Mechanistic Study of the Voltammetry of Nonconducting Microcrystalline cis- and trans-Cr(CO)2(dpe)2 Complexes (dpe = Ph2PCH2CH2PPh2) Mechanically Attached to a Graphite Electrode and Immersed in Different Aqueous Electrolyte Media: Identification by Infrared Spectroscopy of cis-[Cr(CO)2(dpe)2]+ Stabilized at the Electrode–Solid–Solution Interface

Alan M. Bond; Ray Colton; Frank Marken; Jacky N. Walter

doi:10.1021/om00024a063

Mechanistic Study of the Voltammetry of Nonconducting Microcrystalline cis- and trans-Cr(CO)₂(dpe)₂ Complexes (dpe = Ph₂PCH₂CH₂PPh₂) Mechanically Attached to a Graphite Electrode and Immersed in Different Aqueous Electrolyte Media: Identification by Infrared Spectroscopy of cis-[Cr(CO)₂(dpe)₂]⁺ Stabilized at the Electrode–Solid–Solution Interface

Alan M. Bond, Ray Colton, Frank Marken, Jacky N. Walter

La Trobe University

Research output: Contribution to journal › Article › peer-review

Abstract

Electrochemical oxidation of microcrystalline, but nonconducting, cis-Cr(CO)₂(dpe)₂ (dpe = Ph₂PCH₂CH₂PPh₂) mechanically attached to a graphite electrode which has been placed in aqueous electrolyte media enables the thermodynamically unstable cis-[Cr(CO)₂(dpe)₂]⁺ to be identified for the first time by specular reflectance infrared spectroscopy. That is, kinetic stabilization of the thermodynamically favored cis⁺ → trans⁺ isomerization process is achieved at the electrode – solid – electrolyte interface. Detailed studies on the oxidation of microcrystalline trans-Cr(CO)₂(dpe)₂ to trans-[Cr(CO)₂(dpe)₂]⁺ which involve the variation of temperature, scan rate, and electrolyte reveal that “thick”-layer and “thin”-layer processes are present. A zero current extrapolation process enables potentials to be calculated which are independent of crystal size and spacing. Potential data calculated in this manner show virtually no dependence on electrolyte cation but a variation of potential of almost 500 mV when 0.1 M NaF is used instead of 0.1 M NaClO₄ as the electrolyte. The correlation of oxidation potential data with free energies of partition for anion transport across a water-dichloroethane interface coupled with voltammetric and spectroscopic data indicate that the oxidation reaction may be summarized by eqs 1–5: (1) trans_solid ⇌ trans⁺_solid + e^-; (2) cis_solid ⇌ cis⁺_solid e^- (3) A^-_solution⇌ A^- solid; (4) trans⁺_solid +A^-_solid⇌ (trans⁺– A^- _solid); (5) Cis⁺ _solid + A^- _solid ⇌ (cis⁺–A^-_solid) → (trans⁺–A^-_solid). A^- denotes the electrolyte anion, and the cis^0/+ and trans^0/+ nomenclature represents the relevant isomer of [Cr(CO)₂(dpe)]^0/+ in the appropriate oxidation state. The oxidation processes are believed to be accompanied by swelling of crystals, which may aid the transport of ionic species within the solid.

Original language	English
Pages (from-to)	5122-5131
Number of pages	10
Journal	Organometallics
Volume	13
Issue number	12
DOIs	https://doi.org/10.1021/om00024a063
Publication status	Published - 1 Dec 1994

ASJC Scopus subject areas

Physical and Theoretical Chemistry
Organic Chemistry
Inorganic Chemistry

Access to Document

10.1021/om00024a063

Fingerprint

Dive into the research topics of 'Mechanistic Study of the Voltammetry of Nonconducting Microcrystalline cis- and trans-Cr(CO)₂(dpe)₂ Complexes (dpe = Ph₂PCH₂CH₂PPh₂) Mechanically Attached to a Graphite Electrode and Immersed in Different Aqueous Electrolyte Media: Identification by Infrared Spectroscopy of cis-[Cr(CO)₂(dpe)₂]⁺ Stabilized at the Electrode–Solid–Solution Interface'. Together they form a unique fingerprint.

Cite this

Bond, A. M., Colton, R., Marken, F., & Walter, J. N. (1994). Mechanistic Study of the Voltammetry of Nonconducting Microcrystalline cis- and trans-Cr(CO)₂(dpe)₂ Complexes (dpe = Ph₂PCH₂CH₂PPh₂) Mechanically Attached to a Graphite Electrode and Immersed in Different Aqueous Electrolyte Media: Identification by Infrared Spectroscopy of cis-[Cr(CO)₂(dpe)₂]⁺ Stabilized at the Electrode–Solid–Solution Interface. Organometallics, 13(12), 5122-5131. https://doi.org/10.1021/om00024a063

Mechanistic Study of the Voltammetry of Nonconducting Microcrystalline cis- and trans-Cr(CO)₂(dpe)₂ Complexes (dpe = Ph₂PCH₂CH₂PPh₂) Mechanically Attached to a Graphite Electrode and Immersed in Different Aqueous Electrolyte Media: Identification by Infrared Spectroscopy of cis-[Cr(CO)₂(dpe)₂]⁺ Stabilized at the Electrode–Solid–Solution Interface. / Bond, Alan M.; Colton, Ray; Marken, Frank et al.
In: Organometallics, Vol. 13, No. 12, 01.12.1994, p. 5122-5131.

