Felix Faschinger

A Bifunctional Electrocatalyst for Oxygen Evolution and Oxygen Reduction Reactions in Water

Abstract Oxygen reduction and water oxidation are two key processes in fuel cell applications. The oxidation of water to dioxygen is a 4 H+/4 e− process, while oxygen can be fully reduced to water by a 4 e−/4 H+ process or partially reduced by fewer electrons to reactive oxygen species such as H2O2 and O2 −. We demonstrate that a novel manganese corrole complex behaves as a bifunctional catalyst for both the electrocatalytic generation of dioxygen as well as the reduction of dioxygen in aqueous media. Furthermore, our combined kinetic, spectroscopic, and electrochemical study of manganese corroles adsorbed on different electrode materials (down to a submolecular level) reveals mechanistic details of the oxygen evolution and reduction processes.

The evolution of corrole synthesis — from simple one-pot strategies to sophisticated ABC-corroles

This review highlights synthesis procedures to obtain A3-, cis- and trans- A2B- and ABC-corroles. Synthesis methods from the early beginning of “corrole chemistry”, acid-catalyzed condensation methods of various building blocks (pyrrole, aldehyde, dipyrromethane, dipyrromethane-carbinol, and dipyrromethane-dicarbinol etc.), possible side reaction during Bronsted acid catalyzed reactions (scrambling), one-pot synthesis of corroles, and post-macrocyclization modification reactions of meso-substituted A3-corroles are discussed.

Detailed Evidence for an Unparalleled Interaction Mode between Calmodulin and Orai Proteins

Calmodulin (CaM) binds most of its targets by wrapping around an amphipathic α-helix. The N-terminus of Orai proteins contains a conserved CaM-binding segment but the binding mechanism has been only partially characterized. Here, microscale thermophoresis (MST), surface plasmon resonance (SPR), and atomic force microscopy (AFM) were employed to study the binding equilibria, the kinetics, and the single-molecule interaction forces involved in the binding of CaM to the conserved helical segments of Orai1 and Orai3. The results consistently indicated stepwise binding of two separate target peptides to the two lobes of CaM. An unparalleled high affinity was found when two Orai peptides were dimerized or immobilized at high lateral density, thereby mimicking the close proximity of the N-termini in native Orai oligomers. The analogous experiments with smooth muscle myosin light chain kinase (smMLCK) showed only the expected 1:1 binding, confirming the validity of our methods.

Stable Europium(III) Complexes with Short Linkers for Site-Specific Labeling of Biomolecules

Abstract In this study, two new terpyridine‐based EuIII complexes were synthesized, the structures of which were optimized for luminescence resonance energy‐transfer (LRET) experiments. The complexes showed high quantum yields (32 %); a single long lifetime (1.25 ms), which was not influenced by coupling to protein; very high stability in the presence of chelators such as ethylenediamine‐N,N,N′,N′‐tetraacetate and ethylene glycol‐bis(2‐aminoethylether)‐N,N,N′,N′‐tetraacetic acid; and no interaction with cofactors such as adenosine triphosphate and guanosine triphosphate. A special feature is the short length of the linker between the EuIII ion and the maleimide or hydrazide function, which allows for site‐specific coupling of cysteine mutants or unnatural keto amino acids. As a consequence, the new complexes appear particularly suited for accurate distance measurements in biomolecules by LRET.