Linking 31P Magnetic Shielding Tensors to Crystal Structures: Experimental and Theoretical Studies on Metal(II) Aminotris(methylenephosphonates)

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• 作者：Johannes Weber ; Gisbert Grossmann ; Konstantinos D. Demadis ; Nikos Daskalakis ; Erica Brendler ; Martin Mangstl ; J枚rn Schmedt auf der G眉nne
• 刊名：Inorganic Chemistry
• 出版年：2012
• 出版时间：November 5, 2012
• 年：2012
• 卷：51
• 期：21
• 页码：11466-11477
• 全文大小：534K
• 年卷期：v.51,no.21(November 5, 2012)
• ISSN：1520-510X

文摘

The ³¹P chemical shift tensor of the phosphonate group [RC-PO₂(OH)]^{鈭?/sup> is investigated with respect to its principal axis values and its orientation in a local coordinate system (LCS) defined from the P atom and the directly coordinated atoms. For this purpose, six crystalline metal aminotris(methylenephosphonates), MAMP路xH₂O with M = Zn, Mg, Ca, Sr, Ba, and (2Na) and x = 3, 3, 4.5, 0, 0, and 1.5, respectively, were synthesized and identified by diffraction methods. The crystal structure of water-free BaAMP is described here for the first time. The principal components of the 31P shift tensor were determined from powders by magic-angle-spinning NMR. Peak assignments and orientations of the chemical shift tensors were established by quantum-chemical calculations from first principles using the extended embedded ion method. Structure optimizations of the H-atom positions were necessary to obtain the chemical shift tensors reliably. We show that the 31P tensor orientation can be predicted within certain error limits from a well-chosen LCS, which reflects the pseudosymmetry of the phosphonate environment.}