Research output: Contribution to journal › Article › peer-review

Bond, AM, Colton, R, Marken, F & Walter, JN 1994, 'Mechanistic Study of the Voltammetry of Nonconducting Microcrystalline cis- and trans-Cr(CO)₂(dpe)₂ Complexes (dpe = Ph₂PCH₂CH₂PPh₂) Mechanically Attached to a Graphite Electrode and Immersed in Different Aqueous Electrolyte Media: Identification by Infrared Spectroscopy of cis-[Cr(CO)₂(dpe)₂]⁺ Stabilized at the Electrode–Solid–Solution Interface', Organometallics, vol. 13, no. 12, pp. 5122-5131. https://doi.org/10.1021/om00024a063

Bond AM, Colton R, Marken F, Walter JN. Mechanistic Study of the Voltammetry of Nonconducting Microcrystalline cis- and trans-Cr(CO)₂(dpe)₂ Complexes (dpe = Ph₂PCH₂CH₂PPh₂) Mechanically Attached to a Graphite Electrode and Immersed in Different Aqueous Electrolyte Media: Identification by Infrared Spectroscopy of cis-[Cr(CO)₂(dpe)₂]⁺ Stabilized at the Electrode–Solid–Solution Interface. Organometallics. 1994 Dec 1;13(12):5122-5131. doi: 10.1021/om00024a063

Bond, Alan M. ; Colton, Ray ; Marken, Frank et al. / Mechanistic Study of the Voltammetry of Nonconducting Microcrystalline cis- and trans-Cr(CO)₂(dpe)₂ Complexes (dpe = Ph₂PCH₂CH₂PPh₂) Mechanically Attached to a Graphite Electrode and Immersed in Different Aqueous Electrolyte Media : Identification by Infrared Spectroscopy of cis-[Cr(CO)₂(dpe)₂]⁺ Stabilized at the Electrode–Solid–Solution Interface. In: Organometallics. 1994 ; Vol. 13, No. 12. pp. 5122-5131.

@article{3c8977faa1474165a8dd102ca47b99fe,

title = "Mechanistic Study of the Voltammetry of Nonconducting Microcrystalline cis- and trans-Cr(CO)2(dpe)2 Complexes (dpe = Ph2PCH2CH2PPh2) Mechanically Attached to a Graphite Electrode and Immersed in Different Aqueous Electrolyte Media: Identification by Infrared Spectroscopy of cis-[Cr(CO)2(dpe)2]+ Stabilized at the Electrode–Solid–Solution Interface",

abstract = "Electrochemical oxidation of microcrystalline, but nonconducting, cis-Cr(CO)2(dpe)2 (dpe = Ph2PCH2CH2PPh2) mechanically attached to a graphite electrode which has been placed in aqueous electrolyte media enables the thermodynamically unstable cis-[Cr(CO)2(dpe)2]+ to be identified for the first time by specular reflectance infrared spectroscopy. That is, kinetic stabilization of the thermodynamically favored cis+ → trans+ isomerization process is achieved at the electrode – solid – electrolyte interface. Detailed studies on the oxidation of microcrystalline trans-Cr(CO)2(dpe)2 to trans-[Cr(CO)2(dpe)2]+ which involve the variation of temperature, scan rate, and electrolyte reveal that “thick”-layer and “thin”-layer processes are present. A zero current extrapolation process enables potentials to be calculated which are independent of crystal size and spacing. Potential data calculated in this manner show virtually no dependence on electrolyte cation but a variation of potential of almost 500 mV when 0.1 M NaF is used instead of 0.1 M NaClO4 as the electrolyte. The correlation of oxidation potential data with free energies of partition for anion transport across a water-dichloroethane interface coupled with voltammetric and spectroscopic data indicate that the oxidation reaction may be summarized by eqs 1–5: (1) transsolid ⇌ trans+solid + e-; (2) cissolid ⇌ cis+solid e- (3) A-solution⇌ A- solid; (4) trans+solid +A-solid⇌ (trans+– A- solid); (5) Cis+ solid + A- solid ⇌ (cis+–A-solid) → (trans+–A-solid). A- denotes the electrolyte anion, and the cis0/+ and trans0/+ nomenclature represents the relevant isomer of [Cr(CO)2(dpe)]0/+ in the appropriate oxidation state. The oxidation processes are believed to be accompanied by swelling of crystals, which may aid the transport of ionic species within the solid.",

author = "Bond, {Alan M.} and Ray Colton and Frank Marken and Walter, {Jacky N.}",

year = "1994",

month = dec,

day = "1",

doi = "10.1021/om00024a063",

language = "English",

volume = "13",

pages = "5122--5131",

journal = "Organometallics",

issn = "0276-7333",

publisher = "American Chemical Society",

number = "12",

}

TY - JOUR

T1 - Mechanistic Study of the Voltammetry of Nonconducting Microcrystalline cis- and trans-Cr(CO)2(dpe)2 Complexes (dpe = Ph2PCH2CH2PPh2) Mechanically Attached to a Graphite Electrode and Immersed in Different Aqueous Electrolyte Media

T2 - Identification by Infrared Spectroscopy of cis-[Cr(CO)2(dpe)2]+ Stabilized at the Electrode–Solid–Solution Interface

AU - Bond, Alan M.

