Search

The as-prepared NiTAPP-NiACQ exhibits excellent long-term durability and remarkable HER performance with a low overpotential of 117 mV at 10 mA cm−2, which is quite comparable to many reported electrocatalytic HER systems. [Display omitted] To realize efficient water splitting, a highly promising hydrogen evolution reaction (HER) electrocatalyst is needed for the generation of hydrogen. Herein, we demonstrate a novel acenaphthenediimine complex-bridged porphyrin porous organic polymer (NiTAPP-NiACQ) with enriched active metal sites and hierarchical pores. The as-prepared NiTAPP-NiACQ exhibits good long-term durability and remarkable HER performance in 1.0 M KOH with a low overpotential of 117 mV at 10 mA cm−2, which is comparable to many previously reported electrocatalytic HER systems. Furthermore, a simple water-alkali electrolyzer using NiTAPP-NiACQ as the cathode requires a small cell voltage of 1.59 V to deliver a current density of 10 mA cm−2 at room temperature, along with outstanding durability. NiTAPP-NiACQ features not only a metal ion as the catalytic active center in the porphyrin core but also metal ion coordination on the anthraquinone component to promote HER performance, enabling multiple metal ions as the electrocatalytic active sites for the HER reaction. The excellent HER activity of NiTAPP-NiACQ is ascribed to a combination of mechanisms. These findings highlight the viability of porphyrin-derived porous organic polymers in energy conversion processes. [ABSTRACT FROM AUTHOR]

Antibiotic resistance represents a pressing global health challenge, now acknowledged as a critical concern within the framework of One Health. Photodynamic inactivation of microorganisms (PDI) offers an attractive, non-invasive approach known for its flexibility, independence from microbial resistance patterns, broad-spectrum efficacy, and minimal risk of inducing resistance. Various photosensitizers, including porphyrin derivatives have been explored for pathogen eradication. In this context, we present the synthesis, spectroscopic and photophysical characteristics as well as antimicrobial properties of a palladium(II)-porphyrin derivative (PdF2POH), along with its zinc(II)- and free-base counterparts (ZnF2POH and F2POH, respectively). Our findings reveal that the palladium(II)-porphyrin complex can be classified as an excellent generator of reactive oxygen species (ROS), encompassing both singlet oxygen (Φ△ = 0.93) and oxygen-centered radicals. The ability of photosensitizers to generate ROS was assessed using a variety of direct (luminescence measurements) and indirect techniques, including specific fluorescent probes both in solution and in microorganisms during the PDI procedure. We investigated the PDI efficacy of F2POH, ZnF2POH, and PdF2POH against both Gram-negative and Gram-positive bacteria. All tested compounds proved high activity against Gram-positive species, with PdF2POH exhibiting superior efficacy, leading to up to a 6-log reduction in S. aureus viability. Notably, PdF2POH-mediated PDI displayed remarkable effectiveness against S. aureus biofilm, a challenging target due to its complex structure and increased resistance to conventional treatments. Furthermore, our results show that PDI with PdF2POH is more selective for bacterial than for mammalian cells, particularly at lower light doses (up to 5 J/cm2 of blue light illumination). This enhanced efficacy of PdF2POH-mediated PDI as compared to ZnF2POH and F2POH can be attributed to more pronounced ROS generation by palladium derivative via both types of photochemical mechanisms (high yields of singlet oxygen generation as well as oxygen-centered radicals). Additionally, PDI proved effective in eliminating bacteria within S. aureus-infected human keratinocytes, inhibiting infection progression while preserving the viability and integrity of infected HaCaT cells. These findings underscore the potential of metalloporphyrins, particularly the Pd(II)-porphyrin complex, as promising photosensitizers for PDI in various bacterial infections, warranting further investigation in advanced infection models. [ABSTRACT FROM AUTHOR]

Zinc 3-hydroxymethyl-pyroprotopheophorbides-a esterified with a chiral secondary alcohol at the 17-propionate residue were prepared as bacteriochlorophyll-d analogs. The synthetic zinc 31-hydroxy-131-oxo-porphyrins self-aggregated in an aqueous Triton X-100 micellar solution to give red-shifted and broadened Soret and Qy absorption bands in comparison with their monomeric bands. The intense, exciton-coupled circular dichroism spectra of their self-aggregates were dependent on the chirality of the esterifying groups. The observation indicated that the self-aggregates based on the J-type stacking of the porphyrin cores were sensitive to the peripheral 17-propionate residues. The supramolecular structures of the present J-aggregates as models of bacteriochlorophyll aggregates in natural chlorosomes were remotely regulated by the esterifying groups. [ABSTRACT FROM AUTHOR]

Antibacterial photodynamic therapy (a‐PDT) has emerged as a promising non‐invasive therapeutic modality that utilizes the combination of a photosensitive agent, molecular oxygen, and excitation light to generate reactive oxygen species (ROS), demonstrating remarkable activity against multidrug‐resistant bacterial infections. However, the effective use of conventional photosensitizers is significantly limited by a number of their shortcomings, namely, poor water solubility and low selectivity. Herein, we present a novel biocompatible water‐soluble nanocomposite based on hydrophobic tetraphenylporphyrin (TPP) molecules and hydrophilic ternary AgInS2/ZnS quantum dots incorporated into a chitosan matrix as an improved photosensitizer for a‐PDT. We demonstrated that TPP molecules could be successfully transferred into chitosan solution while remaining primarily in the form of monomers, which are capable of singlet oxygen generation. We performed a detailed analysis of the Förster resonance energy transfer (FRET) between quantum dots and TPP molecules within the nanocomposite and proposed the mechanism of the singlet oxygen efficiency enhancement via FRET. [ABSTRACT FROM AUTHOR]

Abstract Photoactive supramolecular porphyrin assemblies are attractive molecules for light‐harvesting applications. This is due to their relatively non‐toxicity, biological activities and charge and energy exchange characteristics. However, the extreme cost associated with their synthesis and requirements for toxic organic solvents during purification pose a challenge to the sustainability characteristics of their applications. This work presents the first report on the sustainable synthesis, spectroscopic and photophysical characterizations of a near‐infrared (NIR) absorbing Ca(II)‐meso‐tetrakis (4‐hydroxyphenyl)porphyrin using an electrolyzed pyrrole solution. The latter was obtained by cycling the pyrrole solution across the silver nanodumbbell particle surface at room temperature. The electrolyzed solution condensed readily with acidified p‐hydroxybenzaldehyde, producing the targeted purple porphyrin. The non‐electrolyzed pyrrole solution formed a green substance with significantly different optical properties. Remarkable differences were observed in the voltammograms of the silver nanodumbbell particles and those of the conventional gold electrode during the pyrrole cycling, suggesting different routes of porphyrin formation. The rationale behind these formations and the associated mechanisms were extensively discussed. Metalation with aqueous Ca2+ ion caused a Stokes shift of 38.75 eV. The current study shows the advantage of the electrochemical method towards obtaining sustainable light‐harvesting porphyrin at room temperature without the need for high‐energy‐dependent conventional processes.

