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
IUPAC name
Iodosylbenzene
Other names
Iodosobenzene
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.007.864
UNII
Properties
C6H5IO
Molar mass 220.01 g mol−1
Appearance colourless solid
Density 1.229 g cm−3
Melting point 210 ˚C
poor
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Preparation and structure

Iodosobenzene is prepared from iodobenzene.[1] It is prepared by first oxidizing iodobenzene by peracetic acid. Hydrolysis of resulting diacetate affords "PhIO":[2]

C6H5I + CH3CO3H + CH3CO2H → C6H5I(O2CCH3)2 + H2O
C6H5I(O2CCH3)2 + H2O → C6H5IO + 2 CH3CO2H

The structure of iodosobenzene remains unverified crystallographically. Related derivatives are polymeric, lacking any evidence for I=O bonds.[3] 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.[4] The related diacetate, C6H5I(O2CCH3)2, illustrates the ability of iodine(III) to adopt a T-shaped geometry without multiple bonds.[5] 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.[6]

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. The active agent in these oxo-transfer reactions is assumed to be monomeric PhI=O, but this aspect remains unverified.

See also
  • Dess-Martin reagent[7]

Safety

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

References
  1. Conrad Willgerodt (1892). "Zur Kenntniss aromatischer Jodidchloride, des Jodoso- und Jodobenzols". Ber. 25 (2): 3494–3502. doi:10.1002/cber.189202502221.
  2. H. Saltzman, J. G. Sharefkin (1963). "Iodosylbenzene". 43: 60. doi:10.15227/orgsyn.043.0060. Cite journal requires |journal= (help)
  3. 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.
  4. 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.
  5. C. J. Carmalt; 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.
  6. 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.
  7. Boeckman, Robert J.; George, Kelly M. (2009). "1,1,1-Triacetoxy-1,1-dihydro-1,2-benziodoxol-3(1H)-one". Encyclopedia of Reagents for Organic Synthesis. doi:10.1002/047084289X.rt157m.pub2.
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