Mechanism of the photochemical oxidation of Fe(CO)5 and CpW(CO)3Cl (Cp = η5-C5H5) by chlorocarbons

Alan S Goldman, David R. Tyler

Research output: Contribution to journalArticle

34 Citations (Scopus)

Abstract

The photochemical oxidation of CpW(CO)3Cl (Cp = η5-C6H5) by carbon tetrachloride and other polychlorocarbons affords CpW(CO)2Cl3. The sole photoprocess is dissociation of CO from the complex to give CpW(CO)2Cl. The major pathway of the oxidation involves the net transfer of two halogen atoms from one halocarbon molecule to the unsaturated metal complex. Pathways involving the formation of trichloromethyl radical were shown to be unimportant. In a related reaction, the photooxidation of Fe(CO)5 in carbon tetrachloride gives FeCl2, tetrachloroethylene, tar, and minor amounts of hexachloroethane. As in the CpW(CO)3Cl system, trichloromethyl radical is produced in, at most, only minor amounts. The reaction proceeds through an iron dichlorocarbene intermediate. Evidence for such an intermediate includes formation of isocyanides, phosgene, and thiophosgene when the oxidation is carried out in the presence of primary amines, dioxygen, and sulfur, respectively. In addition, tetrachloroethylene forms in neat carbon tetrachloride. Various alternative explanations for the above phenomena are considered and found unsatisfactory. The iron carbene species is proposed to arise via oxidative addition of carbon tetrachloride to photolytically generated Fe(CO)4, followed by α-chlorine elimination. Degradation of the complex can then result in either dimerization or telomerization of the dichlorocarbene moiety. The CpW(LO)3Cl system is believed to follow an analogous pathway.

Original languageEnglish
Pages (from-to)449-456
Number of pages8
JournalOrganometallics
Volume3
Issue number3
Publication statusPublished - 1984

Fingerprint

chlorocarbons
carbon tetrachloride
Carbon Monoxide
Carbon Tetrachloride
Oxidation
oxidation
Tetrachloroethylene
phosgene
halocarbons
iron
tars
photooxidation
carbenes
Iron
Phosgene
dimerization
Halocarbons
halogens
chlorine
Tars

ASJC Scopus subject areas

  • Inorganic Chemistry
  • Organic Chemistry

Cite this

Mechanism of the photochemical oxidation of Fe(CO)5 and CpW(CO)3Cl (Cp = η5-C5H5) by chlorocarbons. / Goldman, Alan S; Tyler, David R.

In: Organometallics, Vol. 3, No. 3, 1984, p. 449-456.

Research output: Contribution to journalArticle

@article{e89848e3eed3430283cb8aa134bde1e4,
title = "Mechanism of the photochemical oxidation of Fe(CO)5 and CpW(CO)3Cl (Cp = η5-C5H5) by chlorocarbons",
abstract = "The photochemical oxidation of CpW(CO)3Cl (Cp = η5-C6H5) by carbon tetrachloride and other polychlorocarbons affords CpW(CO)2Cl3. The sole photoprocess is dissociation of CO from the complex to give CpW(CO)2Cl. The major pathway of the oxidation involves the net transfer of two halogen atoms from one halocarbon molecule to the unsaturated metal complex. Pathways involving the formation of trichloromethyl radical were shown to be unimportant. In a related reaction, the photooxidation of Fe(CO)5 in carbon tetrachloride gives FeCl2, tetrachloroethylene, tar, and minor amounts of hexachloroethane. As in the CpW(CO)3Cl system, trichloromethyl radical is produced in, at most, only minor amounts. The reaction proceeds through an iron dichlorocarbene intermediate. Evidence for such an intermediate includes formation of isocyanides, phosgene, and thiophosgene when the oxidation is carried out in the presence of primary amines, dioxygen, and sulfur, respectively. In addition, tetrachloroethylene forms in neat carbon tetrachloride. Various alternative explanations for the above phenomena are considered and found unsatisfactory. The iron carbene species is proposed to arise via oxidative addition of carbon tetrachloride to photolytically generated Fe(CO)4, followed by α-chlorine elimination. Degradation of the complex can then result in either dimerization or telomerization of the dichlorocarbene moiety. The CpW(LO)3Cl system is believed to follow an analogous pathway.",
author = "Goldman, {Alan S} and Tyler, {David R.}",
year = "1984",
language = "English",
volume = "3",
pages = "449--456",
journal = "Organometallics",
issn = "0276-7333",
publisher = "American Chemical Society",
number = "3",

