RuII(α-diimine) or RuIII(α-diimine·–)? Structural, spectroscopic, and theoretical evidence for the stabilization of a prominent metal-to-Ligand charge- transfer excited-state configuration in the ground state

Grupp, A., Bubrin, M., Ehret, F., Zeng, Q., Hartl, F. ORCID: https://orcid.org/0000-0002-7013-5360, Kvapilová, H., Zálisˇ, S. and Kaim, W. (2013) RuII(α-diimine) or RuIII(α-diimine·–)? Structural, spectroscopic, and theoretical evidence for the stabilization of a prominent metal-to-Ligand charge- transfer excited-state configuration in the ground state. European Journal of Inorganic Chemistry, 2014 (1). pp. 110-119. ISSN 1434-1948 doi: 10.1002/ejic.201301206

Abstract/Summary

The new compounds [Ru(R-DAB)(acac)2] (R-DAB = 1,4-diorganyl- 1,4-diazabuta-1,3-diene; R = tert-butyl, 4-methoxyphenyl, 2,6-dimethylphenyl; acac– = 2,4-pentanedionate) exhibit intrachelate ring bond lengths 1.297<d(CN)<1.344 Å and 1.382<d(CC)<1.425 Å, which suggest a RuIII(R-DAB·–) oxidation state formulation. This notion is confirmed by the negligible solvatochromism of the intense (ε ≈ 104 M–1cm–1) charge-transfer absorption band in the visible region and by DFT calculations. Oxidation of the compounds occurs mainly at the R-DAB·– radical ligand to produce UV/Vis/NIR and electron paramagnetic resonance (EPR) spectroelectrochemically detectable RuIII species, whereas the reduction proceeds less reversibly and yields predominantly (R-DAB)-ligand-based spin for the 4-methoxyphenyl derivative, measured at low temperature. The results are discussed with respect to metal-to-ligand chargetransfer (MLCT) excited states of conventional (α-diimine)- ruthenium(II) complexes and in view of other (α-diimine)- metal complexes with ambiguous oxidation-state assignments.

Item Type	Article
URI	https://reading-clone.eprints-hosting.org/id/eprint/35678
Item Type	Article
Refereed	Yes
Divisions	Interdisciplinary centres and themes > Chemical Analysis Facility (CAF) Life Sciences > School of Chemistry, Food and Pharmacy > Department of Chemistry
Publisher	Wiley-Blackwell
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