RELAXATION PROCESS OF THE SINGLET EXCITED-STATE OF WHEEL-AND-AXLE-TYPE PHOSPHORUS(V) POMPHYRIN DIMERS

A series of ''wheel-and-axle-type'' phosphorus(V) porphyrin dimers, wh ose central phosphorus atoms are connected to each other by various le ngths of the alkyldioxy bridge, were synthesized and investigated on t heir excited state for the evaluation of the contribution of a charge- transfer (CT) state. The decrease of the lifetime of the singlet excit ed state of the dimer in the polar solvent suggest the enhancement of the nonradiative decay through the CT state. The lifetime of the symme try-disturbed dimer was shorter than those of symmetric dimers.