Using protonation to change a Cl⋯N halogen bond in N-Base:ClOH complexes to a Cl⋯O halogen bond

Ab initio MP2/aug′-cc-pVTZ calculations demonstrate that protonation of N-Base:ClOH complexes at O leads to complexes (N-Base-Cl)+:OH2, as a traditional N⋯Cl halogen bond is replaced by a chlorine-transferred Cl⋯O bond. For a fixed base, the binding energies of the latter complexes are more than an order of magnitude greater than the former. As a function of the CleN distance, EOM-CCSD CleN coupling constants show the evolution of the traditional halogen bond in the N-Base:ClOH complexes, to a chlorine-shared halogen bond in N2:ClOH2 +, to a covalent bond in (N-Base-Cl)+:OH2. 1J(CleN) values for these complexes resemble 1J(CleN) for the ions (NBase- Cl)+.Comunidad Autónoma de Madrid [grant number S2013/MIT2841, Fotocarbon]; Ministerio de Economía y Competitividad [grant number CTQ2015-63997-C2-2-P].Peer Reviewe