Halogen Bonds between 2,2,6,6-Tetramethylpiperidine-N-oxyl Radical and CxHyFzI Species: DFT Calculations of Physicochemical Properties and Comparison with Hydrogen Bonded Adducts

Structural, thermodynamic, and magnetic properties of adducts between the 2,2,6,6-tetramethylpiperidine-N-oxyl radical and representative hydrogen and halogen bond donors in solution have been investigated by an integrated computational tool including hybrid density functionals and discrete-continuum solvent models. From a quantitative point of view, the computed values show a fair agreement with experiment when environmental effects are taken into the proper account. From a more general point of view, our analysis points out a number of analogies, but also some difference, between hydrogen and halogen bond, which have been interpreted in terms of the various effects tuning thermodynamic and spectroscopic parameters.