Organoxenon chemistry

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Organoxenon chemistry is the study of the properties of organoxenon compounds, which contain carbon to xenon chemical bonds. The first organoxenon compounds were divalent, such as (C6F5)2Xe. The first tetravalent organoxenon compound, [C6F5XeF2][BF4], was synthesized in 2004. [1] So far, more than one hundred organoxenon compounds have been researched.

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Most of the organoxenon compounds are more unstable than xenon fluorides due to the high polarity. The molecular dipoles of xenon difluoride and xenon tetrafluoride are both 0  D. The early synthesized ones only contain perfluoro groups, but later some other groups were found, e.g. 2,4,6-trifluorophenyl. [2]

Organoxenon(II) compounds

The most common bivalent organoxenon compound is C6F5XeF, which is almost always used as a precursor to other organoxenon compounds. Due to the instability of xenon(II), it is difficult to synthesize organoxenon compounds by using general organic reagents. Organoxenon compounds are frequently prepared from organocadmium species including Cd(ArF)2 (where ArF is a fluorine-containing arene), C6F5SiF3, and C6F5SiMe3 (used along with fluoride).

With the use of stronger Lewis acids, such as C6F5BF2, ionic compounds like [RXe][ArFBF3] can be produced. Alkenyl and alkyl organoxenon compounds are prepared in this way as well, for example, C6F5XeCF=CF2 and C6F5XeCF3. [2]

Some typical reactions are listed below:

2 C6F5XeF + Cd(C6F5)2 → 2 Xe(C6F5)2 + CdF2↓
C6F5XeF + (CH3)3SiCN → C6F5XeCN + (CH3)3SiF
2 C6F5XeF + Cd(2,4,6-F3C6H2)2 → 2 (2,4,6-F3C6H2)XeC6F5 + CdF2↓

The third reaction also produces (C6F5)2Xe, Xe(2,4,6-F3C6H2)2 and so on.

The precursor C6F5XeF can be prepared by the reaction of trimethyl(pentafluorophenyl)silane (C6F5SiMe3) and xenon difluoride. Adding fluoride to the adduct of C6F5XeF and arsenic pentafluoride is another method. [2]

Arylxenon compounds with fewer fluorine substituents are also known. For instance, (2,6-F2C6H3)Xe+BF−
4 and (4-FC6H4)Xe+BF−
4 have been prepared, and a crystal structure of the former has been obtained, consisting of a formally 1-coordinate xenon with a long, weak contact with a fluorine on the tetrafluoroborate anion. [3] [4]

Organoxenon(IV) compounds

In 2000, Karel Lutar and Boris Žemva et al. produced an ionic compound. They treated xenon tetrafluoride and difluoro(pentafluorophenyl)borane in dichloromethane at −55 °C:

XeF4 + C6F5BF2DCM→ [C6F5XeF2]+BF−
4

The compound is an extremely strong fluorinating agent, and it is capable of converting (C6F5)3P to (C6F5)3PF2, C6F5I to C6F5IF2, and iodine to iodine pentafluoride. [1]

Related Research Articles

In chemistry, noble gas compounds are chemical compounds that include an element from the noble gases, group 18 of the periodic table. Although the noble gases are generally unreactive elements, many such compounds have been observed, particularly involving the element xenon.

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

Chlorine pentafluoride is an interhalogen compound with formula ClF5. This colourless gas is a strong oxidant that was once a candidate oxidizer for rockets. The molecule adopts a square pyramidal structure with C4v symmetry, as confirmed by its high-resolution 19F NMR spectrum. It was first synthesized in 1963.

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

Xenon tetrafluoride is a chemical compound with chemical formula XeF
4. It was the first discovered binary compound of a noble gas. It is produced by the chemical reaction of xenon with fluorine:

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

Xenon hexafluoride is a noble gas compound with the formula XeF6. It is one of the three binary fluorides of xenon that have been studied experimentally, the other two being XeF2 and XeF4. All known are exergonic and stable at normal temperatures. XeF6 is the strongest fluorinating agent of the series. It is a colorless solid that readily sublimes into intensely yellow vapors.

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

Silver(II) fluoride is a chemical compound with the formula AgF2. It is a rare example of a silver(II) compound. Silver usually exists in its +1 oxidation state. It is used as a fluorinating agent.

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

Xenon difluoride is a powerful fluorinating agent with the chemical formula XeF
2, and one of the most stable xenon compounds. Like most covalent inorganic fluorides it is moisture-sensitive. It decomposes on contact with water vapor, but is otherwise stable in storage. Xenon difluoride is a dense, colourless crystalline solid.

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

Selenium tetrafluoride (SeF4) is an inorganic compound. It is a colourless liquid that reacts readily with water. It can be used as a fluorinating reagent in organic syntheses (fluorination of alcohols, carboxylic acids or carbonyl compounds) and has advantages over sulfur tetrafluoride in that milder conditions can be employed and it is a liquid rather than a gas.

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

Xenon oxytetrafluoride is an inorganic chemical compound. It is an unstable colorless liquid with a melting point of −46.2 °C that can be synthesized by partial hydrolysis of XeF
6, or the reaction of XeF
6 with silica or NaNO
3:

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

Krypton difluoride, KrF2 is a chemical compound of krypton and fluorine. It was the first compound of krypton discovered. It is a volatile, colourless solid at room temperature. The structure of the KrF2 molecule is linear, with Kr−F distances of 188.9 pm. It reacts with strong Lewis acids to form salts of the KrF+ and Kr
2F+
3 cations.

