Details

Autor(en) / Beteiligte

• Hansen, Valerie M
• Batchelor, Raymond J
• Einstein, Frederick W. B
• Male, Jonathan L
• Pomeroy, Roland K
• Zaworotko, Michael J

Titel

Restricted Rotation about the Arene−Iron Bond in (arene)Fe(CO)(SiCl3)2 Complexes

Ist Teil von

• Organometallics, 1997-10, Vol.16 (22), p.4875-4881

Ort / Verlag

American Chemical Society

Erscheinungsjahr

1997

Link zum Volltext

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• Complexes of formula (η6-C6H6 - x R x )Fe(CO)(SiCl3)2 have been prepared from the reaction of Fe(CO)4(SiCl3)2 and the appropriate arene at 210 °C. The characterization of the complexes included the crystal structures of the 1,4-C6H4Pri 2 and C6Me6 derivatives. As ascertained by variable-temperature 1H NMR spectroscopy, the (η6-1,4-C6H4R2)Fe(CO)(SiCl3)2 (R = Me, Et, Pri) compounds exhibit restricted rotation of the arene ring about the iron atom. Line-shape analyses of the NMR spectra reveal the barriers to the rotation in the three compounds are approximately the same (ΔG ⧧ 298 = 9.6−10.8 kcal mol-1). This finding is rationalized in terms of gearing of the R and SiCl3 groups with the rotation. The 1,3,5-C6H3Me3 and C6Me6 derivatives do not show restricted rotation of the arene ring by 1H NMR spectroscopy to −120 °C. It is concluded from these observations that both ground-state and transition-state effects are important in determining the barrier to rotation of the arene ring in organometallic molecules.