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) 3C 6HC(H)N ] (X)} 2C 6H 4} 2] ( Ia, IIa) and [{1,4- { Pd [2,4-(MeO) 2C 6H 2C(H)N(X)} 2C 6H 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) 3C 6- HC(H)N ](X)} 2C 6H 4} 2{μ-Ph 2P(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) 2C 6 H 2C(H)N](X)} 2C 6H 4} 2{μ-Ph 2P(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) 3C 6HC(H)N ]} 2C 6H 4 {Ph 2P(CH 2) n PPh 2- P, P} 2] [PF 6] 2 ( 5a: n = 3; 6a: n = 4) and [1,4-{ Pd [2,4-(MeO) 2C 6-HC(H)N ]} 2 C 6H 4}{Ph 2P(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) 3C 6HC(H)N ](X)} 2C 6 H 4} 2] ( Ia, IIa) and [{1,4-{ Pd [4,5-(OCH 2O)C 6H 2C(H)N](X)} 2C 6H 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) 3C 6HC(H)N ](X)(L)} 2C 6H 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 2O)C 6H 2]C(H)N ](X)(L)} 2C 6H 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) 3C 6HC(H)N](X)(L){ 2} 2C 6H 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 2O)C 6H 2C(H)N](X)(L) 2} 2C 6H 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) 3C 6HC(H)= N ](H 3CCOCHCOCH 3)} 2C 6H 4] ( 19a) and [1,4-{Pd[4,5-(OCH 2O)C 6H 2C(H) N](H 3CCOCHCOCH 3)} 2C6H 4] ( 13c). The compounds were characterized by microanalysis (C, H, N),IR and 31P{ 1H} and 1H spectroscopy.