Magnetic resonance techniques represent a fundamental class of spectroscopic methods used in physics, chemistry, biology, and medicine. Electron paramagnetic resonance (EPR) is an extremely powerful technique for characterizing systems with an open-shell electronic nature, whereas nuclear magnetic resonance (NMR) has traditionally been used to investigate diamagnetic (closed-shell) systems. However, these two techniques are tightly connected by the electron–nucleus hyperfine interaction operating in paramagnetic (open-shell) systems. Hyperfine interaction of the nuclear spin with unpaired electron(s) induces large temperature-dependent shifts of nuclear resonance frequencies that are designated as hyperfine NMR shifts (δ^HF).

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过渡金属络合物核磁共振波谱中的顺磁效应：原理和化学概念


磁共振技术代表了物理、化学、生物学和医学中使用的一类基本光谱方法。电子顺磁共振 (EPR) 是一种极其强大的技术，用于表征具有开壳层电子性质的系统，而核磁共振 (NMR) 传统上用于研究抗磁性（闭壳层）系统。然而，这两种技术通过顺磁（开壳）系统中运行的电子-核超精细相互作用紧密相连。核自旋与不成对电子的超精细相互作用会引起核共振频率随温度的较大变化，被称为超精细核磁共振位移 (δ ^HF )。