Reaction of di-μ-dichloro-bis(N,N-dimethylbenzylamine-C2,N)dipalladium(II) with diphosphines. Six-membered ring complexes bearing spiro rings

Article abstract of DOI:10.1016/S0020-1693(99)00491-0

Reactions of [Pd(C₆H₄CH₂NMe₂-C²,N)(μ-Cl)]₂ with diphosphines (diphos) such as dppf (a), dpmf (b), dppm (c), dppe (d) and dppp (e) gave [PdCl(C₆H₄CH₂NMe₂-C²,N)]₂(μ-diphos) (2). Complexes 2 (a, b, d and e) reacted with NaPF₆ to produce chelate complexes [Pd(C₆H₄CH₂NMe₂-C²,N)(diphos-P,P')][PF₆] (3), whereas 2c gave a six-membered ring complex [Pd₂(C₆H₄CH₂NMe₂-C²,N)₂(μ-Cl)(μ-dppm)][PF₆] (4c) bearing two exocyclic rings shared by each palladium atom. This complex was regenerated to 2c by treatment with [NEt₃(CH₂Ph)]Cl. Treatment of 3 (a, d and e) with one equiv. of aq. HCl caused protonation at the coordinate nitrogen atom to yield [Pd(C₆H₄CH₂NHMe₂-C²)(Cl)(diphos-P,P')][PF₆] (5) (a, d and e). Reaction of 4c with aq. HCl in a 1:1 molar ratio led to protonation at one C-N chelating ring to give [Pd₂(Cl)(C₆H₄CH₂NMe₂-C²,N)(C₆H₄CH₂NHMe₂-C²)(μ-Cl)(μ-dppm)][PF₆] (6c). The structures of 2a, 3e, 4c, 5a and 6c were confirmed by X-ray analyses. (C) 2000 Elsevier Science S.A.