Synthesis of the open-shell 3d-transition metal(ii) bis(phosphinidenide) [Mn{P(sIDipp)}2]

Abstract

The synthesis and characterization of the first homoleptic open-shell transition metal phosphinidenide is presented. By reacting [MnL₂] (L = −N(SiMe₃)₂) with [(sIDipp)PK] (sIDipp = 1,3-bis(2,6-di-iso-propylphenyl)-imidazolidine-2-ylidene), the formation of [Mn{P(sIDipp)}₂] instead of the initially expected adduct [KMn{P(sIDipp)}L₂] is observed. Interestingly, a solvent change from toluene to n-pentane leads to the formation of [(sIDipp)PK₂(Et₂O)₄][MnL₃] after work-up, which can be seen as intermediate in the formation process of [Mn{P(sIDipp)}₂]. Contrary to manganese, the highly reducing phosphinidenide [(sIDipp)P]⁻ cannot be stabilized in an analogous fashion by coordination to a low-coordinate high-spin iron(II) center.