Tuning of non-covalent interactions involving a halogen atom that plays the role of Lewis acid and base simultaneously

摘要

In this work, a series of model complexes (MH3X)(HNC)(N'C'H'), where M = C-Pb and X = Cl-At, is studied using a first-principles computational approach. Each of these complexes possesses a halogen atom (X) simultaneously acting as the Lewis base for X center dot center dot center dot H hydrogen bonding (HB) with HNC and as the Lewis acid for X center dot center dot center dot N' halogen bonding (XB) with N'C'H'. The strengths of these non-covalent interactions are tuned by sharing the same halogen centre and by substituting M and X with consecutive elements from groups 14 and 17. Variations in the strengths are estimated mostly by means of various energetic quantities, such as the total interaction energy (E-int), two- and three-body contributions to E-int, their fundamental physical components and donor-acceptor orbital interaction energies. The coexistence of HB and XB involving the same X-centre weakens these interactions, but the magnitude of the total interaction in the complexes increases due to the three-body interaction and the appearance of additional lateral non-covalent interaction between HNC and N'C'H'. Substituting M and X with consecutive elements from groups 14 and 17 leads to several regularities in the changes of E-int. A dependence of three-body interaction on the kinds of M and X is also detected.