A β-ketoiminato palladium(II) complex for palladium deposition

The β-ketoiminato complex [Pd(OAc)L] (3) can be synthesized by the reaction of bis(benzoylacetone)diethylenetriamine (1, = LH) with [Pd(OAc)₂] (2). The structure of 3 in the solid state has been determined by single X-ray diffraction analysis. Complex 3 crystallizes as a dimer (3₂), which is formed by hydrogen bonds between NH and O_OAc functionalities of two adjacent ligands. Each of the Pd atoms is complexed by one ON₂ donor unit of the polydentate ligand L^- and an acetate group. Pd-Pd interactions and hydrogen bond formation between a NH and the C=O acetate moiety lead to a [4 + 2] coordination at Pd. The non-coordinated part of L exists in its β-keto-enamine form. The thermal decomposition behavior of 3₂ was studied by TG (thermogravimetry) and TG-MS showing that 3₂ decomposes between 200 and 500°C independent of the applied atmosphere. Under oxygen PdO is produced, while under argon Pd is formed as confirmed by PXRD measurements. Complex 3₂ was applied as a spin-coating precursor (conc. 0.1 mol L^-1, volume 1.5 mL, 3000 rpm, deposition time 6 min, heating rate 50 K min^-1, holding time 60 min (Ar) and 120 min (air) at T = 800°C). The as-obtained samples are characterized by granulated particles of Pd/PdO on the substrate surface. EDX (energy-dispersive X-ray spectroscopy) and XPS (X-ray photoelectron spectroscopy) measurements confirmed the formation of Pd (Ar) or PdO (O₂) with up to 12 mol% C impurity.