Synthesis, Characterization, and Reactivity of Neutral and Cationic Pd–C,N,N Pincer Complexes

✍ Scribed by Claudio Bianchini; Géraldine Lenoble; Werner Oberhauser; Sébastien Parisel; Fabrizio Zanobini

• Publisher: John Wiley and Sons
• Year: 2005
• Tongue: English
• Weight: 160 KB
• Volume: 2005
• Category: Article
• ISSN: 1434-1948
• DOI: 10.1002/ejic.200500479

✦ Synopsis

Abstract

The ortho‐palladation of the iminophosphane ligand 6‐phenyl‐2‐[(2,6‐diisopropylphenyl)imino]pyridine (HL) with Pd(OAc)~2~ and PdCl~2~(PhCN)~2~ in benzene yields the neutral Pd–C,N,N pincer complexes Pd(OAc)(κ^3^‐C,N,N‐L) (1) and PdCl(κ^3^‐C,N,N‐L) (2), respectively. In the presence of NaBAr′~4~ [Ar′ = 3,5‐(CF~3~)~2~C~6~H~3~], 2 reacts in CH~2~Cl~2~ with MeCN, PPh~3~, or PH[o‐MeO(C~6~H~4~)]~2~ to give the cationic palladium(II) pincer complexes [Pd(CH~3~CN)(κ^3^‐C,N,N‐L)]BAr′~4~ (3), [Pd(PPh~3~)(κ^3^‐C,N,N‐L)]BAr′~4~ (4) and {PdPH(o‐MeOC~6~H~4~)~2~}BAr′~4~ (5), respectively. Complexes 1–5 have been characterized by multinuclear NMR and IR spectroscopy. The solid‐state structures of 1 and 2 have been determined by single‐crystal X‐ray diffraction techniques. Both the neutral compounds 1 and 2 and the cationic derivatives 3, 4, and 5 were tested as catalyst precursors for the Suzuki cross‐coupling of 4‐bromo‐ and 4‐chloroacetophenone with phenylboronic acid. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)