A heptamethine-based charge-transfer dye was designed based on previous evidence of triplet state formation in orthogonal charge-transfer partners and calculations suggesting the formation of a charge-transfer state in heptamethine dye derivatives.
Photodynamics of an aluminum(iii) porphyrin-phosphorous(v) porphyrin heterodimer reveals initial formation of a singlet CT state which relaxes to a high-energy triplet CT state lasting for about 105 μs.