Fe and Se extended X-ray absorption fine structure (EXAFS) data have been used to determine the structures of the Fe2E2 (E = S, Se) cores of the following compounds: [Fe2E2(CO)6]z (z = 0, 2-), Fe2(μ-ER)2(CO)6 (R = alkyl), [Fe2E2(NO)4]2-, and Fe2(μ-ER)2(NO)4. For the carbonyl compounds, the Fe EXAFS results indicate that the Fe-C, Fe-Fe, and Fe-E distances change little upon conversion of Fe2(E2)(CO)6 to [Fe2E2(CO)6]2- and Fe2(μ-ER)2(CO)6. The Se EXAFS results are consistent with the Fe EXAFS data, also showing that the two-electron reduction of Fe2(Se2)(CO)6 results in breaking of the Se-Se bond. The Fe and Se EXAFS of the related nitrosyls [Fe2E2(NO)4]2- and Fe2(μ-ER)2(NO)4 confirm that the Fe2E2 cores of these complexes are similar. All of the EXAFS results are consistent with the LUMO of Fe2(E2)(CO)6, being mainly E-E antibonding in character.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Inorganic Chemistry