Modeling the Active Sites of [nickel-Iron]- and [iron-Iron]-Hydrogenases

Whaley, Curtis

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Description

Title

Modeling the Active Sites of [nickel-Iron]- and [iron-Iron]-Hydrogenases

Author(s)

Whaley, Curtis

Issue Date

2009

Doctoral Committee Chair(s)

Thomas Rauchfuss

Department of Study

Chemistry

Discipline

Chemistry

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(s)

Chemistry, Inorganic

Language

eng

Abstract

While previous hydride-containing [FeFe]-hydrogenase models featured only bridging hydrides, we sought to prepare complexes of terminal hydrides that would be more relevant to mimicking this hydrogenase. Di-subferrous precursors, such as Fe2(S2C2H4)(CO)4 (PMe3)2, have been known for decades---well before the elucidation of the structure of the active site. Two-electron oxidation of Fe2(S2C2H4)(CO)4(PMe 3)2 in the presence of excess PMe3 in MeCN resulted in the formation of the diferrous [Fe2(S2C2H 4)(mu-CO)(NCMe)(CO)(PMe3)4](PF 6)2. This complex, when treated with hydride sources such as BH4- or AlH4- at low temperature, generated the first terminal hydride-containing [FeFe]-hydrogenase model complex, [HFe2(S2C2H4)(mu-CO)(CO)(PMe 3)4]PF6. This complex readily protonates with strong acids in MeCN to evolve H2 and regenerate the precursor MeCN-complex. The terminal hydride complex is thermally unstable, isomerizing to give an inert bridging hydride, even in the solid state.

Graduation Semester

2009

Type of Resource

text

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