Oligophosphane Ligands, XLI. Oxidative Additions of Transition Metal–Hydrogen Bonds: Reactions of CpM(CO)3H (M = Mo, W) with [tBuP(CH2CH2CH2PPh2)2]M′Cl(M′ = Rh, Ir)

Abstract

AbstractTreatment of (PP2)IrCl[PP2 = tBuP(CH2CH2CH2PPh2)2] with an equimolar quantity of CpM(CO)3H (M = Mo, W) or with HCl in THF resulted in smooth protonation of the d8 substrate producing [(PP2)Ir(H)Cl]X {X– = [CpMo(CO)3]– (1), [CpW(CO)3]– (2), Cl– (3)}. Combination of (PP2)IrCl and CpM(CO)3H in a 2:1 stoichiometry gave (PP2)Ir(H)Cl2 (7) together with [(PP2)IrCO]‐[Mo(CO)3Cp] (8) or [(PP2)IrCO][W(CO)3Cp] (9). The rhodium analogues (PP2)Rh(H)Cl2 (4), [(PP2)RhCO][Mo(CO)3Cp] (5), and [(PP2)RhCO][W(CO)3Cp] (6) were obtained similarly from (PP2)RhCl and CpM(CO)3H. Structural assignments for [(PP2)Ir(H)Cl]+ and (PP2)M′(H)Cl2 (M′ = Rh, Ir) as diastereomers in which the hydrido ligand and the tBu substituent on the central phosphorus atom are located on the same side or on opposite sides of the PP2 reference plane of the meridionally bound tBuP(CH2CH2CH2PPh2)2 ligand are made on the basis of (i) correlations with known structures and reactivities of similar [(RP(CH2CH2CH2PR′2)2M′(H)Cl]+ cations and (ii) an X‐ray structure determination of 4. The crystal structure analysis of a [(PP2)RhCO]+ salt, closely related to 5/6 and 8/9, [(PP2)Rh(CO)][OCO2H] (10), demonstrates that in the solid state the four‐coordinate [(PP2)RhCO]+ cation and its counterion exist as essentially charge‐neutralized Rh ⃛O‐contacted ion pairs, two of which are linked by OH ⃛O bridges to centrosymmetric dimers. Ion pairing was also observed by IR spectroscopy for THF solutions of metalates 5/6 and 8/9.