Regioselective Insertion of Aluminum(I) in the cyclo-P5 Ring of Pentaphosphaferrocene.

Ravi Yadav,Ralf Köppe,Peter W. Roesky,Christoph Schoo,Bhupendra Goswami,Subhayan Dey,Thomas Simler

doi:10.1002/anie.202002774

Ravi Yadav, Ralf Köppe + Show 5 more

Open Access

https://doi.org/10.1002/anie.202002774

Copy DOI

Abstract

A route to directly access mixed Al–Fe polyphosphide complexes was developed. The reactivity of pentaphosphaferrocene, [Cp*Fe(η 5‐P5)] (Cp*=C5Me5), with two different low‐valent aluminum compounds was investigated. The steric and electronic environment around the [AlI] centre are found to be crucial for the formation of the resulting Al–Fe polyphosphides. Reaction with the sterically demanding [Dipp‐BDIAlI] (Dipp‐BDI={[2,6‐iPr2C6H3NCMe]2CH}−) resulted in the first Al‐based neutral triple‐decker type polyphosphide complex. For [(Cp*AlI)4], an unprecedented regioselective insertion of three [Cp*AlIII]2+ moieties into two adjacent P−P bonds of the cyclo‐P5 ring of [Cp*Fe(η5‐P5)] was observed. The regioselectivity of the insertion reaction could be rationalized by isolating an analogue of the reaction intermediate stabilized by a strong σ‐donor carbene.

Highlights

A route to directly access mixed Al–Fe polyphosphide complexes was developed
It is interesting to explore the scope of air-stable starting materials as sources for poly-pnictogen species as alternatives to the conventionally used and highly reactive P4.[7]. Recently, we have shown that the cyclo-P5 ring of [Cp*Fe(h5-P5)] could be used as a polyphosphorous source
The organometallic chemistry of mono-valent aluminum compounds, which was pioneered in the 1990s,[9] has witnessed renewed interest,[10] which can be attributed to their ability to activate small molecules and organic substrates featuring single, double, or triple bonds.[9l,11] The reactivity of [AlI] is not limited to organic substrates: main-group elements, such as S8,[12] Se,[9b] and Te,[9b] have been used to make aluminum heterocyclic complexes

Summary

Introduction

A route to directly access mixed Al–Fe polyphosphide complexes was developed. The reactivity of pentaphosphaferrocene, [Cp*Fe(h5-P5)] (Cp* = C5Me5), with two different low-valent aluminum compounds was investigated. The insertion of three [Cp*AlIII]2+ moieties into PÀP bonds led to the isolation of an unprecedented Al–Fe polyphosphide complex containing four metal centres.

Results

Conclusion