Photodynamic therapy (PDT) is attracting great attention for cancer treatments, while its therapeutic efficacy is limited by unsatisfactory photosensitizers and hypoxic tumor microenvironment (TME). To address these problems, we have developed catalase-loaded manganese-porphyrin frameworks (CAT@MnPFs) for catalytically-assisted PDT of cancer cells. CAT@MnPFs were constructed by the assembly of Mn2+ ions and PpIX into MnPFs and the subsequent loading of catalase. Under 650 nm light irradiation, the porphyrin (Protoporphyrin IX) within the structure of CAT@MnPFs can convert oxygen (O2) into singlet oxygen (1O2), showing the photodynamic effect. Importantly, the loaded catalase can decompose hydrogen peroxide (H2O2) into O2 with a huge elevation of O2 level (13.22 mg L−1) in 600 s, thus promoting 1O2 generation via PDT. As a result, CAT@MnPFs combined with 650 nm light can effectively ablate cancer cells due to the catalase-assisted oxygen-evolving PDT, showing a high therapeutic efficacy. Meanwhile, after the incubation with CAT@MnPFs, unobvious damage can be found in normal and red blood cells. Thus, the obtained CAT@MnPFs integrate the advantage of photosensitizers and catalase for oxygen-evolving PDT, which can provide some insight for treating hypoxic cells.

The greenhouse gas (GHG) emissions from fossil fuel combustion and carbon dioxide (CO2) cause global warming and climate change. In this study, we synthesized three porphyrin-based azo-porous organic polymers (PBPOP1, PBPOP2, and PBPOP3) that enable the capture and one-step conversion of CO2. These catalysts effectively capture the CO2 molecules over N2 in a post-combustion environment. PBPOP3 exhibited an enhanced CO2/N2 selectivity at 313 K, with a value of 534. We characterized the porphyrin-based azo-POPs catalysts using FT-IR, 13C solid-state NMR, XRD, TGA, and HR-FESEM. We evaluated the gas adsorption properties using Brunauer–Emmett–Teller analysis, which included adsorption–desorption isotherms, NLDFT pore-size distribution, and adsorption at 298, 313, and 353 K. The fixation of CO2 with styrene oxide and phenyl glycidyl ether was performed using catalysts for conversion to styrene carbonate (tetra-n-butylammonium bromide was used as a co-catalyst). Thus, our findings can be used for reducing the amount of CO2 gas in the atmosphere by synthesizing porphyrin-based azo-POP catalysts.

The synthesis of a new tetracationic porphyrin derivative is described. Contrary to the best known derivatives in the literature, which are derived from 5,10,15,20-tetrakis-4-pyridylporphyrin (TPyP), in this procedure we start from 5,10,15,20-tetrakis-(4-carboxymethoxyphenyl)porphyrin (TPPCOOMe), obtained by the condensation reaction between pyrrole and 4-formylbenzoate. The reaction is carried out in refluxed xylene, avoiding the use of halogenated solvents. The final product, 5,10,15,20-tetrakis-(4-(3-carbamoyl-pyridyl)-methylphenyl)porphyrin bromide (P15p), exhibits four cationic portions that make it soluble in water and suitable for G4 stabilization. The choice to synthesize a derivative of TPPCOOMe is based on the idea of having a possible stabilizer that, unlike those obtained from TPyP, shows the cationic moieties farther from the porphyrin core and thus closer to the phosphate groups present on the G4 loops.

Abstract Development of efficient, stable, and recyclable photocatalysts for organic synthesis is vital for transformation of traditional thermal organic chemistry into green sustainable organic chemistry. In this work, the study reports an electrostatic approach to assemble meso‐tetra (4‐sulfonate phenyl) porphyrin (TPPS)tetra (4‐sulfonate phenyl) porphyrin (TPPS) as a donor and benzyl viologen (BV) as an acceptor into stable and recyclable photocatalyst for an efficient organic transformation reaction – aryl sulfide oxidation. By use of the electrostatic TPPS‐BV photocatalysts, 0.1 mmol aryl sulfide with electron‐donating group can be completely transformed into aryl sulfoxide in 60 min without overoxidation into sulfone, rendering near 100% yield and selectivity. The photocatalyst can be recycled up to 95% when 10 mg amount is used. Mechanistic study reveals that efficient charge separation between TPPS and BV results in sufficient formation of superoxide which further reacts with the oxidized sulfide by the photocatalyst to produce the sulfoxide. This mechanistic pathway differs significantly from the previously proposed singlet oxygen‐dominated process in homogeneous TPPS photocatalysis.

Interaction of ionic liquids with iron porphyrin (FeP) arises in a number of application of ionic liquids such as dye-sensitized solar cells, batteries, and conversion of CO2 to value-added products, etc. Furthermore, ionic liquid-FeP interactions are thought to be responsible for ionic liquid biodegradation and catalytic breakdown of ionic liquids. Despite the importance of ionic liquid-FeP interactions, there is a lack of information on what conformations ionic liquids adopt when presented to FeP and how thermodynamics of subsequent electron transfer reaction is affected. To begin to answer these questions, electronic structure calculations are performed to assess how the binding propensity of the homologous series of 1-n-alkyl-3-methylimidazolium [Cnmim]Cl (n = 2, 4, 6, 8, 10) to FeP is affected as the alkyl chain length and the initial conformation of the cation presented to FeP are varied. The conceptual density functional theory framework is then invoked to compute the electrophilicity index of the ionic liquid-FeP complex to glean insight into the ability of the complex to acquire an electron. Calculations suggest two equally likely conformations of ionic liquids with similar Gibbs free energy change; however, the enthalpic and entropic contributions differ based on the conformation adopted by ionic liquids which in turn affects the propensity of the subsequent electron transfer process. The importance of results is discussed in terms of experimentally observed alkyl chain length-dependent biodegradability of ionic liquids.

Highlights Strain induces coupling in Bi12O17Br2 and Cu porphyrin-based monoatomic layer (PML-Cu), constructing Bi–O bonding interface in PML-Cu/BOB (PBOB). Surface interface dual polarization boosts internal electric field, promoting electron transfer. PML-Cu provides high density of dispersed active Cu sites in PBOB, enhancing CO2 photoreduction.

To achieve carbon neutrality, the development of effective and durable electrodes for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is of utmost importance. Herein, the Ru 3.4 -PMOF/NF electrode was successfully prepared by immobilizing Ru nanoparticles on porphyrinic metal-organic framework/nickel foam (PMOF/NF), effectively driving both the OER and the HER in an alkaline electrolyte. To achieve 10 mA cm−2, the Ru 3.4 -PMOF/NF electrode only required overpotentials of 19 and 215 mV for HER and OER, respectively. For overall water splitting, an ultra-low cell voltage of 1.468 V was required to drive 10 mA cm−2, surpassing the performance of the integrated Pt/C and RuO 2 couple electrode (1.6627 V). The outperformed electrocatalytic activity could be ascribed to the well-dispersed Ru nanoparticles, the self-reconstruction of PMOF, the synergistic effect, and the lamellar morphology. This study offers a promising approach for the development of ruthenium-doped electrodes that can enhance the efficiency of electrocatalytic water splitting. • The self-supporting electrode was prepared by immobilizing Ru on PMOF/NF. • The Ru 3.4 -PMOF/NF exhibited better HER and OER performance than Pt/C and RuO 2. • The Ru 3.4 -PMOF/NF couple could achieve a low cell voltage for water splitting. • The reasons for the improvement of electrocatalytic performance were summarized. [ABSTRACT FROM AUTHOR]

