Lenoble Géraldine, Hasenknopf Bernold, Thouvenot René
Université Pierre et Marie Curie--Paris 6, Institut de Chimie Moléculaire FR 2769, Laboratoire de Chimie Inorganique et Matériaux Moléculaires (UMR CNRS 7071), Case Courrier 42, 4 place Jussieu, 75252 Paris Cedex 05, France.
J Am Chem Soc. 2006 May 3;128(17):5735-44. doi: 10.1021/ja0575934.
This paper describes the complete assignment of the 183W NMR spectra of the chiral polyoxometalates alpha1-[P2W17O61]10- and alpha1-[YbP2W17O61]7- in aqueous solution. These spectra display each 17 lines of equal intensity with a relatively narrow chemical shift distribution. The identification of signals is based on selective 31P-183W decoupling and recognition of particular sets of coupling constants for tungsten atoms around the lacunary site. Further assignment is obtained by 183W 2D-COSY NMR experiments. We demonstrate herewith a new way for the unambiguous assignment of 183W NMR spectra of polyoxotungstates without any symmetry elements or tungsten atoms in special positions. This way relies on the correlation of the magnitude of 2J(W-W) coupling constants with the geometry of oxo-bridges in polyoxotungstates. These results open the way to monitor interaction sites of chiral polyoxotungstates with organic ligands.
本文描述了手性多金属氧酸盐α1-[P2W17O61]10-和α1-[YbP2W17O61]7-在水溶液中的183W NMR谱的完整归属。这些谱图显示出各有17条强度相等的谱线，化学位移分布相对较窄。信号的识别基于选择性31P-183W去耦以及对缺位位点周围钨原子特定耦合常数集的识别。通过183W二维COSY NMR实验获得了进一步的归属。我们在此展示了一种无需任何对称元素或处于特殊位置的钨原子即可明确归属多钨酸盐183W NMR谱的新方法。这种方法依赖于2J(W-W)耦合常数的大小与多钨酸盐中氧桥几何结构的相关性。这些结果为监测手性多钨酸盐与有机配体的相互作用位点开辟了道路。
