Heui Beom Lee

Reversible CO Binding at a Nickel Complex Supported by an Ambiphilic PBiP Tridentate Ligand A nickel chloride complex supported by a bismuthide diphosphine tridentate ligand reversibly binds CO to afford a nickel dicarbonyl species. Interestingly, this metal-ligand cooperative transformation occurs with chloride migration to the Bi center, highlighting the ambiphilicity of organobismuth donors. Chloride substitution with nitroxide weakens the Ni-Bi interaction and inhibits CO dissociation.

A Stable Radical within a N-Co-N Core A N–Co–N core is embedded within [Co(CNC)2]2+ (1) supported by two bis(4-methyl-2-(3-methyl-imidazolium)phenyl)amine (CNC) ligands. This species reveals a stable S = ½ state and its spin density is significantly delocalized within the N–Co–N core via parallel -bonding interaction. Interestingly, it displays unusual stability towards O2 and water proving the core is well protected.

The S2 state of the Oxygen Evolving Complex (OEC) of Photosystem II (PSII) shows high-spin (HS) and low-spin (LS) EPR signals attributed to distinct structures based on computation. Five-coordinate MnIII centers are proposed in these species but are absent in available spectroscopic model complexes. Herein, we report the synthesis, crystal structure, electrochemistry, SQUID magnetometry, and EPR spectroscopy of a MnIIIMnIV3O4 cuboidal complex featuring five-coordinate MnIII.