Abstract

A possibility of generating a high degree of spin polarization of ¹³C and ¹⁵N nuclei in the cyanide ion, which forms the coordination bond with the metal ion, using parahydrogen is demonstrated for the first time for the new iridium carbene complex as an example. The spin–spin interaction constants in the synthesized complex and the structure of the hydride intermediate are determined by an analysis of the ¹³С NMR spectra detected using broadband and selective heteronuclear decoupling. The cyanide ion is shown to coordinate to the metal ion by the carbon atom in one of two equatorial positions, and two pyridine molecules are arranged in the axial and equatorial positions. The signal amplification factors for ¹³С and ¹⁵N nuclei of the cyanide anion (5665 and –49 555, respectively) are estimated by NMR spectroscopy of the polarized substrate using the SABRE method from an ultralow magnetic field of 0.5 μT. This amplification corresponds to 15.5% polarization of nitrogen nuclei achieved within several seconds at room temperature.

中文翻译：

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SABRE 条件下仲氢分子到铱配合物中氰化物离子的自旋顺序转移

摘要

以新型铱卡宾络合物为例，首次证明了使用仲氢在氰化物离子中产生高度自旋极化的¹³ C 和^{15 N 核，与金属离子形成配位键。}合成配合物中的自旋-自旋相互作用常数和氢化物中间体的结构通过使用宽带和选择性异核解偶检测到的^{13 С NMR 光谱分析来确定。}显示氰化物离子通过两个赤道位置之一的碳原子与金属离子配位，并且两个吡啶分子排列在轴向和赤道位置。¹³ С 和¹⁵的信号放大系数氰化物阴离子的 N 原子核（分别为 5665 和 –49 555）是通过使用 SABRE 方法在 0.5 μT 超低磁场中对极化基质进行 NMR 光谱来估计的。该放大对应于室温下几秒内实现的氮原子核的 15.5% 极化。