Ligand Precursors Research Articles

Recent developments in amino acid-derived imidazole-, imidazolium- and N-heterocyclic carbene-carboxylate complexes

Compounds based on imidazole or imidazolium moieties are excellent building blocks for the preparation of a plethora of ligand precursors. The introduction of chirality in these compounds is relatively easy through the Debus-Radziszewski reaction, in which the chiral pools are natural or non-natural amino acids. Using this synthetic route, enantiopure imidazole-carboxylate, imidazolium-carboxylate, and imidazolium-dicarboxylate ligand precursors can be prepared, from which N-heterocyclic carbenes (NHC) with one or two carboxylate groups can also be obtained. This review is a personal account that summarizes our recent results regarding the use of all these compounds as chiral ligands coordinated to several transition metals (Cu, Zn, Ag and Mo). The structural features of the new synthesized coordination polymers with novel bonding modes will be described, and the bonding capabilities of these ligands rationalized on the basis of theoretical calculations. The efficiency of homochiral imidazolium-dicarboxylate compounds as chiral inductors in asymmetric catalysis will also be discussed. Finally, the antimicrobial and antitumoral activities of imidazolium- and NHC-carboxylate silver complexes and the found chirality-activity and structure–activity relationships will be highlighted.

Antioxidant Chimeric Molecules: Are Chemical Motifs Additive? The Case of a Selenium-Based Ligand.

We set up an in silico experiment and designed a chimeric compound integrating molecular features from different efficient ROS (Reactive Oxygen Species) scavengers, with the purpose of investigating potential relationships between molecular structure and antioxidant activity. Furthermore, a selenium centre was inserted due to its known capacity to reduce hydroperoxides, acting as a molecular mimic of glutathione peroxidase; finally, since this organoselenide is a precursor of a N-heterocyclic carbene ligand, its Au(I) carbene complex was designed and examined. A validated protocol based on DFT (Density Functional Theory) was employed to investigate the radical scavenging activity of available sites on the organoselenide precursor ((SMD)-M06-2X/6-311+G(d,p)//M06-2X/6-31G(d)), as well as on the organometallic complex ((SMD)-M06-2X/SDD (Au), 6-311+G(d,p)//ZORA-BLYP-D3(BJ)/TZ2P), considering HAT (Hydrogen Atom Transfer) and RAF (Radical Adduct Formation) regarding five different radicals. The results of this case study suggest that the antioxidant potential of chemical motifs should not be considered as an additive property when designing a chimeric compound, but rather that the relevance of a molecular topology is derived from a chemical motif combined with an opportune chemical space of the molecule. Thus, the direct contributions of single functional groups which are generally thought of as antioxidants per se do not guarantee the efficient radical scavenging potential of a molecular species.

Unveiling the Role of Precursors in the Byproduct Formation of AgCl-Replicated Bimetallic Nanostructures and Their Stability-Dependent Photothermal Properties.

AgCl nanomaterials recently attracted scientific interest as useful structural building blocks for producing metallic nanomaterials owing to their facile synthesis, controllable morphology, and ease of removal under ambient conditions. However, their complex chemical reactivity has primarily been studied in association with water solubility or reducibility. This study investigates the pivotal role of precursor ligands in the photochemical synthesis of metallic cubic mesh nanostructures on the AgCl templates. The side reactions between AgCl and Au precursors with different ligands are thoroughly discussed along with their influence on the byproduct formation and the structural stability of the resulting metallic nanostructures. Importantly, we introduce for the first time the partial destruction of AgCl and the formation of undesirable byproducts caused by the presence of highly oxidizing and Cl-containing AuCl4-. In addition, a synthetic route for producing highly pure and stable metallic nanostructures using a halogen-free Au precursor or Pt-priming is proposed. Further, the photothermal properties of these replicated metallic nanostructures are presented as a new evaluation tool for analyzing their overall structural stability. Discovering the role of precursor ligands in the reaction system will prove useful as a guide for the synthesis of functional noble metal nanomaterials using silver halide templates.

