A novel BF₂-chelated azadipyrromethene–fullerene dyad: synthesis, electrochemistry and photodynamics

Abstract

The synthesis, structure, electrochemistry and photodynamics of a BF(2)-chelated azadipyrromethene-fullerene dyad are reported in comparison with BF(2)-chelated azadipyrromethene without fullerene. The attachment of fullerene resulted in efficient generation of the triplet excited state of the azadipyrromethene via photoinduced electron transfer.

Visible‐Light‐Harvesting Triphenylamine Ethynyl C60‐BODIPY Dyads as Heavy‐Atom‐Free Organic Triplet Photosensitizers for Triplet‐Triplet Annihilation Upconversion

“…This quenched emission of the antenna can be assigned to the intramolecular energy transfer from the antenna to the C 60 unit. [47,50] This putative intramolecular energy transfer was confirmed by the enhanced C 60 emission at 710 nm (1.75 eV) in C-1, compared with the result of C 60 alone under the same experimental conditions (Figure 2 a, inset). [47] It should be pointed out that the antenna absorbs much more strongly than the C 60 itself at this excitation wavelength ( Figure 1).…”

“…[17d, e] Previously BODIPY-C 60 , styryl-BODIPY-C 60 or aza-BODIPY-C 60 visible-light-harvesting C 60 dyads were prepared and the triplet excited state of the dyads were studied, [27,47,50] but no application of the triplet excited state as a photosensitizer was tested. A fluorene-containing C 60 dyad was reported to be able to produce singlet oxygen ( 1 O 2 ), yet the absorption of the dyad in the visible range is not very satisfying.…”

Excitation‐Wavelength‐Dependent, Ultrafast Photoinduced Electron Transfer in Bisferrocene/BF2‐Chelated‐Azadipyrromethene/Fullerene Tetrads

“…1.8 eV) is excluded, because of its higher energy compared with the 1 ADP* (1.78 eV for 1 and 1.73 eV for 2) and 1 C 60 * (1.75 eV) excited states. [14,15] Photodynamics probed by femtosecond transient spectroscopy: The photodynamics of the tetrads and the control compounds via the singlet ADP was examined by femtosecond transient measurements by using the excitation at 400 nm for the fullerene moiety, as shown in Figure 7. The transient spectra of both 1 and 2 exhibited bands at 1000 nm corresponding to C 60 C À , suggesting formation of Fc + -ADP-C 60 C À radical-ion pair as charge-separated states.…”

“…[14] Alternatively, when C 60 was covalently linked to ADP, the formation of ADPC + -C 60 C À was observed. [15] Excitation transfer was observed when either chlorophyll derivatives or BODIPY was covalently linked to ADP. [16] Interestingly, when a bisporphyrin was covalently linked to ADP, the resulting "molecular clip" supramolecularly assembled C 60 through metal-ligand coordination.…”

Vectorial Charge Separation and Selective Triplet-State Formation during Charge Recombination in a Pyrrolyl-Bridged BODIPY–Fullerene Dyad

“…In combining BDP and ADP to fullerene, one of the elegant approach developed in our laboratory involve utilization of the central boron, viz., replacing fluorines with a catechol group to which fullerene is attached, BDP-C60 (see compound 2 in Figure 1). [51][52][53][54][55][56] In an effort to rationalize the effect of boron-connected fullerene over peripheral carbon-connected fullerene, in the present study we have synthesized a new dyad using 3-pyrrolyl functionalized BDP, BDPPy-C60 (compound 1 in Figure 1). Systematic spectral and photochemical studies have been performed in benzonitrile and toluene on 1, and compared to the results reported earlier on compound 2.…”