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1.
Small ; 20(11): e2305307, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-37926775

RESUMEN

Herein, a facile strategy is illustrated to develop pyrolysis-free out-of-plane coordinated single atomic sites-based M-POP via a one-pot Friedel Craft acylation route followed by a post-synthetic metalation. The optimized geometry of the Co@BiPy-POP clearly reveals the presence of out-of-plane Co-single atomic sites in the porous backbone. This novel photopolymer Co@BiPy-POP shows extensive π-conjugations followed by impressive light harvesting ability and is utilized for photochemical CO2 fixation to value-added chemicals. A remarkable conversion of styrene epoxide (STE) to styrene carbonate (STC) (≈98%) is obtained under optimized photocatalytic conditions in the existence of promoter tert-butyl ammonium bromide (TBAB). Synchrotron-based X-ray adsorption spectroscopy (XAS) analysis reveals the single atom coordination sites along with the metal (Co) oxidation number of +2.16 in the porous network. Moreover, in situ diffuse reflectance spectroscopy (DRIFTS) and electron paramagnetic resonance (EPR) investigations provide valuable information on the evolution of key reaction intermediates. Comprehensivecomputational analysis also helps to understand the overall mechanistic pathway along with the interaction between the photocatalyst and reactants. Overall, this study presents a new concept of fabricating porous photopolymers based on a pyrolysis-free out-of-plane-coordination strategy and further explores the role of single atomic sites in carrying out feasible CO2 fixation reactions.

2.
Inorg Chem ; 63(13): 6092-6102, 2024 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-38507817

RESUMEN

In this work, we illustrated the design and development of a metal-coordinated porous organic polymer (POP) namely VO@TPA-POP via a post-synthetic metalation strategy to incorporate oxo-vanadium sites in a pristine polymer (TPA-POP) having acetylacetonate (acac) as anchoring moiety. The as-synthesized VO@TPA-POP exhibited highly robust and porous framework, which has been utilized for thioanisole (TA) oxidation to its corresponding sulfoxide. The catalyst demonstrated notable stability and recyclability by maintaining its catalytic activity over multiple reaction cycles without any significant loss in activity. The X-ray absorption spectroscopy (XAS) and density functional theory (DFT) analysis establish the existence of V(+4) oxidation state along with the VO(O)4 active sites into the porous network and the most energetically feasible mechanistic pathway involved in the TA oxidation, respectively, indicating the role of electron density associated with vanadium center during the catalytic transformation. Thus, this work aims at the demonstration of versatility and potential of VO@TPA-POP as a porous heterogeneous catalyst for the TA oxidation followed by decontamination of sulfur mustards (HD's) to their corresponding less toxic sulfoxides in a more efficient and greener way.

3.
J Am Chem Soc ; 145(1): 422-435, 2023 Jan 11.
Artículo en Inglés | MEDLINE | ID: mdl-36537351

RESUMEN

The development of an efficient photocatalyst for C2 product formation from CO2 is of urgent importance toward the deployment of solar-fuel production. Here, we report a template-free, cost-effective synthetic strategy to develop a carbazole-derived porous organic polymer (POP)-based composite catalyst. The composite catalyst is comprised of In2.77S4 and porous organic polymer (POP) and is held together by induced-polarity-driven electrostatic interaction. Utilizing the synergy of the catalytically active In centers and light-harvesting POPs, the catalyst showed 98.9% selectivity toward the generation of C2H4, with a formation rate of 67.65 µmol g-1 h-1. Two different oxidation states of the In2.77S4 spinel were exploited for the C-C coupling process, and this was investigated by X-ray photoelectron spectroscopy (XPS), X-ray absorption spectroscopy (XAS), and density functional theory (DFT) calculations. The role of POP was elucidated via several photophysical and photoelectrochemical studies. The electron transfer was mapped by several correlated approaches, which assisted in establishing the Z-scheme mechanism. Furthermore, the mechanism of C2H4 formation was extensively investigated using density functional theory (DFT) calculations from multiple possible pathways.

