Abstract
A route to directly access mixed Al-Fe polyphosphide complexes was developed. The reactivity of pentaphosphaferrocene, [Cp*Fe(η(5) -P(5) )] (Cp*=C(5) Me(5) ), with two different low-valent aluminum compounds was investigated. The steric and electronic environment around the [Al(I) ] centre are found to be crucial for the formation of the resulting Al-Fe polyphosphides. Reaction with the sterically demanding [Dipp-BDIAl(I) ] (Dipp-BDI={[2,6-(i) Pr(2) C(6) H(3) NCMe](2) CH}(-) ) resulted in the first Al-based neutral triple-decker type polyphosphide complex. For [(Cp*Al(I) )(4) ], an unprecedented regioselective insertion of three [Cp*Al(III) ](2+) moieties into two adjacent P-P bonds of the cyclo-P(5) ring of [Cp*Fe(η(5) -P(5) )] 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.