Ceric ammonium nitrate

Last updated
Ammonium cerium(IV) nitrate
Ceric ammonium nitrate.jpg
Names
IUPAC name
Diammonium cerium(IV) nitrate
Other names
Ceric ammonium nitrate
CAN
Diammonium hexanitratocerate(IV)
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.037.100 OOjs UI icon edit-ltr-progressive.svg
EC Number
  • 240-827-6
PubChem CID
UNII
  • InChI=1S/Ce.6NO3.2H3N/c;6*2-1(3)4;;/h;;;;;;;2*1H3/q+4;6*-1;;/p+2
    Key: XMPZTFVPEKAKFH-UHFFFAOYSA-P
  • InChI=1/Ce.6NO3.2H3N/c;6*2-1(3)4;;/h;;;;;;;2*1H3/q+4;6*-1;;/p+2
    Key: XMPZTFVPEKAKFH-SKRXCDHZAV
  • [Ce+4].O=[N+]([O-])[O-].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O.[NH4+].[NH4+]
Properties
[NH4]2[Ce(NO3)6]
Molar mass 548.218 g·mol−1
Appearanceorange-red crystals
Melting point 107 to 108 °C (225 to 226 °F; 380 to 381 K)
141 g/100 mL (25 °C)
227 g/100 mL (80 °C)
Structure
Monoclinic
Icosahedral
Hazards
GHS labelling:
GHS-pictogram-rondflam.svg GHS-pictogram-exclam.svg [1]
Danger
H272, H302, H315, H319, H335
P220, P261, P305+P351+P338
Related compounds
Related compounds
Ammonium nitrate
Cerium(IV) oxide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Ceric ammonium nitrate (CAN) is the inorganic compound with the formula (NH4) 2[Ce(NO3)6]. This orange-red, water-soluble cerium salt is a specialised oxidizing agent in organic synthesis and a standard oxidant in quantitative analysis.

Contents

Preparation, properties, and structure

The anion [Ce(NO3)6]2− is generated by dissolving Ce2O3 in hot and concentrated nitric acid (HNO3). [2]

The salt consists of the hexanitratocerate(IV) anion [Ce(NO3)6]2− and a pair of ammonium cations NH+4. The ammonium ions are not involved in the oxidising reactions of this salt. In the anion each nitrate group chelates the cerium atom in a bidentate manner as shown below:

Hexanitratocerat.svg
Hexanitratocerate anion

The anion [Ce(NO3)6]2− has Th (idealized Oh) molecular symmetry. The CeO12 core defines an icosahedron. [4]

Ce4+ is a strong one-electron oxidizing agent. In terms of its redox potential (E° ≈ 1.61 V vs. N.H.E.) it is an even stronger oxidizing agent than Cl2 (E° ≈ 1.36 V). Few shelf-stable reagents are stronger oxidants. In the redox process Ce(IV) is converted to Ce(III), a one-electron change, signaled by the fading of the solution color from orange to a pale yellow (providing that the substrate and product are not strongly colored).

Applications in organic chemistry

In organic synthesis, CAN is useful as an oxidant for many functional groups (alcohols, phenols, and ethers) as well as C–H bonds, especially those that are benzylic. Alkenes undergo dinitroxylation, although the outcome is solvent-dependent. Quinones are produced from catechols and hydroquinones and even nitroalkanes are oxidized. [5] [6]

CAN provides an alternative to the Nef reaction; for example, for ketomacrolide synthesis where complicating side reactions usually encountered using other reagents. Oxidative halogenation can be promoted by CAN as an in situ oxidant for benzylic bromination, and the iodination of ketones and uracil derivatives.

For the synthesis of heterocycles

Catalytic amounts of aqueous CAN allow the efficient synthesis of quinoxaline derivatives. Quinoxalines are known for their applications as dyes, organic semiconductors, and DNA cleaving agents. These derivatives are also components in antibiotics such as echinomycin and actinomycin. The CAN-catalyzed three-component reaction between anilines and alkyl vinyl ethers provides an efficient entry into 2-methyl-1,2,3,4-tetrahydroquinolines and the corresponding quinolines obtained by their aromatization.

As a deprotection reagent

CAN is traditionally used to release organic ligands from metal carbonyls. In the process, the metal is oxidised, CO is evolved, and the organic ligand is released for further manipulation. [7] For example, with the Wulff–Dötz reaction an alkyne, carbon monoxide, and a chromium carbene are combined to form a chromium half-sandwich complex [8] [9] and the phenol ligand can be isolated by mild CAN oxidation.