The efficient synthesis of nanosheets containing two metal ions is currently a formidable challenge. Here, we attempted to dope lanthanide-based bimetals into porphyrin-based metal-organic skeleton materials (MOFs) by microwave-assisted heating. The results of the EDX, ICP, and XPS tests show that we have successfully synthesized porphyrin-based lanthanide bimetallic nanosheets (Tb-Eu-TCPP) using a household microwave oven. In addition, it is tested and experimentally evident that these nanosheets have a thinner thickness, a larger BET surface area, and higher photogenerated carrier separation efficiency than bulk porphyrin-based bimetallic materials, thus exhibiting enhanced photocatalytic activity and n-type semiconductor properties. Furthermore, the prepared Tb-Eu-TCPP nanomaterials are more efficient in generating single-linear state oxygen under visible light irradiation compared to pristine monometallic nanosheets due to the generation of bimetallic nodes. The significant increase in catalytic activity is attributed to the improved separation and transfer efficiency of photogenerated carriers. This study not only deepens our understanding of lanthanide bimetallic nanosheet materials but also introduces an innovative approach to improve the photocatalytic performance of MOFs. [ABSTRACT FROM AUTHOR]

Self-organized, well-defined porphyrin-based nanostructures with controllable sizes and morphologies are in high demand for the photodegradation of hazardous contaminants under sunlight. From this perspective, this review summarizes the development progress in the fabrication of porphyrin-based nanostructures by changing their synthetic strategies and designs. Porphyrin-based nanostructures can be fabricated using several methods, including ionic self-assembly, metal–ligand coordination, reprecipitation, and surfactant-assisted methods. The synthetic utility of porphyrins permits the organization of porphyrin building blocks into nanostructures, which can remarkably improve their light-harvesting properties and photostability. The tunable functionalization and distinctive structures of porphyrin nanomaterials trigger the junction of the charge-transfer mechanism and facilitate the photodegradation of pollutant dyes. Finally, porphyrin nanomaterials or porphyrin/metal nanohybrids are explored to amplify their photocatalytic efficiency. [ABSTRACT FROM AUTHOR]

The fossil record demonstrates the preservation of porphyrins (e.g., heme) in organic sediments and the fossilized remains of animals. These molecules are essential components in modern metabolic processes, such as electron transport (cytochromes) and oxygen transport (hemoglobin), and likely originated before the emergence of life. The integration and adaptation of porphyrins and structurally similar molecules (e.g., chlorophylls) are key aspects in the evolution of energy production (i.e., aerobic respiration and photosynthesis) and complex life (i.e., eukaryotes and multicellularity). Here, we discuss the evolution and functional diversity of heme-bound hemoglobin proteins in vertebrates, along with the preservation of these molecules in the fossil record. By elucidating the pivotal role of these molecules in the evolution of life, this review lays the groundwork necessary to explore hemoglobin as a means to investigate the paleobiology of extinct taxa, including non-avian dinosaurs. [ABSTRACT FROM AUTHOR]

A new family of macrocyclic host molecules that possess two bisporphyrin clefts was synthesized. The tetrameric porphyrin macrocycle provides the two guest binding sites in which two electron‐deficient aromatic molecules are encapsulated through donor‐acceptor and π‐π stacking interactions. The tetrameric porphyrin macrocycle showed positive cooperativity, whereas the nonmacrocyclic analog did not. The preorganization concept drives positive cooperativity, which is directed by the entropy benefit to macrocyclization. [ABSTRACT FROM AUTHOR]

We present the fabrication of a novel Starfruit‐shaped metal‐organic framework (SMOF) composed of zirconium and Tetra(4‐carboxyphenyl)porphine linkers. The SMOF exhibits a unique morphology with edge‐sharing two‐dimensional (2D) nanosheet petals. Our investigation unravels a captivating transformation process, wherein three‐dimensional (3D) shuttle‐shaped MOFs form initially and subsequently evolve into 2D nanosheet‐based SMOF structures. The distinct morphology of SMOF showcases superior catalytic activity in detoxifying G‐type nerve agent and blister agent simulants, surpassing that of its 3D counterparts. This discovery of the 3D‐to‐2D transition growth pathway unlocks exciting opportunities for exploring novel strategies in advanced MOF nanostructure development, not only for catalysis but also for various other applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • Cobalt protoporphyrin (CoPpIX) grafted MIL-101(Cr)–NH 2 was constructed through facile post-synthetic modification. • The porphyrins are covalently linked to amino groups of the parent MOF without impairing its well-defined porous framework. • The parent MOF with superior CO 2 capture ability exposes Co porphyrins to elevated local CO 2 concentration by CO 2 enrichment. • A remarkably high CO Faradaic efficiency of 97.1% and a turnover frequency up to 0.63 s−1 are achieved. Electrocatalytic carbon dioxide reduction reaction (CO 2 RR) presents a sustainable route to address energy crisis and environmental issues, where the rational design of catalysts remains crucial. Metal–organic frameworks (MOFs) with high CO 2 capture capacities have immense potential as CO 2 RR electrocatalysts but suffer from poor activity. Herein we report a redox-active cobalt protoporphyrin grafted MIL-101(Cr)–NH 2 for CO 2 electroreduction. Material characterizations reveal that porphyrin molecules are covalently attached to uncoordinated amino groups of the parent MOF without compromising its well-defined porous structure. Furthermore, in situ spectroscopic techniques suggest inherited CO 2 concentrate ability and more abundant adsorbed carbonate species on the modified MOF. As a result, a maximum CO Faradaic efficiency (FE CO) up to 97.1% and a turnover frequency of 0.63 s−1 are achieved, together with FE CO above 90% within a wide potential window of 300 mV. This work sheds new light on the coupling of MOFs with molecular catalysts to enhance catalytic performances. [ABSTRACT FROM AUTHOR]

The replacement of palladium catalysts for Wacker‐type oxidation of olefins into ketones by first‐row transition metals is a relevant approach for searching more sustainable protocols. Besides highly sophisticated iron catalysts, all the other first‐row transition metal complexes have only led to poor activities and selectivities. Herein, we show that the cobalt‐tetraphenylporphyrin complex is a competent catalyst for the aerobic oxidation of styrenes into ketones with silanes as the hydrogen sources. Remarkably, under room temperature and air atmosphere, the reactions were exceedingly fast (up to 10 minutes) with a low catalyst loading (1 mol %) while keeping an excellent chemo‐ and Markovnikov‐selectivity (up to 99 % of ketone). Unprecedently high TOF (864 h−1) and TON (5,800) were reached for the oxidation of aromatic olefins under these benign conditions. Mechanistic studies suggest a reaction mechanism similar to the Mukaiyama‐type hydration of olefins with a change in the last fundamental step, which controls the chemoselectivity, thanks to a unique hydrogen bonding network between the ethanol solvent and the cobalt peroxo intermediate. [ABSTRACT FROM AUTHOR]

