Bis(triphenylphosphine)iminium chloride

Last updated
Bis(triphenylphosphine)iminium chloride
PPNCl.png
Names
Preferred IUPAC name
Hexaphenyl-1λ5-diphosphaz-1-en-3-ium chloride
Other names
PNP chloride
PPN chloride
Bis(triphenylphosphine)iminium chloride
Bis(triphenylphosphoranylidene)iminium chloride
Bis(triphenylphosphoranylidene)ammonium chloride
Hexaphenyldiphosphazenium chloride
Selectophore
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.040.139 OOjs UI icon edit-ltr-progressive.svg
EC Number
  • 244-170-6
PubChem CID
  • InChI=1S/C36H30NP2.ClH/c1-7-19-31(20-8-1)38(32-21-9-2-10-22-32,33-23-11-3-12-24-33)37-39(34-25-13-4-14-26-34,35-27-15-5-16-28-35)36-29-17-6-18-30-36;/h1-30H;1H/q+1;/p-1 Yes check.svgY
    Key: LVRCYPYRKNAAMX-UHFFFAOYSA-M Yes check.svgY
  • InChI=1/C36H30NP2.ClH/c1-7-19-31(20-8-1)38(32-21-9-2-10-22-32,33-23-11-3-12-24-33)37-39(34-25-13-4-14-26-34,35-27-15-5-16-28-35)36-29-17-6-18-30-36;/h1-30H;1H/q+1;/p-1
    Key: LVRCYPYRKNAAMX-REWHXWOFAO
  • [Cl-].N([P+](c1ccccc1)(c2ccccc2)c3ccccc3)=P(c4ccccc4)(c5ccccc5)c6ccccc6
Properties
[((C6H5)3P)2N]Cl
Molar mass 574.03 g/mol
Appearancecolourless solid
Melting point 260 to 262 °C (500 to 504 °F; 533 to 535 K)
moderate
Hazards
GHS labelling:
GHS-pictogram-exclam.svg
Warning
H315, H319, H332, H335
P261, P264, P271, P280, P302+P352, P304+P312, P304+P340, P305+P351+P338, P312, P321, P332+P313, P337+P313, P362, P403+P233, P405, P501
Related compounds
Related compounds
Tetraphenylarsonium chloride
Tetrabutylammonium chloride
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Bis(triphenylphosphine)iminium chloride is the chemical compound with the formula [((C6H5)3P)2N]Cl, often abbreviated [(Ph3P)2N]Cl, where Ph is phenyl C6H5, or even abbreviated [PPN]Cl or [PNP]Cl or PPNCl or PNPCl, where PPN or PNP stands for (Ph3P)2N. This colorless salt is a source of the [(Ph3P)2N]+ cation (abbreviated PPN+ or PNP+), which is used as an unreactive and weakly coordinating cation to isolate reactive anions. [(Ph3P)2N]+ is a phosphazene.

Contents

Synthesis and structure

[(Ph3P)2N]Cl is prepared in two steps from triphenylphosphine Ph3P: [1]

Ph3P + Cl2 → Ph3PCl2

This triphenylphosphine dichloride Ph3PCl2 is related to phosphorus pentachloride PCl5. Treatment of this species with hydroxylamine in the presence of Ph3P results in replacement of the two single P–Cl bonds in Ph3PCl2 by one double P=N bond:

2 Ph3PCl2 + NH2OH·HCl + Ph3P → [(Ph3P)2N]Cl + 4HCl + Ph3PO

Triphenylphosphine oxide Ph3PO is a by-product.

Bis(triphenylphosphine)iminium chloride is described as [(Ph3P)2N]+Cl. The structure of the bis(triphenylphosphine)iminium cation [(Ph3P)2N]+ is [Ph3P=N=PPh3]+. The P=N=P angle in the cation is flexible, ranging from ~130 to 180° depending on the salt. Bent and linear forms of the P=N=P connections have been observed in the same unit cell. [2] The same shallow potential well for bending is observed in the isoelectronic species bis(triphenylphosphoranylidene)methane, Ph3P=C=PPH3, as well as the more distantly related molecule carbon suboxide, O=C=C=C=O. For the solvent-free chloride salt [(Ph3P)2N]Cl, the P=N=P bond angle was determined to be 133°. [3] The two P=N bonds are equivalent, and their length is 1.597(2) Å.

thermal ellipsoid model the bis(triphenylphosphine)iminium cation PPN-cation-from-xtal-CM-3D-ellipsoids.png
thermal ellipsoid model the bis(triphenylphosphine)iminium cation

Use as reagent

In the laboratory, [(Ph3P)2N]Cl is the main precursor to [(Ph3P)2N]+ salts. Using salt metathesis reactions, nitrite, azide, and other small inorganic anions can be obtained with [(Ph3P)2N]+ cations. The resulting salts [(Ph3P)2N]+NO2, [(Ph3P)2N]+N3, etc. are soluble in polar organic solvents.

