Metaloxylation of cyclopalladated 1-(1′-naphthylazo)naphthalene complexes by m-chloroperbenzoic acid:: Oxygen insertion into metal-carbon(naphthyl) bond

The cyclopalladation of symmetrical 1-(1'-naphthylazo)naphthalene(HL) affords dimeric complexes of the type [Pd-2(L)(2)X-2]1 (where X represents Cl or OAc). Thallium(I) cyclopentadienide cleaves the di-mu-chloro-bridge of [Pd2L2Cl2] and yields air-stable deep violet coloured monomer [PdLCp] 2 (Cp = eta(5)-cyclopentadienyl). Complexes 1 undergo regiospecific metaloxylation (M-C -> M-O-C) reaction with m-chloroperbenzoic acid (m-CPBA) at C2 and produce complexes [Pd-2(LO)(2)X-2] 3 where LOH is 1-(1'-naphthylazo)-2-hydroxynaphthalene. m-CPBA selectively metaloxylates the palladium-naphthyl sigma-bond of complex 2 giving rise to azonaphtholatocyclopenta-dienidepalladium(II) species in solution. (c) 2005 Elsevier Ltd. All rights reserved.