Amido PNP pincer complexes of palladium(II) and platinum(II): Synthesis, structure, and reactivity

The synthesis of a series of divalent palladium and platinum complexes containing amido PNP pincer ligands of the type [N( o ‐C 6 H 4 PR 2 ) 2 ] − (R = Ph ( 1a ), i Pr ( 1b )) is reported. Metathetical reactions of [ 1a–b ]PdCl or [ 1a–b ]PtCl with a variety of alkyl Grignard reagents or LiHBEt 3 in ethereal or arene solutions generate their corresponding alkyl or hydride complexes [ 1a ]PdR 1 (R 1 = Me, Et, n Bu), [ 1b ]PdR 1 (R 1 = Me, Et, H), [ 1a ]PtR 1 (R 1 = Me, Et, n Bu, n Hexyl, H), and [ 1b ]PtR 1 (R 1 = Me, H). Although these organometallic complexes are all thermally stable, including those containing β‐hydrogen atoms even at elevated temperatures, compounds [ 1a ]PdH and [ 1b ]PtR 1 (R 1 = Et, n Bu, n Hexyl) are not isolable due to facile decomposition. The stability and reactivity of these complexes are discussed. The chloro [ 1a ]PdCl is a superior catalyst precursor to [ 1b ]PdCl, [ 1a ]PtCl, and [ 1b ]PtCl in Kumada couplings, affording, for instance, n ‐butyl arenes nearly quantitatively. The X‐ray structures of [ 1b ]PtCl, [ 1b ]PtMe, [ 1b ]PdEt, [ 1a ]Pt n Bu, [ 1b ]PdH, and [ 1b ]PtH are presented.