Metal-organic frameworks (MOFs) are a novel category of porous crystalline materials with an exceptionally high surface area and adjustable pore structure. They possess a designable composition and can be easily functionalized with different units. Porphyrins with conjugated tetrapyrrole macrocyclic structures can absorb light from ultraviolet to visible light regions, and their structures and properties can be facilely regulated by altering their peripheral groups or central metal ions. Porphyrin-based MOFs constructed from porphyrin ligands and metal nodes combine the unique features of porphyrins and MOFs as well as overcoming their respective limitations. This paper reviewed the design and construction, light absorption and charge transfer pathways, and strategy for improving the photocatalytic performance of porphyrin-based MOFs, and highlighted the recent progress in the field of CO2 reduction, hydrogen evolution, organic synthesis, organic pollutant removal, and nitrogen fixation. The intrinsic relationships between the structure and the property of porphyrin-based MOFs received special attention, especially the relationships between the arrangements of porphyrin ligands and metal nods and the charge transfer mechanism. We attempted to provide more valuable information for the design and construction of advanced photocatalysts in the future. Finally, the challenges and future perspectives of the porphyrin-based MOFs are also discussed. [ABSTRACT FROM AUTHOR]

The development of nanotools for chemical sensing and macromolecular modifications is a new challenge in the biomedical field, with emphasis on artificial peptidases designed to cleave peptide bonds at specific sites. In this landscape, metal porphyrins are attractive due to their ability to form stable complexes with amino acids and to generate reactive oxygen species when irradiated by light of appropriate wavelengths. The issues of hydrophobic behavior and aggregation in aqueous environments of porphyrins can be solved by using its PEGylated derivatives. This work proposes the design of an artificial photo-protease agent based on a PEGylated mercury porphyrin, able to form a stable complex with l-Tryptophan, an amino acid present also in the lysozyme structure (a well-known protein model). The sensing and photodegradation features of PEGylated mercury porphyrin were exploited to detect and degrade both l-Trp and lysozyme using ROS, generated under green (532 nm) and red (650 nm) light lasers. The obtained system (Star3600_Hg) and its behavior as a photo-protease agent were studied by means of several spectroscopies (UV-Vis, fluorescence and circular dichroism), and MALDI-TOF mass spectrometry, showing the cleavage of lysozyme and the appearance of several short-chain residues. The approach of this study paves the way for potential applications in theranostics and targeted bio-medical therapies. [ABSTRACT FROM AUTHOR]

Highlights: Strain induces coupling in Bi12O17Br2 and Cu porphyrin-based monoatomic layer (PML-Cu), constructing Bi–O bonding interface in PML-Cu/BOB (PBOB). Surface interface dual polarization boosts internal electric field, promoting electron transfer. PML-Cu provides high density of dispersed active Cu sites in PBOB, enhancing CO2 photoreduction. The insufficient active sites and slow interfacial charge transfer of photocatalysts restrict the efficiency of CO2 photoreduction. The synchronized modulation of the above key issues is demanding and challenging. Herein, strain-induced strategy is developed to construct the Bi–O-bonded interface in Cu porphyrin-based monoatomic layer (PML-Cu) and Bi12O17Br2 (BOB), which triggers the surface interface dual polarization of PML-Cu/BOB (PBOB). In this multi-step polarization, the built-in electric field formed between the interfaces induces the electron transfer from conduction band (CB) of BOB to CB of PML-Cu and suppresses its reverse migration. Moreover, the surface polarization of PML-Cu further promotes the electron converge in Cu atoms. The introduction of PML-Cu endows a high density of dispersed Cu active sites on the surface of PBOB, significantly promoting the adsorption and activation of CO2 and CO desorption. The conversion rate of CO2 photoreduction to CO for PBOB can reach 584.3 μmol g−1, which is 7.83 times higher than BOB and 20.01 times than PML-Cu. This work offers valuable insights into multi-step polarization regulation and active site design for catalysts. [ABSTRACT FROM AUTHOR]

In this work, we present Zn, CoII, and MnIII metalated meso‐tetra‐[4‐(methylthio) phenyl] porphyrin ([Zn(TMtPP)], [CoII(TMtPP], and [MnIII(TMtPP)Cl]) as electrocatalysts and photoelectrocatalysts for electrochemical detection and photoelectrocatalytic degradation of pentachlorophenol (PCP). The complexes were characterized using UV‐visible spectroscopy, mass spectroscopy, and elemental analysis. Proton nuclear magnetic resonance (1H NMR) studies were only conducted for the Zn derivative. The electrochemical detection of PCP was carried out using cyclic voltammetry and chronoamperometry. [CoII(TMtPP)] showed better detection limit. For photoelectrocatalytic (PEC) degradation studies of PCP, linear sweep voltammetry and UV‐visible spectra were employed. [Zn(TMtPP)] showed better removal efficiency. The main species responsible for the PEC degradation were found to be superoxide radicals (⋅O2) and electron holes (h+). [ABSTRACT FROM AUTHOR]

Exposure to certain metal ions can lead to many diseases including cardiovascular, reproductive, and kidney disorders. Certain inorganic anions and organic species can also adversely affect living organisms as well as pose a severe threat to the environment. Detection and determination of biological analytes or biomarkers can help in the early diagnosis and treatment of several human diseases. Accordingly, great efforts have been devoted to the development of fluorescent and colorimetric sensors. Compared to many other detection techniques, the optical sensor stands unique. Porphyrins are excellent fluorophores with strong absorption and emission in the visible region. This highly conjugated macrocycle can be tuned to desirable properties with proper substituents at the periphery and complex formation with a vast number of metal ions. This detailed review discusses optical sensors that encompass both colorimetric and fluorescence sensors based on porphyrin/metalloporphyrin and their various forms for sensing metal ions, inorganic anions, organic moieties, and biologically significant molecules. In the presence of the concerned analyte, rearrangement of energy level of optical probe occurs and further facilitates interaction with the analyte which is mainly operated through various mechanisms like FRET, PET, ground state complex formation, intramolecular charge transfer, exciplex formation, etc. [ABSTRACT FROM AUTHOR]

In the current study, a chemiresistive SO2 sensor based on a composite of reduced graphene oxide (rGO) and 5, 10, 15, 20-tetra-p-tolyl-21H, 23H-porphine (TPTP) was developed and extensively studied. Improved Hummers methods were used to synthesize graphene oxide (GO), and a thermally heating bottom-up approach was used to reduce GO to rGO. Gold electrodes were thermally coated on the transparent sheet using a thermal evaporator. The composite of rGO/TPTP was synthesized using a simple chemical method. Structural, morphological, spectroscopic, electrical, and optical studies were carried out using X-ray diffraction, atomic force microscopy, field emission scanning electron microscopy, Fourier-transfer infrared spectroscopy, Raman spectroscopy, current–voltage, and UV–vis spectroscopy, respectively. The sensing response of rGO/TPTP for various concentrations of sulfur dioxide (SO2) was investigated in chemiresistive modality. The rGO/TPTP composite chemiresistive sensor displayed exceptional performance, with a consistent response spanning 1 ppm to 10 ppm. It exhibited outstanding repeatability, linearity, stability, and boasted an impressive limit of detection (LOD) of 1 ppm. This LOD is significantly lower than the recommended permissible exposure limit (PEL) of 5 ppm set by OSHA (Occupational Safety and Health Administration), USA. The sensor based on the rGO/TPTP composite exhibited a very fast response and recovery time of 33 s. and 27 s. respectively. [ABSTRACT FROM AUTHOR]

