Synthesis and structural studies of cyclopalladated complexes of secondary benzylamines

Di-nuclear cyclopalladated acetato-bridged complexes derived from secondary benzylamines, [Pd 2 {( C , N )-C 6 H 4 CH 2 NH(R)} 2 (μ-OAc) 2 ] (R = Et ( 1 ), R = t-Bu ( 2 )) were obtained by refluxing of corresponding benzylamines and Pd(OAc) 2 in a 1:1 M ratio. Complex 1 was also prepared by heating the bis-amine complex [Pd(OAc) 2 (PhCH 2 NH(Et)) 2 ] ( 3 ) in toluene at 60 °C. Complex 3 reacted with an excess of NaCl to give [Pd(Cl) 2 (PhCH 2 NH(Et)) 2 ] ( 4 ). Metathetical reaction of 1 and 2 with an excess of NaCl or NaBr afforded the corresponding dimers [Pd 2 {( C , N )-C 6 H 4 CH 2 NH(R)} 2 (μ-X) 2 ] (X = Cl, R = Et ( 5 ); X = Cl, R = t-Bu ( 6 ); X = Br, R = t-Bu ( 7 )). The cationic complex [Pd( C , N )-C 6 H 4 CH 2 NH(Et)(phen)]BF 4 ( 8 ) can be obtained by reacting chloro bridge dimer 5 with AgBF 4 and 1,10-phenanthroline (phen). Neutral ligands split the halide bridges in 6 and 7 to give monomeric complexes [Pd( C , N )-C 6 H 4 CH 2 NH(t-Bu)X(L)] (X = Cl, L = PPh 3 ( 9 ); X = Br, L = Me 3 Py ( 10 )). Complexes 1 – 10 were fully characterized by elemental analysis, IR and NMR spectroscopies. In addition, the crystal structures of 2 , 3 , 4 , 8 , 9 and 10 were determined by single-crystal X-ray diffraction analysis. In all these structures, the palladium atom shows a distorted or slightly distorted square-planar geometry.