Ni(II)-Salophen-Comprehensive Analysis on Electrochemical and Spectral Characterization and Biological Studies.

New aspects of the Ni(II)-salophen complex and salophen ligand precursor were found during deep electrochemical and optical characterization, as well as biological studies for new pharmacological applications. Physicochemical and spectroscopic methods (1H- and 13C-NMR, FT-IR and UV-Vis, electrospray ionization mass spectroscopy, thermogravimetric analysis, and molar conductance measurements) were also used to prove that the salophen ligand acts as a tetradentate and coordinates to the central metal through nitrogen and oxygen atoms. The electrochemical behavior of the free Schiff salophen ligand (H2L) and its Ni(II) complex (Ni(II)L) was deeply studied in tetrabutylammonium perchlorate solutions in acetonitrile via CV, DPV, and RDE. Blue films on the surfaces of the electrodes as a result of the electropolymerization processes were put in evidence and characterized via CV and DPV. (H2L) and Ni(II)L complexes were tested for their antimicrobial, antifungal, and antioxidant activity, showing good antimicrobial and antifungal activity against several bacteria and fungi.

Decarboxylative Functionalization of β,γ‐Unsaturated Carboxylic Acids: New Perspective for the Synthesis of Functionalized Allylic Compounds

AbstractDue to the versatile reactivity of allyl moieties for further transformations and their omnipresence in biologically and pharmaceutically active molecules, significant efforts have been devoted to the efficient introduction of such groups into organic compounds. Although a large variety of allylating reagents have been successfully developed, development of new, efficient and environmentally benign allylating reagents remains in high demand. Recently, easily accessible β,γ‐unsaturated carboxylic acids have been explored as promising allylating agents in decarboxylative allylation reactions. This type of transformation provides facile access to various functionalized allyl compounds including those that are difficult to prepare using the classic allylating reagents with high efficiency and regiocontrol, and can be rendered enantioselective by choosing a suitable catalyst precursor and chiral ligand. Moreover, utilizing such allylating reagents allows for the discovery of novel transformations, especially under visible light photocatalysis.

A Computational Study of a Prebiotic Synthesis of a Tripeptide: Thyrotropic Releasing Hormone (TRH)

Ab initio calculations are used to calculate the viability of a prebiotic mechanism for the synthesis of L-proteins considered as a one-dimensional cooperative system having interlocking terms involving two neighbouring amino-acid residues yielding the inter-bond energy, optimum conformation, and charge distribution leading to an estimate of the secondary structure. The prebiotic synthesis of poly amino acids is illustrated with the synthesis of a tripeptide, thyrotropic releasing hormone. The magnesium ion metalloporphyrin complex is shown to bind the prebiotic stereospecific ligand precursors of the amino acids proline, histidine, and pyroglutamic on the metal or nitrogen pyrrole sites as a two-site catalyst in their copolymerization to form Glu-His-Pro-NH2. The order of addition of the monomers is the reverse of pyroglutamylhistidinylprolamide to form the tripeptide. which is separated from the catalyst by hydrogen ions. The reactions are feasible from the overall enthalpy changes in the ZKE approximation at the HF and MP2 /6-31G* level, and with acceptable activation energies.

Blue emitting phosphorescent platinum(II) complexes with cyclometalated 4,5-dimethylimidazolylidene ligands

Three different imidazolylidene ligand precursors with methyl groups in 4- and 5-position were synthesized and selected to build a series of nine cyclometalated platinum(II) complexes. Next to the carbene ligands, β-diketonate and bis(pyrazolyl)borate motifs were used as auxiliary ligands. All complexes were fully characterized by standard techniques, five of them also by solid-state structure determinations. All of the synthesized platinum complexes show phosphorescence at room temperature in a PMMA matrix with quantum yields of up to 92% in the green-blue to pure blue area (CIE color coordinates of 0.154; 0.119) of the visible spectrum. Quantum chemical calculations (PBE0/6-311G*) as well as electrochemical experiments provided additional insight into the properties of these compounds.

