Related Experiment Video
Updated: Jun 1, 2026

Preparation of 6-aminocyclohepta-2,4-dien-1-one Derivatives via Tricarbonyl(tropone)iron
Published on: August 12, 2019
Redetermination of (η-s-cis-1,3-butadiene)tricarbonyl-iron(0)
1Institut für Anorganische Chemie und Strukturchemie, Lehrstuhl II: Material- und Strukturforschung, Heinrich-Heine-Universität Düsseldorf, Universitätsstrasse 1, D-40225 Düsseldorf, Germany.
Abstract:
The crystal structure of the title compound, [Fe(C(4)H(6))(CO)(3)], was previously reported by Mills & Robinson [Acta Cryst. (1963) ▶, 16, 758-761]. The compound crystallizes in the centrosymmetric space goup Pnma with the complex located on a mirror plane. The redetermination of this structure at 100 K yielded almost equilibrated C-C bond lengths within the butadiene ligand according to a metal-to-ligand bonding-back-bonding mechanism. The C-C bond lengths presented herein are significantly shorter than those reported earlier. The H-atom positions that have not been reported so far were located by difference Fourier maps. The positional parameters of all H atoms and individual U(iso) values were refined freely.
Related Concept Videos
Stability of Conjugated Dienes
A comparison of the enthalpies of hydrogenation of dienes reveals that conjugated dienes release less heat on hydrogenation, rendering them more stable than their nonconjugated analogs.
Woodward–Hoffmann Selection Rules and Microscopic Reversibility
Thermal Electrocyclic Reactions: Stereochemistry
Selection Rules: Thermal Activation
Conjugated systems containing an even number of π-electron pairs undergo a conrotatory ring closure. For example, thermal electrocyclization of (2E,4E)-2,4-hexadiene, a conjugated diene containing two π-electron pairs, gives trans-3,4-dimethylcyclobutene.
Thermal and Photochemical Electrocyclic Reactions: Overview
Naming Enantiomers
Disubstituted Cyclohexanes: cis-trans Isomerism
In cyclohexane, the substituents can occupy different positions generating distinct isomers.

