Iodosobenzene

Iodosobenzene or iodosylbenzene is an organoiodine compound with the empirical formula C₆H₅IO. This colourless solid compound is used as an oxo transfer reagent in research laboratories examining organic and coordination chemistry.

Iodosobenzene

Names
Preferred IUPAC name Iodosylbenzene[1]
Other names Iodosobenzene
Identifiers
CAS Number	536-80-1 Y
3D model (JSmol)	Interactive image
ChemSpider	83171 Y
ECHA InfoCard	100.007.864
EC Number	208-648-8
PubChem CID	92125
UNII	TWW7V7Q50P Y
CompTox Dashboard (EPA)	DTXSID1060213
InChI InChI=1S/C6H5IO/c8-7-6-4-2-1-3-5-6/h1-5H Y Key: JYJVVHFRSFVEJM-UHFFFAOYSA-N Y InChI=1/C6H5IO/c8-7-6-4-2-1-3-5-6/h1-5H Key: JYJVVHFRSFVEJM-UHFFFAOYAR
SMILES c1ccc(cc1)I=O
Properties
Chemical formula	C6H5IO
Molar mass	220.01 g/mol
Appearance	colourless solid
Density	1.229 g cm−3
Melting point	210 ˚C
Solubility in water	poor
Hazards
GHS labelling:[2]
Pictograms
Signal word	Danger
Hazard statements	H228, H271, H315, H319, H335
Precautionary statements	P210, P220, P240, P241, P261, P264, P264+P265, P271, P280, P283, P302+P352, P304+P340, P305+P351+P338, P306+P360, P319, P321, P332+P317, P337+P317, P362+P364, P370+P378, P371+P380+P375, P403+P233, P405, P420, P501
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Y verify (what is YN ?) Infobox references

Preparation and structure

Iodosobenzene is prepared from iodobenzene.^[3] It is prepared by first oxidizing iodobenzene by peracetic acid. Hydrolysis of resulting diacetate affords "PhIO":^[4]

C₆H₅I + CH₃CO₃H + CH₃CO₂H → C₆H₅I(O₂CCH₃)₂ + H₂O

C₆H₅I(O₂CCH₃)₂ + H₂O → C₆H₅IO + 2 CH₃CO₂H

The structure of iodosobenzene has been verified by crystallographically.^[5] Related derivatives are also oligomeric.^[6] Its low solubility in most solvents and vibrational spectroscopy indicate that it is not molecular, but is polymeric, consisting of –I–O–I–O– chains.^[7] The related diacetate, C₆H₅I(O₂CCH₃)₂, illustrates the ability of iodine(III) to adopt a T-shaped geometry without multiple bonds.^[8] Theoretical studies show that the bonding between the iodine and oxygen atoms in iodosobenzene represents a single dative I-O sigma bond, confirming the absence of the double I=O bond.^[9]

A monomeric derivative iodosylbenzene is known in the form of 2-(tert-butylsulfonyl)iodosylbenzene, a yellow solid. C-I-O angle is 94.78°, C-I and I-O distances are 2.128 and 1.848 Å.^[10]

Structure of 2-(tert-butylsulfonyl)iodosylbenzene.

Applications

Iodosobenzene has no commercial uses, but in the laboratory it is employed as an "oxo-transfer reagent." It epoxidizes certain alkenes and converts some metal complexes into the corresponding oxo derivatives. Although it is an oxidant, it is also mildly nucleophilic. These oxo-transfer reactions operate by the intermediacy of adducts PhI=O→M, which release PhI.^[11]

A mixture of iodosobenzene and sodium azide in acetic acid converts alkenes to vicinal diazides:.^[12][13]

R₂C=CR₂ + 2 NaN₃ + PhIO + 2 AcOH → (N₃)R₂C−CR₂(N₃) + PhI + 2 AcONa + H₂O

Safety

This compound is explosive and should not be heated under vacuum.

