Fe(II) oxidation Project

Molecular Orbital Printouts

This page is part of a collaborative project on Fe(II) oxidation. These spartan molecular orbital printouts are under review, and are not critically evaluated sources of data. Please don't use these results unless you verify their correctness. Part of the printouts are from PM3 calculations and part are from DFT calculations at the LSDA/VWN level. Many of the PM3 results suffer from considerable spin contamination are are meant only as qualitative guides to the differences amoung the listed complexes. The PM3 results are from calculations where the Fe-O bond lengths were constrained to either 2.00 (experimental for Fe(III) or 2.13Ang (experimental for Fe(II)). The DFT results are unconstrained geometry optimizations.

CO3-O2nosym and the structure
CO32-_dft and the structure
Fe_III_CO3_constrained200PM3 and the structure
Fe_III_CO3_constrainedPM3 and the structure
Fe_III_OH2_Ci_2.13PM3 and the structure
Fe_III_OH2_Ci_200PM3 and the structure
The cis bis hydroxo Fe(III) complex rearranged to a very distorted trans structure at the PM3 level.
Fe_III_OH_c200PM3 and the structure
Fe_III_OH_constrainedPM3 and the structure
Fe_III_cOHCO3_c200PM3 and the structure
The cis hydroxo carbonato Fe(III) complex dissociated to give carbon dioxide at the dft level.
Fe_III_hexaaquo_200PM3 and the structure
Fe_III_hexaaquo_213PM3 and the structure
Fe_III_hexaaquo_dft new 4/7i and the structure
Fe_III_tOHCO3_c200PM3 and the structure
Fe_II_CO3_C2_constrainedPM3 and the structure
Fe_II_CO3_constrainedPM3 and the structure
Fe_II_OH2_C1_PM3 and the structure
Fe_II_OH2_Ci_PM3 and the structure
Fe_II_OH_C2v_constrainedPM3 and the structure
Fe_II_OH_HCO3_c213PM3 new 4/4 and the structure
This next one started out as the carbonato complex, but during the dft minimization converted to the trans-hydroxy bicarbonato complex. I then went back and did the PM3 calculation, as listed above. At the PM3 level the carbonato complex is more stable. But, apparently at the dft level the hydroxo bicarbonato complex is more stable: Fe_II_OH_HCO3_dft new 4/4 and the structure
Fe_II_OH_dft and the structure
Fe_II_cOHCO3_constrainedPM3 and the structure
Fe_II_hexaaquo_Cs_PM3 and the structure
Fe_II_hexaaquo_dft and the structure
Fe_II_tOHCO3_constrainedPM3 and the structure
The trans hydroxo carbonato Fe(II) complex dissociated to give carbon dioxide at the dft level.
Fe_II_transOH2_symdft and the structure
Fe_cisOHCO3_dft and the structure
H2O_dft and the structure
O2-_dft and the structure
O2_dft and the structure
OH-_dft and the structure

Bicarbonato Complexes, with protonated oxygen coordinated

Calculations on bicarbonato species where the uncoordinated oxygen was protonated dissoicated to give carbon dioxide. However, bicarbonato complexes where the protonated oxygen is also coordinated to the metal are stable, and have low energies. The example of Fe_II_OH_HCO3_dft complex from above showed this to be true. Here are some other similar complexes:

Fe_III_cOH_HCO3_c200PM3 and the structure
Fe_III_ccOH2_HCO3_c200PM3 and the structure
Fe_III_ctOH2_HCO3_c200PM3 and the structure
Fe_III_tOH_HCO3_c200PM3 and the structure
Fe_II_OH_HCO3_cPM3 and the structure
Fe_II_aOH_HCO3_c213PM3 and the structure
Fe_II_ccOH2_HCO3_c213PM3 and the structure
Fe_II_tOH_HCO3_c213PM3 and the structure

For more information or corrections contact Tom Shattuck at twshattu@Colby.edu.


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Last modified: 4/7/97 8:41 pm EST