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

The synthesis and characterization of the first homoleptic open-shell transition metal phosphinidenide is presented. By reacting [MnL] (L = -N(SiMe)) with [(sIDipp)PK] (sIDipp = 1,3-bis(2,6-di-iso-propylphenyl)-imidazolidine-2-ylidene), the formation of [Mn{P(sIDipp)}] instead of the initially expected adduct [KMn{P(sIDipp)}L] is observed. Interestingly, a solvent change from toluene to -pentane leads to the formation of [(sIDipp)PK(EtO)][MnL] after work-up, which can be seen as intermediate in the formation process of [Mn{P(sIDipp)}]. 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.