Spectroscopic identification of an Fe(III) center, not Fe(IV), in the crystalline Sc-O-Fe adduct derived from [Fe(IV)(O)(TMC)]²⁺.
The apparent Sc(3+) adduct of [Fe(IV)(O)(TMC)](2+) (1, TMC = 1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane) has been synthesized in amounts sufficient to allow its characterization by various spectroscopic techniques. Contrary to the earlier assignment of a +4 oxidation state for the iron center of 1, we establish that 1 has a high-spin iron(III) center based on its Mössbauer and EPR spectra and its quantitative reduction by 1 equiv of ferrocene to [Fe(II)(TMC)](2+). Thus, 1 is best described as a Sc(III)-O-Fe(III) complex, in agreement with previous DFT calculations (Swart, M. Chem. Commun. 2013, 49, 6650.). These results shed light on the interaction of Lewis acids with high-valent metal-oxo species.
†Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, Minnesota 55455, United States.
Jai
J
Prakash
†Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, Minnesota 55455, United States.
Gregory T
GT
Rohde
‡Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States.
Katlyn K
KK
Meier
†Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, Minnesota 55455, United States.
Andrew J
AJ
Jasniewski
†Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, Minnesota 55455, United States.
Katherine M
KM
Van Heuvelen
‡Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States.
Eckard
E
Münck
†Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, Minnesota 55455, United States.
Lawrence
L
Que
D004578:Electron Spin Resonance Spectroscopy; D005290:Ferric Compounds / Q000737:chemistry*; D007501:Iron / Q000737:chemistry*; D008958:Models, Molecular; D008968:Molecular Conformation; D010100:Oxygen / Q000737:chemistry*; D011789:Quantum Theory; D012538:Scandium / Q000737:chemistry*; D015204:Spectroscopy, Mossbauer
D005290:Ferric Compounds; C518394:peroxo(1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane)iron(III); D007501:Iron; D010100:Oxygen; D012538:Scandium