Cyclic Triradicals Composed of Iminonitroxide–Gold(I) with Intramolecular Ferromagnetic Interactions

Suzuki, Shuichi; Wada, Tomoyuki; Tanimoto, Ryu; Kozaki, Masatoshi; Shiomi, Daisuke; Sugisaki, Kenji; Sato, Kazunobu; Takui, Takeji; Miyake, Yota; Hosokoshi, Yuko; Okada, Keiji

doi:10.1002/ange.201604320

Cited by 7 publications

(1 citation statement)

References 60 publications

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“…Stable radicals have played important roles in our understanding of the electronic structures of open shell molecules in terms of quantum chemistry, 1,2 as spin probes in biological systems, as building blocks in molecule-based magnetic materials 3,4 for a long time, and in emerging heterospin exchange clusters with multiparamagnetic centers. 4 Their recent applications to marked dynamic nuclear polarization (DNP) effects in solid-state nuclear magnetic resonance (NMR) spectroscopy 5−16 and to building components of two-qubit molecular spin systems capable of CNOT gate operations of quantum computing in the solid state 17 have encouraged further development of radical chemistry in synthetic aspects.…”

Section: Introductionmentioning

confidence: 99%

Trityl-Aryl-Nitroxide-Based Genuinely g-Engineered Biradicals, As Studied by Dynamic Nuclear Polarization, Multifrequency ESR/ENDOR, Arbitrary Wave Generator Pulse Microwave Waveform Spectroscopy, and Quantum Chemical Calculations

et al. 2019

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Trityl and nitroxide radicals are connected by π-topologically controlled aryl linkers, generating genuinely g-engineered biradicals. They serve as a typical model for biradicals in which the exchange (J) and hyperfine interactions compete with the g-difference electronic Zeeman interactions. The magnetic properties underlying the biradical spin Hamiltonian for solution, including J's, have been determined by multifrequency CW-ESR and 1 H ENDOR spectroscopy and compared with those obtained by quantum chemical calculations. The experimental J values were in good agreement with the quantum chemical calculations. The g-engineered biradicals have been tested as a prototype for AWG (Arbitrary Wave Generator)-based spin manipulation techniques, which enable GRAPE (GRAdient Pulse Engineering) microwave control of spins in molecular magnetic resonance spectroscopy for use in molecular spin quantum computers, demonstrating efficient signal enhancement of specific weakened hyperfine signals. Dynamic nuclear polarization (DNP) effects of the biradicals for 400 MHz nuclear magnetic resonance signal enhancement have been examined, giving efficiency factors of 30 for 1 H and 27.8 for 13 C nuclei. The marked DNP results show the feasibility of these biradicals for hyperpolarization.

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Section: Introductionmentioning

confidence: 99%

Trityl-Aryl-Nitroxide-Based Genuinely g-Engineered Biradicals, As Studied by Dynamic Nuclear Polarization, Multifrequency ESR/ENDOR, Arbitrary Wave Generator Pulse Microwave Waveform Spectroscopy, and Quantum Chemical Calculations

et al. 2019

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Aurophilic Interactions in Multi‐Radical Species: Electronic‐Spin and Redox Properties of Bis‐ and Tris‐[(Nitronyl Nitroxide)‐Gold(I)] Complexes with Phosphine‐Ligand Scaffolds

Kira

Miyamae

Yoshida

et al. 2021

Chemistry A European J

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Multinuclear AuI complexes with two or three nitronyl nitroxide‐2‐ide radical anion and phosphine‐ligand scaffolds, (NN‐Au)2‐1 o, (NN‐Au)2‐1 m, and (NN‐Au)2‐1 p, have been synthesized to investigate the influence of AuI−AuI (aurophilic) interactions on the properties of multispin molecular systems. The desired complexes were successfully prepared in moderate yields in a one‐pot synthesis from the corresponding phosphine ligand, AuI source, parent NN, and sodium hydroxide. Among the prepared complexes, (NN‐Au)2‐1 o, in which an aurophilic interaction was clearly observed by crystal structure analysis, showed characteristic spin−spin interactions, electrochemical properties, and solvatochromic behavior. The results from theoretical calculations also suggested that the differences in properties between complex (NN‐Au)2‐1 o and the other complexes are due to intramolecular aurophilic interactions.

