title: Differential Many-Body Cooperativity in Electronic Spectra of Oligonuclear Transition-Metal Complexes.
abstract: In computational chemistry, non-additive and cooperative effects can be defined in terms of a (differential) many-body expansion of the energy or any other physical property of the molecular system of interest. One-body terms describe energies or properties of the subsystems, two-body terms describe non-additive but pairwise contributions and three-body as well as higher-order terms can be interpreted as a measure for cooperativity. In the present article, this concept is applied to the analysis of ultraviolet/visible (UV/Vis) spectra of homotrinuclear transition-metal complexes by means of a many-body expansion of the change in the spectrum induced by replacing each of the three transition-metal ions by another transition-metal ion to yield a different homotrinuclear transition-metal complex. Computed spectra for the triangulo-complexes [M3 {Si(mt(Me) )3}2] (M=Pd/Pt, mt(Me) =methimazole) and tritopic triphenylene-based N-heterocyclic carbene Rh/Ir complexes illustrate the concept, showing large and small differential three-body cooperativity, respectively.
authors.affiliation: Institute of Physical Chemistry, Karlsruhe Institute of Technology (KIT), Fritz-Haber-Weg 2, 76131, Karlsruhe, Germany.
authors.forename: Jiří
authors.initials: J
authors.lastname: Chmela
authors.affiliation: Institute of Nanotechnology, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany.
authors.forename: Michael E
authors.initials: ME
authors.lastname: Harding
authors.affiliation: Institute of Inorganic Chemistry, Karlsruhe Institute of Technology (KIT), Engesserstraße 15, 76131, Karlsruhe, Germany.
authors.forename: Dimitri
authors.initials: D
authors.lastname: Matioszek
authors.affiliation: Institute of Inorganic Chemistry, Karlsruhe Institute of Technology (KIT), Engesserstraße 15, 76131, Karlsruhe, Germany.
authors.forename: Christopher E
authors.initials: CE
authors.lastname: Anson
authors.affiliation: Institute of Inorganic Chemistry, Karlsruhe Institute of Technology (KIT), Engesserstraße 15, 76131, Karlsruhe, Germany. breher@kit.edu.
authors.forename: Frank
authors.initials: F
authors.lastname: Breher
authors.affiliation: Institute of Physical Chemistry, Karlsruhe Institute of Technology (KIT), Fritz-Haber-Weg 2, 76131, Karlsruhe, Germany. klopper@kit.edu.|Institute of Nanotechnology, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany. klopper@kit.edu.
authors.forename: Wim
authors.identifier: http://orcid.org/0000-0002-5219-9328
authors.initials: W
authors.lastname: Klopper
keywords: carbene complexes; cooperativity; electronic spectra; many-body expansions; non-additivity