Ott Jonas C, Suturina Elizaveta A, Kuprov Ilya, Nehrkorn Joscha, Schnegg Alexander, Enders Markus, Gade Lutz H
Anorganisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 276, 69120, Heidelberg, Germany.
Department of Chemistry, University of Bath, Bath, BA2 7AY, UK.
Angew Chem Int Ed Engl. 2021 Oct 11;60(42):22856-22864. doi: 10.1002/anie.202107944. Epub 2021 Sep 15.
We report an experimental observation of P NMR resonances shifted by over 10 000 ppm (meaning percent range, and a new record for solutions), and similar H chemical shifts, in an intermediate-spin square planar ferrous complex [ (PNP)Fe-H], where PNP is a carbazole-based pincer ligand. Using a combination of electronic structure theory, nuclear magnetic resonance, magnetometry, and terahertz electron paramagnetic resonance, the influence of magnetic anisotropy and zero-field splitting on the paramagnetic shift and relaxation enhancement is investigated. Detailed spin dynamics simulations indicate that, even with relatively slow electron spin relaxation (T ≈10 s), it remains possible to observe NMR signals of directly metal-bonded atoms because pronounced rhombicity in the electron zero-field splitting reduces nuclear paramagnetic relaxation enhancement.
我们报道了在一种中间自旋的平面四方亚铁配合物[（PNP）Fe-H]中对磷核磁共振共振位移超过10000 ppm（表示百分比范围，是溶液中的新纪录）以及类似氢化学位移的实验观察，其中PNP是一种基于咔唑的钳形配体。结合电子结构理论、核磁共振、磁强计和太赫兹电子顺磁共振，研究了磁各向异性和零场分裂对顺磁位移和弛豫增强的影响。详细的自旋动力学模拟表明，即使电子自旋弛豫相对较慢（T≈10 s），由于电子零场分裂中明显的菱形度降低了核顺磁弛豫增强，仍然有可能观察到直接与金属键合原子的核磁共振信号。