[Display omitted] • Porphyrin-based POPs with different heteroatoms were constructed. • N and S heteroatoms were embed into the backbone structure. • PS 2 F showed high Hg2+ capacity of 1049 mg/g. • Functional groups play more important role in heavy metal adsorption. Development of novel sulf-functionalized porous organic polymers (POPs) for Mercury (II) (Hg2+) removal is of great significant, but the adsorbents always suffered by the low adsorption capacity, stability, and efficiency for the reason that the common construction of functionalized POPs from the functionalized monomers or post-functionalization of the POPs always sacrifice the porosity. In this paper, porphyrin-based POPs with different heteroatoms were constructed through the aldehyde monomer (benzene, 2,5-thiophenedicarboxaldehyde and thieno[3,2- b ]thiophene-2,5-dicarboxaldehyde) and pyrrole according to the Adler-Longo method. In this way, nitrogen (N) in pyrrole and sulfur (S) in thiophene structures were embed into the backbone structure of the polymers. The functional structures not only act as the linking building block into the stable cross-linking structure, but also offer abundant uncovered functional sites for Hg2+ adsorption, resulting the porphyrin-based POPs high Hg2+ capacity (1049 mg/g), removal efficiency (more than 99.9%), good reusability and selectivity for its highest heteroatoms contents. The adsorption mechanism confirmed the cooperative coordination of N in porphyrin and S in thiophene with Hg2+. This work confirmed the functional groups play more important role in heavy metal adsorption, and the embedded functional sites into backbone also promotes the stability and the adsorption performance. [ABSTRACT FROM AUTHOR]

In this study, FeTOMPP (Tetrakis(4-methoxyphenyl) phenylporphyrinatoiron(III)) was synthesized and investigated for its peroxidase-like activity. The catalytic performance of FeTOMPP as a peroxidase mimic was explored by utilizing the colorless peroxidase substrate, 3,3',5,5'-tetramethylbenzidine (TMB), in the presence of hydrogen peroxide (H2O2). The oxidation of TMB by FeTOMPP resulted in the formation of its blue oxidized state. This enzymatic reaction was employed for the quantitative detection of H2O2, with a linear detection range spanning from 1.0 to 100 µM. The detection limit achieved using FeTOMPP as the catalyst was determined to be 2.4 µM. Furthermore, kinetic studies were conducted to investigate the interaction between FeTOMPP and H2O2. The results indicated that FeTOMPP exhibited favorable affinity towards H2O2, further highlighting its potential as a peroxidase mimic. In addition to its peroxidase-like activity, a simple and sensitive visual and colorimetric method was developed for the detection of ethanol by combining FeTOMPP with alcohol oxidase. The method relied on the use of TMB as the substrate. Ethanol-containing samples were subjected to the enzymatic reaction, resulting in the generation of a color change. The detection of ethanol was achieved with a minimum detection limit of 0.95 % v/v, and the linear range for quantification extended from 0 to 15 % v/v. This study demonstrates the potential application of FeTOMPP as a peroxidase mimic for the sensitive detection of H2O2 and the development of a colorimetric method for ethanol detection. The findings highlight the versatility and promising capabilities of FeTOMPP in various analytical and diagnostic applications. [ABSTRACT FROM AUTHOR]

Molecular layer deposition (MLD) is an incredibly powerful and flexible tool for designing completely new materials with novel and unique properties. The low temperature layer‐by‐layer approach and the use of highly reactive reactants allows one to combine vastly different organic and inorganic species and construct nanostructures with subnanometer precision. If not limited by the volatility of the reactants involved, the possibilities will be endless. This is most notable for the organic building blocks where an overall low volatility severely limits the toolbox of large molecules with interesting optical and electrical properties such as red‐ox activity and optical conversion. In this work, different strategies for molecular design of large molecules are investigated that allow vaporization while still having the necessary reactivity for MLD growth. Using these strategies, film growth with perylene and porphyrin derivatives, both molecules well known for their functional and optical properties are successfully achieved. With this knowledge, there is an opening to include much larger and more complex organic molecules into the world of vapor phase chemistry. [ABSTRACT FROM AUTHOR]

This study investigated the adsorption of CO[sub 2] molecules on transition metal ions (TM) porphyrins induced carbon nanocone (TM-PICNC) (TM = Sc[sup 2+], Ti[sup 2+], V[sup 2+], Cr[sup 2+], Fe[sup 2+], Co[sup 2+], Ni[sup 2+], Cu[sup 2+], and Zn[sup 2+]) using density functional theory (DFT) to determine the stabilities, energetic, structural, and electronic properties. The results showed that the CO2 molecule is adsorbed on TM-PICNC with adsorption energies ranging from 0.03 to -12.12 kcal/mol. The weak interactions of CO2 gas with Cr, Ni, Cu, and Zn-PICNC were observed, while strong adsorption was found on Sc, Ti, and V-PICNC. The Ti, V, and Cr-PCNC structures were shown to have a suitable energy gap (Eg) for sensing ability because of the effective and physical interaction between these structures and CO2 gas, leading to a short recovery time. DFT calculations also revealed that V-PCNC had a high %ΔEg (about %56.79) and hence high sensitivity to CO2 gas, making it a promising candidate for having good sensing ability to CO2 gas in presence of O2 and H2O gas. [ABSTRACT FROM AUTHOR]

[Display omitted] • The nitrogen vacancies-zinc porphyrin (NVs-ZnTCPP) ultrathin nanosheets was fabricated through a simple surface N 2 plasma treatment. • The optimized NVs-ZnTCPP exhibits superior photocatalytic carbon dioxide (CO 2) reduction activity and selectivity to carbon monoxide (CO). • The promoted photocatalytic performance of NVs-ZnTCPP could be mainly attributed to nitrogen vacancy-induced spin polarization. Metalloporphyrin compounds have excellent electron transfer and visible light absorption ability, demonstrating broad application prospects in the field of photocatalysis. In this work, the nitrogen vacancies (NVs) were successfully introduced into zinc porphyrin (ZnTCPP) ultrathin nanosheets through surface N 2 plasma treatment, which is environmentally friendly and can react in low temperatures. Furthermore, the prepared nitrogen vacancies-zinc porphyrin (NVs-ZnTCPP) materials exhibited excellent photocatalytic CO 2 reduction activity and selectivity, specifically, the CO production rate of ZnTCPP-1 (N 2 plasma treatment, 1 min) achieved as high as 12.5 µmol g–1h−1, which is about 2.7 times greater than that of untreated ZnTCPP. Based on the experimental and density functional theory calculation (DFT) results, it is found that the promoted photocatalytic performance of NVs-ZnTCPP could be mainly attributed to nitrogen vacancy-induced spin polarization by reducing the reaction barriers and inhibiting the recombination of photoexcited carriers. This work provides a new perspective for the construction of vacancy-based metalloporphyrin, and further explores the intrinsic mechanism between the electron spin property and the performance of the photocatalyst. [ABSTRACT FROM AUTHOR]

