Langmuir–Blodgett films of tris(4,4′diisopropyldibenzylideneacetone)palladium(0): study of the photochemical conversion into catalytically active films

A study of Langmuir–Blodgett (LB) films of tris(4,4′-diisopropyldibenzylideneacetone)palladium(0) 1 and their photochemical decomposition under formation of catalytic palladium particles is presented. Studying π-A isotherms and A-t isobars at the air–water interface, the conditions for the formation of LB films have been optimized. Best conditions are a subphase temperature of 7°C and a surface pressure of 8 mN m−1. Photoirradiation of LB films at wavelengths λ<450 nm leads to a rapid photoreaction. Spectroscopic and chromatographic studies indicate a trans–cis isomerization of the ligand molecules in 1, which destabilizes the complex and causes its accelerated decomposition. Catalytic palladium particles are formed, which are able to catalyze the electroless nickel plating of the substrate, for example. Dependence of nickel plating on photoirradiation conditions of the LB film is reported. The photodecomposible LB films might be useful as precursor for a patterned metal plating of the substrate.