Schroeder, Guenter; Butenschon, Holger; Boese, Roland; Lendvai, Tomas; de Meijere, Armin:

h4-Complexes of 4,7-dihydroacepentalene: facile degenerate haptotropic rearrangement of (h5-cyclopentadienyl)(h4-4,7-dihydroacepentalene)cobalt(I) in contrast to its tricarbonyliron counterpart.

In: Chemische Berichte (Chem.Ber.), Jg. 124 (1991) ; Nr. 11, S. 2423-2427
ISSN: 0009-2940
Zeitschriftenaufsatz / Fach: Chemie
(Cyclopentadienyl)cobalt(I) complex I was prepd by the reaction of the 4,7-dihydroacepentalene ligand with (cyclopentadienyl)bis(ethene)cobalt(I). NOE expts. indicate a complexation at the convex face of the polyolefinic ligand. 1H NMR spectra establish a degenerate haptotropic rearrangement with CpCo migration from one diene unit to the adjacent one. The activation energy of this process is estd. to be 15 kcal/mol. An x-ray crystal structure detn. of (h4-4,7-dihydroacepentalene)tricarbonyliron deriv. II shows a distorted coordination of Fe(CO)3 at the convex face of the ligand, too.