Acidithiobacillus ferrooxidans are beneficial bacteria for bioleaching in the mining industry to extract useful fractions from tons of waste. These bacteria are able to oxidize ferrous iron (Fe2+) to ferric iron (Fe3+) and use the released energy to assimilate carbon from carbon dioxide or carbonates, and can be used in the desulfurization of coal and gas. In this regard, activators of the growth of these bacteria may be useful. During the experiments on these bacterial strains, an unexpected effect of growth activation was revealed. This gives rise to further research in this direction and the identification of patterns of "structure‐activity" derivatives of ferrocene and porphyrins in relation to A. ferrooxidans. [ABSTRACT FROM AUTHOR]

Pollutant degradation has been a very important topic in environmental research. The present paper presents an approach to degrade atrazine, an environmentally harmful herbicide that has been widely used in the agriculture industry. Ti/TiO2 nanotube electrodes modified by porphyrins were prepared for photolysis, photocatalysis, and photoelectrocatalysis (PEC) applications. Manganese- and free base porphyrin were studied, and it was possible to verify the kinetic model more suitable for each system. Unfortunately, Mn-porphyrins had an inhibitory effect on the ATZ degradation activity by Ti/TiO2 nanotube electrodes. Although the Ti/TiO2-free base porphyrin under the PEC experiment (using surface water from a Brazilian river) did not lead to the best degradation system, we could verify the formed products, which have been not described for other porphyrin-mediated atrazine degradation, are equal or more toxic than the original atrazine. We highlight the importance of verifying the products formed in the degradation systems and determining their toxicities. [ABSTRACT FROM AUTHOR]

Treatment regimens are regularly evolving alongside novel therapies and drugs. Such evolution is necessary to circumvent resistance mechanisms and to give patients the best possible health care. When dealing with cancer, most regimens involve multiple treatments (surgery, radiation therapy, chemotherapy, immunotherapy, etc.). The purpose of this study was to associate in a single compound metal-based drugs and photosensitizers to combine chemotherapy and photodynamic therapy. Two arene–ruthenium tetrapyridylporphyrin compounds (2H-TPyP-arene-Ru and Zn-TPyP-arene-Ru) have been synthesized and evaluated on two colorectal cancer cell lines (HCT116 and HT-29). Their cytotoxicity and phototoxicity have been evaluated. In addition, the anticancer mechanism and the cell death process mediated by the two compounds were studied. The results showed that the two arene–ruthenium photosensitizer-containing complexes have a strong phototoxic effect after photoactivation. The 2H-TPyP-arene-Ru complex induced outstanding cytotoxicity when compared to the Zn-TPyP-arene-Ru analogue. Moreover, under light, these two arene–ruthenium photosensitizers induce an apoptotic process in human colorectal cancer cell lines. [ABSTRACT FROM AUTHOR]

Novel hybrid TiO2-based materials were obtained by adsorption of two different porphyrins on the surface of nanoparticles—commercially available 5,10,15,20-tetrakis(4-sulfonatophenyl)porphyrin (TPPS) and properly modified metalloporphyrin—5,10,15,20-tetrakis(2,6-difluoro-3-sulfophenyl)porphyrin palladium(II) (PdF2POH). The immobilization of porphyrins on the surface of TiO2 was possible due to the presence of sulfonyl groups. To further elevate the adsorption of porphyrin, an anchoring linker—4-hydroxybenzoic acid (PHBA)—was used. The synthesis of hybrid materials was proven by electronic absorption spectroscopy, dynamic light scattering (DLS), and photoelectrochemistry. Results prove the successful photosensitization of TiO2 to visible light by both porphyrins. However, the presence of the palladium ion in the modifier structure played a key role in strong adsorption, enhanced charge separation, and thus effective photosensitization. The incorporation of halogenated metalloporphyrins into TiO2 facilitates the enhancement of the comprehensive characteristics of the investigated materials and enables the evaluation of their performance under visible light. The effectiveness of reactive oxygen species (ROS) generation was also determined. Porphyrin-based materials with the addition of PHBA seemed to generate ROS more effectively than other composites. Interestingly, modifications influenced the generation of singlet oxygen for TPPS but not hydroxyl radical, in contrast to PdF2POH, where singlet oxygen generation was not influenced but hydroxyl radical generation was increased. Palladium (II) porphyrin-modified materials were characterized by higher photostability than TPPS-based nanostructures, as TPPS@PHBA-P25 materials showed the highest singlet oxygen generation and may be oxidized during light exposure. Photocatalytic activity tests with two model pollutants—methylene blue (MB) and the opioid drug tramadol (TRML)—confirmed the light dose-dependent degradation of those two compounds, especially PdF2POH@P25, which led to the virtually complete degradation of MB. [ABSTRACT FROM AUTHOR]

The harmful pollutant perfluorooctane sulfonate (PFOS) is difficult to detect without extensive laboratory equipment used by trained personnel. Herein, we report the use of a micelle-encapsulated porphyrin host molecule as a rapid colorimetric indicator for PFOS and its anionic salts. A range of common commercially available surfactants were tested and optimised to encapsulate the hydrophobic highly pigmented porphyrin sensor molecule. This method was used for the detection of PFOS in aqueous solutions at concentrations as low as 3 ppm. Colour space RGB information was extracted from a mobile phone photograph and parameterised, allowing for threshold PFOS detection, demonstrating the applicability of this method as an easily accessible approach to inform an untrained user. A proof-of-concept method has been developed to detect perfluorooctanesulfonate (PFOS). A coloured porphyrin host molecule suspended in micelles changes colour when it encounters PFOS. Photographs of the coloured solutions were analysed allowing for the detection of PFOS in water at concentrations as low as 3 ppm. CH23061_TOC.jpg [ABSTRACT FROM AUTHOR]

[Display omitted] • Minor structural differences of hydrophobic porphyrins can distinctly influence their release properties from liposomes. • mTHPP (meta OH) redistributes much slower than pTHPP (para OH) from liposomal membranes. • Reversed-phase HPLC experiments indicate a higher partition coefficient for mTHPP. • In MD simulations, mTHPP has a higher tendency for hydrogen bonding, a larger tilt angle and locates deeper in the membrane. • Both HPLC and MD simulation results support the observed differences in release and redistribution of mTHPP and pTHPP from liposomal membranes. The release of hydrophobic compounds from liposomal membranes occurs by partitioning and is thus determined by the physicochemical properties (e.g. logP and water solubility) of the drug. We postulate that even minor structural differences, e.g. the position of the phenolic OH-group of the hydrophobic porphyrins mTHPP and pTHPP (meta vs. para substitution), distinctly affect their partitioning and release behavior from liposomes. The release and redistribution of mTHPP and pTHPP from lecithin or POPC/POPG liposomes to different acceptor particles (DSPE-mPEG micelles and liposomes) was studied by asymmetrical flow field-flow fractionation to separate donor and acceptor particles. Reversed phase HPLC was applied to detect differences in partitioning. Molecular dynamics (MD) simulations were carried out to obtain molecular insight in the different behavior of the two compounds inside a lipid bilayer. Despite the minor differences in chemical structure, mTHPP is more hydrophobic and redistributes much slower to both acceptor phases than pTHPP. MD simulations indicate that compared to pTHPP, mTHPP makes stronger hydrogen bonds with the lipid head groups, is oriented more parallel to the lipid tails and is embedded slightly deeper in the membrane. [ABSTRACT FROM AUTHOR]

