Non-innocent ligands were indirectly defined in 1960's by Jørgensen when he stated that "Ligands are innocent when they allow oxidation states of the central atoms to be defined." While his definition does not directly define a non-innocent ligand he further described "suspect" ligands in which NO is a classic example. Developing this definition and understanding what it means for a ligand to be non-innocent is the overarching topic of the Ringenberg group. Besides further studying this phenomenon we are also keenly interesting in developing novel electrocatalysts containing non-innocent ligands.
Metallocene Based Ligands
Ligands with 1,1'‐bis(donor)ferrocene motif are capable of a wide range of binding modes, including the chelation mode in which there is a Fe‐M interaction (κ3‐D,Fe‐D), that has a dative Fe→TM bond (TM = transition metal). This phenomenon is one of the current topics under investigation in our group. The goal of this research is to show how this interaction can be used to stablize open coordination sites in transition metal complexes. We do this by characterizing the Fe→TM dative bond using physical, computational, and spectroscopic techniques.
Combining electrochemistry and spectroscopy allows us to study different electronic stuctures in situ. This allows for the study of short lived or quasi-stable states. We are also able to perform low temperature(-50 C) absorption and vibrational spectroscopy, which is especially useful for studying metal-carbonyls.
Electronic Stuctures and Calculations
Density Functional Theory is used quite often by our group to help explain the electronic stuctures of our complexes. Our approach is that calcuations should complement the spectroscopy and vise versa. This is important because it allows us to have a higher level of trust in the calcuations and can help to explain the spectroscopy.