The peculiar isomer-selective reduction of (α)-hydroxyiminophosphonates (oxime isomers) into (α)-hydroxyaminophosphonate (hydroxylamine) derivatives is presented. A library of 16 (α)-hydroxyiminophosphonates is prepared and studied via a unique multifaceted approach involving the interplay of NMR, XRD, MS, IM-MS and computational chemistry techniques. The combination of NMR, XRD and HPLC enables the seamless separation, identification and quantification of the oxime isomers (E/Z). Tandem MS (MS/MS) enables the determination of the fragmentation patterns for both isomers. Collision energy breakdown curves highlight the order of apparition of the fragments as well as their related energy of fragmentation, demonstrating that the strength of the C–P bond in the Z isomers is much weaker than in the E isomers. Computational chemistry demonstrates that favorable protonation site is isomer-dependent with the phosphonate moiety being the favorable protonation site for the E isomers, while protonation occurs preferentially on the amino moiety for Z isomers regardless of the phosphite source. The combination of these various methods led an unprecedented level of characterization of oxime isomers, providing a better uderstanding of the isomer-dependent behavior of (α)-hydroxyiminophosphonates.

中文翻译：

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理解（α）-羟基亚氨基膦酸盐的特殊行为的多方面方法

介绍了 (α)-羟基亚氨基膦酸酯 (肟异构体) 到 (α)-羟基氨基膦酸酯 (羟胺) 衍生物的独特异构体选择性还原。16 (α)-羟基亚氨基膦酸酯库是通过一种独特的多方面方法制备和研究的，涉及 NMR、XRD、MS、IM-MS 和计算化学技术的相互作用。NMR、XRD 和 HPLC 的结合能够实现肟异构体 ( E / Z )的无缝分离、鉴定和定量。串联质谱 (MS/MS) 能够确定两种异构体的碎裂模式。碰撞能量击穿曲线突出了碎片出现的顺序以及它们相关的碎片能量，证明了 C-P 键的强度Z异构体比E异构体弱得多。计算化学表明，有利的质子化位点取决于异构体，其中膦酸酯部分是E异构体的有利质子化位点，而无论亚磷酸酯来源如何，质子化优先发生在Z异构体的氨基部分。这些不同方法的结合导致了对肟异构体的前所未有的表征水平，提供了对 (α)-羟基亚氨基膦酸酯的异构体依赖性行为的更好理解。