Hydrogen Production From Model Complexes of the [iron-Iron]- and [nickel-Iron]-Hydrogenase Active Sites

Barton, Bryan E.

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Description

Title

Hydrogen Production From Model Complexes of the [iron-Iron]- and [nickel-Iron]-Hydrogenase Active Sites

Author(s)

Barton, Bryan E.

Issue Date

2010

Doctoral Committee Chair(s)

Rauchfuss, Thomas B.

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

Unlike the [FeFe]-hydrogenases, model complexes for the [NiFe]-hydrogenases were unknown prior to the crystal structure in 1996. However, most synthetic efforts focused on structural models for the active site, and neglected the catalytically imperative hydride ligand. Thus, we sought a nickel-iron hydride complex to explore the relevant reactivity of the first (mu-H)Ni(mu-SR) 2Fe complex. We found that the previously reported (dppe)Ni(mu-pdt)Fe(CO) 3, a Ni(I)Fe(I) complex, reacted with acid to provide [(dppe)Ni(mu-H)(mu-pdt)Fe(CO) 3]+, the first nickel-iron hydride. After protonation, the hydride complex is amenable to substitution chemistry at the Fe(CO) 3 subunit. Further derivatives altering the Ni(diphosphine)(SR) 2 subunit have been achieved through an alternative synthetic procedure to the Ni(I)Fe(I) complex. All nickel-iron hydrides investigated are active catalysts for the reduction of protons. As the catalytic mechanism of [NiFe]-hydrogenase is widely speculative, the reactivity of this new class of nickel-iron hydrides offers powerful insights into Nature's catalytic mechanism. (Abstract shortened by UMI.).

Graduation Semester

2010

Type of Resource

text

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http://hdl.handle.net/2142/84354

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