Structural and magnetic effects of successive protonations of oxo bridges in high-valent manganese dimers

Journal Article · Wed Dec 14 04:00:00 EST 1994 · Journal of the American Chemical Society; (United States)

DOI:https://doi.org/10.1021/ja00104a014· OSTI ID:6631915

Baldwin, M J; Stemmler, T L; Riggs-Gelasco, P J; Penner-Hahn, J E; Pecoraro, V L ^[1]; Kirk, M L ^[2]

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1. Univ. of Michigan, Ann Arbor, MI (United States)
2. Univ. of New Mexico, Albuquerque, NM (United States)

The preparation and characterization of [Mn[sup IV] (salpn) ([mu]-OH)][sub 2],(CF[sub 3]SO[sub 3])[sub 2], 1H[sub 2](CF[sub 3]SO[sub 3])[sub 2], the first bis(hydroxo)-bridged manganese(IV) dimer, is reported. Along with the previously reported complexes [Mn[sup IV] (salpn)([mu]-O)][sub 2], 1, and [Mn[sup IV] (salpn)][sub 2]([mu]-O) ([mu]-OH) (CF[sub 3]SO[sub 3]), this provides the first series of oxo-bridged manganese complexes which are isolated in three different protonation states of the bridges without a change in the other ligands or the manganese oxidation state. The effects of oxo bridge protonations on the structure and magnetism of these Mn(IV) dimers are studied using this series of complexes. Each successive protonation of the oxo bridges results in a 2200 cm[sup [minus]1] decrease in the energy of the lowest energy (presumably, phenolate-to-manganese) charge transfer transition, a lengthening of the Mn-Mn distance, and a dramatic decrease in the antiferromagnetic coupling, without a significant change in the manganese X-ray absorption edge energies. The edge energies are all within 0.3 eV of each other, at ca. 6553 eV. The extended X-ray absorption fine structure spectra indicate that the Mn-Mn distance increases from 2.73 angstroms for 1 to 2.83 and 2.93 angstroms with successive protonations. 34 refs., 5 figs., 3 tabs.

• OSTI ID: 6631915
• Journal Information: Journal of the American Chemical Society; (United States), Journal Name: Journal of the American Chemical Society; (United States) Vol. 116:25; ISSN JACSAT; ISSN 0002-7863
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
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Photobiological
& Thermochemical Conversion-- (1980-)
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400102 -- Chemical & Spectral Procedures
400201 -- Chemical & Physicochemical Properties
ABSORPTION SPECTROSCOPY
CHEMICAL REACTIONS
COMPILED DATA
COMPLEXES
DATA
INFORMATION
MAGNETIC PROPERTIES
MANGANESE COMPLEXES
MATHEMATICAL MODELS
NUMERICAL DATA
PHOTOCHEMICAL REACTIONS
PHOTOSYNTHESIS
PHYSICAL PROPERTIES
REDOX REACTIONS
SPECTROSCOPY
SYNTHESIS
TRANSITION ELEMENT COMPLEXES
X-RAY SPECTROSCOPY