Photosensitization of proteins mediated by chromophores is a mechanism commonly employed by nature and mimicked in a broad array of laboratory research and applications. Nature has evolved specialized complexes of proteins and photosensitizers (PS) that assemble to form photoreceptor proteins (PRP). These are used by many organisms in diverse processes, such as energy conversion, protection against photodamage, etc. The same concept has been used in laboratory settings for many applications, such as the stimulation of neurons or the selective depletion of proteins in a signaling pathway. A key issue in laboratory settings has been the relationship between the photooxidation of proteins and conformational changes in host proteins. For several years, we have been interested in creating non-native PRP using porphyrin PS. In this study, we investigated the self-assembled complex between zinc protoporphyrin IX (ZnPPIX) and bovine β-lactoglobulin (BLG) as a model of non-native PRP. Since BLG undergoes a significant conformational transition near physiological pH, the study was carried out at acidic (pH 5) and alkaline (pH 9) conditions where the two conformations are respectively prevalent. We employed a series of steady-state and time-resolved optical spectroscopies as well as gel electrophoresis to experimentally characterize the photosensitization mechanisms and their effect on the host protein. Our results show that ZnPPIX prompts light-dependent modifications of BLG, which appear to be much more significant at alkaline pH. The modifications seem to be driven by photooxidation of amino acid residues that do not lead to the formation of cross-links or protein fragmentation. [ABSTRACT FROM AUTHOR]

The emergence of toxic pollutants due to heavy human intervention in the ecosystem causes serious environmental problems. Therefore, sensors based on material having a strong affinity towards specific environmental gaseous pollutants are urgently needed. The present study deals with chemiresistive gas sensors for the detection of sulfur dioxide (SO2) based on a composite of reduced graphene oxide (rGO) and 5,10,15,20-tetrakis(4-aminophenyl) porphyrin (TAPP). The improved Hummers method was used to synthesize graphene oxide (GO); it was further thermally reduced to rGO. The pattern of the copper electrode was coated on glass slides with a shadow mask using thermal evaporation. Then, GO was drop-cast between the two copper electrodes, thermally reduced to obtain rGO, and then modified by TAPP. The spectroscopic, structural, morphological, electrical, and optical studies were carried out using Fourier transform infrared spectroscopy, x-ray diffraction, Raman spectroscopy, atomic force microscopy, field emission scanning electron microscopy, current–voltage (I–V) and UV–visible spectroscopy, respectively. The developed sensor shows high selectivity towards SO2 gas analytes among exposed gaseous analytes. It exhibited reproducible response from 50 ppm to 200 ppm with enhanced repeatability at 50 ppm. The rGO/TAPP sensor exhibited a significant response (57 s) and recovery time (61 s), with a 5 ppm limit of detection. [ABSTRACT FROM AUTHOR]

The interaction of cationic porphyrin with gold nanoparticles (GNPs) coated with polymer shells with positive and negative surface potentials in an aqueous solution is studied. The criteria for the formation of hybrid molecular-plasmon nanostructures based on the determination of the luminescence quenching mechanism according to the Stern–Volmer equation and the change in the shape of the porphyrin luminescence spectrum are established. The effect of the sign of the zeta potential of GNPs on the formation of hybrid molecular-plasmon nanostructures due to electrostatic interaction is established. [ABSTRACT FROM AUTHOR]

The investigation employed cyclic voltammetry (CV) assays to assess the scavenging efficacy of two recently developed compounds, namely meso-tetramethophenyl-porphyrin TPPH2(o-methyl) and meso-tetrabiphenyl-porphyrin (TbiPPH2), against the superoxide anion radical ( ). The IC50 values derived from the CV assays indicated significant scavenging activity for both compounds, with TbPPH2 exhibiting superior potency (85.79 ± 0.11 µg ml-1) compared to the standard antioxidant alpha-tocopherol (353.27 ± 3.21 µg ml-1). Additionally, molecular docking simulations elucidated the interaction of the investigated compounds with specific amino acid residues of glutathione reductase through hydrogen bonding and hydrophobic interactions. The in vitro and in silico results were concordant, highlighting TbiPPH2 as the least active compound against glutathione reductase, boasting the highest inhibitory concentration of 0.63 μM and the lowest docking score of -35.36 kJ mol-1, thus positioning it as a promising candidate for antioxidant applications.

Abstract Photoacoustic imaging (PAI)‐guided photothermal therapy (PTT) in the second near‐infrared (NIR‐II, 1000–1700 nm) window has been attracting attention as a promising cancer theranostic platform. Here, it is reported that the π‐extended porphyrins fused with one or two nanographene units (NGP‐1 and NGP‐2) can serve as a new class of NIR‐responsive organic agents, displaying absorption extending to ≈1000 and ≈1400 nm in the NIR‐I and NIR‐II windows, respectively. NGP‐1 and NGP‐2 are dispersed in water through encapsulation into self‐assembled nanoparticles (NPs), achieving high photothermal conversion efficiency of 60% and 69%, respectively, under 808 and 1064 nm laser irradiation. Moreover, the NIR‐II‐active NGP‐2‐NPs demonstrated promising photoacoustic responses, along with high photostability and biocompatibility, enabling PAI and efficient NIR‐II PTT of cancer in vivo.

Singlet oxygen (1O2) is a potent biocide potentially deployable for integrated control of tropical diseases and their insect vectors. This very short-lived free radical is highly destructive of cellular molecules when generated intracellularly. Most organisms, including parasites and vectors, are defenseless against 1O2 except for plants, which produce it abundantly during photosynthesis, hence, the acquisition of specific mechanisms for its detoxification. In the presence of O2 under physiological conditions, certain dyes or photosensitizers (PS), e.g., porphyrins and phthalocyanines (PC), are excitable by light to produce biocidal 1O2. Its half-life is in the order of microseconds, necessitating its intracellular generation in order to harness its biocidal activity most effectively. This is achievable by loading cells with PS for excitation with light to produce 1O2in situ. One example to achieve this is the genetic engineering of Leishmania to complement its inherent defects in porphyrin biosynthesis, resulting in cytosolic accumulation of abundant PS in the form of uroporphyrin 1 (URO). Another example is the chemical engineering of PC for hydrophilicity, thereby facilitating the endocytosis of such PS by cells. Leishmania loaded with cytosolic URO and endosomal PC are inactivated by the 1O2 produced via light-activation of these PS in the two different cell compartments. The inactivated Leishmania are nonviable, but have their natural vaccines and adjuvants well-preserved for prophylactic vaccination against experimental leishmaniasis. 1O2-inactivated Leishmania is potentially useful to serve as a platform for the safe and effective delivery of transgenically add-on vaccines against malignant and viral diseases in experimental models. Hydrophilic and cationic PC were also shown experimentally to act as a new type of dim light-activable insecticides, i.e., their mosquito larvicidal activities with

