title: Extending the motif of the [FeFe]-hydrogenase active site models: protonation of Fe2(NR)2(CO)6-xLx species.
abstract: Studies on diiron dithiolato complexes have proven fruitful for modeling the active site of the [FeFe]-hydrogenases. Here we present a departure from the classical Fe(2)S(2) motif by examining the viability of Fe(2)N(2) butterfly compounds as functional models for the diiron active site of [FeFe]-hydrogenases. Derivatization of Fe(2)(BC)(CO)(6) (1, BC=benzo-[c]-cinnoline) with PMe(3) affords Fe(2)(BC)(CO)(4)(PMe(3))(2), which subsequently undergoes protonation at the Fe-Fe bond. The hydride [(mu-H)Fe(2)(BC)(CO)(4)(PMe(3))(2)]PF(6) was characterized crystallographically as the C(2v) isomer. It represents a rare example of a hydrido diiron complex that exists as observable isomers, depending on the location of the phosphine ligands--diapical and apical-basal. This hydride catalyzes the electrochemical reduction of protons.
authors.affiliation: Department of Chemistry, University of Illinois, 601 S. Goodwin Ave., Urbana, IL 61801, USA.
authors.forename: Phillip I
authors.initials: PI
authors.lastname: Volkers
authors.forename: Thomas B
authors.initials: TB
authors.lastname: Rauchfuss
mesh_terms: D001665:Binding Sites; D005296:Ferrous Compounds / Q000737:chemistry*; D006864:Hydrogenase / Q000737:chemistry* / Q000378:metabolism; D007506:Iron-Sulfur Proteins / Q000737:chemistry* / Q000378:metabolism; D008958:Models, Molecular; D015394:Molecular Structure; D010084:Oxidation-Reduction; D017434:Protein Structure, Tertiary
chemical_list: D005296:Ferrous Compounds; D007506:Iron-Sulfur Proteins; C118830:iron hydrogenase; D006864:Hydrogenase