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

Abstract

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.

Keywords

• nmr spectroscopy
• chemical shift
• bis(thio)phosphorylated amides
• phosphorylotropy
• prototropy
• tautomeric form
• integral intensity
• amide proton
• concentration dependence of nh proton signals
• temperature nmr spectra