Closely positioned donor-acceptor pairs facilitate electron- and energy-transfer events, relevant to light energy conversion. Here, a triad system TPACor-C60 , possessing a free-base corrole as central unit that linked the energy donor triphenylamine (TPA) at the meso position and an electron acceptor fullerene (C60) at the β-pyrrole position was newly synthesized, as were the component dyads TPA-Cor and Cor-C60. Spectroscopic, electrochemical, and DFT studies confirmed the molecular integrity and existence of a moderate level of intramolecular interactions between the components. Steady-state fluorescence studies showed efficient energy transfer from (1) TPA* to the corrole and subsequent electron transfer from (1) corrole* to fullerene. Further studies involving femtosecond and nanosecond laser flash photolysis confirmed electron transfer to be the quenching mechanism of corrole emission, in which the electron-transfer products, the corrole radical cation (Cor(⋅+) in Cor-C60 and TPA-Cor(⋅+) in TPACor-C60) and fullerene radical anion (C60(⋅-)), could be spectrally characterized. Owing to the close proximity of the donor and acceptor entities in the dyad and triad, the rate of charge separation, kCS , was found to be about 10(11)  s(-1), suggesting the occurrence of an ultrafast charge-separation process. Interestingly, although an order of magnitude slower than kCS , the rate of charge recombination, kCR , was also found to be rapid (kCR ≈10(10)  s(-1)), and both processes followed the solvent polarity trend DMF>benzonitrile>THF>toluene. The charge-separated species relaxed directly to the ground state in polar solvents while in toluene, formation of (3) corrole* was observed, thus implying that the energy of the charge-separated state in a nonpolar solvent is higher than the energy of (3) corrole* being about 1.52 eV. That is, ultrafast formation of a high-energy charge-separated state in toluene has been achieved in these closely spaced corrole-fullerene donor-acceptor conjugates.

Utilization of polyethyleneglycol (PEG) functionalized zinc phthalocyanine, (PEG)4ZnPc in (i) singlet oxygen generation, and (ii) in building energy harvesting donor‐acceptor systems using fullerene, C60 as an acceptor via the well‐known metal‐ligand axial coordination approach is reported. The (PEG)4ZnPc was found to be capable of producing singlet oxygen with a quantum yield, ΦΔ of 0.77 in toluene, a value higher than that obtained for pristine (t‐bu)4ZnPc (ΦΔ=0.54) carrying no PEG groups, revealing its usefulness in photodynamic therapy applications. Spectroscopic studies revealed efficient binding of phenylimidazole functionalized fullerene, C60Im with 1:1 stoichiometry to (PEG)4ZnPc. Binding constant K for the formation of (PEG)4ZnPc:ImC60 dyad was found to be 6×103 M−1 revealing moderate stability. Geometric and electronic studies of the dyad was arrived by B3LYP/3‐21G(∗︁) method. The HOMO level was found to be on zinc phthalocyanine entity while the LUMO level was found to be on the C60 entity suggesting formation of (PEG)4ZnPc·+:ImC60· − charge separated state during the process of electron transfer reaction. Redox studies on the (PEG)4ZnPc:ImC60 dyad enabled accurate determination of the oxidation and reduction potentials of the donor‐acceptor system, and to evaluate free‐energy changes associated for the charge separation process. Kinetics of photoinduced charge separation and recombination in the (PEG)4ZnPc:ImC60 dyad was investigated using femtosecond transient absorption studies. Relatively long‐lived charge separated states were confirmed for the dyad suggesting their potential usefulness in energy harvesting applications.