Oxidative additions of transition metal-hydrogen bonds: Reactions of CpM(CO)3H (M = Mo,W) with [tBuP(CH2CH2CH2PPH2) 2]M′Cl (M′ = Rh, Ir)

Article abstract of DOI:10.1002/cber.19961290614

Treatment 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 phosphoras 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(CH₂CH₂CH₂PR₂) 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. VCH Verlagsgesellschaft mbH, 1996.