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Fused porphyrinoids have received increasing interest in light of their extended conjugation and unique coordination behavior. On the basis of our previously reported multiply fused pentaphyrin isomers 1 and 2, a novel isomer 3 has been synthesized in this work. 3 possesses a hexacyclic fused moiety with a nearly coplanar CCNN cavity involving an inverted pyrrole, which is slightly different from the CNNN ones of 1 and 2 involving an N-confused pyrrole. 1-3 possess cavities with three depronatable protons and thus they all can generate Cu(III) complexes. However, only 3Cu is stable under ambient conditions. On the other hand, 3 remains intact upon treatment with Pd(II) ions, while 1 and 2 could undergo structural rearrangement to accommodate Pd(II), affording 1Pd and 2Pd accompanied by the formation of a lactone ring and the addition of a methoxy group, respectively. Compared with the free bases, the complexes show distinct aromaticity and more intense near-infrared (NIR) absorption up to ca. 1600, 1170, and 1500 nm, respectively. The results indicate that the subtle modification of the linking modes between the pyrrolic units in the fused pentaphyrinoids is effective in modulating the coordination behavior for synthesizing complexes with tunable aromaticity and NIR absorption.

Chemodynamic therapy (CDT) is a highly targeted approach to treat cancer since it converts hydrogen peroxide into harmful hydroxyl radicals (OH & BULL;) through Fenton or Fenton-like reactions. However, the systemic toxicity of metal-based CDT agents has limited their clinical applications. Herein, a metal-free CDT agent: 2,4,6-tri(4-pyridyl)-1,3,5-triazine (TPT)/ [closo-B12H12]2-(TPT@ B12H12) is reported. Compared to the traditional metal-based CDT agents, TPT@B12H12 is free of metal avoiding cumulative toxicity during long-term therapy. Density functional theory (DFT) calculation revealed that TPT@B12H12 decreased the activation barrier more than 3.5 times being a more effective catalyst than the Fe2+ ion (the Fenton reaction), which decreases the barrier about twice. Mechanismly, the theory calculation indicated that both [B12H12]-& BULL; and [TPT-H]2+ have the capacity to decompose hydrogen into 1O2, OH & BULL;, and O2-& BULL;. With electron paramagnetic resonance and fluorescent probes, it is confirmed that TPT@B12H12 increases the levels of 1O2, OH & BULL;, and O2-& BULL;. More importantly, TPT@B12H12 effectively suppress the melanoma growth both in vitro and in vivo through 1O2, OH & BULL;, and O2-& BULL; generation. This study specifically highlights the great clinical translational potential of TPT@B12H12 as a CDT reagent. 2,4,6-Tri(4-pyridyl)-1,3,5-triazine (TPT)/ [closo-B12H12]2-(TPT@B12H12), a metal-free chemodynamic therapy (CDT) agent, decreases the activation barrier more than 3.5 times being a more effective catalyst than the Fe2+ ion (the Fenton reaction), which decreases the barrier about twice. More importantly, TPT@B12H12 effectively suppress the melanoma growth both in vitro and in vivo through 1O2, OH & BULL;, and O2-& BULL; generation. image

Utilizing water molecules to regulate the luminescence properties of solid materials is highly challenging. Herein, we develop a strategy to produce water-triggered luminescence-switching cocrystals by coassembling hydrophilic donors with electron-deficient acceptors, where 1,2,4,5-Tetracyanobenzene (TCNB) was used as the electron acceptor and pyridyl benzimidazole derivatives were used as the electron donors enabling multiple hydrogen-bonds. Two cocrystals, namely 2PYTC and 4PYTC were obtained and showed heat-activated emission, and such emission could be quenched or weakened by adding water molecules. The cocrystal structure exhibited the donor molecule that can form multiple hydro bonds with water and acceptor molecules due to the many nitrogen atoms of them. The analyses of the photophysical data, powder X-ray diffraction, and other data confirmed the reversible fluorescence "on-off" effects were caused by eliminating and adding water molecules in the crystal lattice. The density functional theory calculations indicate that the vibration of the O-H bond of water molecules in the cocrystal can absorb the excitation energy and suppress fluorescence. Furthermore, the obtained cocrystals also showed temperature, humidity, and H+/NH4+ responsive emission behavior, which allows their applications as thermal and humidity sensors, and multiple information encryptions. This research paves the way for preparing intelligent hydrophilic organic cocrystal luminescent materials. Hydrophilic donors with electron-deficient acceptors were coassembled to achieve luminescence-switching cocrystals triggered by water molecules. The obtained cocrystals show a strong water absorption ability and excellent fluorescence properties. The emission of cocrystals can be reversibly switched by heating and water. Finally, the obtained cocrystals show potential applications in temperature-humidity and acid-base responses.+image

