Reaction of Phenyl and Methyl Disulfide with ·Cr(CO)3C5Me5 and HCr(CO)3C5Me5. Metal Radical and Metal Hydride Reactivity at the Sulfur-Sulfur Bond. Different Mechanisms for Oxidative Addition of Alkyl and Aryl Disulfides

Telvin D. Ju, Kenneth B. Capps, Russell F. Lang, Gerald C. Roper, Carl Hoff

Research output: Contribution to journalArticle

22 Citations (Scopus)

Abstract

The enthalpies of reaction of the ·Cr(CO)3C5Me5 and disulfides (RSSR) forming RS-Cr(CO)3C5Me5 have been measured by solution calorimetry, ΔH = -13.3 + 1.5 kcal/mol (R = Ph) and -11.2 + 1.2 kcal/mol (R = Me). These data lead to Cr-SR bond strength estimates of 35 and 43 kcal/mol, respectively. The rates of oxidative addition have been investigated by FTIR spectroscopy. Phenyl disulfide reacts by a second-order mechanism whose rate-determining step is the attack of the chromium radical on the sulfur-sulfur bond, yielding chromium thiolate and a thiyl radical [k(298 K) = 1.3 M-1 s-1, ΔHΦ = +10.2 kcal/mol, ΔSΦ = -24.4 cal/(mol deg)]. Methyl disulfide reacts by a third-order mechanism going through a termolecular transition state in which the stronger sulfur-sulfur bond in the alkyl disulfide is attacked simultaneously by two chromium radicals [k(298 K = 393 M-2 s-1, ΔHΦ = -0.2 kcal/mol, ΔSΦ = -47 cal/(mol deg)]. The rates of reaction of MeSSMe and PhSSPh with the hydride H-Cr(CO)3C5Me5 have also been investigated in the presence of varying amounts of added ·Cr(CO)3C5Me5 radical. MeSSMe shows no apparent reaction with HCr(CO)3C5Me5, even in the presence of added ·Cr(CO)3C5Me5. PhSSPh reacts with HCr(CO)3C5Me5 primarily by a radical chain process involving ·Cr(CO)3C5Me5 and PhS· radicals. The upper limit to the rate of reaction by nonradical concerted addition is kobs < 4 × 10-4 M-1 s-1.

Original languageEnglish
Pages (from-to)614-621
Number of pages8
JournalInorganic Chemistry
Volume36
Issue number4
StatePublished - Feb 12 1997

Fingerprint

metal hydrides
disulfides
Carbon Monoxide
Sulfur
Hydrides
Disulfides
hydrides
sulfur
reactivity
Metals
metals
chromium
Chromium
attack
dimethyl disulfide
Calorimetry
heat measurement
enthalpy
Enthalpy
Spectroscopy

ASJC Scopus subject areas

  • Inorganic Chemistry

Cite this

Reaction of Phenyl and Methyl Disulfide with ·Cr(CO)3C5Me5 and HCr(CO)3C5Me5. Metal Radical and Metal Hydride Reactivity at the Sulfur-Sulfur Bond. Different Mechanisms for Oxidative Addition of Alkyl and Aryl Disulfides. / Ju, Telvin D.; Capps, Kenneth B.; Lang, Russell F.; Roper, Gerald C.; Hoff, Carl.

In: Inorganic Chemistry, Vol. 36, No. 4, 12.02.1997, p. 614-621.

Research output: Contribution to journalArticle

@article{c8fbdece20634feeab394359c4a5e30e,
title = "Reaction of Phenyl and Methyl Disulfide with ·Cr(CO)3C5Me5 and HCr(CO)3C5Me5. Metal Radical and Metal Hydride Reactivity at the Sulfur-Sulfur Bond. Different Mechanisms for Oxidative Addition of Alkyl and Aryl Disulfides",
abstract = "The enthalpies of reaction of the ·Cr(CO)3C5Me5 and disulfides (RSSR) forming RS-Cr(CO)3C5Me5 have been measured by solution calorimetry, ΔH = -13.3 + 1.5 kcal/mol (R = Ph) and -11.2 + 1.2 kcal/mol (R = Me). These data lead to Cr-SR bond strength estimates of 35 and 43 kcal/mol, respectively. The rates of oxidative addition have been investigated by FTIR spectroscopy. Phenyl disulfide reacts by a second-order mechanism whose rate-determining step is the attack of the chromium radical on the sulfur-sulfur bond, yielding chromium thiolate and a thiyl radical [k(298 K) = 1.3 M-1 s-1, ΔHΦ = +10.2 kcal/mol, ΔSΦ = -24.4 cal/(mol deg)]. Methyl disulfide reacts by a third-order mechanism going through a termolecular transition state in which the stronger sulfur-sulfur bond in the alkyl disulfide is attacked simultaneously by two chromium radicals [k(298 K = 393 M-2 s-1, ΔHΦ = -0.2 kcal/mol, ΔSΦ = -47 cal/(mol deg)]. The rates of reaction of MeSSMe and PhSSPh with the hydride H-Cr(CO)3C5Me5 have also been investigated in the presence of varying amounts of added ·Cr(CO)3C5Me5 radical. MeSSMe shows no apparent reaction with HCr(CO)3C5Me5, even in the presence of added ·Cr(CO)3C5Me5. PhSSPh reacts with HCr(CO)3C5Me5 primarily by a radical chain process involving ·Cr(CO)3C5Me5 and PhS· radicals. The upper limit to the rate of reaction by nonradical concerted addition is kobs < 4 × 10-4 M-1 s-1.",
author = "Ju, {Telvin D.} and Capps, {Kenneth B.} and Lang, {Russell F.} and Roper, {Gerald C.} and Carl Hoff",
year = "1997",
month = "2",
day = "12",
language = "English",
volume = "36",
pages = "614--621",
journal = "Inorganic Chemistry",
issn = "0020-1669",
publisher = "American Chemical Society",
number = "4",

