Light Absorption and Energy Transfer in Polyene‐porphyrin Esters*

Two examples of a new class of compounds, polyenes covalently linked to meso‐ tetraarylporphyrins, have been prepared. Optical studies revealed that energy transfer from a 26 π electron polyene moiety to the porphyrin was zero, whereas energy transfer efficiency from a polyene containing 18 π electrons was ˜80%. The results demonstrate that the polyene moiety can function as an efficient light gathering antenna for possible application to porphyrin‐based solar energy conversion schemes. In addition, such polyene‐porphyrin esters may serve as probes of the structural requisites for light harvesting by carotenoids in the photosynthetic membranes of green plants.