Local 3d Electronic Structures of Co-Based Complexes with Medicinal Molecules Probed by Soft X-Ray Absorption

TL;DR

This study investigates the local 3d electronic structures of Co-based multinuclear complexes with medicinal molecules using soft X-ray absorption spectroscopy, revealing their ionic states and spin configurations.

Contribution

It provides detailed spectroscopic analysis and simulation confirming the ionic and spin states of cobalt in specific medicinal complexes, advancing understanding of their electronic structures.

Findings

Co ions are in low-spin Co3+ state in one complex

Co ions are in high-spin Co2+ state in another complex

Spectral simulations match experimental XAS spectra

Abstract

We have examined the local 3d electronic structures of Co-Au multinuclear complexes with the medicinal molecules D-penicillaminate (D-pen) [Co{Au(PPh3)(D-pen)}2]ClO4 and [Co3{Au3(tdme)(D-pen)3}2] by Co L_2,3-edge soft X-ray absorption (XAS) spectroscopy, where PPh3 denotes triphenylphosphine and tdme stands for 1,1,1-tris[(diphenylphosphino)methyl]ethane. The Co L_2,3-edge XAS spectra indicate the localized ionic 3d electronic states in both materials. The experimental spectra are well explained by spectral simulation for a localized Co ion under ligand fields with the full multiplet theory, which verifies that the ions are in the low-spin Co3+ state in the former compound and in the high-spin Co2+ state in the latter.