The paramagnetic spin relaxation (PSR) filter allows the selective NMR signal suppression of components in mixtures according to their complexation ability to a paramagnetic ion. It relies on the faster relaxation of nuclei in paramagnetic environments and thus is complementary to classical diffusion and relaxation filters. So far, the PSR filter has established Gd³⁺ as the sole PSR agent, restricting the paramagnetic filtering repertoire. Herein, we present Cu²⁺ as a robust PSR agent with characteristic filtering properties. While Gd³⁺ depends on unspecific ion-pair interactions with anionic components, Cu²⁺ stands out for filtering species via ordered coordination complexes. An evaluation of the paramagnetic effect of Cu²⁺ over more than 50 small molecules and polymers has unveiled different sensitivities to Cu²⁺ (especially high for pyridines, diamines, polyamines, and amino alcohols) and precise filtering conditions for mixtures (¹H, COSY, and HMQC) that were challenged with a test bed of commercial drugs. The advantage of integrating Cu²⁺ and Gd³⁺ for the stepwise PSR filtering of complex mixtures is also shown.

中文翻译：

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通过与顺磁性 Cu2+ 的配位过滤混合物的 NMR 光谱

顺磁自旋弛豫 (PSR) 滤波器允许根据混合物中组分与顺磁离子的络合能力选择性地抑制 NMR 信号。它依赖于顺磁环境中原子核的更快弛豫，因此是对经典扩散和弛豫滤波器的补充。到目前为止，PSR 过滤器已将 Gd ³⁺确定为唯一的 PSR 代理，限制了顺磁过滤的曲目。在此，我们将 Cu ²⁺作为一种具有特征过滤特性的鲁棒 PSR 代理。虽然 Gd ³⁺依赖于与阴离子成分的非特异性离子对相互作用，但 Cu ²⁺通过有序的配位配合物过滤物种而脱颖而出。Cu的顺磁效应的评价²⁺超过 50 种小分子和聚合物揭示了对 Cu ^{2+的不同敏感性（尤其是对吡啶、二胺、多胺和氨基醇的敏感性）以及对受到挑战的混合物（ 1} H、COSY 和 HMQC）的精确过滤条件有商业药物的试验台。还显示了将 Cu ²⁺和 Gd ³⁺积分用于复杂混合物的逐步 PSR 过滤的优势。