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

摘要

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 center dot center dot center dot Cl halogen bond is replaced by a chlorine-transferred Cl center dot center dot center dot 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 Cl-N distance, EOM-CCSD Cl-N coupling constants show the evolution of the traditional halogen bond in the N-Base: ClOH complexes, to a chlorine-shared halogen bond in N-2:ClOH2+, to a covalent bond in (N-Base-Cl)(+):OH2. (1)J(Cl-N) values for these complexes resemble (1)J(Cl-N) for the ions (N-Base- Cl)(+).