Panchromatic Light Harvesting and Stabilizing Charge‐Separated States in Corrole–Phthalocyanine Conjugates through Coordinating a Subphthalocyanine

Owing to the electron‐donating and ‐accepting nature of corroles (Corr) and phthalocyanines (Pc), respectively, we designed and developed two novel covalently linked Corr‐Pc conjugates. The synthetic route allows the preparation of the target conjugates in satisfying yields. Comprehensive steady‐state absorption, fluorescence, and electrochemical assays enabled insights into energy and electron‐transfer processes upon photoexcitation. Coordinating a pyridine‐appended subphthalocyanine (SubPc) to the Pc of the conjugate sets up the ways and means to realize the first example of an array composed by three different porphyrinoids, which drives a cascade of energy and charge‐transfer processes. Importantly, the SubPc assists in stabilizing the charge‐separated state, that is, one‐electron oxidized Corr and the one electron‐reduced Pc, upon photoexcitation by means of a reductive charge transfer to the SubPc. To the best of our knowledge, this is the first case of an intramolecular oxidation of a Corr within electron‐donor–acceptor conjugates by means of just photoexcitation. Moreover, the combination of Corr, Pc, and SubPc guarantees panchromatic absorption across the visible range of the solar spectrum, with the SubPc covering the „green gap“ that usually affects porphyrinoids.
Cascades: The preparation of two covalently linked corrole‐Zn phthalocyanine dyads is reported. The coordination of a pyridine‐appended perfluorinated subphthalocyanine to the zinc phthalocyanine leads to the formation of supramolecular triads. Corrole acts as electron donor upon photoexcitation, with subphthalocyanine as the final acceptor. These cascade‐like charge phenomena make these triads promising materials in molecular photovoltaics (see figure).