See also

• Dess-Martin reagent

References

1. International Union of Pure and Applied Chemistry (2014). Nomenclature of Organic Chemistry: IUPAC Recommendations and Preferred Names 2013. The Royal Society of Chemistry. p. 661. doi:10.1039/9781849733069. ISBN 978-0-85404-182-4.
2. "Iodosylbenzene". pubchem.ncbi.nlm.nih.gov.
3. Conrad Willgerodt (1892). "Zur Kenntniss aromatischer Jodidchloride, des Jodoso- und Jodobenzols". Ber. 25 (2): 3494–3502. doi:10.1002/cber.189202502221.
4. H. Saltzman, J. G. Sharefkin (1963). "Iodosylbenzene". Organic Syntheses. 43: 60. doi:10.15227/orgsyn.043.0060.
5. Wegeberg, Christina; Frankær, Christian Grundahl; McKenzie, Christine J. (2016). "Reduction of hypervalent iodine by coordination to iron(III) and the crystal structures of PhIO and PhIO2". Dalton Transactions. 45 (44): 17714–17722. doi:10.1039/C6DT02937J. PMID 27761533.
6. Richter, Helen W.; Koser, Gerald F.; Incarvito, Christopher D.; Rheingold, Arnold L. (2007). "Preparation and Structure of a Solid-State Hypervalent-Iodine Polymer Containing Iodine and Oxygen Atoms in Fused 12-Atom Hexagonal Rings". Inorganic Chemistry. 46 (14): 5555–5561. doi:10.1021/ic0701716. PMID 17569525.
7. Hans Siebert; Monika Handrich (1976). "Schwingungsspektren und Struktur von Jodosyl- und Jodyl-Verbindungen". Z. anorg. allg. Chem. 426 (2): 173–183. doi:10.1002/zaac.19764260206.
8. C. J. Carmalt, Claire J.; J. G. Crossley; J. G. Knight; P. Lightfoot; A. Martín; M. P. Muldowney; N. C. Norman; A. G. Orpen (1994). "An examination of the structures of iodosylbenzene (PhIO) and the related imido compound, PhINSO₂-4-Me-C₆H₄, by X-ray powder diffraction and EXAFS (extended X-ray absorption fine structure) spectroscopy". J. Chem. Soc., Chem. Commun. (20): 2367–2368. doi:10.1039/C39940002367.
9. Ivanov, A.; Popov, A.; Boldyrev, A.; Zhdankin, V. (2014). "The I=X (X = O,N,C) Double Bond in Hypervalent Iodine Compounds: Is it Real?". Angew. Chem. Int. Ed. 53 (36): 9617–9621. doi:10.1002/anie.201405142. PMID 25045143.
10. MacIkenas, Dainius; Skrzypczak-Jankun, Ewa; Protasiewicz, John D. (2000). "Redirecting Secondary Bonds to Control Molecular and Crystal Properties of an Iodosyl- and an Iodylbenzene". Angewandte Chemie International Edition. 39 (11): 2007–2010. doi:10.1002/1521-3773(20000602)39:11<2007::AID-ANIE2007>3.0.CO;2-Z. PMID 10941012.
11. Lennartson, Anders; McKenzie, Christine J. (2012). "An Iron(III) Iodosylbenzene Complex: A Masked Non-Heme FeVO". Angewandte Chemie International Edition. 51 (27): 6767–6770. doi:10.1002/anie.201202487. PMID 22639404.
12. Robert M.Moriarty; Jaffar S.Khosrowshahi (1986). "A versatile synthesis of vicinal diazides using hypervalent iodine". Tetrahedron Lett. 27 (25): 2809–2812. doi:10.1016/S0040-4039(00)84648-1.
13. March, J.; Smith, M. B. (2007). Advanced Organic Chemistry (6th ed.). New York: John Wiley & Sons. p. 1182. ISBN 978-0-471-72091-1.