The global energy crisis and environmental pollution issues caused by the continuous consumption of fossil fuels are increasingly becoming severe. Developing clean and sustainable hydrogen (H2) energy and corresponding storage and conversion devices have attracted increasing attention. The utilization of H2 energy highly depends on the fuel cell (FC). However, the slow kinetics of oxygen reduction reaction (ORR) on the cathode of FC cannot be improved without efficient catalysts. Currently, precious metal platinum (Pt) and its alloys are commonly used catalysts for ORR process. However, the scarcity and high cost of Pt hinder their large-scale practical application. To replace typical Pt-based catalysts, non-precious metal electrocatalysts have been investigated for ORR. Inspired by the catalytic ORR active center Fe porphyrin of cytochrome c oxidase in nature, metalloporphyrin-based frameworks and their derivatives have become promising electrocatalysts due to their abundant conjugated electronic structure, tunable functional groups, and large specific surface area. First, this review briefly introduces porphyrins and catalytic ORR mechanisms. Second, recent progress on porphyrin-based ORR catalysts including porphyrin-based frameworks, framework@substrate composites, and framework-based derivatives was summarized. Porphyrin-based frameworks mainly include metal-organic frameworks (MOFs), covalent organic frameworks (COFs), hydrogen-bonded organic frameworks (HOFs), and polymers constructed with porphyrin building blocks. Porphyrin-based framework@substrate composites were usually assembled and constructed to improve the electron transfer rate of frameworks. To further improve the conductivity, framework-based derivatives, usually named metal, nitrogen-doped carbon (M-N-C) materials, were synthesized through pyrolyzing frameworks at high temperatures. Finally, research challenges and directions of porphyrin-based electrocatalysts for ORR were discussed. This review is meaningful and enlightening for designing and developing other porphyrin-based electrocatalysts for ORR.

Abstract In this manuscript, the development of an experimental and mathematical toolset is reported that allows for improved in vivo measurements of optical transcutaneous oxygen tension measurements (TCOM) wearable technology in humans. In addition to optimizing O2‐sensing films for higher sensitivity oxygen detection, calibration algorithms are additionally developed to account for excitation source leakage, as well as algorithms to combine readings of partial pressure of oxygen (pO2), derived from phosphorescence intensity and lifetime, into a single metric. This new iteration of the TCOM wearable device is then tested in a pilot human study. By implementing characterization and calibration algorithms, the data from the pilot study demonstrates the ability to obtain reliable transcutaneous pO2 readings with a TCOM sensor regardless of size and without the need for strict conditions of constant temperature, humidity, or motion that have limited the range of applications of this technology in the past.

Abstract Photodynamic therapy (PDT) is a promising treatment against bacteria‐caused infections. By producing large amounts of reactive oxygen species (ROS), PDT can effectively eliminate pathogenic bacteria, without causing drug resistance. However, excessive ROS may also impose an oxidative stress on surrounding tissues, resulting in local inflammation. To avoid this major drawback and limit pro‐inflammation during PDT, this work prepared a supramolecular photosensitizer (TPP‐CN/CP5) based on host‐guest interactions between a cysteine‐responsive cyano‐tetraphenylporphyrin (TPP‐CN) and a water‐soluble carboxylatopillar[5]arene (CP5). TPP‐CN/CP5 not only possesses excellent photodynamic antibacterial properties, but also shows good anti‐inflammatory and cell protection capabilities. Under 660 nm light irradiation, TPP‐CN/CP5 could rapidly produce abundant ROS for sterilization. After the PDT process, the addition of cysteine (Cys) triggers the release of H2S from TPP‐CN. H2S then stops the induced inflammation by inhibiting the production of related inflammatory factors. Both in vitro and in vivo experiments show the excellent antibacterial effects and anti‐inflammatory abilities of TPP‐CN/CP5. These results will certainly promote the clinical application of PDT in the treatment of bacterial infectious diseases.

PrPSc, a misfolded, aggregation-prone isoform of the cellular prion protein (PrPC), is the infectious prion agent responsible for fatal neurodegenerative diseases of humans and other mammals. PrPSc can adopt different pathogenic conformations (prion strains), which can be resistant to potential drugs, or acquire drug resistance, posing challenges for the development of effective therapies. Since PrPC is the obligate precursor of any prion strain and serves as the mediator of prion neurotoxicity, it represents an attractive therapeutic target for prion diseases. In this minireview, we briefly outline the approaches to target PrPC and discuss our recent identification of Zn(II)-BnPyP, a PrPC-targeting porphyrin with an unprecedented bimodal mechanism of action. We argue that in-depth understanding of the molecular mechanism by which Zn(II)-BnPyP targets PrPC may lead toward the development of a new class of dual mechanism anti-prion compounds.

Photosensitization of proteins mediated by chromophores is a mechanism commonly employed by nature and mimicked in a broad array of laboratory research and applications. Nature has evolved specialized complexes of proteins and photosensitizers (PS) that assemble to form photoreceptor proteins (PRP). These are used by many organisms in diverse processes, such as energy conversion, protection against photodamage, etc. The same concept has been used in laboratory settings for many applications, such as the stimulation of neurons or the selective depletion of proteins in a signaling pathway. A key issue in laboratory settings has been the relationship between the photooxidation of proteins and conformational changes in host proteins. For several years, we have been interested in creating non-native PRP using porphyrin PS. In this study, we investigated the self-assembled complex between zinc protoporphyrin IX (ZnPPIX) and bovine β-lactoglobulin (BLG) as a model of non-native PRP. Since BLG undergoes a significant conformational transition near physiological pH, the study was carried out at acidic (pH 5) and alkaline (pH 9) conditions where the two conformations are respectively prevalent. We employed a series of steady-state and time-resolved optical spectroscopies as well as gel electrophoresis to experimentally characterize the photosensitization mechanisms and their effect on the host protein. Our results show that ZnPPIX prompts light-dependent modifications of BLG, which appear to be much more significant at alkaline pH. The modifications seem to be driven by photooxidation of amino acid residues that do not lead to the formation of cross-links or protein fragmentation.

Abstract Background Since effective antiviral drugs for COVID-19 are still limited in number, the exploration of compounds that have antiviral activity against SARS-CoV-2 is in high demand. Porphyrin is potentially developed as a COVID-19 antiviral drug. However, its low solubility in water restricts its clinical application. Reconstruction of porphyrin into carbon dots is expected to possess better solubility and bioavailability as well as lower biotoxicity. Methods and results In this study, we investigated the antiviral activity of porphyrin and porphyrin-derived carbon dots against SARS-CoV-2. Through the in silico analysis and assessment using a novel drug screening platform, namely dimer-based screening system, we demonstrated the capability of the antivirus candidates in inhibiting the dimerization of the C-terminal domain of SARS-CoV-2 Nucleocapsid. It was shown that porphyrin-derived carbon dots possessed lower cytotoxicity on Vero E6 cells than porphyrin. Furthermore, we also assessed their antiviral activity on the SARS-CoV-2-infected Vero E6 cells. The transformation of porphyrin into carbon dots substantially augmented its performance in disrupting SARS-CoV-2 propagation in vitro. Conclusions Therefore, this study comprehensively demonstrated the potential of porphyrin-derived carbon dots to be developed further as a promisingly safe and effective COVID-19 antiviral drug.

[Display omitted] Water-soluble phosphorus(v) porphyrin with p -amino- phenoxy groups as axial ligands was obtained, and its photophysical and photochemical properties were investigated and rationalized using quantum chemical calculations. It was demonstrated that at pH ≥ 6.1 this porphyrin did not emit or generate singlet oxygen, whereas at pH ≤ 2.0 it completely converted into the N-protonated form, which exhibited fluorescence and the ability to generate singlet oxygen. [ABSTRACT FROM AUTHOR]