Electronic Structure of Anilinopyridinate-Supported Ru25+ Paddlewheel Compounds

TitleElectronic Structure of Anilinopyridinate-Supported Ru25+ Paddlewheel Compounds
Publication TypeJournal Article
Year of Publication2017
AuthorsCorcos AR, Roy MD, Killian MM, Dillon S, Brunold TC, Berry JF
JournalInorganic Chemistry
Volume56
Start Page14662
Date Published11/2017
Abstract

The electronic structures of the diruthenium compounds Ru2(ap)4Cl (1, ap = 2-anilinopyridinate) and Ru2(ap)4OTf (2) were investigated with UV–vis, resonance Raman, and magnetic circular dichroism (MCD) spectroscopies; SQUID magnetometry; and density functional theory (DFT) calculations. Both compounds have quartet spin ground states with large axial zero-field splitting of ∼60 cm–1 that is characteristic of Ru25+ compounds having a (π*, δ*)3 electron configuration and a Ru–Ru bond order of ∼2.5. Two major visible absorption features are observed at ∼770 and 430 nm in the electronic spectra, the assignments of which have previously been ambiguous. Both bands have significant charge-transfer character with some contributions from d → d transitions. MCD spectra were measured to enable the identification of d → d transitions that are not easily observable by UV–vis spectroscopy. In this way, we are able to identify bands due to δ → δ* and δ → π* transitions at ∼16 100 and 11 200–12 300 cm–1, respectively, the latter band being sensitive to the π-donating character of the axial ligand. The Ru–Ru stretches are coupled with pyridine rocking motions and give rise to observed resonance Raman peaks at ∼350 and 420 cm–1, respectively.

URLhttps://pubs.acs.org/doi/10.1021/acs.inorgchem.7b02557
DOI10.1021/acs.inorgchem.7b02557