine compound with the formula C7H5ClO. It is a colourless, fuming liquid with an irritating odour. It is mainly useful for the production of peroxides but is generally useful in other areas such as in the preparation of dyes, perfumes, pharmaceuticals, and resins.

The phosphonium cation describes polyatomic cations with the chemical formula PR+
4. These anions have tetrahedral structures. The salts are generally colorless or take the color of the anions.

Radical anion free radical species

In organic chemistry, radical anion is a subset of charged free radical species that carry a negative charge. Radical anions are encountered in organic chemistry as reduced derivatives of polycyclic aromatic compounds, e.g. sodium naphthenide. An example of a non-carbon radical anion is the superoxide anion, formed by transfer of one electron to an oxygen molecule. Radical anions are typically indicated by .

Lawessons reagent Chemical compound

Lawesson's reagent, or LR, is a chemical compound used in organic synthesis as a thiation agent. Lawesson's reagent was first made popular by Sven-Olov Lawesson, who did not, however, invent it. Lawesson's reagent was first made in 1956 during a systematic study of the reactions of arenes with P4S10.

Thiophenol Chemical compound

Thiophenol is an organosulfur compound with the formula C6H5SH, sometimes abbreviated as PhSH. This foul-smelling colorless liquid is the simplest aromatic thiol. The chemical structures of thiophenol and its derivatives are analogous to phenols except the oxygen atom in the hydroxyl group (-OH) bonded to the aromatic ring is replaced by a sulfur atom. The prefix thio- implies a sulfur-containing compound and when used before a root word name for a compound which would normally contain an oxygen atom, in the case of 'thiol' that the alcohol oxygen atom is replaced by a sulfur atom.

Alpha-Haloketone

In organic chemistry, an α-haloketone is a functional group consisting of a ketone group or more generally a carbonyl group with an α-halogen substituent. α-haloketones are alkylating agents. Prominent α-haloketones include phenacyl bromide and chloroacetone.

Pyrylium is a cation with formula C5H5O+, consisting of a six-membered ring of five carbon atoms, each with one hydrogen atom, and one positively charged oxygen atom. The bonds in the ring are conjugated as in benzene, giving it an aromatic character. In particular, because of the positive charge, the oxygen atom is trivalent. Pyrilium is a mono-cyclic and heterocyclic compound, one of the oxonium ions.

Organophosphorus compounds are organic compounds containing phosphorus. They are used primarily in pest control as an alternative to chlorinated hydrocarbons that persist in the environment. Some organophosphorus compounds are highly effective insecticides, although some are extremely toxic to humans, including sarin and VX nerve agents.

Organophosphines are organophosphorus compounds with the formula PRnH3−n, where R is an organic substituent. These compounds can be classified according to the value of n: primary phosphines (n = 1), secondary phosphines (n = 2), tertiary phosphines (n = 3). All adopt pyramidal structures. Organophosphines are generally colorless, lipophilic liquids or solids. The parent of the organophosphines is phosphine (PH3).

The McCormack reaction is a method for the synthesis of organophosphorus compounds. In this reaction a 1,3-diene and a source of R2P+ are combined to give phospholenium cation. The reaction is named after W. B. McCormack, a research chemist at duPont.

Dimethylphenylphosphine Chemical compound

Dimethylphenylphosphine is an organophosphorus compound with a formula P(C6H5)(CH3)2. The phosphorus is connected to a phenyl group and two methyl groups, making it the simplest aromatic alkylphosphine. It is colorless air sensitive liquid. It is a member of series (CH3)3-n(C6H5)2P that also includes n = 0, n = 2, and n = 3 that are often employed as ligands in metal phosphine complexes.

Montréalone

Montréalone is a mesoionic heterocyclic chemical compound.

Diethylphosphite Chemical compound

Diethylphosphite is the organophosphorus compound with the formula (C2H5O)2P(O)H. It is a popular reagent for generating other organophosphorus compounds, exploiting the high reactivity of the P-H bond. Diethylphosphite is a colorless liquid. The molecule is tetrahedral.

In organophosphorus chemistry, an aminophosphine is a compound with the formula R3−nP(NR2)n where R = H or an organic substituent, and n = 0, 1, 2. At one extreme, the parent H2PNH2 is lightly studied and fragile, but at the other extreme tris(dimethylamino)phosphine (P(NMe2)3) is commonly available. Intermediate members are known, such as Ph2PN(H)Ph. These compounds are typically colorless and reactive toward oxygen. They have pyramidal geometry at phosphorus.

References

  1. ↑ Nomenclature of Organic Chemistry: IUPAC Recommendations and Preferred Names 2013 (Blue Book). Cambridge: The Royal Society of Chemistry. 2014. p. 146. doi:10.1039/9781849733069-00130. ISBN   978-0-85404-182-4.
  2. ↑ D. B. Chesnut; L. D. Quin (2007). "The important role of the phosphorus lone pair in phosphole aromaticity". Heteroatom Chemistry. 18: 754. doi:10.1002/hc.20364.
  3. ↑ Philip Hindenberg; Carlos Romero-Nieto (2016). "Phosphaphenalenes: An Evolution of the Phosphorus Heterocycles". Synlett. 27: 2293–2300. doi:10.1055/s-0035-1562506.
  4. ↑ Almaz Zagidullin; Vasily A. Miluykov (2013). "Phospholes – development and recent advances". Mendeleev Communications. 23: 117–130. doi:10.1016/j.mencom.2013.05.001.
  5. 1 2 3 Claude Charrier; Hubert Bonnard; Guillaume De Lauzon; Francois Mathey (1983). "Proton [1,5] shifts in P-unsubstituted 1H-phospholes. Synthesis and chemistry of 2H-phosphole dimers". J. Am. Chem. Soc. 105: 6871–6877. doi:10.1021/ja00361a022.
  6. ↑ A Guide to Organophosphorus Chemistry Louis D. Quin 2000 John Wiley & Sons ISBN   0-471-31824-8
  7. ↑ W. B. McCormack (1973). "3-Methyl-1-Phenylphospholene oxide". Organic Syntheses .; Collective Volume, 5, p. 787
  8. ↑ Paul J. Fagan; William A. Nugent (1998). "1-Phenyl-2,3,4,5-Tetramethylphosphole". Organic Syntheses .; Collective Volume, 9, p. 653
  9. ↑ Magali Clochard; Joanna Grundy; Bruno Donnadieu & François Mathey (2005). "A straightforward synthesis of 3-acylphospholes". Organic Letters. 7 (20): 4511–4513. doi:10.1021/ol051816d. PMID   16178571.
  10. ↑ Grundy, J. & Mathey, F. (2005). "One-Pot Conversion of Phospholide Ions into β-Functional Phosphinines". Angewandte Chemie International Edition. 44: 1082–1084. doi:10.1002/anie.200462020. PMID   15662672.
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