Bimetallic complexes are synthesized with the aim of obtaining a catalyst for hydrogen evolution based on first-row transition metals. Inspired by the H-cluster of the hydrogenases, a bimetallic molecular design was used, in which one complex is low-spin and electron-rich (low-spin FeII) and the other complex acts as a metallo-ligand and can host Ni(II), Co(II) or Fe(II) in high-spin configuration. The metalloligand features an N2S2 ligand and can also be an Fe-NO complex. A comparison of the Mössbauer spectra of these bridged dinuclear complexes found no electronic effect of the metalloligand on the low-spin complex. Secondly, the dinuclear complex nominally written as FeII(NO)7-FeCp(CO) was studied with variable field-variable temperature Mössbauer spectroscopy. The isomer shift of the N2S2Fe(NO) is 0.23 mm/s, thus the assignment as high-spin FeII is in question. Paramagnetic Mössbauer spectra in high applied magnetic field were studied with the aim to distinguish between multiple configurations, such as FeIII-NO-(S=1/2) and FeII-NO (S=3/2).

Mössbauer spectroscopy and electronic structure of bimetallic iron-nitrosyl complexes

251st National Meeting (2016)

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