A Systematic (Spectro-) Electrochemical Approach to the Synthesis and Characterisation of Co(II) and Ni(II) Compounds Containing Reduced Forms of TCNQF

Nguyen T. Vo; Lisandra L. Martin; Alan M. Bond

doi:10.1002/celc.201800678

A Systematic (Spectro-) Electrochemical Approach to the Synthesis and Characterisation of Co(II) and Ni(II) Compounds Containing Reduced Forms of TCNQF

Nguyen T. Vo, Lisandra L. Martin, Alan M. Bond

School of Chemistry

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

1 Citation (Scopus)

Abstract

The electrochemistry of TCNQF (2-fluoro-7,7,8,8-tetracyanoquinodimethane) in acetonitrile (0.1 M Bu₄NPF₆) in the presence of either Co²⁺ or Ni²⁺ is reported. Cyclic voltammetry over an extensive range of potentials revealed that the reduction of TCNQF to either TCNQF¹⁻ or the TCNQF²⁻ species provides a route for electrocrystallisation of the respective M(TCNQF)₂(H₂O)₂ and M(TCNQF) materials on the electrode surface. These materials were independently prepared by addition of the corresponding metal salts to a solution of either TCNQF¹⁻ or TCNQF²⁻ prepared by bulk electrolysis. Comprehensive characterisation of these solids by Infrared and Raman spectroscopy indicated that the M(TCNQF)₂(H₂O)₂ complexes were similar to other transition metal complexes in the M(TCNQX)₂(S)₂ series where S=solvent (H₂O or CH₃OH) and X = H₄ or F₄. The M(TCNQF) materials containing the TCNQF²⁻ anion were not stable in air, similar to the highly air-sensitive TCNQ²⁻ derivatives. Scanning Electron Microscopy (SEM) images of electrocrystallised samples of Ni(TCNQF)₂(H₂O)₂ were rod-like, whereas the Co(TCNQF)₂(H₂O)₂ formed needles. Energy-dispersive X-ray spectroscopy (EDX) analysis of these samples together with elemental microanalysis and thermogravimetric analysis (TGA) supported the composition and stoichiometry. The solubility products (K_sp values) of M(TCNQF)₂(H₂O)₂ materials were determined spectrophotometrically and voltammetrically in acetonitrile, where K_sp for Co(TCNQF)₂(H₂O)₂ was 3.37×10⁻¹¹ M³ (or 1.14×10⁻¹⁰ M³ in the presence of electrolyte, 0.1 M Bu₄NPF₆) and Ni(TCNQF)₂(H₂O)₂ was 5.54×10⁻¹² M³ (or 2.65×10⁻¹⁰ M³ in the presence of electrolyte, 0.1 M Bu₄NPF₆).

Original language	English
Pages (from-to)	221-228
Number of pages	8
Journal	ChemElectroChem
Volume	6
Issue number	1
DOIs	https://doi.org/10.1002/celc.201800678
Publication status	Published - 2 Jan 2019

Keywords

bulk electrolysis
cyclic voltammetry
electrocrystallisation
morphology
vibrational spectroscopy

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10.1002/celc.201800678

259280652-oaFinal published version, 5.17 MB

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title = "A Systematic (Spectro-) Electrochemical Approach to the Synthesis and Characterisation of Co(II) and Ni(II) Compounds Containing Reduced Forms of TCNQF",

abstract = "The electrochemistry of TCNQF (2-fluoro-7,7,8,8-tetracyanoquinodimethane) in acetonitrile (0.1 M Bu4NPF6) in the presence of either Co2+ or Ni2+ is reported. Cyclic voltammetry over an extensive range of potentials revealed that the reduction of TCNQF to either TCNQF1− or the TCNQF2− species provides a route for electrocrystallisation of the respective M(TCNQF)2(H2O)2 and M(TCNQF) materials on the electrode surface. These materials were independently prepared by addition of the corresponding metal salts to a solution of either TCNQF1− or TCNQF2− prepared by bulk electrolysis. Comprehensive characterisation of these solids by Infrared and Raman spectroscopy indicated that the M(TCNQF)2(H2O)2 complexes were similar to other transition metal complexes in the M(TCNQX)2(S)2 series where S=solvent (H2O or CH3OH) and X = H4 or F4. The M(TCNQF) materials containing the TCNQF2− anion were not stable in air, similar to the highly air-sensitive TCNQ2− derivatives. Scanning Electron Microscopy (SEM) images of electrocrystallised samples of Ni(TCNQF)2(H2O)2 were rod-like, whereas the Co(TCNQF)2(H2O)2 formed needles. Energy-dispersive X-ray spectroscopy (EDX) analysis of these samples together with elemental microanalysis and thermogravimetric analysis (TGA) supported the composition and stoichiometry. The solubility products (Ksp values) of M(TCNQF)2(H2O)2 materials were determined spectrophotometrically and voltammetrically in acetonitrile, where Ksp for Co(TCNQF)2(H2O)2 was 3.37×10−11 M3 (or 1.14×10−10 M3 in the presence of electrolyte, 0.1 M Bu4NPF6) and Ni(TCNQF)2(H2O)2 was 5.54×10−12 M3 (or 2.65×10−10 M3 in the presence of electrolyte, 0.1 M Bu4NPF6).",

keywords = "bulk electrolysis, cyclic voltammetry, electrocrystallisation, morphology, vibrational spectroscopy",

author = "Vo, {Nguyen T.} and Martin, {Lisandra L.} and Bond, {Alan M.}",

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doi = "10.1002/celc.201800678",

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T1 - A Systematic (Spectro-) Electrochemical Approach to the Synthesis and Characterisation of Co(II) and Ni(II) Compounds Containing Reduced Forms of TCNQF

AU - Vo, Nguyen T.

