Mainz 2017 – wissenschaftliches Programm
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MO: Fachverband Molekülphysik
MO 4: Spectroscopy of Cold Molecules and Complexes
MO 4.6: Vortrag
Montag, 6. März 2017, 18:15–18:30, N 25
Vibrational Blue Shift of coordinated N2 in [Fe3O(OAc)6(N2)n]+: "Non Classical" Dinitrogen Complexes — •Johannes Lang, Jennifer Mohrbach, Sebastian Dillinger, Joachim Hewer, and Gereon Niedner-Schatteburg — Fachbereich Chemie and Forschungszentrum OPTIMAS, Technische Universität Kaiserslautern, 67663 Kaiserslautern, Germany.
The discovery of transition metal dinitrogen complexes in 1965 launched the ever growing research field of N2 coordination chemistry. Spectroscopically, metal-N2 bonding manifests itself by shifted N2 stretching vibration frequencies in relation to the (IR inactive) frequency of the free N2 molecule. Predominantly, N2 complexes exhibit vibrational red shifts[1,2], which is well understood terms of the Dewar-Chatt-Duncanson (DCD) model[3].
Here, were present "non classical" dinitrogen complexes [Fe3O(OAc)6(N2)n]+ (n = 1,2,3) in the gas phase at cryo temperatures. Infrared photo dissociation (IR-PD) as well as density functional theory (DFT) calculations reveal blue shifted N2 stretching vibration bands. A detailed analysis of the electronic and steric interplay between N2 and the [Fe3O(OAc)6]+ unit indicates strengthened N-N bonds due to pronounced σ bonding and a lack of π back donation.
[1] S. Dillinger, J. Mohrbach, J. Hewer, M. Gaffga, G. Niedner-Schatteburg, PCCP 2015, 17, 10358-10362.
[2] F. Studt, F. Tuczek, J. Comp. Chem. 2006, 27, 1278-1291.
[3] G. Frenking and N. Fröhlich, Chem. Rev., 2000, 100, 717-774.