We report IR active N2 stretching frequencies in isolated and size selected cobalt cluster nitrogen adsorbate complexes, [Con(N2)1](+) as recorded by virtue of InfraRed Photon Dissociation (IRPD) spectroscopy. The observed frequencies of the [Con(N2)1](+) complexes (n = 8-17) are significantly redshifted (2180 to 2290 cm(-1)) with respect to the IR inactive vibrations of free N2 (2359 cm(-1)). These bands are assigned to a μ1 head-on type of coordination of the N2 to the cobalt cluster surface, revealing remarkable cluster size dependent features to interpret.

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We present "non-classical" dinitrogen Fe(iii) oxo acetate complexes in vacuo utilizing Infrared Photodissociation (IR-PD) at cryo temperatures. The IR-PD spectra reveal a blue shift of the N stretching vibration frequencies in the complexes. Density Functional Theory (DFT) calculations confirm the experiments and indicate strengthened N-N bonds due to pronounced σ bonding and a lack of π back donation.

We present the cryogenic (26 K) IR spectra of selected [Ni(N)] (n = 5-20, m = 1 - m), which strongly reveal n- and m-dependent features in the N stretching region, in conjunction with density functional theory modeling of some of these findings. The observed spectral features allow us to refine the kinetic classification [cf. J. Mohrbach, S. Dillinger, and G. Niedner-Schatteburg, J. Chem. Phys. 147, 184304 (2017)] and to define four classes of structure related surface adsorption behavior: Class (1) of Ni, Ni, and Ni are highly symmetrical clusters with all smooth surfaces of equally coordinated Ni atoms that entertain stepwise N adsorption up to stoichiometric N:Ni saturation. Class (2) of Ni and Ni are highly symmetrical clusters minus one. Their relaxed smooth surfaces reorganize by enhanced N uptake toward some low coordinated Ni surface atoms with double N occupation. Class (3) of Ni and Ni through Ni are small clusters of rough surfaces with low coordinated Ni surface atoms, and some reveal semi-internal Ni atoms of high next-neighbor coordination. Surface reorganization upon N uptake turns rough into rough surface by Ni atom migration and turns octahedral based structures into pentagonal bipyramidal structures. Class (4) of Ni through Ni and Ni are large clusters with rough and smooth surface areas. They possess smooth icosahedral surfaces with some proximate capping atom(s) on one hemisphere of the icosahedron with the other one largely unaffected.

The stepwise N2 adsorption on size selected Ni9 + and Ni13 + clusters at 26 K is studied in a hybrid tandem ion trap instrument. Adsorption kinetics of these clusters in conjunction with infrared photon dissociation (IR-PD) spectroscopy of their cluster adsorbate complexes allows for the elucidation of various N2 coverage and cluster size dependent effects, which are related to the rough Ni9 + and smooth Ni13 + cluster surface morphologies. Pseudo-first-order kinetic fits confirm consecutive adsorption steps by single exponential decays exclusively. The recorded IR-PD spectra of all observed cluster adsorbate complexes reveal IR active vibrational bands at frequencies of 2170–2260 cm–1, which coincides with the range of metal head-on coordinated N–N stretching modes. Density functional theory (DFT) calculations confirm the experiments and reinforce a possible isomerization with low N2 coverage in the case of Ni9 +.