ENERGY AND ELECTRON-TRANSFER PROCESSES IN SELF-ORGANIZED PORPHYRIN AND CHLORIN TRIADIC AND PENTADIC COMPLEXES

Self-organized arrays stable at room temperature containing three or f ive macrocyclic fragments have been constructed using two-fold ligatio n of Zn-porphyrin and Zn-chlorin chemical dimers by di- or tetrapyridy l substituted porphyrins, chlorins or tetrahydroporphyrins. Spectral, photophysical and thermodynamic properties of the ensembles have been studied in the temperature range from 140 to 360 K. Kinetic behavior o f the complexes upon optical excitation was investigated using a fluor escent picosecond laser setup (Delta t congruent to 30 ps) with 2-D (w avelength-lifetime) registration. Observed spectral properties are exp lained in terms of extra-ligation and excitonic coupling. Nonradiative forward and backward excitation energy transfer (ET), electron transf er and d-pi interactions are discussed as the main paths of electronic excitation deactivation in the complexes.