Dinuclear cyclometallated complexes of PdII with diphosphines. X-ray crystal structure of [1,4-{Pd[2,4-(MeO) 2C6H2C(H)=N]}2- C6H4{Ph2P(CH2)3PPh2−P,P}2][PF6]2

Treatment of the cyclometallated halide-bridged complexes [1,4-{Pd[2,3,4-(MeO)3C6HC(H)=N](X)}2C6H4]2 (1a, 2a), [1,4-{Pd[2,4-(MeO)2C6H2C(H)=N](X)}2C6H4]2 (1b, 2b), [1,4-{Pd[3-(Me-4-MeOC6H2C(H)=N](X)}2C6H4]2 (1c, 2c), [1,4-{Pd[4,5-(OCH2O)C6H2C(H)=N](X)}2C6H4]2 (1d, 2d), (X = Cl, Br) with ditertiary diphosphines in a complex/diphosphine 1:4 molar ratio and ammonium hexafluorophosphate gave the dinuclear cyclometallated complexes [1,4-{Pd[2,3,4-(MeO)3C6HC(H)N]}2C6H4(LL)2][PF6]2[LL  Ph2PCH(CH)3)PPh2, Ph2P(CH2)2PPh2, 3a, 4a], [1,4-{Pd[2,4-(MeO)2C6H2C(H)=N]}2C6H4(LL)2][PF6]2[LL  Ph2PCH(CH3)PPh2, Ph2P(CH2)2PPh2, 3b, 4b] [1,4-{Pd[3-(Me-4-MeOC6H2C(H)=N]}C6H4(LL)2][PF6]2[LL  Ph2PCH(CH3)PPh2, Ph2P(CH2)nPPh2, n = 2, 3, 3c, 4c, 5c], [1,4-{Pd[4,5-(OCH2O)C6H2C(H)=N]}2C6H4(LL)2] [PF6]2[LL = Ph2PCH(CH3)PPh2, Ph2P(CH2)nPPh2, n = 2, 3, 4, 3d, 4d, 5d, 6d]. The influence of ring size on the phosphorus chemical shift is discussed. The compounds were characterized by microanalysis (C, H, N), IR and 31P-{1H} and 1H NMR spectroscopy. The structure of the dinuclear cyclometallated palladium(II) complex [1,4-{Pd[2,4-(MeO)2C6H2C(H)=N]}2C6H4{Ph2P(CH2)3 PPh2−PP}2][PF6]2 is described. There are two different crystallographic molecules per asymmetric unit.