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

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.