Binuclear Pentalene Iron Carbonyl Complexes (pages 2746–2755)
Huidong Li, Hao Feng, Weiguo Sun, Yaoming Xie, R. Bruce King and Henry F. Schaefer III
Article first published online: 4 MAY 2011 | DOI: 10.1002/ejic.201100155
The lowest energy C8H6Fe2(CO)6 structure is trans-(η5,η5-C8H6)Fe2(CO)6 but a cis-(η5,η1-C8H6)Fe2(CO)6 structure lies only ca. 3 kcal/mol above this global minimum. The experimentally known cis-(η5,η5-C8H6)Fe2(CO)4(μ-CO) structure is found to be the lowest energy C8H6Fe2(CO)5 structure by more than 25 kcal/mol (BP86). Two triplet and two singlet cis-C8H6Fe2(CO)4 structures lie within 7 kcal/mol of each other (BP86) with the triplet structures having slightly lower energies.