Versatile (1)H-(31)P-(31)P COSY 2D NMR techniques for the characterization of polyphosphorylated small molecules

Di- and triphosphorylated small molecules represent key intermediates in a wide range of biological and chemical processes. The importance of polyphosphorylated species in biology and medicine underscores the need to develop methods for the detection and characterization of this compound class. We have reported two-dimensional HPP-COSY spectroscopy techniques to identify diphosphate-containing metabolic intermediates at submillimolar concentrations in the methylerythritol phosphate (MEP) isoprenoid biosynthetic pathway. (1) In this work, we explore the scope of HPP-COSY-based techniques to characterize a diverse group of small organic molecules bearing di- and triphosphorylated moieties. These include molecules containing P-O-P and P-C-P connectivities, multivalent P(III)-O-P(V) phosphorus nuclei with widely separated chemical shifts, as well as virtually overlapping (31)P resonances exhibiting strong coupling effects. We also demonstrate the utility of these experiments to rapidly distinguish between mono- and diphosphates. A detailed protocol for optimizing these experiments to achieve best performance is presented.