Two-photon excitable fluorescent dyes with integrated functions of targeted imaging and photodynamic therapy (PDT) are highly desired for the development of cancer theranostic agents. Herein, fluorescence resonance energy transfer (FRET) dyads, AceDAN-HPor-Lyso (1a) and AceDAN-ZnPor-Lyso (1b), were developed for two-photon excited (TPE) lysosome-targeted fluorescence imaging and PDT of cancer cells. Under one-photon or two-photon excitation, the AceDAN donor can effectively transfer the excited state energy to the porphyrin acceptor via high efficient FRET, leading to the generation of deep-red fluorescence and singlet oxygen for cell imaging and PDT, respectively. 1a and 1b exhibit high photocytotoxicity and low dark cytotoxicity, in addition to strong lysosomal targeting capability in living cells. By taking the advantages of the two-photon absorption properties of the AceDAN donor and the properly distributed S and T states of the porphyrin acceptor, the AceDAN-porphyrin dyads 1a and 1b have been successfully applied to TPE-fluorescence imaging for tracking the significant morphology changes of cancer cells under two-photon laser irradiation.

As a vital biological mediator and a widely used industrial oxidant, the accurate detection of hydrogen peroxide (H 2 O 2 ) is of significance for both academic purpose and practical applications. Herein, we report a novel approach for the development of a high-performance electrochemical H 2 O 2 sensor constructed by iron phthalocyanine (FePc)based diyne-linked conjugated polymeric nanosheets (NSs), FePc-CP NSs. The FePc-CP NSs were delaminated from the bulk material via a defect-and disorder-induced synthetic strategy. By the quasi-Langmuir−Shafer method, the prepared FePc-CP NSs were self-assembled into multilayer films with controllable thickness on electrodes. Owing to the highly exposed active centers on the surfaces, the FePc-CP NS filmmodified electrodes exhibited excellent H 2 O 2 determination performance with a wide linear detection range (0.1−1000 μM), a short response time (the response current approached the maximum value within 0.1 s), a low limit of detection (0.017 μM), and excellent sensitivity (97 μA cm −2 mM −1 ), which are comparable to the best results reported so far for electrochemical H 2 O 2 sensors. In addition, the fabricated electrochemical H 2 O 2 sensor also displayed satisfactory stability, reproducibility, and selectivity. Furthermore, the obtained FePc-CP NS film sensor can be applied in real-time monitoring of H 2 O 2 in commercial orange juice and beer as well as H 2 O 2 secreted from A549 live cells, revealing its application potential toward the accurate detection of H 2 O 2 in real-sample analysis.

Two-photon excitedf luorescent (TPEF) materials are highly desirable for bioimaging applications owing to their unique characteristics of deep-tissue penetration and high spatiotemporal resolution. Herein, by connectingo ne, two, or three electron-deficient zinc porphyrin units to an electron-rich triazatruxene core via ethynyl p-bridges, conjugated multipolar molecules TAT-(ZnP) n (n = 1-3) were developed as TPEF materialsf or cell imaging. The three new dyes presenth igh fluorescence quantum yields (0.40-0.47) and rationally improved two-photon absorption (TPA) properties. In particular, the peak TPAc ross sectiono fTAT-ZnP (436 GM) is significantly largert han that of the ZnP reference (59 GM). The d TPA values of TAT-(ZnP) 2 and TAT-(ZnP) 3 further increase to 1031 and up to 1496 GM, respectively,i ndicatingt he effect of incorporated ZnP units on the TPA properties. The substantial improvemento ft he TPEF properties is attributed to the formation of p-conjugated quadrapole/octupole molecules and the extensiono fD-p-AD systems,w hich has been rationalized by density function theory(DFT) calculations. Moreover, all of the three new dyes displayg ood biocompatibility and preferential targeting ability towardc ytomembrane, thusc an be superior candidates for TPEF imaging of living cells. Overall, this work demonstratedapromisings trategy for the development of porphyrin-based TPEF materials by the construction and extensiono fD-p-AD multipolar array.

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A FRET based AceDAN–porphyrin(Zn) dyad was designed to generate red emission and singlet oxygen (1O2) simultaneously, which were utilized successfully for two-photon excited fluorescence imaging and PDT of cancer cells.

There has been considerable research interest in the ligand nature of N-heterocyclic carbenes (NHCs). In this work, two six-coordinate NHC iron porphyrin complexes [FeII(TTP)­(1,3-Me2Imd)2] (TTP = tetratolylporphyrin, 1,3-Me2Imd = 1,3-dimethylimidazol-2-ylidene) and [FeIII(TDCPP)­(1,3-Me2Imd)2]­ClO4 (TDCPP = 5,10,15,20-tetrakis­(2,6-dichlorophenyl)­porphyrin) are reported. Single-crystal X-ray characterizations demonstrate that both complexes have strongly ruffled conformations and relatively perpendicular ligand orientations which are forced by the sterically bulky 1,3-Me2Imd NHC ligands. Multitemperature (4.2–300 K) and high magnetic field (0–9 T) Mössbauer and low-temperature (4.0 K) EPR spectroscopies definitely confirmed the low-spin states of [FeII(TTP)­(1,3-Me2Imd)2] (S = 0) and [FeIII(TDCPP)­(1,3-Me2Imd)2]­ClO4 (S = 1/2). The similarity of 1,3-Me2Imd and imidazole, as well as the well-established correlations between the ligand nature and spectroscopic characteristics of [FeII,III(Porph)­(L)2]0,+ (Porph: porphyrin; L: planar base ligand) species, allowed direct comparisons between the pair of ligands which revealed for the first time that NHC has a stronger π-acceptor ability than imidazoles, in addition to its very strong σ-donation.

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A new pair of 2,2ʹ-diamino-1,1ʹ-binaphthyl linked porphyrin dimers, (R)-/(S)-H, were synthesized to study their supramolecular interactions with a pair of chiral diamines ((R)-/(S)-PPDA) by using UV-Vis absorption, fluorescence and NMR titrations. The spectroscopic titrations indicated that sandwich-type 1:1 complexes were formed at low guest concentration and then transformed to 1:2 open complexes at high guest concentration. The supramolecular interactions afforded sensitive circular dichroism responses, and the CD signs of the 1:1 complexes are decided by the stereostructure of chiral diamine guests. Moreover, due to the shortened linking units, (R)-/(S)-H show more sensitive and predicable CD response than the previously reported hosts (R)-/(S)-H1 and this can be reasonably explained by DFT molecular modeling. The present results suggest (R)-/(S)-H are promising for chiral optical sensing.