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Covalent organic frameworks (COFs) have been explored for photodynamic therapy (PDT) of cancer, but their antitumor efficacy is limited by excited state quenching and low reactive oxygen species generation efficiency. Herein, we report a simultaneous protonation and metalation strategy to significantly enhance the PDT efficacy of a nanoscale two-dimensional imine-linked porphyrin-COF. The neutral and unmetalated porphyrin-COF (Ptp) and the protonated and metalated porphyrin-COF (Ptp-Fe) were synthesized via imine condensation between 5,10,15,20-tetrakis(4-aminophenyl)porphyrin and terephthalaldehyde in the absence and presence of ferric chloride, respectively. The presence of ferric chloride generated both doubly protonated and Fe 3+ -coordinated porphyrin units, which red-shifted and increased the Q-band absorption and disrupted exciton migration to prevent excited state quenching, respectively. Under light irradiation, rapid energy transfer from protonated porphyrins to Fe 3+ -coordinated porphyrins in Ptp-Fe enabled 1 O 2 and hydroxyl radical generation via type II and type I PDT processes. Ptp-Fe also catalyzed the conversion of hydrogen peroxide to hydroxy radical through a photoenhanced Fenton-like reaction under slightly acidic conditions and light illumination. As a result, Ptp-Fe-mediated PDT exhibited much higher cytotoxicity than Ptp-mediated PDT on CT26 and 4T1 cancer cells. Ptp-Fe-mediated PDT afforded potent antitumor efficacy in subcutaneous CT26 murine colon cancer and orthotopic 4T1 murine triple-negative breast tumors and prevented metastasis of 4T1 breast cancer to the lungs. This work underscores the role of fine-tuning the molecular structures of COFs in significantly enhancing their PDT efficacy.

Metal-organic layers (MOLs), a monolayered version of metal-organic frameworks (MOFs), have recently emerged as a novel two-dimensional molecular material platform to design multifunctional catalysts. MOLs inherit the intrinsic molecular tunability of MOFs and yet have more accessible and modifiable building blocks. Here we report molecular engineering of six MOLs via modulated solvothermal synthesis between HfCl 4 and three photosensitizing ligands followed by postsynthetic modification with two carboxylate-containing cobaloximes for tandem and synergistic photocatalysis. Morphological and structural characterization by transmission electron microscopy and atomic force microscopy and compositional analysis by inductively coupled plasma-mass spectrometry and nuclear magnetic resonance spectroscopy establish the MOLs as flat nanoplates with a periodic lattice structure of hexagonal symmetry. The MOLs efficiently catalyze tandem dehydrogenative coupling reactions and synergistic Heck-type coupling reactions. The most active MOL catalyst was used for the gram-scale synthesis of vesnarinone, a cardiotonic agent, in 80% yield with a turnover number of 400 and in eight consecutive reaction cycles without significant loss of activities.

Intermolecular photoredox ene-carbonyl reductive coupling reactions typically have low product selectivity owing to competing dimerization and/or reduction of ketyl radicals. Herein, we report a metal-organic layer (MOL), Hf-Ir-OTf, as a bifunctional photocatalyst for selective photoredox reductive coupling of ketones or aldehydes with electron-deficient alkenes. Composed of iridium-based photosensitizers (Ir-PSs) and triflated Hf 12 clusters, Hf-Ir-OTf uses Lewis acidic Hf sites to bind and activate electron-deficient alkenes to accept ketyl radicals generated by adjacent Ir-PSs, thereby suppressing undesired dimerization and reduction of ketyl radicals to enhance the selectivity for the cross-coupling products. The MOL-catalyzed reductive coupling reaction accommodates a variety of olefinic substrates and tolerates reducible groups, nicely complementing current methods for cross-coupling reactions.

Low-ash-melting-point bituminous coal and high-ash-melting-point anthracite coal are mixed and burned in different proportions. The ash melting characteristics of blended coal were determined experimentally. At the same time, the ash samples of bituminous coal, anthracite, and blended coal were analyzed by X-ray diffraction (XRD), and the ash melting characteristic improvement mechanism of blended coal was analyzed by quantum chemical calculations. The results show that when high-ash-melting-point anthracite is added, the ash melting characteristics of blended coal are improved, and the deformation temperature, softening temperature, hemispheric temperature, and flow temperature of the blended coal are significantly increased. The melting point of blended coal ash with a bituminous coal ratio of less than 50% can meet the requirements of blast furnace injection. The reason for the improved melting characteristics of the blended coal ash is that mullite in anthracite ash reacts with gehlenite in bituminous coal ash during the combustion process to produce anorthite., Competing Interests: The authors declare no competing financial interest., (© 2021 The Authors. Published by American Chemical Society.)

We report the design of a new multifunctional metal-organic layer (MOL), Hf 12 -Ir-OTf, comprising triflate (OTf)-capped Hf 12 secondary building units (SBUs) and photosensitizing Ir(DBB)[dF(CF 3 )ppy] 2 + [DBB-Ir-F, DBB = 4,4'-di(4-benzoato)-2,2'-bipyridine; dF(CF 3 )ppy = 2-(2,4-difluorophenyl)-5-(trifluoromethyl)pyridine] bridging ligands. Hf 12 -Ir-OTf effectively catalyzed dehydrogenative cross-couplings of heteroarenes with ethers, amines, and unactivated alkanes with turnover numbers of 930, 790, and 950, respectively. Hf 12 -Ir-OTf also competently catalyzed late-stage functionalization of bioactive and drug molecules such as caffeine, Fasudil, and Metyrapone. The superior catalytic performance of Hf 12 -Ir-OTf over a mixture of photoredox catalyst and stoichiometric amounts of Brønsted acids or substoichiometric amounts (20 mol %) of Lewis acids is attributed to the close proximity (1.2 nm) between photoredox and Lewis acid catalysts in Hf 12 -Ir-OTf, which not only facilitates the reaction between the carbon radical and the activated heteroarene but also accelerates the electron transfer from the nitrogen radical intermediate to the Ir(IV) species in the catalytic cycle.