4.
Small ; 19(34): e2302045, 2023 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-37165579

RESUMEN

The development of efficient metal-free photocatalysts for the generation of reactive oxygen species (ROS) for sulfur mustard (HD) decontamination can play a vital role against the stockpiling of chemical warfare agents (CWAs). Herein, one novel concept is conceived by smartly choosing a specific ionic monomer and a donor tritopic aldehyde, which can trigger linker-independent regioselective protonation/deprotonation in the polymeric backbone. In this context, the newly developed vinylene-linked ionic polymers (TPA/TPD-Ionic) are further explored for visible-light-assisted detoxification of HD simulants. Time-resolved-photoluminescence (TRPL) study reveals the protonation effect in the polymeric backbone by significantly enhancing the life span of photoexcited electrons. In terms of catalytic performance, TPA-Ionic outperformed TPD-Ionic because of its enhanced excitons formation and charge carrier abilities caused by the donor-acceptor (D-A) backbone and protonation effects. Moreover, the formation of singlet oxygen (1 O2 ) species is confirmed via in-situ Electron Spin Resonance (ESR) spectroscopy and density functional theory (DFT) analysis, which explained the crucial role of solvents in the reaction medium to regulate the (1 O2 ) formation. This study creates a new avenue for developing novel porous photocatalysts and highlights the crucial roles of sacrificial electron donors and solvents in the reaction medium to establish the structure-activity relationship.

5.
Angew Chem Int Ed Engl ; 62(50): e202311304, 2023 Dec 11.
Artículo en Inglés | MEDLINE | ID: mdl-37872849

RESUMEN

Herein, we have specifically designed two metalated porous organic polymers (Zn-POP and Co-POP) for syngas (CO+H2 ) production from gaseous CO2 . The variable H2 /CO ratio of syngas with the highest efficiency was produced in water medium (without an organic hole scavenger and photosensitizer) by utilizing the basic principle of Lewis acid/base chemistry. Also, we observed the formation of entirely different major products during photocatalytic CO2 reduction and water splitting with the help of the two catalysts, where CO (145.65 µmol g-1 h-1 ) and H2 (434.7 µmol g-1 h-1 ) production were preferentially obtained over Co-POP & Zn-POP, respectively. The higher electron density/better Lewis basic nature of Co-POP was investigated further using XPS, XANES, and NH3 -TPD studies, which considerably improve CO2 activation capacity. Moreover, the structure-activity relationship was confirmed via in situ DRIFTS and DFT studies, which demonstrated the formation of COOH* intermediate along with the thermodynamic feasibility of CO2 reduction over Co-POP while water splitting occurred preferentially over Zn-POP.

6.
Anal Chem ; 94(35): 12159-12166, 2022 09 06.
Artículo en Inglés | MEDLINE | ID: mdl-35998619

RESUMEN

Cancer metastasis counts for 90% of cancer fatalities, and its development process is still a mystery. The dynamic process of tumor metastatic transport in the blood vessel is not well understood, in which some biomechanical factors, such as shear stress and various flow patterns, may have significant impacts. Here, we report a microfluidic vessel-on-a-chip platform for recapitulating several key metastatic steps of tumor cells in blood vessels on the same chip, including intravasation, circulating tumor cell (CTC) vascular adhesion, and extravasation. Due to its excellent adaptability, our system can reproduce various microenvironments to investigate the specific interactions between CTCs and blood vessels. On the basis of this platform, effects of important biomechanical factors on CTC adhesion such as vascular surface properties and vessel geometry-dependent hemodynamics were specifically inspected. We demonstrated that CTC adhesion is more likely to occur under certain mechano-physiological situations, such as vessels with vascular glycocalyx (VGCX) shedding and hemodynamic disturbances. Finally, computational models of both the fluidic dynamics in vessels and CTC adhesion were established based on the confocal scanned 3D images. The modeling results are believed to provide insights into exploring tumor metastasis progression and inspire new ideas for anticancer therapy development.


