| Abstrakt: |
Treatment of Pd(AcO)2 with 1-methyl-2-phenylimidazole, and subsequent treatment with sodium chloride or sodium bromide gave the corresponding halide-bridged cyclometallated complexes [Pdo-C6H4C=NC(H)=C(H)NMe(μ-X)]2 (2, X = Cl; 3, X = Br). Complexes 2 and 3 react with tertiary diphosphines in a 1:1 molar ratio to give dinuclear cyclometallated compounds with bridging diphosphine and halogen ligands [Pdo-C6H4C=NC(H)=C(H)NMe(μ-L-L)(μ-X)]X (4–9) or with only bridging diphosphine ligands [Pdo-C6H4C=NC(H)=C(H)NMe(μ-L-L)(X)2] (10–17), [X = Cl, Br; L-L = Ph2PCH2PPh2 (dppm), Ph2PC(=CH2)PPh2 (vdpp), Ph2PCH(CH3)PPh2 (1,1-dppe), trans-Ph2P(CH=CH)PPh2 (trans-dppe), Ph2P(CH2)2PPh2 (dppe), Ph2P(CH2)3PPh2 (dppp), Ph2P(CH2)4PPh2 (dppb), as appropriate]. When the reaction is carried out in a 1:2 molar ratio and in the presence of NH4PF6 or NaClO4, mononuclear cyclometallated compounds with a chelating diphosphine ligand are obtained [Pdo-C6H4C=NC(H)=C(H)NMe(L-L-P,P)][Y] (18–27) [Y = PF6, ClO4; L-L = Ph2PCH2PPh2 (dppm), Ph2PC(=CH2)PPh2 (vdpp), Ph2PCH(CH3)PPh2 (1,1-dppe), Ph2PN(CH3)PPh2 (dppma), cis-Ph2P(CH=CH)PPh2 (cis-dppe), Ph2P(CH2)2PPh2 (dppe), Ph2P(CH2)PPh2 (dppp), Ph2P(CH2)4PPh2 (dppb)]. Compounds 18–22 and 25–27 could also be obtained by reaction of complexes 4–17 with the appropriate diphosphine and NH4PF6 or NaClO4. The diphosphines dppma and cis-dppe failed to behave as bridging ligands and only gave mononuclear compounds. The complexes were characterized by their elemental analysis (C, H, N) and by IR and 31P-1H and 1H NMR data. The X-ray crystal structure of complex 22 is described. |
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