Molecular architecture in the field of photonic devices

We report the synthesis and photophysical properties of two different photonic devices. The first system describes dinuclear metal complexes with a rigid and linear bridging ligand (PAP) that contains an adamantane spacer. We discuss the correlation between the nature of the bridging ligand and the electrochemical as well as photophysical properties of the metal complexes. Two interesting observations can already be pointed out: (i) the lifetime of the intermediate electron-transfer product Ru-III-PAP-Os-II is very long (130 mu s); and (ii) for the first time in a dinuclear Ru/Os system, the rate constant of energy transfer from the Ru(II) to the Os(II) unit is faster than the rate of the electron transfer from the Ru(II) to the Os(III) unit. The second system represents a photonic switch which is built up by two subunits, a rhenium complex as the active switching part and an anthracene moiety as detector. We discuss the synthesis, the reversibility of the switch and the energy transfer properties of the new system. (C) 1999 Elsevier Science S.A. All rights reserved.