Iron L₃-edge energy shifts for the full range of possible 3d occupations within the same oxidation state of iron halides

Abstract

Oxidation states are integer in number but dn configurations of transition metal centers vary continuously in polar bonds. We quantify the shifts of the iron L3 excitation energy, within the...

Direct spectroscopic evidence for the high-spin state of dioxidomanganese(v)

“…13 From the median L 3 excitation energy of 642.6 ± 0.2 eV, also shown in Fig. 1(a) as a dashed black line, we can deduce the oxidation state 28 of the manganese center in [OMnO] + to be +5 in agreement with the earlier report, 13 cf . ESI,† Fig.…”

Electronic Structure of the Complete Series of Gas-Phase Manganese Acetylacetonates by X-ray Absorption Spectroscopy

“…The shift toward higher excitation energy could be induced by a reduced fractional 3d occupation in Mn II (acac) 2 still representing the same oxidation state of +2. 75 However, in both cases the X-ray absorption spectrum at the Mn L 2,3 edges could reasonably well be reproduced by CF simulations only and DFT calculations give the same Mulliken spin population 63 indicating the same or at least very similar 3d occupation in both cases. It previously has been shown that the excitation energy systematically decreases within one oxidation state when decreasing the average coordination of the metal center.…”

“…There is a striking difference in the L 3 excitation energy of 0.8 eV for oxidation state +2 when comparing neutral Mn II (acac) 2 and cationic Mn II (acac) 1 + . The shift toward higher excitation energy could be induced by a reduced fractional 3d occupation in Mn II (acac) 2 still representing the same oxidation state of +2 . However, in both cases the X-ray absorption spectrum at the Mn L 2,3 edges could reasonably well be reproduced by CF simulations only and DFT calculations give the same Mulliken spin population indicating the same or at least very similar 3d occupation in both cases.…”

“…86 Furthermore, we extracted oxidation states from L 3 median excitation energy shifts for both cationic and neutral Mn(acac) n 0,+ . In the case of Mn(acac) n 0,+ in the same oxidation state +2, we were able to disentangle the effects of varying 3d occupation 75 and coordination. 76 We show that this is a sizable effect of about 40−50% of the expected shift in L 3 excitation energy per oxidation state 66,71 and may be considered by spectroscopists employing L-edge shifts to determine oxidation states.…”

Exposing the Oxygen‐Centered Radical Character of the Tetraoxido Ruthenium(VIII) Cation [RuO4]+

“…Furthermore, the ruthenium M 3 excitation energy median of [RuO 4 H] + , included in Figure 3, is 466.7 � 0.3 eV, which matches the ruthenium M 3 edge median of [RuO 4 ] + of 466.3 � 0.3 eV within the error bars. Here, the 0.35 eV difference between [RuO 4 ] + and [RuO 4 H] + ruthenium M 3 edge median is considered to be in the range of chemical shifts observed at the L 3 edge median within a same oxidation state of iron with halogen ligands of different electronegativity, [50] as should also be the case for oxido and hydroxido ligands. [50] Hence, the ruthenium M 3 edge median of [RuO 4 H] + is consistent with the ruthenium center in the same oxidation state of + 8 as in [RuO 4 ] + , and, therefore, with the predicted structure of [Ru(O) 3 (OH)] + , since hydrogenation adds an electron to the oxygen-centered SOMO of [RuO 4 ] + , with only little metal character, but does not induce a chemical shift at the ruthenium M 3 edge.…”