Syntheses, characterization and catalytic application of palladacycles containing phosphane or phosphane oxide functionalities

Abstract

The preparation of ligand precursors PhN=C(CMe(2))(NPh)C=N(CH(2))(2)PPh(2) (1) and PhN=C(CMe(2))(NPh)C=N(CH(2))(2)P(O)Ph(2) (2) are described. Treatment of 1 or 2 with 1 molequiv. Pd(OAc)(2) affords orthometallated palladium(II) complexes [PhN=C(CMe(2))(N-eta(1)-Ph)C=N(CH(2))(2)PPh(2)]Pd(OAc) (3) as a mononuclear complex or {[PhN=C(CMe(2))(N-eta(1)-Ph)C=N-(CH(2))(2)P(O)Ph(2)]Pd(OAc)}(2) (4) as an acetate-bridged dinuclear complex, respectively. Reaction of 3 with excess LiCl in methanol affords a mononuclear palladium(II) complex [PhN=C(CMe(2))(N-eta(1)-Ph)C=N(CH(2))(2)PPh(2)]PdCl (5). The crystal and molecular structures are reported for compounds 3-5. Application of these novel palladacyclic complexes to the Suzuki and Heck reactions with aryl halide substrates was examined. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008).