Development of functional dye with redshifted absorption based on Knoevenagel condensation at 1-site in phenyl[b]-fused BODIPY

Integrating ring-fused modification withπ-conjugated extension is an effective approach for designing,synthesizing,and application for novel borondipyrromethene(BODIPY)structures.In this work,based on phenyl[b]-fused BODIPY,we made reasonable modification of the methyl group at 1-site to generate dye NBDP.NBDP possessed near-infrared region(NIR)absorption and emission properties,and the intramolecular charge transfer(ICT)resulted in low fluorescence.Whereas,heat energy is evidently released in the presence of light,which can be exploited for intracellular photothermal therapy via the cell apoptosis process,reducing the inflammatory side-effects induced by necrosis.This research provides a crucial foundation for the novel molecule via BODIPY multi-directional alteration and its potential application in anti-tumor phototherapy.

Heavy-atom-free orthogonal configurative dye 1,7-di-anthra-aza-BODIPY for singlet oxygen generation

Spin-orbit,charge-transfer intersystem crossing(SOCT-ISC)can directly overcome the disadvantages of the traditional heavy-atom effect and improve the generation efficiency of reactive oxygen species(ROS).Since orthogonal molecular orbitals of donor-acceptor(D-A)pairs favor the SOCT-ISC transition,herein aza-borondipyrromethenes(aza-BODIPYs)with 1,7-di-anthracyl groups(An-azaBDP)was successfully prepared,owing to steric hindrance to produce a big dihedral angle between the two molecular orbital(MO)planes.Moreover,according to density functional theory(DFT)and time-dependent density functional theory(TDDFT),the energy difference between the S1-T1orbitals of An-aza BDP is small and more inclined towards ISC.An-aza BDP can effectively generate singlet oxygen under light irradiation.An-aza BDP with light irradiation can induce apoptosis in SW620 cells,and can serve as a potential candidate for the treatment of cancer cells and tumors.

Aniline as a TICT rotor to derive methine fluorogens for biomolecules:A curcuminoid-BF2 compound for lighting up HSA/BSA

The unique structure of fluorescent proteins in which the fluorophore is encapsulated by the protein shell to restrict rotation and emit light inspired the screening of chromophores that selectively bind to biomolecules to generate fluorescence. In this paper, we report a curcuminoid-BF2-like fluorescent dye NBF2containing 4-dimethylaniline as an electron-donating group. When this dye is combined with HSA or BSA, the fluorescence is enhanced 90/112-fold, and the fluorescence quantum yield increases from <0.001to 0.16/0.19. Such a large change in fluorescence enhancement is due to the encapsulation of N-BF2in the protein cavity by HSA/BSA, which inhibits the intramolecular rotation of the aniline moiety caused by charge transfer after the fluorophore is excited by light. N-BF2has fast and strong binding to HSA or BSA and was found to be reversible in solution and intracellularly. Since N-BF2also has the ability to target lipid droplets, the complex of N-BF2/HSA realizes the regulation of reversible lipid droplet staining in cells.

Engineering J-aggregates for NIR-induced meso-CF_(3)-BODIPY nanoparticles by activated apoptosis mechanism in photothermal therapy

Forming J-aggregates by organic monomer is a fascinating strategy to urge spectroscopic redshift with respect to that of the monomer.Herein,we designed 1,7-diphenyl-substituted meso–CF_(3)-BDP monomer confirmed by X-ray crystallographic analysis.The low-barrier rotation of the–CF_(3)group in meso–CF_(3)-BDP1 significantly enhances the non-radiative efficiency,and the photothermal conversion efficiency(PCE)of the self-assembled nanoparticles(1-NPs:λ_(abs)=746 nm)by J-aggregates was 82%.1-NPs could effectively block cell cycle progression,inhibit cancer cell proliferation and trigger cell apoptosis under low power laser irradiation(0.2 W/cm^(2)).This study proposes an alternate molecular design platform by J-aggregates to promote PCE through the insertion of rotating segment and trigger the cancer cells apoptosis in photothermal therapy at low power laser density.