SYNTHESIS AND CHARACTERIZATION OF ARYLAMIDE-BRIDGED BINUCLEAR PALLADIUM(II) COMPLEXES - CRYSTAL-STRUCTURE OF ANTI-[(PD(C6F5)(T-BUNC)(MU-NHPH))2]

Binuclear mu-hydroxo-mu-amido palladium(II) complexes of the type [{Pd(C6F5)(PPh3)}2(mu-OH)(mu-NHC6H4X-p] (X = H (1), MeO (2), Cl (3), Br (4), and NO2 (5)) have been prepared by reaction of [{Pd(C6F5)(PPh3)(mu-OH)}2] with the corresponding aromatic amine in dichloromethane. The F-19 and P-31 NMR spectroscopic data indicate that the isolated complexes are the anti isomers. The reaction of [{Pd(C5F5)(t-BuNC)(mu-Cl}2] With 20% aqueous [NBu4]OH and the arylamine (1:2:2 mol ratio) in methanol leads to the formation of syn and anti isomers of the bis(amido) complexes [{Pd(C6F5)(t-BuNC)(mu-NHC6H4X-p)}2] (X = H (6), Me (7), MeO (8), Cl (9), and Br (10)). Complexes 6-9 are obtained as equimolar mixtures of syn and anti isomers and complex 10 as the anti isomer, but all the syn-anti mixtures are readily converted to the anti isomers by recrystallization from dichloromethane-hexane. The X-ray structure determination of anti-6 has been established. The geometry at each palladium atom center is distorted square planar, and the Pd2N2 is substantially puckered.