Cover Picture

The cover picture shows a schematic representation of a supramolecular rod composed of meso-meso-coupled porphyrins. The Ag(I)-promoted meso-meso coupling of Zn(II) 5,15-diarylporphyrins enabled regularly arranged arrays with 2-128 porphyrins to be assembled. An examination of the absorption spectra of these rods show that they all exhibit split Soret bands as a result of exciton coupling. As the number of porphyrins increases the low-energy Soret band is shifted to longer wavelength while the high-energy Soret band stays at nearly the same wavelength, which results in a progressive increase in the splitting energy. A study of the fluorescence spectra of the arrays shows the S(1) states are delocalized over 6-8 porphyrin units. The 128mer at 0.1-μm long is the longest monodisperse, rodlike molecule so far known, and should, together with the smaller arrays, have the potential for application as light-harvesting wires. Further details are reported by A. Osuka et al. on p. 1458 ff. Magnified Cover Picture ]