Protonation of [FeFe]-hydrogenase sub-site analogues: revealing mechanism using FTIR stopped-flow techniques

Joseph A. Wright; Lee Webster; Aušra Jablonskytė; Pei Meng Woi; Saad Ibrahim; Christopher J Pickett

doi:10.1039/C004692B

Protonation of [FeFe]-hydrogenase sub-site analogues: revealing mechanism using FTIR stopped-flow techniques

Joseph A. Wright, Lee Webster, Aušra Jablonskytė, Pei Meng Woi, Saad Ibrahim, Christopher J Pickett

Research output: Contribution to journal › Article › peer-review

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Abstract

The formation of transient metal hydride(s) at the metallo-sulfur active sites of [FeFe]-hydrogenase is implicated in both hydrogen evolution and uptake reactions. Stopped-flow spectroscopic techniques can provide insight into the reactivity patterns of model {2Fe2S} sub-sites towards protons, and this information contributes to understanding the nature of the biological systems. In this study we have focussed on the influence of the nature of the bridging dithiolate ligand in influencing the kinetics and activation energy parameters for protonation in synthetic sub-sites including Fe₂{µ-[S(CH₂)_nS]}(CO)₄(PMe₃)₂ [n = 2, ethane-1,2-dithiolate (edt) or n = 3, propane-1,3-dithiolate (pdt)], Fe₂[(µ-SCH₂)₂NH](CO)₄(PMe₃)₂ and (NEt₄)₂{Fe₂[(µ-SCH₂)₂NH](CO)₄(CN)₂}. Notably we find that (i) the presence of a nitrogen in the dithiolate bridge does not accelerate metal–metal bond protonation, and that (ii) immobilisation of (NEt₄)₂[Fe₂(µ-pdt)(CO)₄(CN)₂] in a polymer matrix stabilises otherwise short-lifetime protonation products.

Original language	English
Pages (from-to)	359-371
Number of pages	13
Journal	Faraday Discussions
Volume	148
DOIs	https://doi.org/10.1039/C004692B
Publication status	Published - 2011

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10.1039/C004692B

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@article{ec0b0c594da6483d8476634bdc46c2dd,

title = "Protonation of [FeFe]-hydrogenase sub-site analogues: revealing mechanism using FTIR stopped-flow techniques",

abstract = "The formation of transient metal hydride(s) at the metallo-sulfur active sites of [FeFe]-hydrogenase is implicated in both hydrogen evolution and uptake reactions. Stopped-flow spectroscopic techniques can provide insight into the reactivity patterns of model {2Fe2S} sub-sites towards protons, and this information contributes to understanding the nature of the biological systems. In this study we have focussed on the influence of the nature of the bridging dithiolate ligand in influencing the kinetics and activation energy parameters for protonation in synthetic sub-sites including Fe2{µ-[S(CH2)nS]}(CO)4(PMe3)2 [n = 2, ethane-1,2-dithiolate (edt) or n = 3, propane-1,3-dithiolate (pdt)], Fe2[(µ-SCH2)2NH](CO)4(PMe3)2 and (NEt4)2{Fe2[(µ-SCH2)2NH](CO)4(CN)2}. Notably we find that (i) the presence of a nitrogen in the dithiolate bridge does not accelerate metal–metal bond protonation, and that (ii) immobilisation of (NEt4)2[Fe2(µ-pdt)(CO)4(CN)2] in a polymer matrix stabilises otherwise short-lifetime protonation products.",

author = "Wright, {Joseph A.} and Lee Webster and Au{\v s}ra Jablonskytė and Woi, {Pei Meng} and Saad Ibrahim and Pickett, {Christopher J}",

year = "2011",

doi = "10.1039/C004692B",

language = "English",

volume = "148",

pages = "359--371",

journal = "Faraday Discussions",

issn = "1364-5498",

publisher = "Royal Society of Chemistry",

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T1 - Protonation of [FeFe]-hydrogenase sub-site analogues: revealing mechanism using FTIR stopped-flow techniques

AU - Wright, Joseph A.

AU - Webster, Lee

AU - Jablonskytė, Aušra

AU - Woi, Pei Meng

AU - Ibrahim, Saad

AU - Pickett, Christopher J

PY - 2011

Y1 - 2011

N2 - The formation of transient metal hydride(s) at the metallo-sulfur active sites of [FeFe]-hydrogenase is implicated in both hydrogen evolution and uptake reactions. Stopped-flow spectroscopic techniques can provide insight into the reactivity patterns of model {2Fe2S} sub-sites towards protons, and this information contributes to understanding the nature of the biological systems. In this study we have focussed on the influence of the nature of the bridging dithiolate ligand in influencing the kinetics and activation energy parameters for protonation in synthetic sub-sites including Fe2{µ-[S(CH2)nS]}(CO)4(PMe3)2 [n = 2, ethane-1,2-dithiolate (edt) or n = 3, propane-1,3-dithiolate (pdt)], Fe2[(µ-SCH2)2NH](CO)4(PMe3)2 and (NEt4)2{Fe2[(µ-SCH2)2NH](CO)4(CN)2}. Notably we find that (i) the presence of a nitrogen in the dithiolate bridge does not accelerate metal–metal bond protonation, and that (ii) immobilisation of (NEt4)2[Fe2(µ-pdt)(CO)4(CN)2] in a polymer matrix stabilises otherwise short-lifetime protonation products.

AB - The formation of transient metal hydride(s) at the metallo-sulfur active sites of [FeFe]-hydrogenase is implicated in both hydrogen evolution and uptake reactions. Stopped-flow spectroscopic techniques can provide insight into the reactivity patterns of model {2Fe2S} sub-sites towards protons, and this information contributes to understanding the nature of the biological systems. In this study we have focussed on the influence of the nature of the bridging dithiolate ligand in influencing the kinetics and activation energy parameters for protonation in synthetic sub-sites including Fe2{µ-[S(CH2)nS]}(CO)4(PMe3)2 [n = 2, ethane-1,2-dithiolate (edt) or n = 3, propane-1,3-dithiolate (pdt)], Fe2[(µ-SCH2)2NH](CO)4(PMe3)2 and (NEt4)2{Fe2[(µ-SCH2)2NH](CO)4(CN)2}. Notably we find that (i) the presence of a nitrogen in the dithiolate bridge does not accelerate metal–metal bond protonation, and that (ii) immobilisation of (NEt4)2[Fe2(µ-pdt)(CO)4(CN)2] in a polymer matrix stabilises otherwise short-lifetime protonation products.

U2 - 10.1039/C004692B

DO - 10.1039/C004692B

M3 - Article

VL - 148

SP - 359

EP - 371

JO - Faraday Discussions

JF - Faraday Discussions

SN - 1364-5498

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