Organic biomolecules bind to phosphate through borate linkages in aqueous solutions

Solutions of salicyclic, ascorbic, and citric acids were reacted with boric acid, followed by NaH2PO4. The products, triphosphateborate ester of salicylic acid (1), orthosphateborate ester of ascorbic acid (2), triphosphateborate ester of ascorbic acid (3), and orthosphateborate ester of citric acid (4), were flash precipitated with cold acetone and characterised by microanalysis, thermal analysis, FT-IR, Raman, 11B NMR, 31P MAS NMR, and mass spectroscopic techniques. Analytical results indicated the presence of –C–O–B–O–P– linkages with the attached phosphate groups varying between orthophosphate and triphosphate, depending on the starting material. The biomolecules studied in this work may serve as models in the B–P-organic system and the results would provide a possible contribution to boron prebiotic chemistry.