AU - Martin, Lisandra L.

AU - Bond, Alan M.

PY - 2019/1/2

Y1 - 2019/1/2

N2 - The electrochemistry of TCNQF (2-fluoro-7,7,8,8-tetracyanoquinodimethane) in acetonitrile (0.1 M Bu4NPF6) in the presence of either Co2+ or Ni2+ is reported. Cyclic voltammetry over an extensive range of potentials revealed that the reduction of TCNQF to either TCNQF1− or the TCNQF2− species provides a route for electrocrystallisation of the respective M(TCNQF)2(H2O)2 and M(TCNQF) materials on the electrode surface. These materials were independently prepared by addition of the corresponding metal salts to a solution of either TCNQF1− or TCNQF2− prepared by bulk electrolysis. Comprehensive characterisation of these solids by Infrared and Raman spectroscopy indicated that the M(TCNQF)2(H2O)2 complexes were similar to other transition metal complexes in the M(TCNQX)2(S)2 series where S=solvent (H2O or CH3OH) and X = H4 or F4. The M(TCNQF) materials containing the TCNQF2− anion were not stable in air, similar to the highly air-sensitive TCNQ2− derivatives. Scanning Electron Microscopy (SEM) images of electrocrystallised samples of Ni(TCNQF)2(H2O)2 were rod-like, whereas the Co(TCNQF)2(H2O)2 formed needles. Energy-dispersive X-ray spectroscopy (EDX) analysis of these samples together with elemental microanalysis and thermogravimetric analysis (TGA) supported the composition and stoichiometry. The solubility products (Ksp values) of M(TCNQF)2(H2O)2 materials were determined spectrophotometrically and voltammetrically in acetonitrile, where Ksp for Co(TCNQF)2(H2O)2 was 3.37×10−11 M3 (or 1.14×10−10 M3 in the presence of electrolyte, 0.1 M Bu4NPF6) and Ni(TCNQF)2(H2O)2 was 5.54×10−12 M3 (or 2.65×10−10 M3 in the presence of electrolyte, 0.1 M Bu4NPF6).

AB - The electrochemistry of TCNQF (2-fluoro-7,7,8,8-tetracyanoquinodimethane) in acetonitrile (0.1 M Bu4NPF6) in the presence of either Co2+ or Ni2+ is reported. Cyclic voltammetry over an extensive range of potentials revealed that the reduction of TCNQF to either TCNQF1− or the TCNQF2− species provides a route for electrocrystallisation of the respective M(TCNQF)2(H2O)2 and M(TCNQF) materials on the electrode surface. These materials were independently prepared by addition of the corresponding metal salts to a solution of either TCNQF1− or TCNQF2− prepared by bulk electrolysis. Comprehensive characterisation of these solids by Infrared and Raman spectroscopy indicated that the M(TCNQF)2(H2O)2 complexes were similar to other transition metal complexes in the M(TCNQX)2(S)2 series where S=solvent (H2O or CH3OH) and X = H4 or F4. The M(TCNQF) materials containing the TCNQF2− anion were not stable in air, similar to the highly air-sensitive TCNQ2− derivatives. Scanning Electron Microscopy (SEM) images of electrocrystallised samples of Ni(TCNQF)2(H2O)2 were rod-like, whereas the Co(TCNQF)2(H2O)2 formed needles. Energy-dispersive X-ray spectroscopy (EDX) analysis of these samples together with elemental microanalysis and thermogravimetric analysis (TGA) supported the composition and stoichiometry. The solubility products (Ksp values) of M(TCNQF)2(H2O)2 materials were determined spectrophotometrically and voltammetrically in acetonitrile, where Ksp for Co(TCNQF)2(H2O)2 was 3.37×10−11 M3 (or 1.14×10−10 M3 in the presence of electrolyte, 0.1 M Bu4NPF6) and Ni(TCNQF)2(H2O)2 was 5.54×10−12 M3 (or 2.65×10−10 M3 in the presence of electrolyte, 0.1 M Bu4NPF6).

KW - bulk electrolysis

KW - cyclic voltammetry

KW - electrocrystallisation

KW - morphology

KW - vibrational spectroscopy

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A Systematic (Spectro-) Electrochemical Approach to the Synthesis and Characterisation of Co(II) and Ni(II) Compounds Containing Reduced Forms of TCNQF

Abstract

Keywords

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Photochemical toolkit based on TCNQ(F) Metal -organic semiconducting hybrids

Integration of crystal engineering and electrochemistry: tuneable multifunctional organic-inorganic hybrid materials with redox capability

Centre for Electron Microscopy (MCEM)

Cite this

A Systematic (Spectro-) Electrochemical Approach to the Synthesis and Characterisation of Co(II) and Ni(II) Compounds Containing Reduced Forms of TCNQF

Abstract

Keywords

Access to Document

Other files and links

Projects

Photochemical toolkit based on TCNQ(F) Metal -organic semiconducting hybrids

Integration of crystal engineering and electrochemistry: tuneable multifunctional organic-inorganic hybrid materials with redox capability

Equipment

Centre for Electron Microscopy (MCEM)

Cite this