New developments in the studies of the reactivity of cyclometallated palladium(II) compounds with homo- ([P,P],[As,As]) and heterobidentate ([P,N],[P,O]) ligands

Treatment of the chloro-bridged dinuclear compounds {PdRC₆H₃C(H)NCy-C2,N]}(μ-Cl)]₂ (R = 4-(COH), 1; R = 5-(COH), 2) with bidentate phosphorus or arsenic diphosphines or diarsine ligands in 1:1 molar ratio gave the dinuclear complexes {PdRC₆H₃C(H)NCy-C2,N](Cl)}₂{μ-(o-Tol)₂P(CH₂)₂P(o-Tol)₂}] (R = 4-(COH), 3; R = 5-(COH), 4), {PdRC₆H₃C(H)NCy-C2,N](Cl)}₂{μ-Ph₂PC₄H₂(NH)CH₂PPh₂}] (R = 4-(COH), 5; R = 5-(COH), 6) and {PdRC₆H₃C(H)NCy-C2,N](Cl)}₂{μ-Ph₂As(CH₂)₂AsPh₂}] (R = 4-(COH), 7; R = 5-(COH), 8) with the homobidentate P,P] and As,As] ligands in a bridging mode. Treatment of 1 and 2 with the aminophosphine Ph₂P(CH₂)₂NH₂ yields the dinuclear complexes {PdRC₆H₃C(H)NCy-C2,N](Cl)}₂{μ-Ph₂P(CH₂)₂NH₂}] (R = 4-(COH), 9; R = 5-(COH), 10). The analogous reactions carried out in a 1:2 molar ratio, in the presence of NH₄PF₆ or NaClO₄, gave the mononuclear compounds Pd{RC₆H₃C(H)NCy-C2,N}{(o-Tol)₂P(CH₂)₂P(o-Tol)₂-P,P}]PF₆] (R = 4-(COH), 11; R = 5-(COH), 12), Pd{RC₆H₃C(H)NCy-C2,N}{Ph₂PC₄H₂(NH)CH₂PPh₂-P,P}]ClO₄] (R = 4-(COH), 13; R = 5-(COH), 14) and Pd{RC₆H₃C(H)NCy-C2,N}{Ph₂As(CH₂)₂AsPh₂-As,As}]ClO₄](R = 4-(COH), 15; R = 5-(COH), 16), with the P,P] and As,As] ligands chelated to the palladium atom.Treatment of 2 with Ph₂P(CH₂)₃NH₂ in a 1:2 molar ratio in acetone in the presence of NH₄PF₆ afforded the mononuclear compound Pd{5-(COH)C₆H₃C(H)NCy-C2,N}{Ph₂P(CH₂)₃N(Me₂)-P,N}]PF₆], 17, via intermolecular condensation between the aminophosphine and the solvent. Condensation was precluded using toluene as solvent to give Pd{RC₆H₃C(H)NCy-C2,N}{Ph₂P(CH₂)_nNH₂-P,N}]PF₆], (n = 3, R = 5-(COH), 18; n = 2, R = 4-(COH), 19; n = 2, R = 5-(COH), 20). Treatment of 1 and 2 with Ph₂P(C₆H₄)CHO in a 1:2 molar ratio in the presence of NH₄PF₆ gave the mononuclear complexes Pd{RC₆H₃C(H)NCy-C2,N}{2-(Ph₂P)C₆H₄CHO-P,O}]PF₆] (R = 4-(COH), 21; R = 5-(COH), 22) with the palladium atom bonded to four different atoms (C, N, P, O) and a chelating P,O] ligand. The crystal structures of compounds 7, 11, 15 and 21 have been determined by X-ray crystallography.