A Structural Diversity of Molecular Alkaline‐Earth‐Metal Polyphosphides: From Supramolecular Wheel to Zintl Ion
Ravi Yadav, Martin Weber, Akhil K. Singh, Luca Münzfeld, Johannes Gramüller, Ruth M. Gschwind, Manfred Scheer, Peter W. Roesky
Abstract
Abstract A series of molecular group 2 polyphosphides has been synthesized by using air‐stable [Cp*Fe(η 5 ‐P 5 )] (Cp*=C 5 Me 5 ) or white phosphorus as polyphosphorus precursors. Different types of group 2 reagents such as organo‐magnesium, mono‐valent magnesium, and molecular calcium hydride complexes have been investigated to activate these polyphosphorus sources. The organo‐magnesium complex [( Dipp BDI−Mg(CH 3 )) 2 ] ( Dipp BDI={[2,6‐ i Pr 2 C 6 H 3 NCMe] 2 CH} − ) reacts with [Cp*Fe(η 5 ‐P 5 )] to give an unprecedented Mg/Fe‐supramolecular wheel. Kinetically controlled activation of [Cp*Fe(η 5 ‐P 5 )] by different mono‐valent magnesium complexes allowed the isolation of Mg‐coordinated formally mono‐ and di‐reduced products of [Cp*Fe(η 5 ‐P 5 )]. To obtain the first examples of molecular calcium‐polyphosphides, a molecular calcium hydride complex was used to reduce the aromatic cyclo ‐P 5 ring of [Cp*Fe(η 5 ‐P 5 )]. The Ca‐Fe‐polyphosphide is also characterized by quantum chemical calculations and compared with the corresponding Mg complex. Moreover, a calcium coordinated Zintl ion (P 7 ) 3− was obtained by molecular calcium hydride mediated P 4 reduction.