Similarities and Differences among Monolayers of a Free Base Porphyrin and its Copper Complex: Synthesis and Characterization of a Luminescent Copper(II) Porphyrin Monolayer

SiO2 substrates were functionalized with a covalent 4-ClCH2C6H4SiCl3 monolayer. Addnl. covalent bonding of the 5,10,15-tri-(p-dodecanoxyphenyl)-20-(p-hydroxyphenyl) Cu porphyrin to the silylated substrates was further achieved. The optical properties of this robust monolayer system were studied at room temp. by both UV-visible and photoluminescence measurements. The UV-visible spectrum reveals the Soret band and of a Q-band envelope only. The surface chem. characterization was carried out by x-ray photoelectron measurements. The N 1s spectrum shows two peaks in tune with the Cu porphyrin axial grafted to the silylated substrate. Luminescence measurements gave emission intensity values larger than those obsd. for the free base monolayer.