Ab Initio Molecular Dynamics Simulations of the Interaction between Organic Phosphates and Goethite

• Published in: Molecules (Basel, Switzerland) Switzerland), 2020-12, Vol.26 (1), p.160
• Main Authors: Ganta, Prasanth B, Kühn, Oliver, Ahmed, Ashour A
• Format: Article
• Language: English
• Subjects: Adsorption; Agricultural production; Chemical bonds; Fertilizers; Food security; glycerolphosphate; Goethite; Hydrogen bonding; Hydrogen bonds; Hydrogen-Ion Concentration; Infrared spectra; Inositol; inositol hexaphosphate; Iron Compounds - chemistry; Iron Compounds - metabolism; MD simulations; Minerals; Minerals - chemistry; Minerals - metabolism; Molecular dynamics; Molecular Dynamics Simulation; Organic phosphorus; Organophosphates - chemistry; Organophosphates - metabolism; Oxygen; Phosphates; Phosphorus; P–inefficiency; QMMM; Quantum mechanics; Rocks; Simulation; Soil dynamics; Soil fertility; Water - chemistry; Water - metabolism
• ISSN: 1420-3049; 1420-3049
• DOI: 10.3390/molecules26010160

Today's fertilizers rely heavily on mining phosphorus (P) rocks. These rocks are known to become exhausted in near future, and therefore effective P use is crucial to avoid food shortage. A substantial amount of P from fertilizers gets adsorbed onto soil minerals to become unavailable to plants. Understanding P interaction with these minerals would help efforts that improve P efficiency. To this end, we performed a molecular level analysis of the interaction of common organic P compounds (glycerolphosphate (GP) and inositol hexaphosphate (IHP)) with the abundant soil mineral (goethite) in presence of water. Molecular dynamics simulations are performed for goethite-IHP/GP-water complexes using the multiscale quantum mechanics/molecular mechanics method. Results show that GP forms monodentate ( ) and bidentate mononuclear ( ) motifs with being more stable than . IHP interacts through multiple phosphate groups with the motif being most stable. The order of goethite-IHP/GP interaction energies is GP < GP < IHP < IHP . Water is important in these interactions as multiple proton transfers occur and hydrogen bonds are formed between goethite-IHP/GP complexes and water. We also present theoretically calculated infrared spectra which match reasonably well with frequencies reported in literature.