title: Anagostic interactions under pressure: attractive or repulsive?
abstract: Square-planar d(8)-ML4 complexes might display subtle but noticeable local Lewis acidic sites in axial direction in the valence shell of the metal atom. These sites of local charge depletion provide the electronic prerequisites to establish weakly attractive 3c-2e M⋅⋅⋅H-C agostic interactions, in contrast to earlier assumptions. Furthermore, we show that the use of the sign of the (1)H NMR shifts as major criterion to classify M⋅⋅⋅H-C interactions as attractive (agostic) or repulsive (anagostic) can be dubious. We therefore suggest a new characterization method to probe the response of these M⋅⋅⋅H-C interactions under pressure by combined high pressure IR and diffraction studies.
authors.affiliation: Institut für Physik, Universität Augsburg, 86135 Augsburg (Germany). wolfgang.scherer@physik.uni-augsburg.de.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Scherer
authors.forename: Andrew C
authors.initials: AC
authors.lastname: Dunbar
authors.forename: José E
authors.initials: JE
authors.lastname: Barquera-Lozada
authors.forename: Dominik
authors.initials: D
authors.lastname: Schmitz
authors.forename: Georg
authors.initials: G
authors.lastname: Eickerling
authors.forename: Daniel
authors.initials: D
authors.lastname: Kratzert
authors.forename: Dietmar
authors.initials: D
authors.lastname: Stalke
authors.forename: Arianna
authors.initials: A
authors.lastname: Lanza
authors.forename: Piero
authors.initials: P
authors.lastname: Macchi
authors.forename: Nicola P M
authors.initials: NP
authors.lastname: Casati
authors.forename: Jihaan
authors.initials: J
authors.lastname: Ebad-Allah
authors.forename: Christine
authors.initials: C
authors.lastname: Kuntscher
keywords: agostic interactions; bond activation; charge density; high pressure