Spin-state effects on the outer core-level multiplet structures for high-spin Mn molecular clusters

Abstract

Oxo-bridged manganese polynuclear complexes have applications in a variety of technologies, such as single-molecule nanomagnets, catalysis, and photosynthetic redox chemistry. X-ray photoemission spectroscopy was used to study the Mn 3p, 3s, and valence band electronic behavior as a function of Mn cluster structural properties, where the cluster size and nuclearity are systematically varied. Results show a chemical shift of the Mn 3p3/2,1/2 spin–orbit pair related to the cluster size and nuclearity. In addition, the Mn 3s S7 and S5 final state multiplet components shift since they involve the binding energy of a ligand valence electron. In addition, the branching ratio of the S7:S5 states is related to the 3s–3d electron correlation. Specifically, in the S7 state, the remaining 3s electron is well correlated with 3d electrons of parallel spin, while in the S5 state, the two spins are antiparallel. Changes in this electron correlation are clearly observed in the S7:S5 branching ratio as a function of cluster size and ligand electronegativity.