Wulff-Dotz reaction to a chromium half-sandwich complex.png

CAN is used to cleave para-methoxybenzyl and 3,4-dimethoxybenzyl ethers, which are protecting groups for alcohols. [10] [11] Two equivalents of CAN are required for each equivalent of para-methoxybenzyl ether. The alcohol is released, and the para-methoxybenzyl ether converts to para-methoxybenzaldehyde. The balanced equation is as follows:

2 [NH4]2[Ce(NO3)6] + H3COC6H4CH2OR + H2O → 4 NH+4 + 2 Ce3+ + 12 NO3 + 2 H+ + H3COC6H4CHO + HOR

Other applications

CAN is also a component of chrome etchant, [12] a material that is used in the production of photomasks and liquid crystal displays.[ citation needed ]

Related Research Articles

<span class="mw-page-title-main">Oxidizing agent</span> Chemical compound used to oxidize another substance in a chemical reaction

An oxidizing agent is a substance in a redox chemical reaction that gains or "accepts"/"receives" an electron from a reducing agent. In other words, an oxidizer is any substance that oxidizes another substance. The oxidation state, which describes the degree of loss of electrons, of the oxidizer decreases while that of the reductant increases; this is expressed by saying that oxidizers "undergo reduction" and "are reduced" while reducers "undergo oxidation" and "are oxidized". Common oxidizing agents are oxygen, hydrogen peroxide, and the halogens.

<span class="mw-page-title-main">Alkylation</span> Transfer of an alkyl group from one molecule to another

Alkylation is a chemical reaction that entails transfer of an alkyl group. The alkyl group may be transferred as an alkyl carbocation, a free radical, a carbanion, or a carbene. Alkylating agents are reagents for effecting alkylation. Alkyl groups can also be removed in a process known as dealkylation. Alkylating agents are often classified according to their nucleophilic or electrophilic character. In oil refining contexts, alkylation refers to a particular alkylation of isobutane with olefins. For upgrading of petroleum, alkylation produces a premium blending stock for gasoline. In medicine, alkylation of DNA is used in chemotherapy to damage the DNA of cancer cells. Alkylation is accomplished with the class of drugs called alkylating antineoplastic agents.

<span class="mw-page-title-main">Protecting group</span> Group of atoms introduced into a compound to prevent subsequent reactions

A protecting group or protective group is introduced into a molecule by chemical modification of a functional group to obtain chemoselectivity in a subsequent chemical reaction. It plays an important role in multistep organic synthesis.

In environmental chemistry, the chemical oxygen demand (COD) is an indicative measure of the amount of oxygen that can be consumed by reactions in a measured solution. It is commonly expressed in mass of oxygen consumed over volume of solution which in SI units is milligrams per litre (mg/L). A COD test can be used to easily quantify the amount of organics in water. The most common application of COD is in quantifying the amount of oxidizable pollutants found in surface water or wastewater. COD is useful in terms of water quality by providing a metric to determine the effect an effluent will have on the receiving body, much like biochemical oxygen demand (BOD).

<span class="mw-page-title-main">Cerium(IV) sulfate</span> Chemical compound

Cerium(IV) sulfate, also called ceric sulfate, is an inorganic compound. It exists as the anhydrous salt Ce(SO4)2 as well as a few hydrated forms: Ce(SO4)2(H2O)x, with x equal to 4, 8, or 12. These salts are yellow to yellow/orange solids that are moderately soluble in water and dilute acids. Its neutral solutions slowly decompose, depositing the light yellow oxide CeO2. Solutions of ceric sulfate have a strong yellow color. The tetrahydrate loses water when heated to 180-200 °C.

<span class="mw-page-title-main">Benzyl group</span> Chemical group (–CH₂–C₆H₅)

In organic chemistry, benzyl is the substituent or molecular fragment possessing the structure R−CH2−C6H5. Benzyl features a benzene ring attached to a methylene group group.

<span class="mw-page-title-main">1,4-Benzoquinone</span> Chemical compound

1,4-Benzoquinone, commonly known as para-quinone, is a chemical compound with the formula C6H4O2. In a pure state, it forms bright-yellow crystals with a characteristic irritating odor, resembling that of chlorine, bleach, and hot plastic or formaldehyde. This six-membered ring compound is the oxidized derivative of 1,4-hydroquinone. The molecule is multifunctional: it exhibits properties of a ketone, being able to form oximes; an oxidant, forming the dihydroxy derivative; and an alkene, undergoing addition reactions, especially those typical for α,β-unsaturated ketones. 1,4-Benzoquinone is sensitive toward both strong mineral acids and alkali, which cause condensation and decomposition of the compound.

