Figure - available from: Advanced Science
This content is subject to copyright. Terms and conditions apply.
a) EPR spectra of COF‐TPA‐TMTA and COF‐TPA‐TMTAO before and after exposure to light. b) UV–vis spectra (inset: digital photographs). c) Tauc plots. d,e) Mott–Schottky curves. f) The energy band structure.
Source publication
There is growing interest in developing triplet photosensitizers in terms of implementing photochemical strategies in synthetic chemistry. However, synthesis of stable triplet organic photosensitizers is nontrivial and often requires the use of heavy atoms. Herein, an alternative strategy is demonstrated to enhance the triplet generation efficiency...
Citations
... However, these PSs often had low energy absorption for the visible light, and the oxygen atom in the n-π* state of carbanyl group was susceptible to hydrogen atom, causing the degradation of the PS (Buck et al., 2019). To further solve this dilemma, Liu et al. (2021b) implanted the lonepair donor-acceptor bonds in the conjugated frameworks to boost the generation of 1 O 2 . ...
The photodynamic inactivation (PDI) is a novel and effective nonthermal inactivation technology. This review provides a comprehensive overview on the bactericidal ability of endogenous photosensitizers (PSs)‐mediated and exogenous PSs‐mediated PDI against planktonic bacteria and their biofilms, as well as fungi. In general, the PDI exhibited a broad‐spectrum ability in inactivating planktonic bacteria and fungi, but its potency was usually weakened in vivo and for eradicating biofilms. On this basis, new strategies have been proposed to strengthen the PDI potency in food system, mainly including the physical and chemical modification of PSs, the combination of PDI with multiple adjuvants, adjusting the working conditions of PDI, improving the targeting ability of PSs, and the emerging aggregation‐induced emission luminogens (AIEgens). Meanwhile, the mechanisms of PDI on eradicating mono‐/mixed‐species biofilms and preserving foods were also summarized. Notably, the PDI‐mediated antimicrobial packaging film was proposed and introduced. This review gives a new insight to develop the potent PDI system to combat microbial contamination and hazard in food industry.
... Following our constant research interest in the design of efficient, stable catalytic materials and their applications in selective hydrogenation reactions [29,30], herein, a series of N-doped mesoporous carbon materials (CN x ) deriving from biomass D-glucosamine hydrochloride (GAH) and melamine supported ultra-dispersed Pd NPs (Pd/CN x ) catalysts were fabricated for the hydrogenation of benzylidenethiazolidinedione exocyclic alkene to study their catalytic and antipoisoning performance. Among these, Pd/CN 1.2 possessing largest specific surface area (395.9 m 2 ·g −1 ) and pore volume (0.26 cm 3 ·g −1 ) as well as highest Pd 2+ /Pd 0 and Pd-N content exhibited best activity and selectivity for hydrogenation reaction with nearly 100% conversion and 95.5% selectivity. ...
Pioglitazone has been developed as an effective insulin-sensitizing agent for the treatment of type II diabetes mellitus. Selective hydrogenation of the benzylidenethiazolidinedione exocyclic alkene is a committed step in the industrial manufacturing of pioglitazone. However, the strong coordination between metallic sites of commercial hydrogenation catalysts and benzylidenethiazolidinedione might cause catalyst poisoning and lead to poor activity and selectivity. In this context, an effective and anti-poisoning catalyst with highly dispersed palladium nanoparticles supported on biomass-derived nitrogen-doped carbon with mesoporous structures has been established. A systematic investigation of the structure–activity relationship was performed with a series of Pd/CNx by regulating the ratio of precursors D-glucosamine hydrochloride (GAH) and melamine, and it demonstrated that large specific surface area, rich pore structure and strong Pd–N interaction were essential for the high catalytic performance. The optimal Pd/CN1.2 catalyst exhibited nearly 100% conversion and 95.5% selectivity under optimized reaction conditions. Remarkably, compared with commercial Pd/C catalyst, Pd/CN1.2 displayed almost twice the catalytic productivity and provided better poisoning resistance and leaching resistance. Moreover, its stability was also acceptable and good activity could be maintained after exposed in the air for 4 months.
Graphical Abstract
... Photocatalyzed selective oxidation of sulfides using oxygen as the oxidizer is an environment-friendly way to produce sulfoxides, which are key intermediates for bioactive ingredients in the pharmaceutical industry [40][41][42]. Generally, oxygen is activated by the photocatalyst through energy transfer or electron transfer to generate reactive oxygen species (ROS) such as 1 O2 and O2 −• , followed by the reaction with sulfide to produce sulfoxide [43][44][45][46][47][48]. Due to the high activity of ROS, the generated sulfoxide and some substituent groups with low stability would also be oxidized, causing low selectivity and poor substrate compatibility. ...
Heterogeneous Brønsted acidic catalysts such as phosphoric acids are the conventional activators for organic transformations. However, the photocatalytic performance of these catalysts is still rarely explored. Herein, a novel Zr-based metal−organic framework Zr-MOF-P with phosphoric acids as a heterogeneous photocatalyst has been fabricated, which shows high selectivity and reactivity towards the photo-oxidation of sulfides under white light illumination. A mechanism study indicates that the selective oxygenation of sulfides occurs with triplet oxygen rather than common reactive oxygen species (ROS). When Zr-MOF-P is irradiated, the hydroxyl group of phosphoric acid is converted into oxygen radical, which takes an electron from the sulfides, and then the activated substrates react with the triplet oxygen to form sulfoxides, avoiding the destruction of the catalysts and endowing the reaction with high substrate compatibility and fine recyclability.
