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OXIDATIVE ADDITION; COMPLEXES; ELIMINATION; MECHANISM
Abstract:
Water, alkanol, and amine activation reactions of transition metals may lead to complexes in which a hydro substituent is paired with an hydroxy, alkoxy, or amide substituent, all of which are potential reactive sites. 2 Well-studied examples are the d6 Ir(III) cis hydro hydroxy complexes [(Me3P)4Ir(H)OH]+PF6- 3a (ionic; stable at 100 °C) and (R3P)3Ir(H)OH(Cl) (R = Me, Et; neutral; reversible water elimination at 20 °C). 3b Of the d10 metal complexes, {(c-C6H11)3P}2Pt oxidatively adds phenols (ArOH; Ar = C6H5, C6F5) at 20 °C to afford stable trans-{(c-C6H11)3P}2Pt(H)OAr. 4 Similarly, (iPr3P)2Pt reacts with H2O to give thermally unstable trans-(iPr3P)2Pt(H)OH. 5a,b In contrast, (iPr3P)2Pd does not react with water at 20 °C. 5c Furthermore, the stannylene SnR2 (R = CH(SiMe3)2) 6a is reported to decompose in water and alkanol. 6b,c As we have recently discovered, the adducts L2Pd(0)=SnR2 (L2 = chelating bidentate phosphane) 7 undergo reversible oxidative additions of water and methanol. 8
