Trityl-Aryl-Nitroxide Based Genuinely g-Engineered Biradicals, as Studied by Dynamic Nuclear Polarization, Multi-Frequency 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, Multi-Frequency ESR/ENDOR, Arbitrary Wave Generator Pulse Microwave Waveform Spectroscopy and Quantum Chemical Calculations.
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DOI：
10.1021/acs.jpca.9b07169
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发表时间：
2019-08
期刊：
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通讯作者：
Kazunobu Sato;Rei Hirao;I. Timofeev;O. Krumkacheva;E. Zaytseva;O. Rogozhnikova;V. Tormyshev;D. Trukhin;E. Bagryanskaya;T. Gutmann;V. Klimavičius;G. Buntkowsky;K. Sugisaki;S. Nakazawa;H. Matsuoka;K. Toyota;D. Shiomi;T. Takui
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文献类型：
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作者：
Kazunobu Sato;Rei Hirao;I. Timofeev;O. Krumkacheva;E. Zaytseva;O. Rogozhnikova;V. Tormyshev;D. Trukhin;E. Bagryanskaya;T. Gutmann;V. Klimavičius;G. Buntkowsky;K. Sugisaki;S. Nakazawa;H. Matsuoka;K. Toyota;D. Shiomi;T. Takui
三苯甲基和氮氧自由基通过π-拓扑控制的芳基连接基连接，产生真正的g-工程化双自由基。它们作为双自由基的典型模型，其中交换（J）和超精细相互作用与g-差电子塞曼相互作用竞争。用多频CW-ESR和~ 1H-ENDOR谱确定了溶液的双自由基自旋哈密顿量（包括J）的磁性，并与量子化学计算结果进行了比较。实验J值与量子化学计算结果吻合较好。g-工程双自由基已经作为基于AWG（任意波发生器）的自旋操纵技术的原型进行了测试，该技术使GRAPE（梯度脉冲工程）微波控制分子磁共振光谱中的自旋，用于分子自旋量子计算机，证明了特定弱化超精细信号的有效信号增强。双自由基对400 MHz NMR信号增强的DNP效应已被研究，给出了1H和13 C核的效率因子分别为30和27.8。显着的DNP（动态核极化）结果表明，这些双自由基的超极化的可行性。
Trityl and nitroxide radicals are connected by π-topologically controlled aryl linkers, generating genuinely g-engineered bi-radicals. 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 multi-frequency CW-ESR and 1H-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. DNP effects of the biradicals for 400 MHz NMR signal enhancement have been examined, giving an efficiency factor of 30 for 1H and 27.8 for 13C nuclei. The marked DNP (dynamic nuclear polarization) results show the feasibility of these biradicals for hyperpolarization.