Journal article
Quantifying Variations in Metal–Ligand Cooperative Binding Strength with Cyclic Voltammetry and Redox-Active Ligands
Inorganic chemistry, Vol.61(5), pp.2391-2401
02/07/2022
DOI: 10.1021/acs.inorgchem.1c03014
PMID: 35073063
Abstract
Metal–ligand cooperativity (MLC), a phenomenon that leverages reactive ligands to promote synergistic reactions with metals, has proven to be a powerful approach to achieving new and unprecedented chemical transformations with metal complexes. While many examples of MLC are known with a wide range of substrates, experimentally quantifying how ligand modifications affect MLC binding strength remains a challenge. Here we describe how cyclic voltammetry (CV) was used to quantify differences in MLC binding strength in a series of square-pyramidal Ru complexes. This method relies on using multifunctional ligands (those capable of both MLC and ligand-centered redox activity) as electrochemical reporters of MLC binding strength. The synthesis and characterization of Ru complexes with three different redox-active tetradentate ligands and two different ancillary phosphines (PPh3 and PCy3) are described. Titration CV studies conducted using BH3·THF with BH3 as a model MLC substrate allowed ΔG MLC to be quantified for each complex. Compared to our base triaryl ligand, increasing π conjugation in the backbone of the redox-active ligand enhanced MLC binding, whereas increasing π conjugation in the flanking groups decreased the MLC binding strength. Structures and spectroscopic data collected for the isolated MLC complexes are also described along with supporting DFT calculations that were used to illuminate electronic factors that likely account for the observed differences in the MLC binding strength. These results demonstrate how redox-active ligands and CV can be used to quantify subtle differences in the MLC binding strength across a series of structurally related complexes with different ligand modifications.
Details
- Title: Subtitle
- Quantifying Variations in Metal–Ligand Cooperative Binding Strength with Cyclic Voltammetry and Redox-Active Ligands
- Creators
- Kyle D Spielvogel - Department of ChemistryNathan C Stumme - Department of ChemistryTaylor V Fetrow - Department of ChemistryLi Wang - Department of ChemistryJavier A Luna - Department of ChemistryJason M Keith - Department of ChemistryScott K Shaw - Department of ChemistryScott R Daly - Department of Chemistry
- Resource Type
- Journal article
- Publication Details
- Inorganic chemistry, Vol.61(5), pp.2391-2401
- Publisher
- American Chemical Society
- DOI
- 10.1021/acs.inorgchem.1c03014
- PMID
- 35073063
- ISSN
- 0020-1669
- eISSN
- 1520-510X
- Grant note
- DOI: 10.13039/100000165, name: Division of Chemistry, award: 1650894, 1651381
- Language
- English
- Date published
- 02/07/2022
- Academic Unit
- Chemistry
- Record Identifier
- 9984216607102771
Metrics
7 Record Views