What is the Driving Force Behind Molecular Triangles and its guests? A Quantum Chemical Perspective about Host-Guest Interactions
The physical nature of the Host-Guest (HG) interactions occurred between molecular triangles and linear anions were explored using Density Functional Theory (DFT) calculations combined with energy decomposition analyses (EDA), nuclear independent chemical shift (NICS), and non- covalent interactions (NCI). We demonstrated that: (i) in addition to the host being globally rigid, the strain energies are not negligible, in special to host 2; (ii) halogen anions interact mainly by electrostatic force (∆Eelst > ∆Eorbtot > ∆Edisp), meanwhile (iii) trihalogen anions interacts mostly by dispersion forces (∆Edisp > ∆Eelst ≈ ∆Eorbtot ). The NICS and NCI calculations corroborate the idea of which HG interactions are considerably mediated through dispersion term, and also indicates an antiaromatic character inside host walls.