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Published February 12, 2016 | public
Journal Article

Immobilization and electrochemical properties of ruthenium and iridium complexes on carbon electrodes

Abstract

We report the synthesis and surface immobilization of two new pyrene-appended molecular metal complexes: a ruthenium tris(bipyridyl) complex (1) and a bipyridyl complex of [Cp^*Ir] (2) (Cp^*  =  pentamethylcyclopentadienyl). X-ray photoelectron spectroscopy confirmed successful immobilization on high surface area carbon electrodes, with the expected elemental ratios for the desired compounds. Electrochemical data collected in acetonitrile solution revealed a reversible reduction of 1 near  −1.4 V, and reduction of 2 near  −0.75 V. The noncovalent immobilization, driven by association of the appended pyrene groups with the surface, was sufficiently stable to enable studies of the molecular electrochemistry. Electroactive surface coverage of 1 was diminished by only 27% over three hours soaking in electrolyte solution as measured by cyclic voltammetry. The electrochemical response of 2 resembled its soluble analogues, and suggested that ligand exchange occurred on the surface. Together, the results demonstrate that noncovalent immobilization routes are suitable for obtaining fundamental understanding of immobilized metal complexes and their reductive electrochemical properties.

Additional Information

© 2016 IOP Publishing Ltd. Received 10 June 2015, revised 30 July 2015. Accepted for publication 11 August 2015. Published 12 February 2016. This research was carried out in part at the Molecular materials Research Center of the Beckman Institute at Caltech. The research was supported by the Resnick Sustainability Institute at Caltech (Postdoctoral Fellowship to J D B) and the NSF CCI Solar Fuels Program (CHE-1305124 and a CCI Postdoctoral Fellowship to J D B). The x-ray photoelectron spectroscopy was supported by a contract with the California Energy Commission (500-11-023).

Additional details

Created:
August 20, 2023
Modified:
October 17, 2023