AU - Colton, Ray

AU - Marken, Frank

AU - Walter, Jacky N.

PY - 1994/12/1

Y1 - 1994/12/1

N2 - Electrochemical oxidation of microcrystalline, but nonconducting, cis-Cr(CO)2(dpe)2 (dpe = Ph2PCH2CH2PPh2) mechanically attached to a graphite electrode which has been placed in aqueous electrolyte media enables the thermodynamically unstable cis-[Cr(CO)2(dpe)2]+ to be identified for the first time by specular reflectance infrared spectroscopy. That is, kinetic stabilization of the thermodynamically favored cis+ → trans+ isomerization process is achieved at the electrode – solid – electrolyte interface. Detailed studies on the oxidation of microcrystalline trans-Cr(CO)2(dpe)2 to trans-[Cr(CO)2(dpe)2]+ which involve the variation of temperature, scan rate, and electrolyte reveal that “thick”-layer and “thin”-layer processes are present. A zero current extrapolation process enables potentials to be calculated which are independent of crystal size and spacing. Potential data calculated in this manner show virtually no dependence on electrolyte cation but a variation of potential of almost 500 mV when 0.1 M NaF is used instead of 0.1 M NaClO4 as the electrolyte. The correlation of oxidation potential data with free energies of partition for anion transport across a water-dichloroethane interface coupled with voltammetric and spectroscopic data indicate that the oxidation reaction may be summarized by eqs 1–5: (1) transsolid ⇌ trans+solid + e-; (2) cissolid ⇌ cis+solid e- (3) A-solution⇌ A- solid; (4) trans+solid +A-solid⇌ (trans+– A- solid); (5) Cis+ solid + A- solid ⇌ (cis+–A-solid) → (trans+–A-solid). A- denotes the electrolyte anion, and the cis0/+ and trans0/+ nomenclature represents the relevant isomer of [Cr(CO)2(dpe)]0/+ in the appropriate oxidation state. The oxidation processes are believed to be accompanied by swelling of crystals, which may aid the transport of ionic species within the solid.

AB - Electrochemical oxidation of microcrystalline, but nonconducting, cis-Cr(CO)2(dpe)2 (dpe = Ph2PCH2CH2PPh2) mechanically attached to a graphite electrode which has been placed in aqueous electrolyte media enables the thermodynamically unstable cis-[Cr(CO)2(dpe)2]+ to be identified for the first time by specular reflectance infrared spectroscopy. That is, kinetic stabilization of the thermodynamically favored cis+ → trans+ isomerization process is achieved at the electrode – solid – electrolyte interface. Detailed studies on the oxidation of microcrystalline trans-Cr(CO)2(dpe)2 to trans-[Cr(CO)2(dpe)2]+ which involve the variation of temperature, scan rate, and electrolyte reveal that “thick”-layer and “thin”-layer processes are present. A zero current extrapolation process enables potentials to be calculated which are independent of crystal size and spacing. Potential data calculated in this manner show virtually no dependence on electrolyte cation but a variation of potential of almost 500 mV when 0.1 M NaF is used instead of 0.1 M NaClO4 as the electrolyte. The correlation of oxidation potential data with free energies of partition for anion transport across a water-dichloroethane interface coupled with voltammetric and spectroscopic data indicate that the oxidation reaction may be summarized by eqs 1–5: (1) transsolid ⇌ trans+solid + e-; (2) cissolid ⇌ cis+solid e- (3) A-solution⇌ A- solid; (4) trans+solid +A-solid⇌ (trans+– A- solid); (5) Cis+ solid + A- solid ⇌ (cis+–A-solid) → (trans+–A-solid). A- denotes the electrolyte anion, and the cis0/+ and trans0/+ nomenclature represents the relevant isomer of [Cr(CO)2(dpe)]0/+ in the appropriate oxidation state. The oxidation processes are believed to be accompanied by swelling of crystals, which may aid the transport of ionic species within the solid.

UR - http://www.scopus.com/inward/record.url?scp=0000785707&partnerID=8YFLogxK

U2 - 10.1021/om00024a063

DO - 10.1021/om00024a063

M3 - Article

AN - SCOPUS:0000785707

SN - 0276-7333

VL - 13

SP - 5122

EP - 5131

JO - Organometallics

JF - Organometallics

IS - 12

ER -

Abstract

ASJC Scopus subject areas

Access to Document

Other files and links

Fingerprint

Cite this