Mimicking the structure and reactivity of metalloenzyemes without the protein environment can be difficult; however, chemists are able to use organometallic compounds and ligands that are not found in the biosphere to adopt certain enzymatic properties. Among the numerous ligand systems, phosphane ligands are common in transition metal chemistry because they can be easily modified to tune electronic and structural parameters by variation of their substitution patterns. Ferrocenyl based phosphanes, especially 1,1’-bis(diphenylphosphino)ferrocene (dppf) are a key class of ligands in catalysis, however, their role in stabilizing unpaired electrons and open coordination sites is a relatively new undertaking. Furthermore, ferrocene is a classic redox active organometallic center, although this is often discounted in catalysis. We have recently reported a case of η3-dppf that is, in fact, noninnocent, and unpaired spin density was distributed over the ligand metal site. Using several spectroscopic techniques (Cyclicvoltammetry, EPR (X-band, High-field, and pulse), UV-Vis, IR and Mössbauer, as well hybrid spectroelectrochemical techniques) we have shown that spin density (Figure 1) from either a tricarbonyliron(I) ([dppfFe(CO)3]+) or tricarbonylmanganses(0) ([dppfMn(CO)3]) was stabilized by the ferrocene backbone, confirming that ferrocenyl-based ligands such as dppf can behave noninnocently (Figure 1). The hydride chemistry of both [dppfFe(CO)3H]+ and [dppfMn(CO)3H] were also explored, and both complexes show reactivity towards the formation of dihydrogen followed by the formation of a Fe-&gt;M interaction. The flexability offered by the dppf ligand helps stabilize the high valent metal centers after H2 release.

Beyond common bonding, ferrocene-transition metal interactions

255th National Meeting (2018)

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