Photodynamic therapy (PDT) is a temporally and spatially precisely controllable, noninvasive, and potentially highly efficient method of phototherapy. The three components of PDT primarily include photosensitizers, oxygen, and light. PDT employs specific wavelengths of light to active photosensitizers at the tumor site, generating reactive oxygen species that are fatal to tumor cells. Nevertheless, traditional photosensitizers have disadvantages such as poor water solubility, severe oxygen‐dependency, and low targetability, and the light is difficult to penetrate the deep tumor tissue, which remains the toughest task in the application of PDT in the clinic. Here, we systematically summarize the development and the molecular mechanisms of photosensitizers, and the challenges of PDT in tumor management, highlighting the advantages of nanocarriers‐based PDT against cancer. The development of third generation photosensitizers has opened up new horizons in PDT, and the cooperation between nanocarriers and PDT has attained satisfactory achievements. Finally, the clinical studies of PDT are discussed. Overall, we present an overview and our perspective of PDT in the field of tumor management, and we believe this work will provide a new insight into tumor‐based PDT.
The synthesis of covalent organic frameworks (COFs) at bulk scale require robust, straightforward, and cost‐effective techniques. However, the traditional solvothermal synthetic methods of COFs suffer low scalability as well as requirement of sensitive reaction environment and multiday reaction time (2–10 days) which greatly restricts their practical application. Here, we report microwave assisted rapid and optimized synthesis of a donor‐acceptor (D−A) based highly crystalline COF, TzPm‐COF in second (10 sec) to minute (10 min) time scale. With increasing the reaction time from seconds to minutes crystallinity, porosity and morphological changes are observed for TzPm‐COF . Owing to visible range light absorption, suitable band alignment, and low exciton binding energy (E b =64.6 meV), TzPm‐COF can efficaciously produce superoxide radical anion (O 2 ⋅ ⁻ ) after activating molecular oxygen (O 2 ) which eventually drives aerobic photooxidative amidation reaction with high recyclability. This photocatalytic approach works well with a variety of substituted aromatic aldehydes having electron‐withdrawing or donating groups and cyclic, acyclic, primary or secondary amines with moderate to high yield. Furthermore, catalytic mechanism was established by monitoring the real‐time reaction progress through in situ diffuse reflectance infrared Fourier transform spectroscopic (DRIFTS) study.
The synthesis of covalent organic frameworks (COFs) at bulk scale require robust, straightforward, and cost‐effective techniques. However, the traditional solvothermal synthetic methods of COFs suffer low scalability as well as requirement of sensitive reaction environment and multiday reaction time (2–10 days) which greatly restricts their practical application. Here, we report microwave assisted rapid and optimized synthesis of a donor‐acceptor (D−A) based highly crystalline COF, TzPm‐COF in second (10 sec) to minute (10 min) time scale. With increasing the reaction time from seconds to minutes crystallinity, porosity and morphological changes are observed for TzPm‐COF. Owing to visible range light absorption, suitable band alignment, and low exciton binding energy (Eb=64.6 meV), TzPm‐COF can efficaciously produce superoxide radical anion (O2⋅⁻) after activating molecular oxygen (O2) which eventually drives aerobic photooxidative amidation reaction with high recyclability. This photocatalytic approach works well with a variety of substituted aromatic aldehydes having electron‐withdrawing or donating groups and cyclic, acyclic, primary or secondary amines with moderate to high yield. Furthermore, catalytic mechanism was established by monitoring the real‐time reaction progress through in situ diffuse reflectance infrared Fourier transform spectroscopic (DRIFTS) study.
Tailor‐made materials featuring large tunability in their thermal transport properties are highly sought‐after for diverse applications. However, achieving `user‐defined’ thermal transport in a single class of material system with tunability across a wide range of thermal conductivity values requires a thorough understanding of the structure‐property relationships, which has proven to be challenging. Herein, large‐scale computational screening of covalent organic frameworks (COFs) for thermal conductivity is performed, providing a comprehensive understanding of their structure‐property relationships by leveraging systematic atomistic simulations of 10,750 COFs with 651 distinct organic linkers. Through the data‐driven approach, it is shown that by strategic modulation of their chemical and structural features, the thermal conductivity can be tuned from ultralow (≈0.02 W m ⁻¹ K ⁻¹ ) to exceptionally high (≈50 W m ⁻¹ K ⁻¹ ) values. It is revealed that achieving high thermal conductivity in COFs requires their assembly through carbon–carbon linkages with densities greater than 500 kg m ⁻³ , nominal void fractions (in the range of ≈0.6–0.9) and highly aligned polymeric chains along the heat flow direction. Following these criteria, it is shown that these flexible polymeric materials can possess exceptionally high thermal conductivities, on par with several fully dense inorganic materials. As such, the work reveals that COFs mark a new regime of materials design that combines high thermal conductivities with low densities.