Thermally activated delayed fluorescence (TADF) and room-temperature phosphorescence (RTP) are two highly applicable emissive processes due to their time-resolved characteristics and their ability to respond to external stimuli. They have recently been integrated for comprehensive use in some solid-state luminogens; however, there remains a lack of molecular systems that can integrate them in the solution aggregated state, which considerably limits relevant biological applications. In this study, we present a molecular design enabling aggregation-induced TADF-RTP dual emission in the solution aggregated state, relying on the coexistence of T-1-to-S-1 and T-1-to-S-0 electronic processes in push-pull structures. This dual emission feature constitutes a broad spectral band with full width at half-maximum up to 175 nm, providing the ability to select different channels for biological detection and imaging. Moreover, deoxygenation is shown to promote molecular aggregation, leading to a significantly strengthened dual emission that enables a high-contrast hypoxia probing effect. These results not only reveal new photophysical mechanisms on organic molecules but also expand the detection functionality of luminescent materials in the biological field., Funding Agencies|National Natural Science Foundation of China [22275038]; NSFC/China [K2024-33]; State Key Laboratory of Molecular Engineering of Polymers (Fudan University) [2130011540027, NAISS 2023/5-77]; Ningbo University of Technology [2020-04600]; Swedish Research Council [2009-00971]; Swedish Government Strategic Research Area in Materials Science on Advanced Functional Materials at Linkoping University [212-0136]; Olle Engkvists Stiftelse (Sweden)

Reversibly switching visible light excited phosphorescence emission by external stimuli is highly challenging. Herein, we report a series of tetrakis(arylthio)benzene derivatives with a D-A structure, exhibiting visible-light excited room-temperature phosphorescence. Significantly, the emission from their crystalline powder state responded to mechanical forces, attributed to alterations in molecular stacking changes, resulting in their phosphorescence color changes. Moreover, the monomer and aggregated phosphorescence transition could be reversibly switched by temperature when doping these molecules into a phase-changing matrix saturated fatty acid (FA) because the FA matrix is transformed between solid and fluid states under different temperatures. In addition, multi-color luminescent materials were also obtained by further introducing triphenylamine dye molecules. Finally, these doping systems exhibited excellent application potential in temperature indication and anti-counterfeiting. This successful design strategy provides a new idea for preparing reversible external stimuli-responsive phosphorescent materials. D-A-type tetrakis(arylthio)benzene derivatives exhibited visible-light excited phosphorescence, mechanical-stimuli responsive phosphorescence in solid and temperature-induced phosphorescence changes in the phase-changing doping state., Funding Agencies|Fundamental Research Funds for the Central Universities [2232022A-03, 2232022G-04]; National Natural Science Foundation of China [22375036, 21975046]; Natural Science Foundation of Shanghai [21ZR1402000]; International Cooperation Fund of Science and Technology Commission of Shanghai Municipality [21130750100]; Swedish Research Council [2020-04600, 2022-06725]; Swedish Government Strategic Research Area in Materials Science on Advanced Functional Materials at Linkoping University [2009-00971]

