Cyclometallated complexes of palladium(II) with a C,N,N' terdentate Schiff base donor ligand. Oxidative addition of an aryl-chlorine bond to palladium(0)

Treatment of N-(2-chlorobenzylidene)-N,N'-dimethylethylenediamine, 2-ClC6H4C(H)=NCH2CH2NMe2, with tris(dibenzylideneacetone)dipalladium(0) in chloroform gave the oxidative addition cyclometallated product [Pd{C6H4C(H)=NCH2CH2NMe2}(Cl)] (1) with the palladium atom bonded to a C,N,N' terdentate donor ligand. Treatment of 1 with tertiary monophosphines gave the cyclometallated complexes [Pd{C6H4C(H)=NCH2CH2NMe2}(Cl)(L)] (2: L = PPh3; 3: L = PEtPh2; 4: L = PEt2Ph; 5: L = PEt3), where the phosphine ligand is either trans to the phenyl carbon atom (2, 3) or trans to the imine nitrogen atom (4, 5). Treatment of 1 with silver perchlorate followed by reaction with tertiary monophosphines gave the cyclometallated complexes [Pd{C6H4C(H)=N-CH2CH2NMe2}(L)][ClO4] (6: L = PPh3; 7: L = PEtPh2; 8: L = PEt2Ph; 9: L = PEt3). Reaction of 1 with thalliium acetylacetonate gave the cyclometallated complex [Pd{C6H4C(H)=NCH2CH2NMe2}(H3CCOCHCOCH3)]. (10). Treatment of 1 with ditertiary diphosphines in a complex 1/diphosphine 2:1 molar ratio gave the dinuclear cyclometallated complexes [{Pr[C6H4C(H)=NCH2CH2NMe2](Cl)}(2)(L-L)] (11: L-L = trans-Ph2PCH=CHP-Ph-2; 12: L-L = Ph2P(CH2)(3)PPh2; 13: L-L = Ph2P(CH2)(4)PPh2), where the phosphorus atom is trans to the phenyl carbon atom. Treatment of 1 with silver perchlorate followed by ditertiary diphosphines in a complex 1/diphosphine 2:1 molar ratio gave the dinuclear cyclometallated complexes [{Pd[C6H4C(H)=NCH2CH2NMe2]}(2)(L-L)][ClO4](2) [14: L-L = trans-Ph2P-CH=CHPPh2; 15: L-L = Ph2P(CH2)(3)PPh2; 16: L-L = Ph2P(CH2)(4)PPh2)]. Reaction of 1 with ditertiary diphosphines in a complex molar ratio, and silver perchlorate as appropriate, gave the cyclometallated complexes [Pd{C6H4C(H)=NCH2CH2PNMe2}(Ph2P(CH2)(2)PPh2-P,P)][ClO2] (17), [Pd{C6H4C(H)=NCH2CH2NMe2}(Ph2P(CH2)(3)PPh2-P,P)][ClO4] (18), [Pd{C6H4C(H)=NCH2CH2NMe2}(cis-Ph2PCH=CHPPh2-P,P)][Cl] (19) and [Pd{C6H4C-(H)=NCH2CH2NMe2}(Cl)(Ph2P(CH2)(4)PPh2-P,P)] (20).