}

TY - JOUR

T1 - Mechanism of the photochemical oxidation of Fe(CO)5 and CpW(CO)3Cl (Cp = η5-C5H5) by chlorocarbons

AU - Goldman, Alan S

AU - Tyler, David R.

PY - 1984

Y1 - 1984

N2 - The photochemical oxidation of CpW(CO)3Cl (Cp = η5-C6H5) by carbon tetrachloride and other polychlorocarbons affords CpW(CO)2Cl3. The sole photoprocess is dissociation of CO from the complex to give CpW(CO)2Cl. The major pathway of the oxidation involves the net transfer of two halogen atoms from one halocarbon molecule to the unsaturated metal complex. Pathways involving the formation of trichloromethyl radical were shown to be unimportant. In a related reaction, the photooxidation of Fe(CO)5 in carbon tetrachloride gives FeCl2, tetrachloroethylene, tar, and minor amounts of hexachloroethane. As in the CpW(CO)3Cl system, trichloromethyl radical is produced in, at most, only minor amounts. The reaction proceeds through an iron dichlorocarbene intermediate. Evidence for such an intermediate includes formation of isocyanides, phosgene, and thiophosgene when the oxidation is carried out in the presence of primary amines, dioxygen, and sulfur, respectively. In addition, tetrachloroethylene forms in neat carbon tetrachloride. Various alternative explanations for the above phenomena are considered and found unsatisfactory. The iron carbene species is proposed to arise via oxidative addition of carbon tetrachloride to photolytically generated Fe(CO)4, followed by α-chlorine elimination. Degradation of the complex can then result in either dimerization or telomerization of the dichlorocarbene moiety. The CpW(LO)3Cl system is believed to follow an analogous pathway.

AB - The photochemical oxidation of CpW(CO)3Cl (Cp = η5-C6H5) by carbon tetrachloride and other polychlorocarbons affords CpW(CO)2Cl3. The sole photoprocess is dissociation of CO from the complex to give CpW(CO)2Cl. The major pathway of the oxidation involves the net transfer of two halogen atoms from one halocarbon molecule to the unsaturated metal complex. Pathways involving the formation of trichloromethyl radical were shown to be unimportant. In a related reaction, the photooxidation of Fe(CO)5 in carbon tetrachloride gives FeCl2, tetrachloroethylene, tar, and minor amounts of hexachloroethane. As in the CpW(CO)3Cl system, trichloromethyl radical is produced in, at most, only minor amounts. The reaction proceeds through an iron dichlorocarbene intermediate. Evidence for such an intermediate includes formation of isocyanides, phosgene, and thiophosgene when the oxidation is carried out in the presence of primary amines, dioxygen, and sulfur, respectively. In addition, tetrachloroethylene forms in neat carbon tetrachloride. Various alternative explanations for the above phenomena are considered and found unsatisfactory. The iron carbene species is proposed to arise via oxidative addition of carbon tetrachloride to photolytically generated Fe(CO)4, followed by α-chlorine elimination. Degradation of the complex can then result in either dimerization or telomerization of the dichlorocarbene moiety. The CpW(LO)3Cl system is believed to follow an analogous pathway.

UR - http://www.scopus.com/inward/record.url?scp=0000278178&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0000278178&partnerID=8YFLogxK

M3 - Article

AN - SCOPUS:0000278178

VL - 3

SP - 449

EP - 456

JO - Organometallics

JF - Organometallics

SN - 0276-7333

IS - 3

ER -