Cyclometallated complexes of palladium(II) with a C, N, N′ terdentate Schiff base donor ligand. Oxidative addition of an arylchlorine bond to palladium(O)

Abstract Treatment of N -(2-chlorobenzylidene)- N,N′ -dimethylethylenediamine, 2-ClC 6 H 4 C(H)NCH 2 CH 2 NMe 2 , with tris(dibenzylideneacetone)dipalladium(0) in chloroform gave the oxidative addition cyclometallated product [Pd{C 6 H 4 C(H)NCH 2 CH 2 N Me 2 }(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{C 6 H 4 C(H)N CH 2 CH 2 NMe 2 }(Cl)(L)](2: L  PPh 3 ; 3: L  PEtPh 2 ; 4: L  PEt 2 Ph; 5: L  PEt 3 ), 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{C 6 H 4 C(H)NCH 2 CH 2 N Me 2 }(L)][ClO 4 ] (6: L  PPh 3 ; 7: L  PEtPh 2 ; 8: L  PEt 2 Ph; 9: L  PEt 3 ). Reaction of 1 with thallium acetylacetonate gave the cyclometallated complex [Pd{C 6 H 4 C(H)N CH 2 CH 2 NMe 2 }(H 3 CCOCHCOCH 3 )] (10). Treatment of 1 with ditertiary diphosphines in a complex 1/diphosphine 2:1 molar ratio gave the dinuclear cyclometallated complexes [{Pd[C 6 H 4 C(H)N CH 2 CH 2 NMe 2 ](Cl)} 2 (LL)(11: LL = trans -Ph 2 PCHCHPPh 2 ; 12: LL  Ph 2 P(CH 2 ) 3 PPh 2 ;13: LL  Ph 2 P(CH 2 ) 4 PPh 2 ), 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[C 6 H 4 C(H)NCH 2 CH 2 N Me 2 ]} 2 (LL)][ClO 4 ] 2 [14: LL= trans -Ph 2 PCHCHPPh 2 ; 15: LL  Ph 2 P(CH 2 ) 3 PPh 2 ; 16: LL  Ph 2 P(CH 2 ) 4 PPh 2 )]. Reaction of 1 with ditertiary diphosphines in a complex 1/diphosphine 1:1 molar ratio, and silver perchlorate as appropriate, gave the cyclometallated complexes [Pd{C 6 H 4 C(H)N CH 2 CH 2 NMe 2 }(Ph 2 P(CH 2 ) 2 PPh 2 - P,P )][ClO 4 ] (17), [Pd{C 6 H 4 C(H)N CH 2 CH 2 NMe 2 }(Ph 2 P(CH 2 ) 3 PPh 2 - P,P )][ClO 4 ] (18), [ Pd{C 6 H 4 C(H)N CH 2 CH 2 NMe 2 }( cis -Ph 2 PCHCHPPh 2 - P,P )][Cl] (19) and [Pd{C 6 H 4 C-(H)NCH 2 CH 2 NMe 2 }(Cl)(Ph 2 P(CH 2 ) 4 PPh 2 - P,P )] (20).