Conjugated-linker dependence of the photophysical properties and electronic structure of chlorin dyads

The synthesis, photophysical properties and electronic structure of seven new chlorin dyads associated benchmark monomers are described. Each dyad contains two identical chlorins linked at the macrocycle [Formula: see text]-pyrrole 13-position. extent communication between constituents depends on nature conjugated linker. is assessed by modification prominent ground-state absorption redox properties, rate constants yields excited-state decay processes, molecular-orbital characteristics. Relative to monomers, in toluene exhibit a substantial bathochromic shift long-wavelength band (30 nm average), two-fold increased radiative constant [average (10 ns)[Formula: text] vs. (22 text]], reduced singlet lifetimes (average 5.0 ns 8.2 ns), fluorescence quantum 0.56 0.42). lifetime yield for with benzothiadiazole linker substantially benzonitrile due largely text]25-fold accelerated internal conversion. results aid design strategies molecular architectures that may find utility solar-energy conversion photomedicine.