Au–Au Chemical Bonding in Nitronyl Nitroxide Gold(I) Derivatives

Zayakin, I. A.; Korlyukov, Alexander A.; Gorbunov, Dmitry; Gritsan, Nina P.; Akyeva, Anna; Syroeshkin, Mikhail A.; Stass, Dmitri V.; Tretyakov, Evgeny V.; Egorov, Mikhail P.

doi:10.1021/acs.organomet.2c00200

Cited by 7 publications

(6 citation statements)

References 77 publications

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“…The reason is that the Okada's reagent (NNÀ AuÀ PPh 3 ), used in the first-generation catalytic system, has limited thermal stability and begins to decompose at temperatures of ~60-65 °C, at which cross-coupling reactions occur. Our systematic search [42,43] led to the creation of a second generation of organogold nitronyl nitroxide derivatives NNÀ AuÀ XPhos, NNÀ AuÀ Me CgPPh and NNÀ AuÀ TTMPP (Figure 2), which have exceptionally high thermal stability and high reactivity in cross-coupling reactions even with diamagnetic aryl bromides. [44] The Blatter moiety is significantly more electron-rich compared to typical diamagnetic π-systems.…”

Section: Introductionmentioning

confidence: 99%

A Nitronyl Nitroxide‐Substituted Benzotriazinyl Tetraradical**

Tretyakov,

Zayakin,

Dmitriev

et al. 2023

Chemistry A European J

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High‐spin organic tetraradicals with significant intramolecular exchange interactions have high potential for advanced technological applications and fundamental research, but those synthesized to date possess limited stability and processability. In this work, we have designed a tetraradical based on the Blatter's radical and nitronyl nitroxide radical moieties and successfully synthesized it by using the palladium‐catalyzed cross‐coupling reaction of a triiodo‐derivative of the 1,2,4‐benzotriazinyl radical with gold(I) nitronyl nitroxide‐2‐ide complex in the presence of a newly developed efficient catalytic system. The molecular and crystal structure of the tetraradical was confirmed by X‐ray diffraction analysis. The tetraradical possesses good thermal stability with decomposition onset at ∼150 °C under an inert atmosphere and exhibits reversible redox waves at −0.54 and 0.45 V versus Ag/AgCl. The magnetic properties of the tetraradical were characterized by SQUID magnetometry of polycrystalline powders and EPR spectroscopy in various matrices. The collected data, analyzed by using high‐level quantum chemical calculations, confirmed that the tetraradical has a triplet ground state and a nearby excited quintet state. The unique high stability of the prepared triazinyl‐nitronylnitroxide tetraradical is a new milestone in the field of creating high‐spin systems.

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Section: Introductionmentioning

confidence: 99%

A Nitronyl Nitroxide‐Substituted Benzotriazinyl Tetraradical**

Tretyakov,

Zayakin,

Dmitriev

et al. 2023

Chemistry A European J

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“…Attempts to achieve complete conversion of Vrd-I 3 and high purity of the target tetraradical product using the classical Pd(PPh 3 ) 4 or rarely applied Pd[( t -Bu) 3 P] 2 catalysts (up to 30 mol %) were unsuccessful. Careful selection of catalysts and reaction conditions ,− led to a simple and much more efficient method involving a cross-coupling reaction of Vrd-I 3 with 3.5 equiv of readily available NN–Au–PPh 3 in the presence of Pd 2 (dba) 3 (0.4 equiv) and Me CgPPh (1.6 equiv) in toluene at room temperature. Remarkably, this methodology allowed the synthesis of the Vrd-(NN) 3 tetraradical in a single step in high isolated yields (Figure ).…”

Section: Resultsmentioning

confidence: 99%

Toward New Horizons in Verdazyl-Nitroxide High-Spin Systems: Thermally Robust Tetraradical with Quintet Ground State