[(Ph3P)2N]+ forms crystalline salts with a range of anions that are otherwise difficult to crystallize. Its effectiveness is partially attributable to its rigidity, reflecting the presence of six phenyl rings. Often [(Ph3P)2N]+ forms salts that are more air-stable than salts with smaller cations such as those containing quaternary ammonium cation [NR4]+, or alkali metal cations. This effect is attributed to the steric shielding provided by this voluminous cation. Illustrative [(Ph3P)2N]+ salts of reactive anions include [(Ph3P)2N]+[HFe(CO)4], [(Ph3P)2N]+[Co(CO)4], ([(Ph3P)2N]+)2[M2(CO)10]2+ (M = Cr, Mo, W), and [(Ph3P)2N]+[Fe(CO)3(NO)]. [1] The role of ion pairing in chemical reactions is often clarified by examination of the related salt derived from [(Ph3P)2N]+.

A phosphazenium cation related to [(Ph3P)2N]+ is [(((CH3)2N)3P)2N]+. [4]

Related Research Articles

In chemistry, a salt is a chemical compound consisting of an ionic assembly of positively charged cations and negatively charged anions, which results in a compound with no net electric charge. A common example is table salt, with positively charged sodium ions and negatively charged chloride ions.

In organic chemistry, an acyl chloride is an organic compound with the functional group −C(=O)Cl. Their formula is usually written R−COCl, where R is a side chain. They are reactive derivatives of carboxylic acids. A specific example of an acyl chloride is acetyl chloride, CH3COCl. Acyl chlorides are the most important subset of acyl halides.

<span class="mw-page-title-main">Phosphonium</span> Family of polyatomic cations containing phosphorus

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

<span class="mw-page-title-main">Phosphorus trichloride</span> Chemical compound

Phosphorus trichloride is an inorganic compound with the chemical formula PCl3. A colorless liquid when pure, it is an important industrial chemical, being used for the manufacture of phosphites and other organophosphorus compounds. It is toxic and reacts readily with water to release hydrogen chloride.

<span class="mw-page-title-main">Triphenylphosphine</span> Chemical compound

Triphenylphosphine (IUPAC name: triphenylphosphane) is a common organophosphorus compound with the formula P(C6H5)3 and often abbreviated to PPh3 or Ph3P. It is widely used in the synthesis of organic and organometallic compounds. PPh3 exists as relatively air stable, colorless crystals at room temperature. It dissolves in non-polar organic solvents such as benzene and diethyl ether.

<span class="mw-page-title-main">Rhodium(III) chloride</span> Chemical compound

Rhodium(III) chloride refers to inorganic compounds with the formula RhCl3(H2O)n, where n varies from 0 to 3. These are diamagnetic solids featuring octahedral Rh(III) centres. Depending on the value of n, the material is either a dense brown solid or a soluble reddish salt. The soluble trihydrated (n = 3) salt is widely used to prepare compounds used in homogeneous catalysis, notably for the industrial production of acetic acid and hydroformylation.

<span class="mw-page-title-main">Counterion</span> Ion which negates another oppositely-charged ion in an ionic molecule

In chemistry, a counterion is the ion that accompanies an ionic species in order to maintain electric neutrality. In table salt the sodium ion is the counterion for the chloride ion and vice versa.

<span class="mw-page-title-main">Palladium(II) chloride</span> Chemical compound

Palladium(II) chloride, also known as palladium dichloride and palladous chloride, are the chemical compounds with the formula PdCl2. PdCl2 is a common starting material in palladium chemistry – palladium-based catalysts are of particular value in organic synthesis. It is prepared by the reaction of chlorine with palladium metal at high temperatures.

<span class="mw-page-title-main">Chloro(triphenylphosphine)gold(I)</span> Chemical compound

Chloro(triphenylphosphine)gold(I) or triphenylphosphinegold(I) chloride is a coordination complex with the formula (Ph3P)AuCl. This colorless solid is a common reagent for research on gold compounds.

<span class="mw-page-title-main">Triphenylphosphine oxide</span> Chemical compound

Triphenylphosphine oxide (often abbreviated TPPO) is the organophosphorus compound with the formula OP(C6H5)3, also written as Ph3PO or PPh3O (Ph = C6H5). This colourless crystalline compound is a common but potentially useful waste product in reactions involving triphenylphosphine. It is a popular reagent to induce the crystallizing of chemical compounds.

<span class="mw-page-title-main">Hexafluorophosphate</span> Anion with the chemical formula PF6–

Hexafluorophosphate is an anion with chemical formula of [PF6]. It is an octahedral species that imparts no color to its salts. [PF6] is isoelectronic with sulfur hexafluoride, SF6, and the hexafluorosilicate dianion, [SiF6]2−, and hexafluoroantimonate [SbF6]. In this anion, phosphorus has a valence of 5. Being poorly nucleophilic, hexafluorophosphate is classified as a non-coordinating anion.

