White Phosphorus Activation with Cobalt–Zinc Complexes: Access to Phosphorus‐Rich Sandwich Compounds

The utilization of two electronically distinct elements for the cooperative activation of white phosphorus (P 4 ) is a promising route to novel and reactive polyphosphido complexes. Herein, the preparation of cyclooctadiene Co–Zn complexes and their application in the activation of white phosphorus (P 4 ) to synthesize new phosphorus‐rich sandwich complexes are reported. The complexes [Zn{Co( t Bu 2 C 2 P 2 )(COD)} 2 ] ( 1 , COD = cycloocta‐1,5‐diene), [(acac)Zn{Co( t Bu 2 C 2 P 2 )(COD)}] ( 2 , acac = acetylacetonate), [( Dipp nacnac)Zn{Co( t Bu 2 C 2 P 2 )(COD)}] ( 3 , Dipp nacnac = CH({2,6‐ i Pr 2 ‐C 6 H 3 }NCMe) 2 ), and [(Ar)Zn{Co( t Bu 2 C 2 P 2 )(COD)}] ( 4 , Ar = C 6 H 3 ‐2,6{C 6 H 3 ‐2,6‐ i Pr 2 } 2 ) are prepared by transmetalation of [( Dep nacnac)Mg{Co( t Bu 2 C 2 P 2 )(COD)}] ( F , Dep nacnac= CH({2,6‐Et 2 ‐C 6 H 3 }NCMe) 2 ) with zinc(II) salts. Complex 1 reacts with cyclohexyl isonitrile (CyNC) to afford isonitrile complexes [ZnCo 2 ( t Bu 2 C 2 P 2 ) 2 (COD)(CyNC) 2 ] ( 5 ) and [Zn{Co( t Bu 2 C 2 P 2 )(CyNC) 2 } 2 ] ( 6 ). Single‐crystal X‐ray diffraction data and quantum chemical studies employing Atoms In Molecules and Natural Bond Orbital methods reveal weak covalent Co–Zn interactions in complexes 1—6 . Compound 1 reacts with P 4 to produce [Zn 2 Co 4 (μ‐P 2 ) 2 ( t Bu 2 C 2 P 2 ) 4 (COD) 2 ] ( 7 ) and subsequently [Zn 2 Co 4 (μ‐P 2 ) 4 ( t Bu 2 C 2 P 2 ) 4 ] ( 8 ), featuring bridging diphosphorus ligands. A stepwise mechanism for the formation of 8 is elucidated through 31 P nuclear magnetic resonance spectroscopic monitoring studies. Chemical oxidation of 8 generates the triple‐decker sandwich complex [{Co( t Bu 2 C 2 P 2 )} 2 (μ‐P 4 )] ( 9 ) with a cyclo‐P 4 middle deck.