Structure and Intramolecular Mobility of Some Derivatives of Bis(thio)phosphorylated Amides in CD₂Cl₂ and CD₃CN Solutions

The structure and intramolecular mobility of some derivatives of bis(thio)phosphorylated amides in CCl₄, CD₂Cl₂, and CD₃CN solutions were examined by ¹H and ³¹P NMR spectroscopy. A comparative analysis of the temperature-dependent ¹H and ³¹P NMR spectra of the studied compounds with symmetric and asymmetric substitution at phosphorus atoms was carried out. Various intramolecular processes were identified – rotation around C-N bonds, conformational transformations of molecules, tautomerism, and phosphorylotropic rearrangement with the formation of various conformational forms. It was shown that a dynamic equilibrium of several forms is reached, with the amide (phosphazo-) form having a clear advantage.

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