Confining luminophores into modified hydrophilic matrices or polymers is a straightforward and widely used approach for afterglow bioimaging. However, the afterglow quantum yield and lifetime of the related material remain unsatisfactory, severely limiting the using effect especially for deep-tissue time-resolved imaging. This fact largely stems from the dilemma between material biocompatibility and the quenching effect of water environment. Herein an in situ metathesis promoted doping strategy is presented, namely, mixing approximate to 10-3 weight ratio of organic-emitter multicarboxylates with inorganic salt reactants, followed by metathesis reactions to prepare a series of hydrophilic but water-insoluble organic-inorganic doping afterglow materials. This strategy leads to the formation of edible long-afterglow photoluminescent materials with superior biocompatibility and excellent bioimaging effect. The phosphorescence quantum yield of the materials can reach dozens of percent (the highest case: 66.24%), together with the photoluminescent lifetime lasting for coupes of seconds. Specifically, a long-afterglow barium meal formed by coronene salt emitter and BaSO4 matrix is applied into animal experiments by gavage, and bright stomach afterglow imaging is observed by instruments or mobile phone after ceasing the photoexcitation with deep tissue penetration. This strategy allows a flexible dosage of the materials during bioimaging, facilitating the development of real-time probing and theranostic technology. A universal strategy is proposed to construct edible photoluminescent long-afterglow materials by embedding luminophore multicarboxylates into a series of inorganic salt lattices. Particularly, edible afterglow barium meal formed by coronene salt doped BaSO4 can be applied into gastrointestinal afterglow imaging captured by instruments or mobile phone. image, Funding Agencies|National Natural Science Foundation of China; [21975046]; [22275038]

Thiahexaphyrinone 1 and thia-dipyrrin-appended corrorin 2 have been synthesized. Surprisingly, further oxidation of compound 2 with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) in dichloromethane afforded dimer 3 with two molecules of compound 2 linked at the alpha-carbon atoms of the thienyl units. Treatment of compound 3 with DDQ in MeOH and SnCl2 in tetrahydrofuran/H2O afforded the dimethoxy-attached dimer 4 and hydrogenated dihydroxy-attached dimer 5, respectively. These results provide the first examples for synthesizing thiophene-linked porphyrinoid dimers with tunable near-infrared absorption and chirality., Funding Agencies|National Natural Science Foundation of China; East China University of Science and Technology (ECUST) [22131005, 22201074, 22075077, 21971063]; National Natural Science Foundation of China [23QA1402100]; Shanghai Rising-Star Program [23ZR1415600, 22ZR1416100]; Natural Science Foundation of Shanghai [2018-05973, 2020-04600]; Swedish Research Council [JPMXS0320220200]; Ministry of Education, Culture, Sports, Science and Technology (MEXT) Leading Initiative for Excellent Young Researchers

Hybrid dyes comprising 1,4-dihydropyrrolo[3,2-b]pyrrole and two strongly electron-withdrawing benzoxadiazole substituents, differing in their level of planarization, offer an insightful window into the interplay between internal conversion and intersystem crossing as relaxation pathways from the excited state. The emission intensity is strong for non-fused systems whilst it is minimal for fused dyes. Computational evaluation has revealed that internal conversion, and not inter-system crossing, is the main non-radiative process for planar, fused quadrupolar dyes. Planarization of the pyrrolopyrrole chromophore switches the mechanism of non-radiative deactivation from intersystem crossing to internal conversion., Funding Agencies|Polish National Science Center, Poland [212-0136]; Research Council of Norway; Ministry of Education and Science of Ukraine; European Union within the European Regional Development Fund; National Academic Infrastructure for Supercomputing in Sweden (NAISS); Swedish Research Council; Olle Engkvists Stiftelse (Sweden); [OPUS 2020/37/B/ST4/00017]; [2019/33/B/ST4/03144]; [324139]; [0121U107533]; [POIG.02.01.00-14.122/09]; [2023/5-77]; [2022-06725]; [2020-04600]

To further enrich the coordination chemistry of hexaphyrins and probe the underlying property-structural correlations, N-confused dithiahexaphyrin(1.1.1.1.1.0) (1) with 26 pi-electron H & uuml;ckel aromaticity was synthesized. Based on its unprecedented two unsymmetrical cavities, five palladium complexes 2, 3, 4-Ph, 4-Cl and 5 have been successfully synthesized under various coordinations. Thus, two mono-Pd(II) complexes 2 and 3 with the Pd(II) atom coordinated in the two different cavities were obtained by treating 1 with palladium reagents PdCl2, and (PPh3)(2)PdCl2 respectively. On this basis, bis-Pd(II) complexes 4-Ph and 4-Cl were synthesized by treating 2 and 3 with (PPh3)(2)PdCl2 and PdCl2, respectively. As a result, both 4-Ph and 4-Cl contain two Pd(II) atoms coordinated within the two cavities, with one of the Pd(II) atoms further coordinated to a triphenylphosphine ligand in addition to an anionic ancillary ligand of Ph- and Cl-, respectively. Notably, a further contracted mono-Pd(II) complex 5 was synthesized by treating 1 with Pd(PPh3)(4) by eliminating one of the meso-carbon atoms together with the corresponding C6F5 moiety. These complexes present tunable 26 pi aromaticity and NIR absorption up to 1060 nm. This work provides an effective approach for developing distinctive porphyrinoid Pd(II) complexes from a single porphyrinoid, without resorting to tedious syntheses of a series of porphyrinoid ligands., Funding Agencies|Shanghai Rising-Star Program [22131005, 21971063, 22201074, 22075077]; NSFC; Fundamental Research Funds for the Central Universities [23QA1402100]; Shanghai Rising-Star Program [23ZR1415600, 22ZR1416100]; Natural Science Foundation of Shanghai [2018-05973, 2020-04600]; Swedish Research Council

