Structural and computational examination of hydrogen-bonding between the C-H bonds of phenylphosphates and nitrate ions

Abstract

In an effort to understand the packing forces that control the ubiquitous interactions between nitrate (NO3−) anions and phosphate moieties, the C-H structural data concerning phenylphosphates and a NO3− were obtained from the Cambridge Structural Database (CSD) tabulated, averaged, and compared to elucidate these variables. In addition, molecular modeling was undertaken using density functional theory calculations to explore the characteristics of this interaction. In particular, the varying reactivity of the protons on the phenol ring and the resulting impact on NO3− bonding was explored. These electronic structure gas phase calculations identified the different atomic charges of the ortho-, meta-, and para-protons on the phenol ring, which were found to be in agreement with the observed crystallographic trends. Overall, it was determined that based on the strong agreement between the model and experimental data, the charge on the ring protons controls the hydrogen bonding to the NO3− ion and the ultimate construction of the molecule.