}

TY - JOUR

T1 - Reaction of Phenyl and Methyl Disulfide with ·Cr(CO)3C5Me5 and HCr(CO)3C5Me5. Metal Radical and Metal Hydride Reactivity at the Sulfur-Sulfur Bond. Different Mechanisms for Oxidative Addition of Alkyl and Aryl Disulfides

AU - Ju, Telvin D.

AU - Capps, Kenneth B.

AU - Lang, Russell F.

AU - Roper, Gerald C.

AU - Hoff, Carl

PY - 1997/2/12

Y1 - 1997/2/12

N2 - The enthalpies of reaction of the ·Cr(CO)3C5Me5 and disulfides (RSSR) forming RS-Cr(CO)3C5Me5 have been measured by solution calorimetry, ΔH = -13.3 + 1.5 kcal/mol (R = Ph) and -11.2 + 1.2 kcal/mol (R = Me). These data lead to Cr-SR bond strength estimates of 35 and 43 kcal/mol, respectively. The rates of oxidative addition have been investigated by FTIR spectroscopy. Phenyl disulfide reacts by a second-order mechanism whose rate-determining step is the attack of the chromium radical on the sulfur-sulfur bond, yielding chromium thiolate and a thiyl radical [k(298 K) = 1.3 M-1 s-1, ΔHΦ = +10.2 kcal/mol, ΔSΦ = -24.4 cal/(mol deg)]. Methyl disulfide reacts by a third-order mechanism going through a termolecular transition state in which the stronger sulfur-sulfur bond in the alkyl disulfide is attacked simultaneously by two chromium radicals [k(298 K = 393 M-2 s-1, ΔHΦ = -0.2 kcal/mol, ΔSΦ = -47 cal/(mol deg)]. The rates of reaction of MeSSMe and PhSSPh with the hydride H-Cr(CO)3C5Me5 have also been investigated in the presence of varying amounts of added ·Cr(CO)3C5Me5 radical. MeSSMe shows no apparent reaction with HCr(CO)3C5Me5, even in the presence of added ·Cr(CO)3C5Me5. PhSSPh reacts with HCr(CO)3C5Me5 primarily by a radical chain process involving ·Cr(CO)3C5Me5 and PhS· radicals. The upper limit to the rate of reaction by nonradical concerted addition is kobs < 4 × 10-4 M-1 s-1.

AB - The enthalpies of reaction of the ·Cr(CO)3C5Me5 and disulfides (RSSR) forming RS-Cr(CO)3C5Me5 have been measured by solution calorimetry, ΔH = -13.3 + 1.5 kcal/mol (R = Ph) and -11.2 + 1.2 kcal/mol (R = Me). These data lead to Cr-SR bond strength estimates of 35 and 43 kcal/mol, respectively. The rates of oxidative addition have been investigated by FTIR spectroscopy. Phenyl disulfide reacts by a second-order mechanism whose rate-determining step is the attack of the chromium radical on the sulfur-sulfur bond, yielding chromium thiolate and a thiyl radical [k(298 K) = 1.3 M-1 s-1, ΔHΦ = +10.2 kcal/mol, ΔSΦ = -24.4 cal/(mol deg)]. Methyl disulfide reacts by a third-order mechanism going through a termolecular transition state in which the stronger sulfur-sulfur bond in the alkyl disulfide is attacked simultaneously by two chromium radicals [k(298 K = 393 M-2 s-1, ΔHΦ = -0.2 kcal/mol, ΔSΦ = -47 cal/(mol deg)]. The rates of reaction of MeSSMe and PhSSPh with the hydride H-Cr(CO)3C5Me5 have also been investigated in the presence of varying amounts of added ·Cr(CO)3C5Me5 radical. MeSSMe shows no apparent reaction with HCr(CO)3C5Me5, even in the presence of added ·Cr(CO)3C5Me5. PhSSPh reacts with HCr(CO)3C5Me5 primarily by a radical chain process involving ·Cr(CO)3C5Me5 and PhS· radicals. The upper limit to the rate of reaction by nonradical concerted addition is kobs < 4 × 10-4 M-1 s-1.

UR - http://www.scopus.com/inward/record.url?scp=0000703201&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0000703201&partnerID=8YFLogxK

M3 - Article

VL - 36

SP - 614

EP - 621

JO - Inorganic Chemistry

JF - Inorganic Chemistry

SN - 0020-1669

IS - 4

ER -