Chi, Qijin

Ford, Michael J.

Halder, Arnab

Hush, Noel S.

Reimers, Jeffrey R.

Ulstrup, Jens

Zhang, Jingdong

Interfacial electrochemical electron transfer (ET) of redox metalloproteins is long established. For the proteins to retain full ET or enzyme activity, modification of the electrode surfaces, say gold surfaces by self-assembled molecular monolayers (SAMs) is nearly always needed, where functionalized alkanethiols have emerged as core linkers. We have studied molecular linking in the long-range ET (LRET) processes in detail using electrochemistry, in situ STM and AFM, and electronic structure computations. A focus is the electronic structure of the Au-S link and the SAM packing. We have disentangled a wealth of data to identify the nature of the crucial Au-S contact, all suggesting prevalence of a Au(0)-thiyl radical unit. Molecular packing is further determined by the SAM molecular structure and involves binding either to Au-atoms mined out of the surface or directly to a flat surface. We illustrate this by high-resolution in situ STM of straight, branched, and chiral alkanethiols on Au(111)-electrode surfaces. We discuss next LRET of two SAM immobilized multi-copper enzymes, nitrite reductase and laccase, mapped to single-molecule resolution by in situ STM and AFM. The voltammetry is exceedingly sensitive to the structure of the thiol-based SAM molecules, testifying to the crucial importance of SAM packing and Au-S binding, and of the SAM link to the protein. Some of the subtleties are illustrated simpler by similar size (5-6 nm) nanoparticles (NPs). Biomimetic NPs must possess a certain degree of electronic structure sophistication. At the molecular scale this requirement is met by NPs of the renownedmixed-valence Prussian Blue (PB) assembled on Au(111)-electrode surfaces via functionalized alkanethiols. PBNP SAMs show LRET comparable to metalloproteins. Alkanethiols with different terminal groups exhibit, further intriguing LRET differences, reflecting other subtleties. We discuss the molecular LRET mechanisms and the intrinsic conductivity of the PBNPs

Online Research Database In Technology

                       General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.  • Users may download and print one copy of any publication from the public portal for the purpose of private study or research. • You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal   If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.     Downloaded from orbit.dtu.dk on: Dec 16, 2017The Au-S bond and SAM-protein contact in long-range electron transfer of pure andbiomimetic metalloproteins via functionalized alkanethiol linkersChi, Qijin; Ford, Michael J.; Halder, Arnab; Hush, Noel S.; Reimers, Jeffrey R.; Ulstrup, Jens; Zhang,JingdongPublication date:2016Document VersionPublisher's PDF, also known as Version of recordLink back to DTU OrbitCitation (APA):Chi, Q., Ford, M. J., Halder, A., Hush, N. S., Reimers, J. R., Ulstrup, J., & Zhang, J. (2016). The Au-S bond andSAM-protein contact in long-range electron transfer of pure and biomimetic metalloproteins via functionalizedalkanethiol linkers. Abstract from 67th Annual Meeting of the International Society of Electrochemistry, TheHague, Netherlands.The Au-S bond and SAM-protein contact in long-range electron transfer of pure and biomimetic metalloproteins via functionalized alkanethiol linkers  Qijin Chi1, Michael J. Ford2, Arnab Halder1, Noel S. Hush3, Jeffrey R. Reimers2, 5, Jens Ulstrup1 and Jingdong Zhang1 1Department of Chemistry, Technical University of Denmark, DK-2800 Lyngby, Denmark 2School of Mathematic and Physical Sciences, The University of Technology of Sydney, Sydney, NSW 2007, Australia 3School of Chemistry F11, The University of Sydney, Sydney, NSW 2006, Australia 4School of Molecular Bioscience, The University of Sydney, Sydney, NSW 2006, Australia 5International Centre for Quantum and Molecular Structure, College of Sciences, Shanghai University, Shanghai 200444, China E-mail: ju@kemi.dtu.dk  Abstract: Interfacial electrochemical electron transfer (ET) of redox metalloproteins is long established1. For the proteins to retain full ET or enzyme activity, modification of the electrode surfaces, say gold surfaces by self-assembled molecular monolayers (SAMs) is nearly always needed, where functionalized alkanethiols have emerged as core linkers. We have studied molecular linking in the long-range ET (LRET) processes in detail using electrochemistry, in situ STM and AFM, and electronic structure computations2,3. A focus is the electronic structure of the Au-S link and the SAM packing. We have disentangled a wealth of data to identify the nature of the crucial Au-S contact, all suggesting prevalence of a Au(0)-thiyl radical unit. Molecular packing is further determined by the SAM molecular structure and involves binding either to Au-atoms mined out of the surface or directly to a flat surface. We illustrate this by high-resolution in situ STM of straight, branched, and chiral alkanethiols on Au(111)-electrode surfaces. We discuss next LRET of two SAM immobilized multi-copper enzymes, nitrite reductase and laccase, mapped to single-molecule resolution by in situ STM and AFM4,5. The voltammetry is exceedingly sensitive to the structure of the thiol-based SAM molecules, testifying to the crucial importance of SAM packing and Au-S binding, and of the SAM link to the protein. Some of the subtleties are illustrated simpler by similar size (5-6 nm) nanoparticles (NPs)6. Biomimetic NPs must possess a certain degree of electronic structure sophistication. At the molecular scale this requirement is met by NPs of the renowned mixed-valence Prussian Blue (PB) assembled on Au(111)-electrode surfaces via functionalized alkanethiols. PBNP SAMs show LRET comparable to metalloproteins. Alkanethiols with different terminal groups exhibit, further intriguing LRET differences, reflecting other subtleties. We discuss the molecular LRET mechanisms and the intrinsic conductivity of the PBNPs. .   References: [1] J. Zhang, A.M. Kuznetsov, I.G. Medvedev, Q. Chi, T. Albrecht, P.S. Jensen and J. Ulstrup, Chem.  Rev. 108 (2008) 2737-2791.   [2] J. Yan, R. Ouyang, P.S. Jensen, E. Ascic, D. Tanner, B. Mao, J. Zhang, C. Tang, N.S. Hush, J. Ulstrup  and J.R. Reimers, J. Am. Chem. Soc. 136 (2014) 17087-17094, and references there. [3]  J.R. Reimers, M.J. Ford, A. Halder, J. Ulstrup, and N.S. Hush, PNAS USA (2016) in press. [4] J. Zhang, Q. Chi, A.G. Hansen, P. S. Jensen, P. Salvatore and J. Ulstrup, FEBS Letters 586 (2012)  526-535, and references there. [5] V. Climent, J. Zhang, E.P. Friis, L.H. Østergaard and J. Ulstrup, J. Phys. Chem. C 116 (2012)1232- 1243. [6] N. Zhu, S. Han, S. Gan, J. Ulstrup and Q. Chi, Adv. Funct. Mat. 23 (2013) 5297-5306. 

The Au-S bond and SAM-protein contact in long-range electron transfer of pure and biomimetic metalloproteins via functionalized alkanethiol linkers

http://orbit.dtu.dk/ws/files/139269015/AbstractJens_Keynote_Abstract_ISE2016sent.pdf

The Au-S bond and SAM-protein contact in long-range electron transfer of pure and biomimetic metalloproteins via functionalized alkanethiol linkers

Abstract

Similar works

Full text

Available Versions

Online Research Database In Technology