Related Experiment Video
Updated: Feb 16, 2026

The Synthesis, Characterization and Reactivity of a Series of Ruthenium N-triphosPh Complexes
Published on: April 10, 2015
Synthesis and Reactivity of an End-Deck cyclo-P4 Iron Complex
Anthony Cavaillé1, Nathalie Saffon-Merceron2, Noel Nebra1
1Laboratoire Hétérochimie Fondamentale et Appliquée, Université Paul Sabatier, CNRS, 118 Route de Narbonne, 31062, Toulouse, France.
Abstract:
Reduction of the FeII complex [(Ph PP2Cy )FeCl2 ] (2) generated an electron-rich and unsaturated Fe0 species, which was reacted with white phosphorus. The resulting new complex, [(Ph PP2Cy )Fe(η4 -P4 )] (3), is the first iron cyclo-P4 complex and the only known stable end-deck cyclo-P4 complex outside Group V. Complex 3 features an FeII center, as shown by Mössbauer spectroscopy, associated to a P42- fragment. The distinct reactivity of complex 3 was rationalized by analysis of the molecular orbitals. Reaction of complex 3 with H+ afforded the unstable complex [(Ph PP2Cy )Fe(η4 -P4 )(H)]+ (4), whereas with CuCl and BCF, the complexes [(Ph PP2Cy )Fe(η4 :η1 -P4 )(μ-CuCl)]2 (5) and [(Ph PP2Cy )Fe(η4 :η1 -P4 )B(C6 F5 )3 ] (6) were formed.
Related Concept Videos
Cycloaddition Reactions: Overview
Pericyclic Reactions: Introduction
Pericyclic reactions can be classified into three categories: electrocyclic reactions, cycloaddition reactions, and sigmatropic rearrangements. Electrocyclic reactions and sigmatropic...
Cycloaddition Reactions: MO Requirements for Thermal Activation
Thermal and Photochemical Electrocyclic Reactions: Overview
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.
[4+2] Cycloaddition of Conjugated Dienes: Diels–Alder Reaction

