Correlations of axial ligand field strength and zero-field splittings in the carbon-13 NMR spectra of five- and six-coordinate high-spin iron(III) porphyrin complexes

1983 ◽  
Vol 22 (1) ◽  
pp. 66-71 ◽  
Author(s):  
Harold M. Goff ◽  
Eric T. Shimomura ◽  
Martin A. Phillippi
Keyword(s):  
Field Strength ◽  
High Spin ◽  
Nmr Spectra ◽  
Axial Ligand ◽  
Ligand Field ◽  
Zero Field ◽  
High Spin Iron

scholarly journals Tuning ligand field strength with pendent Lewis acids: access to high spin iron hydrides

2019 ◽  
Vol 10 (21) ◽  
pp. 5539-5545 ◽  
Author(s):  
John J. Kiernicki ◽  
James P. Shanahan ◽  
Matthias Zeller ◽  
Nathaniel K. Szymczak
Keyword(s):  
Field Strength ◽  
High Spin ◽  
Lewis Acids ◽  
Ligand Field ◽  
Acid Base ◽  
Biologically Relevant ◽  
High Spin Iron

Pendent borane Lewis acids provide an avenue for changing a ligand's field strength through acid/base interactions; this strategy was highlighted within a series of biologically-relevant high spin iron hydrides.

Pseudohalogenido complexes of iron-2,2′-bidipyrrins

2012 ◽  
Vol 16 (05n06) ◽  
pp. 641-650 ◽  
Author(s):  
Martin Bröring ◽  
Silke Köhler ◽  
Clemens Pietzonka
Keyword(s):  
High Spin ◽  
Spin State ◽  
Elevated Temperatures ◽  
High Spin State ◽  
Spectroscopic Studies ◽  
Axial Ligand ◽  
Ligand Field ◽  
Central Metal ◽  
Exchange Reactions ◽  
Dichloromethane Solution

The chlorido iron(III) complex of octaethyl-2,2′-bidipyrrin has been transformed to a series of pseudohalide complexes by ligand exchange reactions with azide, cyanate, thiocyanate and selenocyanate anions. All new complexes show the expected N-coordination of the axial ligand to the iron(III) center. In the solid state, all four species display an intermediate spin (S = 3/2) ground state, with a gradual increase of a high spin (S = 5/2) contribution at elevated temperatures for the members with the smallest ligand field strengths, i.e. the cyanato and the azido derivatives. In solution, proton NMR, and in particular IR spectroscopic studies support the interpretation of a high-spin state at ambient temperature throughout the series. The dependency of the spin state on the crystalline or dissolved state thus resembles that found for a similar series of halide derivatives before. In dichloromethane solution, the thiocyanato and selenocyanato complexes are very sensitive to aerial oxidation, forming oxacorrole and thiacorrole complexes as the only isolated products. These complexes show a S = 3/2 spin state in the solid as well as in solution, and their structural analyses prove the expected strong π-binding of the linear pseudohalide ion to the iron(III) central metal.

Ligand field transitions and the origin of zero field splitting in [PPh4][FeCl4] and [NEt4][Fe(SR)4] (R = 2,3,5,6-Me4C6H): a model for the high-spin Fe(III) site in rubredoxin

1988 ◽  
Vol 110 (18) ◽  
pp. 6241-6243 ◽  
Author(s):  
Joseph C. Deaton ◽  
Matthew S. Gebhard ◽  
Stephen A. Koch ◽  
Michelle. Millar ◽  
Edward I. Solomon
Keyword(s):  
High Spin ◽  
Ligand Field ◽  
Zero Field ◽  
Zero Field Splitting ◽  
Field Splitting

Analysis of the EPR spectra of transferrin: the importance of a zero-field-splitting distribution and 4th-order terms

2019 ◽  
Vol 21 (31) ◽  
pp. 16937-16948 ◽  
Author(s):  
Mykhailo Azarkh ◽  
Peter Gast ◽  
Anne B. Mason ◽  
Edgar J. J. Groenen ◽  
Guinevere Mathies
Keyword(s):  
High Spin ◽  
Biological Systems ◽  
New Method ◽  
Epr Spectra ◽  
Zero Field ◽  
Zero Field Splitting ◽  
Field Splitting ◽  
Effective Use ◽  
High Spin Iron

A new method is implemented to extract the distribution of zero-field-splitting parameters from the EPR spectra of transferrin. This promotes the effective use of multi-frequency EPR to characterize high-spin iron sites in biological systems.

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