Peripheral ruthenium(II) complexes and orthogonal, ferrocyanide linked bilayers of (beta-tetraethyl-beta-p- and m-tetrapyridyl)porphyrins in bulk water

2,8,12,18-Tetraethyl-3,9,13,17-tetra-m- and p-pyridylporphyrins have been s ynthesized via dipyrromethanes. They form strongly fluorescing planar monol ayer leaflets in water. Upon titration with ferrocyanide the m-pyridylporph yrin adsorbs these anions and the fluorescence decreases drastically. One f errocyanide ion quenches the fluorescence of about 50 porphyrin units. In t he case of the p-isomer the quenching effect is much less pronounced. The z inc complex gives no defined monolayer in water, but assembles in the prese nce of equimolar amounts of ferrocyanide to a triple layer. Here, the centr al porphyrins are rotated into two different orthogonal positions: one of t hese porphyrin molecules provides its beta-pyridyl groups as axial ligands of the central zinc ions for the outer layers, the other takes part in a cl osed hydrophobic region, in which the beta-ethyl groups of two orthogonal p orphyrin ligands interact. Transmission electron and atomic force microscop y were used to characterize this new type of molecular assembly.