Models for the active site of the [FeFe]-Hydrogenase [Elektronische Ressource] / von Ulf-Peter Apfel

Models for the Active Site of the
[FeFe]-Hydrogenase




Dissertation
zur Erlangung des akademischen Grades doctor rerum naturalium
(Dr. rer. nat.)

vorgelegt dem Rat der Chemisch-Geowissenschaftlichen Fakultät
der Friedrich-Schiller-Universität Jena
von Dipl.-Chem. Ulf-Peter Apfel
geboren am 14.03.1984 in Jena























Gutachter:
1. Professor Dr. Wolfgang Weigand (Universität Jena)
2. Professor Dr. Dr. h. c. Dieter Seebach (Eidgenössische Technische Hochschule Zürich)
3. Professor Dr. Nils Metzler-Nolte (Ruhruniversität Bochum)

Tag der öffentlichen Verteidigung: 29.09.2010









“Water will be the coal of the future.”




Jules Verne

1874, in “The Mysterious Island“Table of contents
Abbreviations ...................................................................................................................................... 8
1 Introduction .................................................................................................................................... 11
1.1 [FeFe]-Hydrogenase .................................................................................................................12
1.1.1 Enzymatic Topology ........................................................................................................... 12
-
1.1.2 Biosynthesis of CO, CN and (-S-CH -NH-CH -S-) ............................................................ 15 2 2
1.1.3 States of the Active Site ..................................................................................................... 17
1.2 Active Site Models ....................................................................................................................19
1.2.1 Early Research ................................................................................................................... 19
1.2.2 Sub-Site Structures ............................................................................................................ 21
1.2.3 Proton Relay Models/ Models of the Enzymatic Environment ........................................... 22
1.2.4 Bridging Carbonyls, [2Fe3S] Cluster Compounds and Mixed Valence Species ............... 26
1.2.5 Protonation at the [2Fe2S] Sub-site ................................................................................... 29
1.2.6 Resin Bound Complexes .................................................................................................... 30
1.3 Electrocatalytic Mechanisms for the Dihydrogen Formation on Model Complexes .................31
1.3.1 Electrochemistry of Fe (-pdt)(CO) .................................................................................. 32 2 6
1.3.2 Electrochemistry of Fe (-adt)(CO) .................................................................................. 36 2 6
1.3.3 Electrochemistry of Fe (-sdt)(CO) ................................................................................... 38 2 6
1.4 Analytical Methods ....................................................................................................................40
1.4.1 General Analytical Methods ............................................................................................... 40
1.4.2 Cyclic Voltammetry ............................................................................................................ 40
1.5 Motivation ..................................................................................................................................42
2 Results and Discussions ............................................................................................................... 43
2.1 Hydroxy Functionalized Model Compounds and Derivatives ...................................................43
2.1.1 Hydroxy and Ether Functionalized Complexes .................................................................. 43
2.1.2 Aromatic Esters .................................................................................................................. 48
2.1.3 Sugar Derived Complexes ................................................................................................. 50
2.1.4 Membrane Bound Complexes ............................................................................................ 52
2.2 Peptidic-, Amino- and Amino Acid Containing [2Fe2S] Cluster Compounds ...........................59
2.2.1 Amino Functionalized and Amino Acid [FeS] Complexes .................................................. 60
2.2.2 Macrocyclic Peptidic Complexes........................................................................................ 75
2.3 Complexes Containing Platinum and Iron ................................................................................79
2.4 Silicon Containing Model Complexes .......................................................................................83
2.4.1 Synthesis and Characterization of Silicon-Containing Thiolato Complexes with
R Si(CH SH) and Si(CH SH) Type Ligands .................................................................. 84 2 2 2 2 4
2.4.2 Hydroxy Functionalized [2Fe2S(Si)] Complexes ............................................................... 94
2.4.3 Mixed Valent [FeFe(Si)] Systems ....................................................................................... 96
2.4.4 Sterical Demanding [2Fe2S(Si)] Complexes ..................................................................... 98
2.5 Influence of the Bridgehead Atoms.........................................................................................102
3 Outlook ........................................................................................................................................ 104 4 Publications and Documentation of Authorship .......................................................................... 108
4.1 Synthesis and Characterization of Hydroxy-Functionalized Models for the Active
Site in Fe-Only-Hydrogenases ..............................................................................................108
4.2 Functionalized Sugars as Ligands towards water soluble [Fe-only] Hydrogenase
Models ...................................................................................................................................108
4.3 Oxidation of Diiron and Triiron Sulphurdithiolato Complexes: Mimics for [Fe-
only]-hydrogenase’s Active Site ............................................................................................109
4.4 Investigation of Amino Acid Containing [FeFe] Hydrogenase Models Concerning
Pendant Base Effects ............................................................................................................109
4.5 Preparation and Characterization of Homologous Diiron Dithiolato, Diselenato,
and Ditellurato Complexes: [FeFe]-Hydrogenase Models ....................................................110
4.6 Reaction of Fe (CO) with Octreotide – Chemical, Electrochemical and 3 12
Biological Investigations ........................................................................................................110
4.7 Reactions of 7,8-Dithiabicyclo[4.2.1]nona-2,4-diene 7-exo-Oxide with
Dodecacarbonyl Triiron Fe (CO) : A Novel Type of Sulfenato Thiolato Diiron 3 12
Hexacarbonyl Complexes .....................................................................................................111
4.8 Unpublished Manuscripts .......................................................................................................112
4.9 Presentations ..........................................................................................................................115
5 Summary ..................................................................................................................................... 116
6 Zusammenfassung ...................................................................................................................... 122
7 Experimental Part ........................................................................................................................ 126
Synthesis of 1,3-Dithioacetyl-2-methoxy-propane (43) ................................................................127
Synthesis of 1,3-Disulfanyl-2-methoxy-propane (44) ...................................................................127
Synthesis of Hexacarbonyl (-2-methoxypropane-1,3-dithiolato-S,S’)diiron (45) ........................128
Synthesis of 2-Methyl-3-brom-propene (46) .................................................................................128
Synthesis of 1,3-Dibrom-2-methyl-2-hydroxy-propane (47) .........................................................128
Synthesis of 4-Methyl-4-hydroxy-dithiolane (48) ..........................................................................129
Syntheses of Hexacarbonyl (-2-methyl-2-hydroxypropane-1,3-dithiolato-S,S’)
diiron (49) ..............................................................................................................................129
Tris-(hexacabonyl(-2-hydroxypropane-1,3-dithiolato-S,S’)diiron)-1,3,5-tricarboxylic
acid benzol ester (50) .................................................