ORGANODIPALLADIUM(II) CYCLOMETALLATES OF THE SCHIFF-BASE N,N'-DIETHYL-2,6-DIALDIMINOBENZENE

Syntheses and reactions of dipalladiobenzene derivatives have been reported. Li2[PdCl4] reacts with N,N'-diethyl-2,6-dialdiminobenzene (H2L) to form the cyclometallated compound, [Pd4L2Cl4], in which metallation occurs at the 3,5-carbon atoms of the aromatic ring. The tetrachloro compound can be converted to a dinuclear precursor complex, [Pd2L(MeCN)2(ClO4)2], which reacts with pyridine, 4-methylpyridine, pyrazole and imidazole (B) to produce complexes of the type [Pd2L(B)4](ClO4)2, and with 2,2'-bipyridine to produce [Pd2L(bpy)2](ClO4)2. A tetranuclear neutral complex [Pd4L2(pz)4] is formed when the precursor complex interacts with pyrazole and triethylamine. A series of neutral chelate compounds [Pd2L(AB)2] has been obtained by reacting the precursor with sodium salts of acetylacetone, ethylacetoacetate, N-methylsalicylaldimine (HAB) and N,N'-dimethyldithiocarbamic acid (HAB). The compounds have been characterized from their H-1 NMR spectra.