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Group 11 Metal Complexes Coordinated by the (Nitronyl Nitroxide)‐2‐ide Radical Anion: Facile Oxidation of Stable Radicals Controlled by Metal–Carbon Bonds in Radical‐Metalloids

et al. 2018

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A series of group 11 metal complexes coordinated by (nitronyl nitroxide)-2-ide radical anion NN-M(dtpb) [NN: nitronyl nitroxide; M: Cu I , Ag I , and Au I ; dtpb: 1,2-bis(di-2-tolylphosphanyl)benzene)] was prepared. Their structures, electrochemical properties, and related theoretical calculations were investigated. The oxidation potential (E ox , V vs. Fc/Fc + ) of the NN-moiety in these radical-metalloids significantly shifted to the negative direction in comparison to that of the unsubsti- [a] Preparation of NN + -Ag(dtpb)·SbF 6 -: In a glove box filled with argon, NN-Ag(dtpb) (100 mg, 0.131 mmol, 1.0 equiv.) was dissolved in CH 2 Cl 2 (4 mL). To this stirred solution, a CH 2 Cl 2 solution (4 mL) of TBPA + ·SbF 6 -(97 mg, 0.135 mmol, 1.0 equiv.) was added. After stirring for 30 min, the solution was concentrated to ca. 2 mL under reduced pressure. Et 2 O was added to the solution. The generating precipitate was collected and washed with Et 2 O, to give NN + -Ag(dtpb)·SbF 6 as a dark brown solid (124 mg, 95 %). Crystals suitable for X-ray crystal structure analysis were obtained by recrystallization from CH 2 Cl 2 /n-hexane. NN + -Ag(dtpb)·SbF 6 -: C 41 H 44 AgF 6 N 2 O 2 P 2 Sb, dark brown crystals; MW 1002.37; m.p. 183-184°C. MS (FAB + ) m/z 765 [NN + -Ag(dtpb)], (FAB -) m/z 235 [SbF 6 -].Preparation of NN + -Au(dtpb)·SbF 6 -: In a glove box filled with argon, NN-Au(dtpb) (95 mg, 0.111 mmol, 1.0 equiv.) was dissolved in CH 2 Cl 2 (2 mL). To this stirred solution, a CH 2 Cl 2 solution (2 mL) of TBPA + ·SbF 6 -(80 mg, 0.111 mmol, 1.0 equiv.) was added. After stirring for 30 min, the solution was concentrated to ca. 2 mL under reduced pressure. Et 2 O was added to the solution. The generating precipitate was collected and washed with Et 2 O, to give NN + -Au(dtpb)·SbF 6 as a yellow solid (104 mg, 86 %). Crystals suitable for X-ray crystal structure analysis were obtained by recrystallization from CH 2 Cl 2 /Et 2 O. NN + -Au(dtpb)·SbF 6 -: C 41 H 44 AuF 6 N 2 O 2 P 2 Sb, green crystals; MW 1091.47; m.p. 153°C (decomp.). MS (FAB + ) m/z 855 [NN + -Au(dtpb)], (FAB -) m/z 235 [SbF 6 -]; High resolution MS (FAB + ): found m/z 855.2544; calcd. for C 41 H 44 AuN 2 O 2 P 2 m/z 855. Geometrical Optimizations and Determination of SOMO Energies and NPA Charges of NN-M(dtpb):The geometrical optimizations were achieved using the X-ray structures for the initial input geometries. The determination of HOMO (SOMO) energies of NN-M(dtpb) were achieved using the Gaussian 09 program package [22] with a DFT method at the UB3PW91 level. [25] Basis sets employed were 6-31G(d,p) (for geometrical optimization) and 6-311++(d,p) (for NPA charge calculation [23] ) for C, H, N, O, P, and Cu atoms and Hay-Wadt double-zeta functions with Los Alamos relativistic effective core potential (LANL2DZ) [26] for Ag, Au, Pt, and Hg atoms (Figure 3a, Figure S6). Conflict of Interest:The authors declare no conflict of interest. from JSPS KAKENHI (Grant Number JP17K05790 for M. K. and K. O. and JP26102005 for S. S.).

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Cyclic Triradicals Composed of Iminonitroxide–Gold(I) with Intramolecular Ferromagnetic Interactions

Cited by 7 publications

References 60 publications

Trityl-Aryl-Nitroxide-Based Genuinely g-Engineered Biradicals, As Studied by Dynamic Nuclear Polarization, Multifrequency ESR/ENDOR, Arbitrary Wave Generator Pulse Microwave Waveform Spectroscopy, and Quantum Chemical Calculations

Trityl-Aryl-Nitroxide-Based Genuinely g-Engineered Biradicals, As Studied by Dynamic Nuclear Polarization, Multifrequency ESR/ENDOR, Arbitrary Wave Generator Pulse Microwave Waveform Spectroscopy, and Quantum Chemical Calculations

Aurophilic Interactions in Multi‐Radical Species: Electronic‐Spin and Redox Properties of Bis‐ and Tris‐[(Nitronyl Nitroxide)‐Gold(I)] Complexes with Phosphine‐Ligand Scaffolds

Group 11 Metal Complexes Coordinated by the (Nitronyl Nitroxide)‐2‐ide Radical Anion: Facile Oxidation of Stable Radicals Controlled by Metal–Carbon Bonds in Radical‐Metalloids

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