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Masai H, Terao J. Synthetic Methodologies for Structurally Defined Linked-[n]Rotaxanes with Permethylated Cyclodextrins: Platform for Functionalized Molecular Electronics. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2019. [DOI: 10.1246/bcsj.20180349] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- Hiroshi Masai
- Department of Basic Science, Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo 168-8902, Japan
| | - Jun Terao
- Department of Basic Science, Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo 168-8902, Japan
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Al-Owaedi OA, Bock S, Milan DC, Oerthel MC, Inkpen MS, Yufit DS, Sobolev AN, Long NJ, Albrecht T, Higgins SJ, Bryce MR, Nichols RJ, Lambert CJ, Low PJ. Insulated molecular wires: inhibiting orthogonal contacts in metal complex based molecular junctions. NANOSCALE 2017; 9:9902-9912. [PMID: 28678257 DOI: 10.1039/c7nr01829k] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Metal complexes are receiving increased attention as molecular wires in fundamental studies of the transport properties of metal|molecule|metal junctions. In this context we report the single-molecule conductance of a systematic series of d8 square-planar platinum(ii) trans-bis(alkynyl) complexes with terminal trimethylsilylethynyl (C[triple bond, length as m-dash]CSiMe3) contacting groups, e.g. trans-Pt{C[triple bond, length as m-dash]CC6H4C[triple bond, length as m-dash]CSiMe3}2(PR3)2 (R = Ph or Et), using a combination of scanning tunneling microscopy (STM) experiments in solution and theoretical calculations using density functional theory and non-equilibrium Green's function formalism. The measured conductance values of the complexes (ca. 3-5 × 10-5G0) are commensurate with similarly structured all-organic oligo(phenylene ethynylene) and oligo(yne) compounds. Based on conductance and break-off distance data, we demonstrate that a PPh3 supporting ligand in the platinum complexes can provide an alternative contact point for the STM tip in the molecular junctions, orthogonal to the terminal C[triple bond, length as m-dash]CSiMe3 group. The attachment of hexyloxy side chains to the diethynylbenzene ligands, e.g. trans-Pt{C[triple bond, length as m-dash]CC6H2(Ohex)2C[triple bond, length as m-dash]CSiMe3}2(PPh3)2 (Ohex = OC6H13), hinders contact of the STM tip to the PPh3 groups and effectively insulates the molecule, allowing the conductance through the full length of the backbone to be reliably measured. The use of trialkylphosphine (PEt3), rather than triarylphosphine (PPh3), ancillary ligands at platinum also eliminates these orthogonal contacts. These results have significant implications for the future design of organometallic complexes for studies in molecular junctions.
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Affiliation(s)
- Oday A Al-Owaedi
- Department of Physics, University of Lancaster, Lancaster, LA1 4YB, UK. and Department of Laser Physics, Women Faculty of Science, Babylon University, Hilla, Iraq
| | - Sören Bock
- School of Molecular Sciences, University of Western Australia, 35 Stirling Highway, Perth 6009, Australia
| | - David C Milan
- Department of Chemistry, University of Liverpool, Crown St, Liverpool, L69 7ZD, UK
| | | | - Michael S Inkpen
- Department of Chemistry, Imperial College London, London SW7 2AZ, UK
| | - Dmitry S Yufit
- Department of Chemistry, Durham University, South Rd, Durham, DH1 3LE, UK
| | - Alexandre N Sobolev
- School of Molecular Sciences, University of Western Australia, 35 Stirling Highway, Perth 6009, Australia and Centre for Microscopy Characterization and Analysis, University of Western Australia, 35 Stirling Highway, Perth 6009, Australia
| | - Nicholas J Long
- Department of Chemistry, Imperial College London, London SW7 2AZ, UK
| | - Tim Albrecht
- Department of Chemistry, Imperial College London, London SW7 2AZ, UK
| | - Simon J Higgins
- Department of Chemistry, University of Liverpool, Crown St, Liverpool, L69 7ZD, UK
| | - Martin R Bryce
- Department of Chemistry, Durham University, South Rd, Durham, DH1 3LE, UK
| | - Richard J Nichols
- Department of Chemistry, University of Liverpool, Crown St, Liverpool, L69 7ZD, UK
| | - Colin J Lambert
- Department of Physics, University of Lancaster, Lancaster, LA1 4YB, UK.
| | - Paul J Low
- School of Molecular Sciences, University of Western Australia, 35 Stirling Highway, Perth 6009, Australia
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