<span class="mw-page-title-main">Tetrafluoroborate</span> Anion

Tetrafluoroborate is the anion BF
4
. This tetrahedral species is isoelectronic with tetrafluoroberyllate (BeF2−
4
), tetrafluoromethane (CF4), and tetrafluoroammonium (NF+
4
) and is valence isoelectronic with many stable and important species including the perchlorate anion, ClO
4
, which is used in similar ways in the laboratory. It arises by the reaction of fluoride salts with the Lewis acid BF3, treatment of tetrafluoroboric acid with base, or by treatment of boric acid with hydrofluoric acid.

<span class="mw-page-title-main">Silver compounds</span> Chemical compounds containing silver

Silver is a relatively unreactive metal, although it can form several compounds. The common oxidation states of silver are (in order of commonness): +1 (the most stable state; for example, silver nitrate, AgNO3); +2 (highly oxidising; for example, silver(II) fluoride, AgF2); and even very rarely +3 (extreme oxidising; for example, potassium tetrafluoroargentate(III), KAgF4). The +3 state requires very strong oxidising agents to attain, such as fluorine or peroxodisulfate, and some silver(III) compounds react with atmospheric moisture and attack glass. Indeed, silver(III) fluoride is usually obtained by reacting silver or silver monofluoride with the strongest known oxidizing agent, krypton difluoride.

The Wulff–Dötz reaction (also known as the Dötz reaction or the benzannulation reaction of the Fischer carbene complexes) is the chemical reaction of an aromatic or vinylic alkoxy pentacarbonyl chromium carbene complex with an alkyne and carbon monoxide to give a Cr(CO)3-coordinated substituted phenol. Several reviews have been published. It is named after the German chemist Karl Heinz Dötz (b. 1943) and the American chemist William D. Wulff (b. 1949) at Michigan State University. The reaction was first discovered by Karl Dötz and was extensively developed by his group and W. Wulff's group. They subsequently share the name of the reaction.

In chemistry, π-effects or π-interactions are a type of non-covalent interaction that involves π systems. Just like in an electrostatic interaction where a region of negative charge interacts with a positive charge, the electron-rich π system can interact with a metal, an anion, another molecule and even another π system. Non-covalent interactions involving π systems are pivotal to biological events such as protein-ligand recognition.

<span class="mw-page-title-main">Cerium</span> Chemical element, symbol Ce and atomic number 58

Cerium is a chemical element; it has symbol Ce and atomic number 58. Cerium is a soft, ductile, and silvery-white metal that tarnishes when exposed to air. Cerium is the second element in the lanthanide series, and while it often shows the oxidation state of +3 characteristic of the series, it also has a stable +4 state that does not oxidize water. It is also considered one of the rare-earth elements. Cerium has no known biological role in humans but is not particularly toxic, except with intense or continued exposure.

<span class="mw-page-title-main">Photoredox catalysis</span>

Photoredox catalysis is a branch of photochemistry that uses single-electron transfer. Photoredox catalysts are generally drawn from three classes of materials: transition-metal complexes, organic dyes, and semiconductors. While organic photoredox catalysts were dominant throughout the 1990s and early 2000s, soluble transition-metal complexes are more commonly used today.

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

Cerium nitrate refers to a family of nitrates of cerium in the +3 or +4 oxidation state. Often these compounds contain water, hydroxide, or hydronium ions in addition to cerium and nitrate. Double nitrates of cerium also exist.

GFS Chemicals Inc, formerly known as G. Frederick Smith Chemical Company, is a privately owned fine and specialty chemical company with headquarters in Powell, Ohio and manufacturing facilities in Columbus, Ohio. It was founded by G. Frederick Smith in Urbana, Illinois in 1924, and moved to Columbus, Ohio in 1928.

