Synthesis and Spectroscopic and Electrochemical Properties of an Axially Symmetric Fullerene–Porphyrin Dyad with a Rigid Pyrrolo[3,4-c]pyrrole Spacer

Rigid axially symmetrical C60-BODIPY triplet photosensitizers: effect of bridge length on singlet oxygen generation

Two rigid axially symmetrical C₆₀-BODIPY systems with different bridge lengths have been synthesized and the dyad with short bridge generates a higher quantum yield of singlet oxygen.

Synthesis and Properties of Axially Symmetrical Rigid Visible Light-Harvesting Systems Containing [60]Fullerene and Perylenebisimide

Two visible light-harvesting perylenebisimide (PDI)-[60]fullerene (C₆₀) systems, dyad P1 with one C₆₀ unit and triad P2 with two C₆₀ units, have been synthesized. Both systems are axially symmetrical with a rigid biphenyl linker, ensuring a relatively fixed spatial distance between the donor and acceptor, preventing through-space interaction, and enhancing energy transfer. Steady-state and transient spectroscopy, electrochemistry, as well as theoretical calculations have been used to investigate the electrochemical and photophysical properties of the two systems. Steady-state and time-resolved spectroscopy demonstrate that the excited state is featured by an efficient intramolecular energy transfer from PDI to C₆₀. Then, the high efficient intrinsic intersystem crossing of C₆₀ eventually leads to the production of the triplet C₆₀. The extensive visible light absorption of PDI in the range of 400-650 nm and the final localization of the excited energy at the triplet C₆₀ make these compounds ideal singlet oxygen inducers. Further investigation shows that the photooxidation capability for both compounds is significantly enhanced with respect to either PDI or C₆₀ and even better than that of the commonly used triplet photosensitizer methylene blue (MB). The double C₆₀ moieties in P2 display a better result, and the photooxidation efficiency of P2 increases 1.3- and 1.4-fold compared to that of P1 and MB, respectively. The combination of a light-harvesting unit with an intersystem crossing unit results in a highly efficient photooxidation system, which opens up a new way to triplet photosensitizer design.

Static polarization of the supramolecular dyads of fullerene C60 with porphyrin derivatives

The nonlinear optical properties of four supramolecular dyads consisting of fullerene C 60 non-covalently bonded to porphyrin, porphyrazine, tetrabenzoporphyrin and phthalocyanine were investigated by calculating their electronic polarizability and first- and second-order hyperpolarizabilities using the finite field method and the density functional theory with the Grimme dispersion correction. Large first- and second-order hyperpolarizabilities result in nonlinear dependence of the polarization of dyads on the strength of external electric field. The increase in the size of the π-conjugated electron system of the porphyrin analogs leads to the increase of the polarizability and first- and second-order hyperpolarizabilities of the dyads. The absence of the covalent bonds between the components of the dyads prevents the field-induced electron transfer from porphyrin analogs to fullerene. The main reason for the nonlinear behavior of the polarization of dyads is the mutual polarization of fullerene and porphyrin analogs amplified by the external electric field.

A new heterocyclic skeleton with highly tunable absorption/emission wavelength via H-bonding

A new heterocyclic system, pyrido[2,1-a]pyrrolo[3,2-c]isoquinoline, showing stimuli responsive fluorescence, was synthesized via Pd-catalyzed intramolecular cyclization of 1-[1-benzyl-2-(2-bromophenyl)-1H-pyrrol-3-yl]pyridin-1-ium bromides.

Fulleropyrrolidine molecular dumbbells act as multi-electron-acceptor triads. Spectroscopic, electrochemical, computational and morphological characterizations

Three novel fulleropyrrolidine dumbbells consisting three electron acceptor moieties joined by alkyl linker displaying tunable electrical and morphological properties were synthesized and characterized.