Theoretical Analysis of Solid-Phase F-F, Br-O, and Br-Br Interactions

Abstract

In order to learn more about the nature of the FF, BrBr, and BrO interactions in crystalline 1-bromo-2,3,5,6-tetrafluoro-nitrobenzene (BFNB), a quantum chemistry analysis was conducted. This system was chosen because it has properties that are similar to those of halogen bonds in crystals and biological systems. The poor electrophilic activity of fluorine atoms may be due to their modest positive electrostatic potentials (VS,max +1 kcal mol-1). Calculations based on atomic and molecular quantum theory place the electron density at the FF critical spots in the range of 0.004-0.006 au, whereas the values of 2BCP are all positive and fall in the range of 0.023-0.031 au. This suggests that the nature of all FF interactions in crystalline BFNB is weak and primarily electrostatic. Energy decomposition analysis (EDA) is used to investigate the character of intermolecular interactions. Our findings suggest that nuclear magnetic resonance characteristics undergo significant modifications while transitioning from the solitary gas phase molecule model to crystalline BFNB, particularly for those nuclei involved in intermolecular interactions. The strength of these alterations at each nucleus is, of course, proportional to the relative importance of its role in the interactions.