Asunto(s)
Microfluídica , Células Neoplásicas Circulantes , Línea Celular Tumoral , Humanos , Dispositivos Laboratorio en un Chip , Células Neoplásicas Circulantes/patología , Estrés Mecánico , Microambiente Tumoral
7.
Biophys J ; 119(3): 471-482, 2020 08 04.
Artículo en Inglés | MEDLINE | ID: mdl-32645292

RESUMEN

Transient pore formation on the membrane of red blood cells (RBCs) under high mechanical tensions is of great importance in many biomedical applications, such as RBC damage (hemolysis) and mechanoporation-based drug delivery. The dynamic process of pore formation, growth, and resealing is hard to visualize in experiments. We developed a mesoscale coarse-grained model to study the characteristics of transient pores on a patch of the lipid bilayer that is strengthened by an elastic meshwork representing the cytoskeleton. Unsteady molecular dynamics was used to study the pore formation and reseal at high strain rates close to the physiological ranges. The critical strain for pore formation, pore characteristics, and cytoskeleton effects were studied. Results show that the presence of the cytoskeleton increases the critical strain of pore formation and confines the pore growth. Moreover, the pore recovery process under negative strain rates (compression) is analyzed. Simulations show that pores can remain open for a long time during the high-speed tank-treading induced stretching and compression process that a patch of the RBC membrane usually experiences under high shear flow. Furthermore, complex loading conditions can affect the pore characteristics and result in denser pores. Finally, the effects of strain rate on pore formation are analyzed. Higher rate stretching of membrane patch can result in a significant increase in the critical areal strain and density of pores. Such a model reveals the dynamic molecular process of RBC damage in biomedical devices and mechanoporation that, to our knowledge, has not been reported before.


Asunto(s)
Membrana Eritrocítica , Membrana Dobles de Lípidos , Eritrocitos , Simulación de Dinámica Molecular , Estrés Mecánico
8.
Artif Organs ; 44(8): E348-E368, 2020 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-32017130

RESUMEN

This work introduces a new Lagrangian strain-based model to predict the shear-induced hemolysis in biomedical devices. Current computational models for device-induced hemolysis usually utilize empirical fitting of the released free hemoglobin (Hb) in plasma from damaged red blood cells (RBCs). These empirical correlations contain parameters that depend on specific device and operating conditions, thus cannot be used to predict hemolysis in a general device. The proposed algorithm does not have any empirical parameters, thus can presumably be used for hemolysis prediction in various blood-wetting medical devices. In contrast to empirical correlations in which the Hb release is related to the shear stress and exposure time without considering the physical processes, the proposed model links flow-induced deformation of the RBC membrane to membrane permeabilization and Hb release. In this approach, once the steady-state numerical solution of blood flow in the device is obtained under a prescribed operating condition, sample path lines are traced from the inlet of the device to the outlet to calculate the history of the shear stress tensor. In solving the fluid flow, it is assumed that RBCs do not have any influence on the flow pattern. Along each path line, shear stress tensor will be input into a coarse-grained (CG) RBC model to calculate the RBC deformation. Then the correlations obtained from molecular dynamics (MD) simulations are applied to relate the local areal RBC deformation to the perforated area on the RBC membrane. Finally, Hb released out of transient pores is calculated over each path line via a diffusion equation considering the effects of the steric hindrance and increased hydrodynamic drag due to the size of the Hb molecule. The total index of hemolysis (IH) is calculated by integration of released Hb over all the path lines in the computational domain. Hemolysis generated in the Food and Drug Administration (FDA) nozzle and two blood pumps, that is, a CentriMag blood pump (a centrifugal pump) and HeartMate II (an axial pump), for different flow regimes including the laminar and turbulent flows are calculated via the proposed algorithm. In all the simulations, the numerical predicted IH is close to the range of experimental data. The results promisingly indicate that this multiscale approach can be used as a tool for predicting hemolysis and optimizing the hematologic design of other types of blood-wetting devices.


