Peripherally tetra-palladated phthalocyanines

Phthalocyanines (M = Co, Zn or 2H) with four ({4-[(Z or E)-phenylazo]-1-naphthyl}oxy) substituents on the periphery have been synthesized to enlarge the absorbing range of the dyestuffs. Cyclopalladation of the azobenzene groups lead to network-type oligomeric products by formation of binuclear palladium (II) complexes and they have been further converted into monomeric species by treatment with acetylacetonate. The electronic spectra clearly indicate the absorptions resulting from phenylazo and naphthyl groups along with the Q and B bands of the phthalocyanines. The consequence of the palladation is a relatively intense broad absorption due to LMCT with maxima around 520 nm.