Metal ion cofactors within active sites are essential components for many proteins and have been directly linked to function. Many active sites contain a mixture of metal ions that function cooperatively to perform efficient and selective chemical transformations. The range of systems that utilizes these types of motifs range from O2 activating enzymes (e.g., Fe, Mn ribonucleotide reductase) to H2O oxidation catalyst found within photosynthesis. An additional key to regulating the function of metalloproteins are the unique microenvironments produced within the active site – these protein-induced microenvironments control a variety of properties, including the transfer of protons and electrons. Non-covalent interactions are the major forces that influence the microenviroments within protein active sites with hydrogen bonds (H–bonds) being the most dominant. However, there is still limited information on how H-bonds regulate function at a metal active site and what direct effect disruption of a H-bonding network has on protein dysfunction. This talk discusses the design and preparation of new synthetic heterometallic complexes that have structural components inspired by metalloproteins to fundamentally explore the role of H-bonding networks on function. By examining individual effects of the microenvironement in synthetics systems, we seek to shed light on the correlation of the local environments on function. To this end, new phosphorus containing tripodal ligands have been designed that have two key structural features: 1) they can coordinate one transition metal ion and at least one additional metal ion to form heterometallic systems and 2) they support the formation of intramolecular H-bonding networks proximal to the heterometallic core. Our approach examines the effects these structural components have on the function of small molecule activation. This talk will discuss first row transition metal (e.g. Fe, Mn) complexes with these ligand scaffolds and their reactivity with small molecules such as O2 and H2O will be described. These complexes were investigated utilizing various spectroscopic techniques including electronic absorbance spectroscopy, electronic paramagnetic resonance spectroscopy, and X-ray crystallography.

Bioinspired heterometallic systems for the activation of small molecules

251st National Meeting (2016)

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