Department of Chemistry and Centre for Catalysis Research and Innovation, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada.
Dalton Trans. 2010 Oct 7;39(37):8593-602. doi: 10.1039/c0dt00416b. Epub 2010 Jun 24.
Calcium is an important component of materials, metalloproteins, minerals, glasses, and small inorganic and organic complexes. However, NMR spectroscopy of the quadrupolar (43)Ca nuclide remains difficult primarily due to its low natural abundance and low resonance frequency. In this Perspective, experimental challenges and recent successes in the field are highlighted, with a focus on solid-state (43)Ca NMR spectroscopy. Solution (43)Ca NMR studies of calcium-binding biomolecules are also presented. The structural insights afforded from quadrupolar and chemical shift parameters are examined. For example: isotropic chemical shifts have been shown to correlate with the mean Ca-O distance and also with calcium coordination number; quadrupolar coupling constants and chemical shift tensor spans have been shown to be useful probes of polymorphism; and, distance measurements involving (43)Ca have been recently demonstrated. Lastly, challenges and opportunities for the future are considered.
钙是材料、金属蛋白、矿物质、玻璃以及小型无机和有机配合物的重要组成部分。然而，由于其低天然丰度和低共振频率，四极核（43）Ca 的 NMR 光谱学仍然具有一定难度。在本观点中，我们重点介绍了固态（43）Ca NMR 光谱学领域的实验挑战和近期成果，同时还介绍了钙结合生物分子的溶液（43）Ca NMR 研究。我们还检验了通过四极和化学位移参数获得的结构见解。例如：各向同性化学位移已被证明与平均 Ca-O 距离以及钙配位数相关；四极耦合常数和化学位移张量跨度已被证明是多晶型的有用探针；最近还证明了涉及（43）Ca 的距离测量。最后，我们还考虑了未来的挑战和机遇。
