Elucidating the spectroscopic and physicochemical properties for a pH-dependent glyphosate structure from a computational perspective

Abstract

Glyphosate is the most used broad-spectrum agrochemical due to its non-selective action mechanism. However, there are concerns regarding being a threat to aquatic and terrestrial lifeforms and the environment. In this study, we conducted a systematic theoretical investigation of the effect of pH on the electronic structure, physicochemical, and spectroscopic properties (IR, Raman, UV–vis, ECD, EI-MS, and NMR) of glyphosate and its zwitterionic structures. The lipophilicity of the zwitterions was studied with ADMET and DFT, and a significant discrepancy between the models was observed. Theoretical EI-MS provided insights into the degradation pathways and possible intermediates. The effect of protonation and hydration on the magnetic properties was described based on an implicit-explicit strategy to compute NMR chemical shifts for the zwitterions, in which the solvent has a considerable effect on the chemical shifts. Overall, our findings suggest that spectroscopic properties can be used to describe glyphosate-based zwitterionic structures.