Expanding the Redox Range of Surface-Immobilized Metallocomplexes Using Molecular Interfaces

Brian L. Wadsworth, Diana Khusnutdinova, Jennifer M. Urbine, Ahlea S. Reyes, Gary F. Moore

Research output: Contribution to journalArticle

1 Scopus citations

Abstract

Rationally designed material interfaces offer opportunities to control matter and energy across multiple length scales, yet remain challenging to synthetically prepare. Inspired by nature, where amino acid residues and soft-material coordination environments regulate the midpoint potentials of metals in proteins, thin-film polymeric coatings have been developed to assemble molecular components, including catalysts, onto solid-state (semi)conducting surfaces. In this report, we describe the immobilization of metalloporphyrins onto transparent conductive oxide supports using either direct grafting to the oxide surface or coordination to an initially applied thin-film polypyridyl coating. The composite materials enable direct measurements of electrochemical and optical properties associated with the surface-immobilized components. Despite the similarity of the core cobalt porphyrin units used in assembling these hybrid architectures, the redox potentials assigned to the CoIII/II relays span a 350 mV range across the distinct constructs. This range in redox potential is extended to 960 mV when including comparisons to constructs utilizing polymer-immobilized cobaloxime catalysts in place of cobalt porphyrins, where reduction of the cobaloximes requires significantly more-negative bias potentials. This work illustrates the use of soft-material interfaces for assembling molecular-modified electrodes where the nanoscale connectivity of the surface coatings determines the electrochemical properties of the macroscopic assemblies.

Original languageEnglish (US)
Pages (from-to)3903-3911
Number of pages9
JournalACS Applied Materials and Interfaces
Volume12
Issue number3
DOIs
StatePublished - Jan 22 2020

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Keywords

  • coordinating polymers
  • molecular interfaces
  • optoelectronics
  • porphyrins
  • surface immobilization

ASJC Scopus subject areas

  • Materials Science(all)

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