Asunto(s)
Corazón Auxiliar/efectos adversos , Hemólisis , Algoritmos , Eritrocitos , Eritrocitos Anormales , Hemoglobinas/análisis , Humanos , Modelos Estadísticos , Resistencia al Corte , Estrés Mecánico
9.
10.
Chem Asian J ; : e202400515, 2024 Jun 20.
Artículo en Inglés | MEDLINE | ID: mdl-38899858

RESUMEN

The energy sector has demonstrated significant enthusiasm for investigating post-combustion CO2 capture, storage, and separation. However, the practical application of current porous adsorbents is impeded by challenges related to cost competitiveness, stability, and scalability. Intregation of heteroatoms in the porous organic polymers (POPs) dispense it more susceptible for CO2 adsorption to attenuate green house gases. In this regard, two hydroxy rich hypercrosslinked POPs, namely Ph/Tt-POP have been developed by one-pot condensation polymerization using a facile synthetic strategy. The high surface areas of both the Ph/Tt-POP (1057 and 893 m2g-1, respectively), and the heteroatom functionality in the POP framework instigated us to explore our material for CO2 adsorption study. The CO2 uptake capacities in Ph/Tt-POP are found to be 2.45 and 2.2 mmol g-1, at 273 K respectively. Further, in-situ static 13C NMR experiment shows that CO2 molecules in Tt-POP appear to be less mobile than those in Ph-POP which probably due to the presence of triazine functional groups along with high abundant -OH groups in the Tt-POP framework. An in-depth study of the CO2 adsorption mechanism by density functional theory (DFT) calculations also shows that CO2 adsorption at the cages formed by two benzyl rings represents the most stable interaction and CO2 molecule is more favorably adsorbed on the Ph-POP with the more negative interaction energies values compared to that of Tt-POP. Further, Non-covalent interaction (NCI) plot reveals that CO2 molecules adsorb more on the Ph-POP than Tt-POP, which can be explain by hydrogen bond formation in case of Tt-POP repeating units turning aside CO2 molecule to interact with the Ph component. Overall, our present study reflects the comprising effects of surface area of the solid adsorbents as well as their functionality can be beneficial for developing efficient hypercrosslinked porous polymers as solid CO2 adsorbent.

11.
Artículo en Inglés | MEDLINE | ID: mdl-38652824

RESUMEN

Cancer immunotherapy has emerged as a promising therapeutic strategy to combat cancer effectively. However, it is hard to observe and quantify how this in vivo process happens. Three-dimensional (3D) microfluidic vessel-tumor models offer valuable capability to study how immune cells transport during cancer progression. We presented an advanced 3D vessel-supported tumor model consisting of the endothelial lumen and vessel network for the study of T cells' transportation. The process of T cell transport through the vessel network and interaction with tumor spheroids was represented and monitored in vitro. Specifically, we demonstrate that the endothelial glycocalyx serving in the T cells' transport can influence the endothelium-immune interaction. Furthermore, after vascular transport, how programmed cell death protein 1 (PD-1) immune checkpoint inhibition influences the delivered activated-T cells on tumor killing was evaluated. Our in vitro vessel-tumor model provides a microphysiologically engineered platform to represent T cell vascular transportation during tumor immunotherapy. The reported innovative vessel-tumor platform is believed to have the potential to explore the tumor-induced immune response mechanism and preclinically evaluate immunotherapy's effectiveness.

12.
ACS Appl Mater Interfaces ; 16(27): 34437-34449, 2024 Jul 10.
Artículo en Inglés | MEDLINE | ID: mdl-38940318

RESUMEN

Harvesting solar energy to produce value-added chemicals from carbon dioxide (CO2) presents a promising route for addressing the complexities of sustainable energy systems and environmental issues. In this context, the development of metal-coordinated porous organic polymers (POPs) offers a vital avenue for improving the photocatalytic performance of organic motifs. The current study presents a metal-integrated photocatalytic system (namely, Zn@BP-POP) developed via a one-pot Friedel-Crafts (F.C.) acylation strategy, for solid-gas phase photochemical CO2 reduction to CO (CO2RR). The postsynthetic incorporation of metal (Zn) active sites on the host polymeric backbone of BP-POP significantly influences the catalytic activity. Notably, Zn@BP-POP demonstrates good photocatalytic performance in the absence of any cocatalyst and photosensitizer yielding CO while impeding the competitive hydrogen evolution reaction (HER) from water. The experimental findings collectively propose that the observed catalytic activity and selectivity arise from the synergistic interplay between the singular zinc catalytic centers and the light-harvesting capacity of the highly conjugated polymeric backbone. Further, X-ray absorption spectroscopy (XAS) analysis has significantly highlighted the prominent role played by the ZnN2O4 single sites in the polymeric framework for activating the gaseous CO2 molecules. Further, time-dependent density functional theory (DFT) analysis also reveals the thermodynamic feasibility of CO2RR over HER under optimized reaction conditions. This work cumulatively presents an effective strategy to demonstrate the importance of metal-active sites and effectively establish their structure-activity relationship during photocatalysis.

