CYCLOMETALATED COMPLEXES OF PALLADIUM(II) WITH 1-METHYL-2-PHENYLIMIDAZOLE AND TERTIARY DIPHOSPHINES - CRYSTAL AND MOLECULAR-STRUCTURE OF [O-C6H4C=NC(H)=C(H)NME])(PH2PCH(ME)PPH2-P,P)][PF6]

Treatment of Pd(AcO)(2) with 1-methyl-2-phenylimidazole, and subsequen t treatment with sodium chloride or sodium bromide gave the correspond ing halide-bridged cyclometallated complexes [Pd{o-C6H4C=NC(H)=C(H)NMe }(mu-X)](2) (2, X = Cl; 3, X = Br). Complexes 2 and 3 react with terti ary diphosphines in a 1:1 molar ratio to give dinuclear cyclometallate d compounds with bridging diphosphine and halogen ligands [Pd{o-C6H4C= NC(H)=C(H)NMe}(mu-L-L)(mu-X)]X (4-9) or with only bridging diphosphine ligands [Pd{o-C6H4C=NC(H)=C(H)NMe}( mu-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)(2)PPh2 (dppe ), Ph2P(CH2)(3)PPh2 (dppp), Ph2P(CH2)(4)PPh2 (dppb), as appropriate]. When the reaction is carried out in a 1:2 molar ratio and in the prese nce of NH4PF6 or NaClO4, mononuclear cyclometallated compounds with a chelating diphosphine ligand are obtained [Pd{o-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-P h2P(CH=CH)PPh2 (cis-dppe), Ph2P(CH2)(2)PPh2 (dppe), ph(2)P(CH2)PPh2 (d ppp), Ph2P(CH2)(4)PPh2 (dppb)]. Compounds 18-22 and 25-27 could also b e obtained by reaction of complexes 4-17 with the appropriate diphosph ine and NH4PF6 or NaClO4. The diphosphines dppma and cis-dppe failed t o behave as bridging ligands and only gave mononuclear compounds. The complexes were characterized by their elemental analysis (C, H, N) and by IR and P-31-{H-1} and H-1 NMR data. The X-ray crystal structure of complex 22 is described. (C) 1947 Elsevier Science S.A.