<span class="mw-page-title-main">Tetraphenylphosphonium chloride</span> Chemical compound

Tetraphenylphosphonium chloride is the chemical compound with the formula (C6H5)4PCl, abbreviated Ph4PCl or PPh4Cl. Tetraphenylphosphonium and especially tetraphenylarsonium salts were formerly of interest in gravimetric analysis of perchlorate and related oxyanions. This colourless salt is used to generate lipophilic salts from inorganic and organometallic anions. Thus, Ph4P+ is useful as a phase-transfer catalyst, again because it allows inorganic anions to dissolve in organic solvents.

<span class="mw-page-title-main">Potassium tetrachloroplatinate</span> Chemical compound

Potassium tetrachloroplatinate(II) is the chemical compound with the formula K2PtCl4. This reddish orange salt is an important reagent for the preparation of other coordination complexes of platinum. It consists of potassium cations and the square planar dianion PtCl42−. Related salts are also known including Na2PtCl4, which is brown-colored and soluble in alcohols, and quaternary ammonium salts, which are soluble in a broader range of organic solvents.

Martin Arthur Bennett FRS is an Australian inorganic chemist. He gained recognition for studies on the co-ordination chemistry of tertiary phosphines, olefins, and acetylenes, and the relationship of their behaviour to homogeneous catalysis.

<span class="mw-page-title-main">Sodium tetraphenylborate</span> Chemical compound

Sodium tetraphenylborate is the organic compound with the formula NaB(C6H5)4. It is a salt, wherein the anion consists of four phenyl rings bonded to boron. This white crystalline solid is used to prepare other tetraphenylborate salts, which are often highly soluble in organic solvents. The compound is used in inorganic and organometallic chemistry as a precipitating agent for potassium, ammonium, rubidium, and cesium ions, and some organic nitrogen compounds.

<span class="mw-page-title-main">Chloro(cyclopentadienyl)bis(triphenylphosphine)ruthenium</span> Chemical compound

Chloro(cyclopentadienyl)bis(triphenylphosphine)ruthenium is the organoruthenium half-sandwich compound with formula RuCl(PPh3)2(C5H5). It as an air-stable orange crystalline solid that is used in a variety of organometallic synthetic and catalytic transformations. The compound has idealized Cs symmetry. It is soluble in chloroform, dichloromethane, and acetone.

<span class="mw-page-title-main">Tetrakis(3,5-bis(trifluoromethyl)phenyl)borate</span> Chemical compound

Tetrakis[3,5-bis(trifluoromethyl)phenyl]borate is an anion with chemical formula [{3,5-(CF3)2C6H3}4B], which is commonly abbreviated as [BArF4], indicating the presence of fluorinated aryl (ArF) groups. It is sometimes referred to as Kobayashi's anion in honour of Hiroshi Kobayashi who led the team that first synthesised it. More commonly it is affectionately nicknamed "BARF." The BARF ion is also abbreviated BArF24, to distinguish it from the closely related BArF
20
, [(C6F5)4B].

<span class="mw-page-title-main">Metal-phosphine complex</span>

A metal-phosphine complex is a coordination complex containing one or more phosphine ligands. Almost always, the phosphine is an organophosphine of the type R3P (R = alkyl, aryl). Metal phosphine complexes are useful in homogeneous catalysis. Prominent examples of metal phosphine complexes include Wilkinson's catalyst (Rh(PPh3)3Cl), Grubbs' catalyst, and tetrakis(triphenylphosphine)palladium(0).

<span class="mw-page-title-main">Rhodium carbonyl chloride</span> Chemical compound

Rhodium carbonyl chloride is an organorhodium compound with the formula Rh2Cl2(CO)4. It is a red-brown volatile solid that is soluble in nonpolar organic solvents. It is a precursor to other rhodium carbonyl complexes, some of which are useful in homogeneous catalysis.

<span class="mw-page-title-main">Transition metal chloride complex</span> Coordination complex

In chemistry, a transition metal chloride complex is a coordination complex that consists of a transition metal coordinated to one or more chloride ligand. The class of complexes is extensive.

References

  1. 1 2 Ruff, J.K.; Schlientz, W.J. (1974). "μ‐Nitridobis(triphenylphosphorus)(l+) ("PPN") Salts with Metal Carbonyl Anions". Inorganic Syntheses. pp. 84–90. doi:10.1002/9780470132463.ch19. ISBN   9780470132463.{{cite book}}: |journal= ignored (help)
  2. Hardy GE, Zink JI, Kaska WC, Baldwin JC (December 1978). "Structure and triboluminescence of polymorphs of hexaphenylcarbodiphosphorane". Journal of the American Chemical Society. 100 (25): 8001–8002. doi:10.1021/ja00493a035.
  3. Knapp C, Uzun R (November 2010). "Solvate-free bis-(triphenylphosphine)iminium chloride". Acta Crystallographica Section E. 66 (Pt 12): o3185. doi:10.1107/S1600536810046325. PMC   3011587 . PMID   21589480.
  4. Schwesinger, Reinhard (2001). "1,1,1,3,3,3-Hexakis(dimethylamino)-1λ5,3λ5-diphosphazenium fluoride". e-EROS Encyclopedia of Reagents for Organic Synthesis. pp. 1–2. doi:10.1002/047084289X.rh014m. ISBN   0471936235.