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

Cerium(III) methanesulfonate is a white salt, usually found as the dihydrate with the formula Ce(CH3SO3)3·2H2O that precipitates from the neutralisation of cerium(III) carbonate with methanesulfonic acid, as first reported by L.B. Zinner in 1979. The crystals have a monoclinic polymeric structure were each methanesulfonate ion forms bonds with two cerium atoms, which present a coordination number of 8. The anhydrous salt is formed by water loss at 120 °C. Similar methanesulfonates can be prepared with other lanthanides. Cerium(III) methanesulfonate in solution is used as a precursor of electrogenerated cerium(IV), which is a strong oxidant and whose salts can be used in organic synthesis. The same principle of Ce(IV) electrogeneration is the fundamental reaction in the positive half-cell of the zinc–cerium battery.

In chemistry, decomplexation refers to the removal of a ligand from a coordination complex. 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.

<span class="mw-page-title-main">Cerium(IV) hydroxide</span> Chemical compound

Cerium(IV) hydroxide, also known as ceric hydroxide, is an inorganic compound with the chemical formula Ce(OH)4. It is a yellowish powder that is insoluble in water but soluble in concentrated acids.

A Fischer carbene is a type of transition metal carbene complex, which is an organometallic compound containing a divalent organic ligand. In a Fischer carbene, the carbene ligand is a σ-donor π-acceptor ligand. Because π-backdonation from the metal centre is generally weak, the carbene carbon is electrophilic.

Cerium compounds are compounds containing the element cerium (Ce), a lanthanide. Cerium exists in two main oxidation states, Ce(III) and Ce(IV). This pair of adjacent oxidation states dominates several aspects of the chemistry of this element. Cerium(IV) aqueous solutions may be prepared by reacting cerium(III) solutions with the strong oxidizing agents peroxodisulfate or bismuthate. The value of E(Ce4+/Ce3+) varies widely depending on conditions due to the relative ease of complexation and hydrolysis with various anions, although +1.72 V is representative. Cerium is the only lanthanide which has important aqueous and coordination chemistry in the +4 oxidation state.

References

  1. Sigma-Aldrich Co., Ammonium cerium(IV) nitrate. Retrieved on 2015-05-13.
  2. Smith, G.Frederick (June 1963). "An improved preparation of ammonium hexanitratocerate(IV) and routine analytical testing procedure to prove primary reference standard purity". Talanta. 10 (6): 709–710. doi:10.1016/0039-9140(63)80093-4.
  3. "CSD Entry 1598999, ICSD Entry 22219, H8CeN8O18". Cambridge Structural Database: Access Structures. Cambridge Crystallographic Data Centre . Retrieved 2021-11-05.
  4. 1 2 Thomas A. Beineke; J. Delgaudio (1968). "Crystal structure of ceric ammonium nitrate". Inorg. Chem. 7 (4): 715–721. doi:10.1021/ic50062a020.
  5. Nair, Vijay; Deepthi, Ani (2007). "Cerium(IV) Ammonium NitrateA Versatile Single-Electron Oxidant". Chemical Reviews. 107 (5): 1862–1891. doi:10.1021/cr068408n. PMID   17432919.
  6. Sridharan, Vellaisamy; Menéndez, J. Carlos (2010). "Cerium(IV) Ammonium Nitrate as a Catalyst in Organic Synthesis". Chemical Reviews. 110 (6): 3805–3849. doi:10.1021/cr100004p. PMID   20359233.
  7. L. Brener, J. S. McKennis, and R. Pettit "Cyclobutadiene in Synthesis: endo-Tricyclo[4.4.0.02,5]deca-3,8-diene-7,10-dione" Org. Synth. 1976, 55, 43. doi : 10.15227/orgsyn.055.0043
  8. Waters, M.; Wulff, W. D. (2008). "The Synthesis of Phenols and Quinones via Fischer Carbene Complexes". Organic Reactions . 70 (2): 121–623. doi:10.1002/0471264180.or070.02.
  9. Dötz, K. H. (1983). "Carbon–Carbon Bond Formation via Carbonyl-Carbene Complexes". Pure and Applied Chemistry . 55 (11): 1689–1706. doi: 10.1351/pac198355111689 . S2CID   95165461.
  10. Boons, Geert-Jan.; Hale, Karl J. (2000). Organic Synthesis with Carbohydrates (1st ed.) Sheffield, England: Sheffield Academic Press. pp.33
  11. Kocienski, Phillip J. (1994). Protecting Groups Stuttgart, New York Georg Thieme Verlag. pp 8–9, 52–54
  12. Walker, Perrin; William H. Tarn (1991). CRC Handbook of Metal Etchants . pp.  287–291. ISBN   0-8493-3623-6.