CYCLOMETALATED COMPLEXES OF PDII AND MNI WITH N,N-TEREPHTHALYLIDENEBIS(CYCLOHEXYLAMINE)

Treatment of N,N-terephthalylidenebis(cyclohexylamine), 1,4-(CyN=CH)2C6H4 (Cy = cyclohexyl) with palladium(II) acetate in glacial acetic acid gave the monocyclometallated dimer complex [{Pd[4-(CHO)C6H3CH=NCu](O2CMe)}2] (1) which was shown to have a free formyl group on each phenyl ring by IR and H-1 and C-13-{H-1} NMR spectroscopy. Treatment of 1,4-(CuN=CH)2C6H4 with [MnMe(CO)5] in octane gave the doubly cyclometallated complex [(OC)4MnN(Cy)=C(H)CC6H2C(H)=N(Cy)Mn(CO)4] (2). Reaction of 1 with aqueous sodium chloride, bromide or iodide gave the monocyclometallated dimer complexes [{Pd[4-(CHO)C6H3C(H)=NCy](X)}2] [X=Cl (3), Br (4), or 1 (5)]. Complexes 1, 3 and 4 react with amines to give the corresponding cyclometallated dimer complexes [Pd{4-(CyN=CH)C6H3C(H)=NCy}(O2CMe)], (6) and [{Pd[4-(CyN=CH)C6H3C(H)=NR](X)}2] [X=Cl (7), X=Br (8) R=Cy; X=Cl, R=2,4,6-Me3C6H2 (9)] with an uncoordinated C=N group on each phenyl ring. Treatment of 3, 4 or 5 with thallium acetylacetonate gave the cyclometallated monomer compound [Pd{4-(CHO)C6H3C(H)=NCy}-(CH3COCHCOCH3)] (10) with a chelating 2,4-pentanedionate group. Treatment of 3, 4 or 5 with tertiary phosphines in a dimer/phosphine 1:2 or 1:4 molar ratio afforded the cyclometallated [Pd{4-(CHO)C6H3C(H)=NCy)(X)(L)] (11-18) and non-cyclometallated [Pd{4-(CHO)C6H3C(H)=NCy}(X)(L)2] (25-31) (X = Cl, Br, or 1; L=PPh3, PPh2Et, PPhEt2, or PPh2Me). Reaction of 11-13 with cyclohexylamine (L=PPh3) gave the non-cyclometallated compounds [Pd{4-(CyN=CH)C6H3C-(H)=NCy)(X)(PPh3)(NH2Cy)] (19-21) with two uncoordinated C=N groups whereas reaction of 14-18 with cyclohexylamine (L=PPh2Et, PPhEt2, or PPh2Me) gave the cyclometallated compounds [Pd{4-(CyN=CH)C6H3C(H)=NCy)(X)(L)] (22-24). Compounds 25 and 29 gave [Pd{4-(CyN=CH)C6H3C(H)=NCy}(Cl)(L)2] (32,33) (L=PPh3m or PPh2Et) when treated with cyclohexylamine. IR and H-1, C-13 and P-31 NMR data are discussed.