Aryldihydroborane Coordination to Iridium and Osmium Hydrido Complexes

A series of iridium dihydroborate complexes [(tBuPOCOP)­IrH­(κ2-H2BHR)] (tBuPOCOP = κ3-C6H3-1,3-[OPtBu2]2; R = Mes = 2,4,6-Me3C6H2; R = Dur = 2,3,5,6-Me4C6H) and [LIrH­(κ2-H2BHDur)] (L = tBuPCP = κ3-C6H3-1,3-[CH2PtBu2]2, L = η5-C5Me5) and an osmium dihydroborate compound [OsH­(κ2-H2BHDur)­(CO)­(PiPr3)2] have been prepared by using two different synthetic strategies. The first approach is based on direct borane coordination to the metal center, whereas the second is based on a salt-elimination protocol using the lithium salts Li­[H3BR] (R = Mes or Dur) and the corresponding metal halides. The compounds have been characterized by multinuclear NMR and IR spectroscopy and X-ray diffraction analysis. The results constitute the first syntheses of κ2-σ:σ-dihydroborate complexes featuring bulky aryl groups.