title: Accounting for non-optimal interactions in molecular recognition: a study of ion-π complexes using a QM/MM model with a dipole-polarisable MM region.
abstract: For a quantitative understanding of molecular structure, interaction and dynamics, accurate modelling of the energetics of both near-equilibrium and less optimal contacts is important. In this work, we explore the potential energy surfaces of representative ion-π complexes. We examine the performance of a semi-empirical QM/MM approach and the corresponding QM/MMpol model, where inducible point dipoles are additionally employed in the MM region. The predicted potential energy surfaces of cation-benzene complexes are improved by inclusion of explicit MM polarisation of the π-molecule. For cation-formamide complexes, inducible dipoles appreciably improve energetic estimates at geometries forming non-optimal interactions. Energetic component analysis suggests that the implicit MM polarisation of the fixed charge QM/MM model mirrors the behaviour of the QM/MMpol dipole model for the energetics of near-equilibrium conformations. However, for complexes at less optimal orientations, the QM/MM model exhibits higher errors than the QM/MMpol approach, being unable to capture orientation-dependent variations in polarisation energy.
authors.affiliation: School of Pharmacy and Pharmaceutical Sciences, University of Manchester, Oxford Road, Manchester, M13 9PT, UK.
authors.forename: Qiantao
authors.initials: Q
authors.lastname: Wang
authors.forename: Richard A
authors.initials: RA
authors.lastname: Bryce
mesh_terms: D001554:Benzene / Q000737:chemistry; D003198:Computer Simulation; D056831:Coordination Complexes / Q000737:chemistry*; D005559:Formamides / Q000737:chemistry; D008094:Lithium / Q000737:chemistry; D008274:Magnesium / Q000737:chemistry; D008958:Models, Molecular; D055672:Static Electricity
chemical_list: D056831:Coordination Complexes; D005559:Formamides; C031066:formamide; D008094:Lithium; D008274:Magnesium; D001554:Benzene