Phosphorus-31 and carbon-13 solid-state NMR of tertiary phosphine-palladium complexes bound to silica
Phosphorus-31 and carbon-13 solid-state NMR of tertiary phosphine-palladium complexes bound to silica
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与二氧化硅结合的叔膦-钯配合物的磷 31 和碳 13 固态 NMR
DOI：
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发表时间：
1986
期刊：
影响因子：
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通讯作者：
P. Nicholas
中科院分区：
文献类型：
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作者：
R. Komoroski;A. J. Magistro;P. Nicholas
用交叉极化和幻角旋转的P-31和C-13核磁共振谱表征了钯-叔膦络合物及其共价键合在二氧化硅上的前驱体。P-31核磁共振是一个很好的络合物形成和几何构型的探针，而/sup 13/C核磁共振是一个很好的配体结构探针。(与SiOSiCH/sub2/CH/sub2/Pph/sub2/)/sub2/PdCl/sub2/的36.44 MHz/sup 31/P谱显示两个勉强分辨的峰，分别位于约21ppm和30ppm处，分别属于反式和顺式络合物。这些指认是基于模型化合物在溶液和固体中的化学位移。当从磷化二氧化硅制备络合物时，观察到未络合的膦和氧化膦，但当络合物预制成并连接到二氧化硅时，观察不到。研究了二(二苯基膦)甲烷、乙烷和丙烷的二氯化钯络合物，它们都具有近似正方形的平面构型，作为二氧化硅表面应变顺式络合物的固体模型。在溶液中，这些化合物的固态/超31/P化学位移发生在127ppm的范围内，而P-Pd-P角从73到91/sup 0/。因此，/sup 31/P的化学位移是这类络合物中应变的一个非常敏感的量度，并且证实了溶液中的结构与固体中的结构相似。
Phosphorus-31 and carbon-13 NMR spectra with cross polarization and magic-angle spinning are used to characterize palladium-tertiary phosphine complexes and their precursors covalently bound to silica. Phosphorus-31 NMR is a good probe of complex formation and geometry, whereas /sup 13/C NMR is a good probe of ligand structure. The 36.44-MHz /sup 31/P spectrum of (identical with SiOSiCH/sub 2/CH/sub 2/PPh/sub 2/)/sub 2/PdCl/sub 2/ shows two, barely resolved peaks at about 21 and 30 ppm assigned to the trans and cis complexes, respectively. These assignments are based on the chemical shifts of model compounds in both solution and the solid state. Uncomplexed phosphine and phosphine oxide are observed when complexes are prepared from phosphinated silica but not when the complexes are preformed and then attached to silica. The palladium dichloride complexes of bis(diphenylphosphino)methane, -ethane, and -propane, all of which have an approximately square-planar configuration, were examined as solid-state models for strained cis complexes on the silica surface. As in solution, the solid-state /sup 31/P chemical shifts of these compounds occur over a range of 127 ppm while the P-Pd-P angle varies from 73 to 91/sup 0/. Hence, the /sup 31/P chemical shift is a very sensitive measure of strain in such complexes andmore » confirms that the structures in solution are similar to those in the solid state.« less