13.
ACS Appl Mater Interfaces ; 16(17): 22066-22078, 2024 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-38629710

RESUMEN

Development of crystalline porous materials for selective CO2 adsorption and storage is in high demand to boost the carbon capture and storage (CCS) technology. In this regard, we have developed a ß-keto enamine-based covalent organic framework (VM-COF) via the Schiff base polycondensation technique. The as-synthesized VM-COF exhibited excellent thermal and chemical stability along with a very high surface area (1258 m2 g-1) and a high CO2 adsorption capacity (3.58 mmol g-1) at room temperature (298 K). The CO2/CH4 and CO2/H2 selectivities by the IAST method were calculated to be 10.9 and 881.7, respectively, which were further experimentally supported by breakthrough analysis. Moreover, theoretical investigations revealed that the carbonyl-rich sites in a polymeric backbone have higher CO2 binding affinity along with very high binding energy (-39.44 KJ mol-1) compared to other aromatic carbon-rich sites. Intrigued by the best CO2 adsorption capacity and high CO2 selectivity, we have utilized the VM-COF for biogas purification produced by the biofermentation of municipal waste. Compared with the commercially available activated carbon, VM-COF exhibited much better purification ability. This opens up a new opportunity for the creation of functionalized nanoporous materials for the large-scale purification of waste-generated biogases to address the challenges associated with energy and the environment.

14.
ACS Appl Mater Interfaces ; 15(5): 6431-6441, 2023 Feb 08.
Artículo en Inglés | MEDLINE | ID: mdl-36693007

RESUMEN

The vascular system in living tissues is a highly organized system that consists of vessels with various diameters for nutrient delivery and waste transport. In recent years, many vessel construction methods have been developed for building vascularized on-chip tissue models. These methods usually focused on constructing vessels at a single scale. In this work, a method that can build a hierarchical and perfusable vessel networks was developed. By providing flow stimuli and proper HUVEC concentration, spontaneous anastomosis between endothelialized lumens and the self-assembled capillary network was induced; thus, a perfusable network containing vessels at different scales was achieved. With this simple method, an in vivo-like hierarchical vessel-supported tumor model was prepared and its application in anticancer drug testing was demonstrated. The tumor growth rate was predicted by combining computational fluid dynamics simulation and a tumor growth mathematical model to understand the vessel perfusability effect on tumor growth rate in the hierarchical vessel network. Compared to the tumor model without capillary vessels, the hierarchical vessel-supported tumor shows a significantly higher growth rate and drug delivery efficiency.


Asunto(s)
Modelos Teóricos , Neoplasias , Humanos , Neoplasias/tratamiento farmacológico , Neoplasias/irrigación sanguínea , Simulación por Computador , Anastomosis Quirúrgica , Dispositivos Laboratorio en un Chip
15.
Artículo en Inglés | MEDLINE | ID: mdl-38293281

RESUMEN

The COVID-19 pandemic has presented a significant challenge to the world's public health and led to over 6.9 million deaths reported to date. A rapid, sensitive, and cost-effective point-of-care virus detection device is essential for the control and surveillance of the contagious severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) pandemic. The study presented here aimed to demonstrate a solid-phase isothermal recombinase polymerase amplification coupled CRISPR-based (spRPA-CRISPR) assay for on-chip multiplexed, sensitive and visual COVID-19 DNA detection. The assay targets the SARS-CoV-2 structure protein encoded genomes and can simultaneously detect two specific genes without cross-interaction. The amplified target sequences were immobilized on the one-pot device surface and detected using the mixed Cas12a-crRNA collateral cleavage of reporter-released fluorescent signal when specific genes were recognized. The endpoint signal can be directly visualized for rapid detection of COVID-19. The system was tested with samples of a broad range of concentrations (20 to 2 × 104 copies) and showed analytical sensitivity down to 20 copies per microliter. Furthermore, a low-cost blue LED flashlight (~$12) was used to provide a visible SARS-CoV-2 detection signal of the spRPA-CRISPR assay which could be purchased online easily. Thus, our platform provides a sensitive and easy-to-read multiplexed gene detection method that can specifically identify low concentration genes.