Synthesis and Characterization of Cobalt(II/II) and Cobalt(II/III) Macrocyclic Complexes and Their Application in the Copolymerization of Epoxides and CO2

The synthesis and characterization of six dinuclear cobalt complexes bearing a conjugated macrocyclic ligand are reported. The condensation of 2,6-diformylphenol and o-phenylenediamine led to semi-hydrogenated macrocycles A–C. The ligand precursor A reacted with Co(OAc)2·4H2O and generated the Co(II/II) complex 1, and a conjugated macrocyclic ligand was formed during the complexation. The partial oxidation of 1 with air resulted in mixed-valence Co(II/III) complexes 2 and 3 bearing different anionic ligands. Analogous Co(II/III) complexes 4–6 of Cl- and F-substituted ligand backbones were also synthesized. Structural characterization and charge determination of all complexes were achieved through X-ray diffraction analysis and X-ray photoelectron spectroscopy. These complexes were applied in the copolymerization of CO2 and cyclohexene oxide (CHO), and the mixed valence Co(II/III) complex 2 showed good reactivity and selectivity (>99% polycarbonate).

Silicon oxynitride thin films by plasma-enhanced atomic layer deposition using a hydrogen-free metal-organic silicon precursor and N2 plasma

We investigated the growth mechanism of SiOxNy films deposited via plasma-enhanced atomic layer deposition at low temperatures (100–300 °C) using a tetraisocyanate silane (Si(NCO)4) precursor and N2 plasma. By using tetraisocyanate silane, which does not contain hydrogen, we were able to deposit SiOxNy with notably less hydrogen, around 3–5%, compared to using silicon precursors that contain hydrogen. Additionally, the precursor ligands, including oxygen, react with surface amine groups (-NH2) to form Si–N–O bonds. Therefore, by understanding the adsorption mechanism of the precursor and controlling the temperature that can affect the bond formation, we can successfully produce SiOxNy films without any oxidizing source. We utilized density functional theory to explore the adsorption mechanism during the deposition of SiOxNy films and proposed a possible adsorption pathway of the precursors and by-products on the surface. We also employed various characterization techniques, such as spectroscopic ellipsometry, X-ray photoelectron spectroscopy, X-ray reflectometry, secondary ion mass spectroscopy, and current-electric field and capacitance-voltage analyses to establish correlations between the composition and dielectric properties of the thin films. Increasing the deposition temperature results in an increased presence of stronger and more stable Si–N bonds compared to Si–O and O–N bonds. As a result, the dielectric constant of the SiOxNy film increased from 5.8 to 7.4, while the leakage current density decreased from 1.52 × 10−8 A/cm2 to 8.56 × 10−10 A/cm2. Additionally, the counterclockwise hysteresis decreased from 0.16 V to 0.07 V as the amount of hydrogen in the SiOxNy film decreased. This can be interpreted as a reduction in hydrogen impurities, which act as charge trapping sites within the film, leading to a decrease in hysteresis with increasing temperature.

Review on Isatin- A Remarkable Scaffold for Designing Potential Therapeutic Complexes and Its Macrocyclic Complexes with Transition Metals.

Role of synthetic coordination chemistry in pharmaceutical science is expeditiously increased due to its sundry relevances in this field. The present review endows the synthesized macrocyclic complexes of transition metal ions containing isatin and its derivatives as ligand precursors, their characterization and their copious pharmaceutical applications. Isatin (1H-Indole-2,3-dione) is a protean compound (presence of lactam and keto moiety permits to change its molecular framework) that can be obtained from marine animals, plants, and is also found in mammalian tissues and in human fluids as a metabolite of amino acids. It can be used for the synthesis of miscellaneous organic and inorganic complexes and for designing of drugs since it has remarkable utility in pharmaceutical industry due to its wide range of biological and pharmacological activities, for instance anti-microbial, anti-HIV, anti-tubercular, anti-cancer, anti-viral, anti-oxidant, anti-inflammatory, anti-angiogenic, analgesic activity, anti-Parkinson’s disease, anti-convulsant etc. This review provides extensive information about the latest methods for the synthesis of isatin or its substituted derivatives based macrocyclic complexes of transition metals and their plentiful applications in medicinal chemistry.

