X<sub>4</sub>TCNQ<sup>2−</sup> dianions: versatile building blocks for supramolecular systems

Abrahams, Brendan F.; Elliott, Robert W.; Hudson, Timothy A.; Robson, Richard; Sutton, Ashley L.

doi:10.1039/c8ce00413g

Cited by 21 publications

(31 citation statements)

References 88 publications

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“…Unfortunately, no crystals suitable for X‐Ray Diffraction structural analysis were generated for either the TCNQF 1− or TCNQF 2− derivatives. Indeed, the entire two‐electron reduced TCNQF n 2− field of metal complexes is almost devoid of X‐ray structural data unless other ligands in addition to TNCQF 4 2− are coordinated to the metal and even structures of metal complexes solely containing TCNQF n 1− as a ligand are rare.…”

Section: Resultssupporting

confidence: 78%

“…However, the two‐electron reduced TCNQ 2− compounds are highly air‐sensitive . Such materials, in principle provide novel framework structures and can be stable when additional nitrogen based donors are also present, as reviewed by Abrahams in a recent survey of the field. Another method of enhancing stability is the use of the fluoride derivative, TCNQF 4 , in the chemical synthesis.…”

Section: Introductionmentioning

confidence: 93%

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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

2018

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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).

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Section: Resultssupporting

confidence: 78%

Section: Introductionmentioning

confidence: 93%

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

2018

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“…Schematic illustration of the two-step fabrication procedure of a metal oxide@open-tubular N-doped carbon column (MO x @OTNCC) electrocatalyst for OER. The structure of M@TCNQ (with a formula of M[TCNQ] 2 ) was drawn as inspired from the work of Abrahams et al …”

Section: Introductionmentioning

confidence: 99%

Stoichiometry-Dependent Oxygen Evolution Electrocatalysis on Open-Tubular Nitrogen-Doped Carbon Column Supported Transition Metal Oxides

Yang

Zhang

et al. 2020

ACS Appl. Energy Mater.

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Ni-, Co-, and Fe-based transition metal oxides have been extensively studied as heterogeneous electrocatalysts for water oxidation in alkaline media. Here, we investigated how metal composition affects the oxygen evolution electrocatalysis and plotted the intrinsic catalytic response to metal stoichiometries in 21 unary, binary, and ternary transition metal oxides. For the first time, we developed a charge transfer complex [metal-7,7,8,8-tetracyanoquinodimethane (M@TCNQ)]-templated strategy to prepare transition metal oxides supported on open-tubular nitrogen-doped carbon columns, containing Ni, Co, and Fe with excellent stoichiometric controllability as well as element distribution uniformity. We observed strong synergistic effects between different metal components; in particular, a small concentration of Fe significantly improves the electrocatalytic activity and the presence of Co dramatically reduces the Tafel slopes. Through contour mapping of the intrinsic kinetic parameters, the best electrocatalytic parameters of the series were attained with a composition of Ni40Co40Fe20O x , showing a geometric current density of 10 mA cm–2 at 220 mV overpotential, alongside a Tafel slope of ∼60 mV dec–1 and a good stability over 50 h. This work illuminates the importance of synergistic effects between various metal compositions and provides a solid foundation for the broad exploration of other mixed transition metal oxide combinations.

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“…Achievement of such advanced properties requires, however, an expansion of the library of easily accessible and electroactive molecules with relatively stable radical forms. The most commonly studied radicals comprise α-diimines [12], dithiolenes [13][14][15], oxolenes [16,17], nitronyl nitroxides [18,19], tetrathiafulvalene (TTF) derivatives [20], π-conjugated macrocycles [21], TCNE and TCNQ derivatives [22][23][24][25], and verdazyl radicals [26].…”

Section: Introductionmentioning

confidence: 99%

Bis(triphenylphosphine)iminium Salts of Dioxothiadiazole Radical Anions: Preparation, Crystal Structures, and Magnetic Properties

2019

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Phenanthroline dioxothiadiazoles are redox active molecules that form stable radical anions suitable for the construction of supramolecular magnetic materials. Herein, the preparation, structures and magnetic properties of bis(triphenylphosphine)iminium (PPN) salts of [1,2,5]thiadiazole[3,4-f][1,10]phenanthroline 1,1-dioxide (L), [1,2,5]thiadiazole[3,4-f][4,7]phenanthroline 1,1-dioxide (4,7-L), 5-bromo-[1,2,5]thiadiazolo[3,4-f][1,10]phenanthroline 2,2-dioxide (BrL), and 5,10-dibromo-[1,2,5]thiadiazolo[3,4-f][1,10]phenanthroline 2,2-dioxide (diBrL) are reported. The preparation of new bromo derivatives of the L: 5-bromo-[1,2,5]thiadiazolo[3,4-f][1,10]phenanthroline 2,2-dioxide (BrL) and 5,10-dibromo-[1,2,5]thiadiazolo[3,4-f][1,10]phenanthroline 2,2-dioxide (diBrL)—suitable starting materials for further derivatization—are described starting from a commercially available and cheap 1,10-phenanthroline. All PPN salts show antiferromagnetic interactions between the pairs of radical anions, which in the case of PPN(diBrL) are very strong (−116 cm−1; using Ĥ = −2JSS type of exchange coupling Hamiltonian) due to a different crystal packing of the anion radicals as compared to PPN(L), PPN(4,7-L), and PPN(BrL).

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X₄TCNQ²⁻ dianions: versatile building blocks for supramolecular systems

Abstract: A new synthetic approach has led to the incorporation of TCNQ and F4TCNQ dianions into a wide variety of structures.

Cited by 21 publications

References 88 publications

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

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

Stoichiometry-Dependent Oxygen Evolution Electrocatalysis on Open-Tubular Nitrogen-Doped Carbon Column Supported Transition Metal Oxides

Bis(triphenylphosphine)iminium Salts of Dioxothiadiazole Radical Anions: Preparation, Crystal Structures, and Magnetic Properties

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X4TCNQ2− dianions: versatile building blocks for supramolecular systems

Abstract: A new synthetic approach has led to the incorporation of TCNQ and F4TCNQ dianions into a wide variety of structures.

Cited by 21 publications

References 88 publications

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

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

Stoichiometry-Dependent Oxygen Evolution Electrocatalysis on Open-Tubular Nitrogen-Doped Carbon Column Supported Transition Metal Oxides

Bis(triphenylphosphine)iminium Salts of Dioxothiadiazole Radical Anions: Preparation, Crystal Structures, and Magnetic Properties

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Product

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X₄TCNQ²⁻ dianions: versatile building blocks for supramolecular systems