title: Characterizing agosticity using the quantum theory of atoms in molecules: bond critical points and their local properties.
abstract: In this paper, we extend the work of Popelier and Logothetis [J. Organomet. Chem. 1998, 555, 101] on the characterization of agosticity by considerably enlarging the set of the studied organometallic molecules. To this aim, 23 representative complexes have been considered, including all first line transition metals at various oxidation states and exhibiting four types of agosticity (α, β, γ, and δ). From these examples, the concepts of agostic atom, agostic bond, and agostic interaction are defined and discussed, notably by advocating Bader's analysis of the electron density. The nature and the local properties of the bond critical points are then investigated, and the relationships with the main geometric parameters of the complexes are particularly examined. Moreover, new local descriptors based on kinetic energy densities are developed in order to provide new tools for bond characterization.
authors.affiliation: IRCOF, CNRS UMR 6014 & FR 3038, Université de Rouen et INSA de Rouen, 76821 Mont St Aignan, Cedex, France.
authors.forename: Vincent
authors.initials: V
authors.lastname: Tognetti
authors.forename: Laurent
authors.initials: L
authors.lastname: Joubert
authors.forename: Roman
authors.initials: R
authors.lastname: Raucoules
authors.forename: Theodorus
authors.initials: T
authors.lastname: De Bruin
authors.forename: Carlo
authors.initials: C
authors.lastname: Adamo