Zayakin,

Petunin,

Postnikov

et al. 2024

J. Am. Chem. Soc.

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High-spin organic tetraradicals with significant intramolecular exchange interactions have high potential for advanced technological applications and fundamental research, but examples reported to date exhibit limited stability and processability. In this work, we designed the first tetraradical based on an oxoverdazyl core and nitronyl nitroxide radicals and successfully synthesized it using a palladium-catalyzed crosscoupling reaction of an oxoverdazyl radical bearing three iodophenylene moieties with a gold(I) nitronyl nitroxide-2-ide complex in the presence of a recently developed efficient catalytic system. The molecular and crystal structures of the tetraradical were confirmed by single crystal X-ray diffraction analysis. The tetraradical possesses good thermal stability with decomposition onset at ∼125 °C in an inert atmosphere; in a toluene solution upon prolonged heating at 90 °C in air, no decomposition was observed. The resulting unique verdazyl-nitroxide conjugate was thoroughly studied using a range of experimental and theoretical techniques, such as SQUID magnetometry of polycrystalline powders, EPR spectroscopy in various matrices, cyclic voltammetry, and high-level quantum chemical calculations. All collected data confirm the high thermal stability of the resulting tetraradical and quintet multiplicity of its ground state, which makes the synthesis of this important paramagnet a new milestone in the field of creating high-spin systems.

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“…Attempts to achieve complete conversion of Vrd-I3 and high purity of the target tetraradical product using the widely used Pd(PPh3)4 catalysts or rarely applied Pd[(t-Bu)3P]2 (up to 30 mol%) were unsuccessful. Careful selection of catalysts and reaction conditions 21,[27][28]29 led to a simple and much more efficient method involving a cross-coupling reaction of Vrd-I3 with 3.5 equiv. of readily available NN-Au-PPh3 in the presence of Pd2(dba)3 (0.4 equiv.)…”

Section: Synthesis Of Vrd-(nn)3mentioning

confidence: 99%

Toward New Horizons in Verdazyl-Nitroxide High-Spin Systems: Thermally Robust Tetraradical with Quintet Ground State

Zayakin,

Petunin,

Postnikov

et al. 2023

Preprint

View full text Add to dashboard Cite

High-spin organic tetraradicals with significant intramolecular exchange interactions have high potential for advanced technological applications and fundamental research, but reported to date examples exhibit limited stability and processability. In this work, we designed the first tetraradical based on an oxoverdazyl core and nitronyl nitroxide radicals and successfully synthesized it using a palladium-catalyzed cross-coupling reaction of oxoverdazyl radical bearing three iodo-phenylene moieties with a gold(I) nitronyl nitroxide-2-ide complex in the presence of a recently developed efficient catalytic system. The molecular and crystal structures of the tetraradical were confirmed by single crystal X-ray diffraction analysis. The tetraradical possesses good thermal stability with decomposition onset at ∼115 °C in an inert atmosphere. The resulting unique verdazyl-nitroxide conjugate was thoroughly studied using a complex of SQUID magnetometry of polycrystalline powders, EPR spectroscopy in various matrices, cyclic voltammetry (CV), and high-level quantum chemical calculations. All collected data confirm the high thermal stability of the resulting tetraradical and quintet multiplicity of its ground state, which makes the synthesis of this important paramagnet a new milestone in the field of creating high-spin systems.

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Au–Au Chemical Bonding in Nitronyl Nitroxide Gold(I) Derivatives

Cited by 7 publications

References 77 publications

A Nitronyl Nitroxide‐Substituted Benzotriazinyl Tetraradical**

A Nitronyl Nitroxide‐Substituted Benzotriazinyl Tetraradical**

Toward New Horizons in Verdazyl-Nitroxide High-Spin Systems: Thermally Robust Tetraradical with Quintet Ground State

Toward New Horizons in Verdazyl-Nitroxide High-Spin Systems: Thermally Robust Tetraradical with Quintet Ground State

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