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

The dioxygenyl ion, O+
2, is a rarely-encountered oxycation in which both oxygen atoms have a formal oxidation state of +1/2. It is formally derived from oxygen by the removal of an electron:

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

Manganese tetrafluoride, MnF4, is the highest fluoride of manganese. It is a powerful oxidizing agent and is used as a means of purifying elemental fluorine.

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

Diethylaminosulfur trifluoride (DAST) is the organosulfur compound with the formula Et2NSF3. This liquid is a fluorinating reagent used for the synthesis of organofluorine compounds. The compound is colourless; older samples assume an orange colour.

Dioxygenyl hexafluoroplatinate is a compound with formula O2PtF6. It is a hexafluoroplatinate of the unusual dioxygenyl cation, O2+, and is the first known compound containing this cation. It can be produced by the reaction of dioxygen with platinum hexafluoride. The fact that PtF
6 is strong enough to oxidise O
2, whose first ionization potential is 12.2 eV, led Neil Bartlett to correctly surmise that it might be able to oxidise xenon (first ionization potential 12.13 eV). This led to the discovery of xenon hexafluoroplatinate, which proved that the noble gases, previously thought to be inert, are able to form chemical compounds.

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

The tetrafluoroammonium cation is a positively charged polyatomic ion with chemical formula NF+
4. It is equivalent to the ammonium ion where the hydrogen atoms surrounding the central nitrogen atom have been replaced by fluorine. Tetrafluoroammonium ion is isoelectronic with tetrafluoromethane CF
4, trifluoramine oxide ONF
3 and the tetrafluoroborate BF−
4 anion.

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

Vanadium(V) fluoride is the inorganic compound with the chemical formula VF5. It is a colorless volatile liquid. It is a highly reactive compound, as indicated by its ability to fluorinate organic substances.

Nitrogen pentafluoride (NF5) is a theoretical compound of nitrogen and fluorine that is hypothesized to exist based on the existence of the pentafluorides of the atoms below nitrogen in the periodic table, such as phosphorus pentafluoride. Theoretical models of the nitrogen pentafluoride molecule are either a trigonal bipyramidal covalently bound molecule with symmetry group D3h, or NF+
4F−, which would be an ionic solid.

Chromium pentafluoride is the inorganic compound with the chemical formula CrF5. It is a red volatile solid that melts at 34 °C. It is the highest known chromium fluoride, since the hypothetical chromium hexafluoride has not yet been synthesized.

Fluorine forms a great variety of chemical compounds, within which it always adopts an oxidation state of −1. With other atoms, fluorine forms either polar covalent bonds or ionic bonds. Most frequently, covalent bonds involving fluorine atoms are single bonds, although at least two examples of a higher order bond exist. Fluoride may act as a bridging ligand between two metals in some complex molecules. Molecules containing fluorine may also exhibit hydrogen bonding. Fluorine's chemistry includes inorganic compounds formed with hydrogen, metals, nonmetals, and even noble gases; as well as a diverse set of organic compounds. For many elements the highest known oxidation state can be achieved in a fluoride. For some elements this is achieved exclusively in a fluoride, for others exclusively in an oxide; and for still others the highest oxidation states of oxides and fluorides are always equal.

<span class="mw-page-title-main">Bis(pentafluorophenyl)xenon</span> Chemical compound

Bis(pentafluorophenyl)xenon, is an unstable organic compound of xenon. It consists of two fluorinated phenyl rings connected to xenon.

<span class="mw-page-title-main">Radon compounds</span>

Radon compounds are compounds formed by the element radon (Rn). Radon is a member of the zero-valence elements that are called noble gases, and is chemically not very reactive. The 3.8-day half-life of radon-222 makes it useful in physical sciences as a natural tracer. Because radon is a gas at standard conditions, unlike its decay-chain parents, it can readily be extracted from them for research.

References

  1. 1 2 LeBlond, Nicolas; Lutar, Karel; Žemva, Boris (2000-01-16). "The First Organoxenon(IV) Compound: Pentafluorophenyldifluoroxenonium(IV) Tetrafluoroborate". Angewandte Chemie International Edition. 39 (2): 391–393. doi:10.1002/(SICI)1521-3773(20000117)39:2<391::AID-ANIE391>3.0.CO;2-U. PMID   10649421.
  2. 1 2 3 Frohn, H. (2004-05-31). "C6F5XeF, a versatile starting material in xenon-carbon chemistry". Journal of Fluorine Chemistry. 125 (6): 981–988. doi:10.1016/j.jfluchem.2004.01.019.
  3. ↑ Gilles, T.; Gnann, R.; Naumann, D.; Tebbe, K. F. (1994-03-15). "2,6-Difluorphenylxenon(II)-tetrafluoroborat". Acta Crystallographica Section C. 50 (3): 411–413. doi:10.1107/s0108270193009898. ISSN   0108-2701.
  4. ↑ Naumann, D.; Butler, H.; Gnann, R.; Tyrra, W. (1993-03-01). "Arylxenon tetrafluoroborates: compounds of unexpected stability". Inorganic Chemistry. 32 (6): 861–863. doi:10.1021/ic00058a018. ISSN   0020-1669.
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