16.
Chem Asian J ; 18(1): e202200970, 2023 Jan 03.
Artículo en Inglés | MEDLINE | ID: mdl-36373678

RESUMEN

Herein, we have designed and synthesized two heteroatom (N, O) rich covalent organic frameworks (COF), PD-COF and TF-COF, respectively, to demonstrate their relative effect on CO2 adsorption capacity and also CO2 /N2 selectivity. Compared to the non-fluorinated PD-COF (BET surface area 805 m2 g-1 , total pore volume 0.3647 ccg-1 ), a decrease in BET surface area and also pore volume have been observed for fluorinated TF-COF due to the incorporation of fluorine to the porous framework (BET surface area 451 m2 g-1 , total pore volume 0.2978 ccg-1 ). This fact leads to an enormous decrease in the CO2 adsorption capacity and CO2 /N2 selectivity of TF-COF, though it shows stronger affinity towards CO2 with a Qst of 37.76 KJ/mol. The more CO2 adsorption capacity by PD-COF can be attributed to the large specific surface area with considerable amount of micropore volume compared to the TF-COF. Further, PD-COF exhibited CO2 /N2 selectivity of 16.8, higher than that of TF-COF (CO2 /N2 selectivity 13.4).

17.
Chem Commun (Camb) ; 59(34): 5067-5070, 2023 Apr 25.
Artículo en Inglés | MEDLINE | ID: mdl-37021353

RESUMEN

We have introduced a Friedel-Crafts alkylation strategy of a Ni-salphen complex as derived from 2-hydroxy-5-methoxybenzaldehyde, an isomer of biomass derived vanillin, to construct a Ni-salphen based porous organic polymer (Ni@T-POP). The X-ray absorption spectroscopy (XAS) analysis revealed the existence of Ni-N2O2 core sites in the Ni@T-POP framework, which demonstrates unprecedented catalytic efficiency towards oxidative decontamination of sulfur mustards (HD's) compared to its complex precursor.

18.
Nat Commun ; 14(1): 4520, 2023 Jul 27.
Artículo en Inglés | MEDLINE | ID: mdl-37500653

RESUMEN

Microfluidic devices have found extensive applications in mechanical, biomedical, chemical, and materials research. However, the high initial cost, low resolution, inferior feature fidelity, poor repeatability, rough surface finish, and long turn-around time of traditional prototyping methods limit their wider adoption. In this study, a strategic approach to a deterministic fabrication process based on in-situ image analysis and intermittent flow control called image-guided in-situ maskless lithography (IGIs-ML), has been proposed to overcome these challenges. By using dynamic image analysis and integrated flow control, IGIs-ML provides superior repeatability and fidelity of densely packed features across a large area and multiple devices. This general and robust approach enables the fabrication of a wide variety of microfluidic devices and resolves critical proximity effect and size limitations in rapid prototyping. The affordability and reliability of IGIs-ML make it a powerful tool for exploring the design space beyond the capabilities of traditional rapid prototyping.

