Mild N–O Bond Cleavage Reactions of a Pyramidalized Nitrosyl Ligand Bridging a Dimolybdenum Center

Complex [Mo<sub>2</sub>Cp<sub>2</sub>(μ-PCy<sub>2</sub>)­(μ-NO)­(NO)<sub>2</sub>] (<b>1</b>) was prepared by reacting [Mo<sub>2</sub>Cp<sub>2</sub>(μ-H)­(μ-PCy<sub>2</sub>)­(CO)<sub>4</sub>] with 2 equiv of [NO]­BF<sub>4</sub> and then treating the resulting product [Mo<sub>2</sub>Cp<sub>2</sub>(μ-PCy<sub>2</sub>)­(CO)<sub>2</sub>(NO)<sub>2</sub>]­(BF<sub>4</sub>) with NaNO<sub>2</sub> at 323 K, and it was shown to display a bridging nitrosyl ligand with significant pyramidalization at the N atom, a circumstance related to an unusual behavior concerning degradation of the bridging nitrosyl. Indeed, complex <b>1</b> reacts with HBF<sub>4</sub>·OEt<sub>2</sub> to give the nitroxyl-bridged derivative [Mo<sub>2</sub>Cp<sub>2</sub>(μ-PCy<sub>2</sub>)­(μ-κ<sup>1</sup>:η<sup>2</sup>-HNO)­(NO)<sub>2</sub>]­(BF<sub>4</sub>), is reduced by Zn­(Hg) in the presence of trace H<sub>2</sub>O to give the amido complex [Mo<sub>2</sub>Cp<sub>2</sub>(μ-PCy<sub>2</sub>)­(μ-NH<sub>2</sub>)­(NO)<sub>2</sub>], and reacts with excess P­(OPh)<sub>3</sub> to give the phosphoraniminato-bridged derivative [Mo<sub>2</sub>Cp<sub>2</sub>(μ-PCy<sub>2</sub>)­{μ-NP­(OPh)<sub>3</sub>}­(NO)<sub>2</sub>].