RESUMO
Knowledge of the factors controlling excited state dynamics in excitonically coupled dimers and higher aggregates is critical for understanding natural and artificial solar energy conversion. In this work, we report ultrafast solvent polarity dependent excited state dynamics of the structurally well-defined subphthalocyanine dimer, µ-OSubPc2 . Stationary electronic spectra demonstrate strong exciton coupling in µ-OSubPc2 . Femtosecond transient absorption measurements reveal ultrafast excimer formation from the initially excited exciton, mediated by intramolecular structural evolution. In polar solvents the excimer state decays directly through symmetry breaking charge transfer to form a charge separated state. Charge separation occurs under control of solvent orientational relaxation.
RESUMO
Phthalocyanines and porphyrins are often the scaffolds of choice for use in widespread applications. Synthetic advances allow bespoke derivatives to be made, tailoring their properties. The selective synthesis of unsymmetrical systems, particularly phthalocyanines, has remained a significant unmet challenge. Porphyrin-phthalocyanine hybrids offer the potential to combine the favorable features of both parent structures, but again synthetic strategies are poorly developed. Here we demonstrate strategies that give straightforward, controlled access to differentially substituted meso-aryl-tetrabenzotriazaporphyrins by reaction between an aryl-aminoisoindolene (A) initiator and a complementary phthalonitrile (B). The choice of precursors and reaction conditions allows selective preparation of 1:3 Ar-ABBB and, uniquely, 2:2 Ar-ABBA functionalized hybrids.