19.
J Colloid Interface Sci ; 652(Pt B): 1784-1792, 2023 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-37683406

RESUMEN

Producing hydrogen peroxide (H2O2) from H2O and O2 under visible light irradiation is a promising solar-to-chemical energy conversion technology. Hydrogen peroxide has versatile applications as a green oxidant and liquid energy carrier but has been produced through energy-intensive and complex anthraquinone processes. Herein, we report the rational design of efficient and stable porous organic polymer (POP) containing redox centers, anthraquinone photocatalyst (ANQ-POP) for solar H2O2 production. ANQ-POP is readily synthesized with stable dioxin-linkages via efficient one-pot, transition-metal-free nucleophilic aromatic substitution reactions between 1,2,3,4,5,6,7,8-octafluoro-9,10-anthraquinone (OFANQ) and 2,3,6,7,10,11-hexahydroxytriphenylene (HHTP). Exhibiting a fibrillar morphology, ANQ-POP boasts a high surface area of 380 m2∙g-1 and demonstrates thermal stability. With 10 % ethanol, ANQ-POP yields an H2O2 production rate of 320 µmol g-1 under visible light irradiation. Moreover, ANQ-POP alone can efficiently produce H2O2 without any photosensitizers and cocatalysts. Density functional theory calculations reveal that the quinone groups of the anthraquinone moieties can serve as redox centers for H2O2 production under light irradiation. Furthermore, unlike most conventional photocatalysts, it can produce H2O2 using only water and air by catalyzing both oxygen reduction and evolution reactions under light irradiation. Our findings provide an efficient, eco-friendly pathway for photocatalytic production of H2O2 under mild reaction conditions using a dioxin-derived POP-based photocatalyst.

20.
ACS Appl Mater Interfaces ; 15(17): 21027-21039, 2023 May 03.
Artículo en Inglés | MEDLINE | ID: mdl-37083336

RESUMEN

In recent times, a self-complementary balanced characteristic feature with the combination of both covalent bonds (structural stability) and open metal sites (single-site catalysis) introduced an advanced emerging functional nanoarchitecture termed metalated porous organic polymers (M-POPs). However, the development of M-POPs in view of the current interest in catalysis has been realized still in its infancy and remains a challenge for the years to come. In this work, we built benzothiazole-linked Fe-metalated porous organic polymer (Fc-Bz-POP) using ferrocene dicarboxaldehyde (FDC), 1,3,5-tris(4-aminophenyl) benzene (APB), and elemental sulfur (S8) via a template-free, multicomponent, cost-effective one-pot synthetic approach. This Fc-Bz-POP is endowed with unique features including an extended network unit, isolated active sites, and catalytic pocket with a possible local structure, in which convergent binding sites are positioned in such a way that substrate molecules can be held in close proximity. Prospective catalytic application of this Fc-Bz-POP has been explored in executing catalytic allylic "C-H" bond functionalization of cyclohexene (CHX) in water at room temperature. Catalytic screening results identified that a superior performance with a CHX conversion of 95% and a 2-cyclohexene-1-ol selectivity (COL) of 80.8% at 4 h and 25 °C temperature has been achieved over Fc-Bz-POP, thereby addressing previous shortcomings of the other conventional catalytic systems. Comprehensive characterization understanding with the aid of synchrotron-based extended X-ray absorption fine structure (EXAFS) analysis manifested that the Fe atom with an oxidation state of +2 in our Fc-Bz-POP catalytic system encompasses a sandwich structural environment with the two symmetrical eclipsed cyclopentadienyl (Cp) rings, featuring nearest-neighbor (NN) Fe-C (≈2.05 Å) intramolecular bonds, as validated by the Fe L3-edge EXAFS fitting result. Furthermore, in situ attenuated total reflection-infrared spectroscopy (ATR-IR) analysis data for liquid-phase oxidation of cyclohexene allow for the formulation of a molecular-level reaction mechanistic pathway with the involvement of specific reaction intermediates, which is initiated by the radical functionalization of the allyl hydrogen. A deep insight investigation from density functional theory (DFT) calculations unambiguously revealed that the dominant pathway from cyclohexene to 2-cyclohexene-1-ol is initiated by an allyl-H functionalization step accompanied by the formation of 2-cyclohexene-1-hydroperoxide species as the key reaction intermediate. Electronic properties obtained from DFT simulations via the charge density difference plot, Bader charge, and density of state (DOS) demonstrate the importance of the organic polymer frame structure in altering the electronic properties of the Fe site in Fc-Bz-POP, resulting in its high activity. Our contribution has great implications for the precise design of metalated porous organic polymer-based robust catalysts, which will open a new avenue to get a clear image of surface catalysis.

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