Reactivity of tetranuclear cyclometallated palladium(II) halide-bridged complexes of bis(N-benzylidene)-1,4-phenylenediamines

Abstract Treatment of the cyclometallated halide-bridged complexes [{1,4-{ {Pd[2,3,4-(MeO) 3 C 6 HC(H)N ] (X)} 2 C 6 H 4 } 2 ] ( Ia , IIa ) and [{1,4- { Pd [2,4-(MeO) 2 C 6 H 2 C(H)N(X)} 2 C 6 H 4 } 2 ] ( Ib , IIb ) (X = Cl or Br) with ditertiary diphosphines in a complex/ diphosphine 1 : 2 molar ratio gave the 26- and 28-membered ring tetranuclear cyclometallated complexes [1,4-{{ Pd[2,3,4-(MeO) 3 C 6 - HC(H)N ](X)} 2 C 6 H 4 } 2 {μ-Ph 2 P(CH 2 ) n PPH 2 } 2 ] ( 1a : X = Cl n = 3; 2a : X = Br n = 3; 3a : X = Cl, n = 4; 4a : X = Br, n = 4) and [1,4-{{ Pd[2,4-(MeO) 2 C 6 H 2 C(H)N](X)} 2 C 6 H 4 } 2 {μ-Ph 2 P(CH 2 ) n PPh 2 } 2 ] ( 1b : X = Cl, n = 3; 2b : X = Br, n = 3; 3b :X = Cl, n = 4; 4b : X = Br, n = 4) and in a complex/diphosphine 1:4 molar ratio gave the dinuclear cyclometalled complexes [1,4-{ Pd[2,3,4-(MeO) 3 C 6 HC(H)N ]} 2 C 6 H 4 {Ph 2 P(CH 2 ) n PPh 2 - P , P } 2 ] [PF 6 ] 2 ( 5a : n = 3; 6a : n = 4) and [1,4-{ Pd [2,4-(MeO) 2 C 6 -HC(H)N ]} 2 C 6 H 4 }{Ph 2 P(CH 2 ) n PPh 2 - P , P } 2 ][PF 6 ] 2 ( 5b : n = 3; 6b : n = 4). Treatment of the cyclometallated halide-bridge complexes[{1,4-{ Pd[2,3,4-(MeO) 3 C 6 HC(H)N ](X)} 2 C 6 H 4 } 2 ] ( Ia , IIa ) and [{1,4-{ Pd [4,5-(OCH 2 O)C 6 H 2 C(H)N](X)} 2 C 6 H 4 } 2 ] ( Ic , IIc )(X = Cl, Br) with tertiary monophosphines in a complex/ phosphine 1 : 4 or 1 : 8 molar ratio gave the new dinuclear cyclometallated complexes [1,4-{ Pd[2,3,4-(MeO) 3 C 6 HC(H)N ](X)(L)} 2 C 6 H 4 ] [L = PPh 3 : 7a (X = Cl), 8a (X = Br); L = PPhEt 2 : 9a (X = Cl), 10a (X = Br); L = PPh(CCPh) 2 : 11a (X = Cl), 12a (X = Br)and [1,4-{ Pd[4,5-(OCH 2 O)C 6 H 2 ]C(H)N ](X)(L)} 2 C 6 H 4 ] [L = PPh 3 : 1c (X = Cl), 2c (X = Br); L = PPhEt 2 : 3c (X = Cl), 4c (X = Br); L = PPh(CCPh) 2 : 5c (X = Cl), 6c (X = Br)] and non-cyclometallated complexes [1,4-{Pd[2,3,4-(MeO) 3 C 6 HC(H)N](X)(L){ 2 } 2 C 6 H 4 ] [L = PPh 3 : 13a (X = Cl), 14a (X = Br); L = PPhEt 2 : 15a (X = Cl), 16a (X = Br); L = PPh(CCPh) 2 : 17a (X = Cl), 18a (X = Br)] and [1,4-{(Pd[4,5-(OCH 2 O)C 6 H 2 C(H)N](X)(L) 2 } 2 C 6 H 4 ] [L = PPh 3 : 7c (X = Cl), 8c (X = Br); L = PPhEt 2 : 9c (X = Cl), 10c (X = Br); L = PPh(C CPh) 2 : 11c (X = Cl), 12c (X = Br)], respectively. Reaction of the halide-bridged complexes with thallium acetylacetonate gave the dinuclear [1,4-{ Pd[2,3,4-(MeO) 3 C 6 HC(H)= N ](H 3 CCOCHCOCH 3 )} 2 C 6 H 4 ] ( 19a ) and [1,4-{Pd[4,5-(OCH 2 O)C 6 H 2 C(H) N](H 3 CCOCHCOCH 3 )} 2 C6H 4 ] ( 13c ). The compounds were characterized by microanalysis (C, H, N),IR and 31 P{ 1 H} and 1 H spectroscopy.