Probing Halogen Bonds by Scalar Couplings

As halogen bonding is a weak, transient interaction, its description in solution is challenging. We demonstrate that scalar coupling constants (J) are modulated by halogen bonding. The binding-induced magnitude change of one-bond couplings, even up to five bonds from the interaction site, correlates to the interaction strength. We demonstrate this using the NMR data of 42 halogen-bonded complexes in dichloromethane solution and by quantum chemical calculations. Our observation puts scalar couplings into the toolbox of methods for characterization of halogen bond complexes in solution and paves the way for their applicability for other types of weak sigma-hole interactions.

Automated summary

The study demonstrates that scalar coupling constants are modulated by halogen bonding, with the magnitude change of one-bond couplings correlating to the interaction strength. The findings, based on NMR data and quantum chemical calculations of 42 halogen-bonded complexes in dichloromethane solution, suggest that scalar couplings can be used as a method for characterizing halogen bond complexes in solution and potentially for other types of weak sigma-hole interactions.