Hydrido-derivatives of [Ir4(CO)10(diphosphine)]: X-ray analyses of [Ir4H(CO)9(μ-Ph2PH(CH3)PPh2)]− and [Ir4 H(CO)9(μ-Ph2P(CH2)nPPh2)]− (n = 2, 3)

Some novel hydrido-anions of general formula [Ir4H(CO)9(μ-L–L)]− (L–L = Ph2PCH(CH3)PPh2, Ph2P(CH2)2PPh2, Ph2P(CH2)3PPh2 and Ph2AsCH2AsPh2) have been obtained by the reaction of [Ir4(CO)10(μ-L–L)] with the base 1,8-diazabicyclo[5.4.0]undec-7-ene in wet dichloromethane. According to IR and 1H, 31P and 13C NMR data at low temperature, these anionic derivatives display a single conformation in solution: three edge-bridging COs around the triangular basal face and both the hydride and the bidentate ligands located in axial positions relative to this face. The structures of four compounds were established by X-ray diffraction studies, which confirmed the configuration proposed on the basis of spectroscopic data.

The synthesis of some new hydrido-anions [Ir4H(CO)9(μ-L–L)]−(L–L = diphosphine or diarsine) has been synthesized and characterized structurally and spectroscopically. The complexes exhibit similar stereochemistries in solution and in solid state: three edge-bridging COs around the triangular basal face and both the hydride and the bidentate ligands located in axial position relative to this face. These Ir4 clusters are fluxional at room temperature.Figure optionsDownload as PowerPoint slide