Tri- and Tetra-Substituted Derivatives of [Fe-2(CO)(6)(mu-dithiolate)] as Novel Dinuclear Platforms Related to the H-Cluster of [FeFe]H(2)ases

Novel carbonyl dithiolato diiron complexes [Fe-2(CO)(6-x)L-x(mu-dithiolate)] (x=3, 4), related to the active site of [FeFe]-hydrogenases, have been synthesized by photolysis of hexacarbonyl species [Fe-2(CO)(6)(mu-dithiolate)] (dithiolate={S-2(CH2)(3)} (pdt), {SCH2}(2)NR with R=Pr-i (adt(i-Pr)) or Bn (adt(Bn))). The new compounds were characterized by structural and spectroscopic methods. Variable-temperature (VT) NMR experiments revealed their fluxionality in solution depending on terminal ligands exchanges and dithiolate bridge motions. Preliminary results on their protonation giving hydride species and their electrochemical properties are reported.