Molecular emitters with multi-emissive properties are in high demand in numerous fields, while these properties basically depend on specific molecular conformation and packing. For amorphous systems, special molecular arrangement is unnecessary, but it remains challenging to achieve such luminescent behaviors. Herein, we present a general strategy that takes advantage of molecular rigidity and S1-T1 energy gap balance for emitter design, which enables fluorescence-phosphorescence dual-emission properties in various solid forms, whether crystalline or amorphous. Subsequently, the amorphism of the emitters based polymethyl methacrylate films endowed an in situ regulation of the dual-emissive characteristics. With the ratiometric regulation of phosphorescence by external stimuli and stable fluorescence as internal reference, highly controllable luminescent color tuning (yellow to blue including white emission) was achieved. There properties together with a persistent luminous behavior is of benefit for an irreplaceable set of optical information combination, featuring an ultrahigh-security anti-counterfeiting ability. Our research introduces a concept of eliminating the crystal-form and molecular-conformational dependence of complex luminescent properties through emitter molecular design. This has profound implications for the development of functional materials. A molecular structural strategy enabling single emitter based dual-emission properties in various solid forms is presented. The developed amorphous films endow in situ regulation of the dual-emissive characteristics to show highly controllable multiple luminescent color tuning (yellow to blue including white emission), which benefits to the construction of an irreplaceable set of optical information combination.image, Funding Agencies|National Natural Science Foundation of China [2022-06725]; Swedish Research Council [22275038]; Russian Scientific Foundation [NAISS 2023/5-77]; National Academic Infrastructure for Supercomputing in Swede at the National Supercomputer Centre (NSC) at Linkoeping University; [2020-04600]; [23-73-10081]

Adding nitro groups to aromatic compounds usually quenches their fluorescence via intersystem crossing (ISC) or internal conversion (IC). Herein, we investigated centrosymmetric 1,4-dihydropyrrolo[3,2-b]pyrroles linked to variously substituted nitro-heteroaryls. A 1,4-orientation of the nitro substituent versus the electron rich 1,4-dihydropyrrolo[3,2-b]pyrrole core invokes a strong fluorescence in non-polar solvents and intense two-photon absorption while a 1,3-orientation of push-pull substituents results in a dramatic hypsochromic shift of absorption, weak, bathochromically shifted emission and weak two-photon absorption. The combined experimental and computational study indicates that the primary responsible factors are: (1) the difference in electron density distribution in the LUMO; (2) the difference in mu 10. IC is a dominant mechanism of non-radiative dissipation of energy in all these dyes but as long as the distribution of electron density within the HOMO and LUMO is delocalized on the 1,4-dihydropyrrolo[3,2-b]pyrrole core as well as on the nitroaromatic moieties its rate is slower than the fluorescence rate in non-polar solvents., Funding Agencies|Foundation for Polish Science (TEAM) [POIR.04.04.00-00-3CF4/16-00]; National Science Centre, Poland [2017/25/Z/ST2/03038]; OPUS [2020/37/B/ST4/00017]; European Union [101007804]; JSPS KAKENHI [21H01887]; Ministry of Education and Science of Ukraine [0121U107533]; Academy of Finland [346369]; Swedish Research Council [2022-06725]; Swedish Research Council [2020-04600]; Olle Engkvists Stiftelse (Sweden) [212-0136]