L-edge X-ray absorption and X-ray magnetic circular dichroism of oxygen-bridged dinuclear iron complexes

Journal Article · Wed Mar 08 04:00:00 EST 1995 · Journal of the American Chemical Society; (United States)

DOI:https://doi.org/10.1021/ja00114a014· OSTI ID:6492638

Peng, G ^[1]; Elp, J van ^[2]; Jang, H; Que, L Jr ^[3]; Armstrong, W H ^[4]; Cramer, S P ^[5]

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1. Univ. of California, Davis, CA (United States)
2. Lawrence Berkeley Lab., CA (United States)
3. Univ. of Minnesota, Minneapolis, MN (United States)
4. Boston College, MA (United States)
5. Univ. of California, Davis, CA (United States) Lawrence Berkeley Lab., CA (United States)

Iron L-edge X-ray absorption and X-ray magnetic circular dichroism (XMCD) spectroscopy have been used to study the electronic structure of dinuclear iron-oxo complexes with different types of magnetic and electronic interactions between the iron sites. Trapped-valence systems exhibit L-edges with clear multiplet structure. The L-edges of trapped-valence Fe[sup II]Fe[sup III] complexes such as [Fe[sup III,II]2(salmp)[sub 2]][sup [minus]] and [Fe[sub 2][sup III,II](bpmp)([mu]-O[sub 2]CC[sub 2]H[sub 5])[sub 2]][sup 2[center dot]] can be interpreted as the sum of distinct Fe(II) and Fe(III) component spectra. Furthermore, an atomic multiplet theory including adjustable ligand field splittings can successfully simulate the Fe(II) and Fe(III) X-ray absorption. Reasonable ligand field parameters are obtained by optimizing the correspondence between calculated and experimental spectra. The XMCD for the [Fe[sub 2][sup III,II](bpmp)([mu]-O[sub 2]CC[sub 2]H[sub 5])[sub 2]][sup 2] complex is also reported; it exhibits an interesting magnetic field dependence that reflects the weak magnetic coupling between Fe(II) and Fe(III) ions. In contrast with the trapped-valence complex spectra, the L-edge spectrum for the electronically delocalized complex, [Fe[sub 2](Me[sub 3]tacn)[sub 2]-([mu]-OH)[sub 3]](BPh[sub 4])[sub 2]-2MeOH, exhibits a broad L-edge spectrum with poorly resolved multiplet structure. 35 refs., 4 figs.

• OSTI ID: 6492638
• Journal Information: Journal of the American Chemical Society; (United States), Journal Name: Journal of the American Chemical Society; (United States) Vol. 117:9; ISSN JACSAT; ISSN 0002-7863
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400102 -- Chemical & Spectral Procedures
400201* -- Chemical & Physicochemical Properties
ABSORPTION SPECTRA
ABSORPTION SPECTROSCOPY
CHEMICAL PREPARATION
COMPLEXES
DICHROISM
ELECTRONIC STRUCTURE
INTERACTIONS
IRON COMPLEXES
MAGNETIC CIRCULAR DICHROISM
SPECTRA
SPECTROSCOPY
STRUCTURAL CHEMICAL ANALYSIS
SYNTHESIS
TRANSITION ELEMENT COMPLEXES
VALENCE
X-RAY SPECTROSCOPY