title: Cation-pi interactions of bare and coordinatively saturated metal ions: contrasting structural and energetic characteristics.
abstract: In the present work, we address an apparent disparity in the structural parameters of the X-ray structures and theoretical models of cation-pi complexes in biological and chemical recognition. Hydrated metal ion (Li+, Na+, K+, Mg2+, Ca2+) complexes with benzene (cation-pi) are considered as model systems to perform quantum mechanical calculations in evaluating the geometrical parameters and interaction energies of these complexes. The computations disclose that there is a variation in the structural parameters as well as in the interaction energies of these complexes with the multiple additions of water molecules. The distance between the cation and the pi-system increases with the addition of water molecules, delineating the influence of solvent or the neighborhood atoms on the structural parameters of cation-pi systems present in crystal structures.
authors.affiliation: Molecular Modeling Group, Indian Institute of Chemical Technology, Tarnaka, Hyderabad 500 007, India.
authors.forename: A Srinivas
authors.initials: AS
authors.lastname: Reddy
authors.forename: Hendrik
authors.initials: H
authors.lastname: Zipse
authors.forename: G Narahari
authors.initials: GN
authors.lastname: Sastry