An Electron‐Deficient CpE Iridium(III) Catalyst: Synthesis, Characterization, and Application to Ether‐Directed C−H Amidation

AbstractThe synthesis, characterization, and catalytic performance of an iridium(III) catalyst with an electron‐deficient cyclopentadienyl ligand ([CpEIrI2]2) are reported. The [CpEIrI2]2 catalyst was synthesized by complexation of a precursor of the CpE ligand with [Ir(cod)OAc]2, followed by oxidation, desilylation, and removal of the COD ligand. The electron‐deficient [CpEIrI2]2 catalyst enabled C−H amidation reactions assisted by a weakly coordinating ether directing group. Experimental mechanistic studies and DFT calculations suggested that the high catalytic performance of [CpEIrI2]2 is due to its electron‐deficient nature, which accelerates both C−H activation and IrV‐nitrenoid formation.

An Electron-Deficient CpE Iridium(III) Catalyst: Synthesis, Characterization, and Application to Ether-Directed C-H Amidation.

The synthesis, characterization, and catalytic performance of an iridium(III) catalyst with an electron-deficient cyclopentadienyl ligand ([CpE IrI2 ]2 ) are reported. The [CpE IrI2 ]2 catalyst was synthesized by complexation of a precursor of the CpE ligand with [Ir(cod)OAc]2 , followed by oxidation, desilylation, and removal of the COD ligand. The electron-deficient [CpE IrI2 ]2 catalyst enabled C-H amidation reactions assisted by a weakly coordinating ether directing group. Experimental mechanistic studies and DFT calculations suggested that the high catalytic performance of [CpE IrI2 ]2 is due to its electron-deficient nature, which accelerates both C-H activation and IrV -nitrenoid formation.

Reinvestigating the synthesis and properties of high energetic MOFs based on 5,5′-bistetrazole-1,1′-diolate (BTO2−) and some transition metal cations (Pb2+, Cu2+ and Ag+)

5,5′-Bistetrazole-1,1′-diole (H2BTO), as a high energetic compound, is the precursor for the synthesis of insensitive high explosive (TKX-50, ABTOX and …). It is also considered as an attracting high nitrogen content ligand to prepare high energetic MOFs. Herein, H2BTO has been synthesized following a four steps method from glyoxal with an overall yield of 68%. Then, MOFs based on this ligand and Pb2+, Cu2+, and Ag+ have been prepared via hydrothermal method in a cylindrical glass pressure vessel at 130 °C. ICP-AES analysis confirms the composition of the produced MOFs as [Pb(BTO)(H2O)2]n, [Cu(BTO)(H2O)2]n and [Ag(HBTO)]n that, compared to the ligand precursor (H2BTO), are more dense and thermal stable but are more sensitive toward impact. Among these three MOFs, [Cu(BTO)(H2O)2]n present promising sensitivity properties (friction sensitivity >360 N and impact sensitivity of 28 J).

Molybdenum(VI) complexes with a chiral l-alanine bisphenol [O,N,O,O’] ligand. Synthesis, structure, spectroscopic properties and catalytic activity

Dioxidomolybdenum(VI) compound [MoO2Cl2(dmso)2] reacts with a chiral tetradentate O3N-type l-alanine bisphenol ligand precursor (Et3NH)H2Lala to form an oxidochloridomolybdenum(VI) complex [MoOCl(Lala)] (1) as two separable geometric isomers with phenolate groups in cis or trans positions. The single crystal X-ray and NMR analyses of cis- and trans-1 reveal that the complexes are formed of monomeric molecules, in which the ligand has a tetradentate coordination through three oxygen donors and one nitrogen donor. The reaction of Na2MoO4·2H2O with the same ligand precursor in an acidic methanol solution leads to the formation of an anionic dioxido complex (Et3NH)[MoO2(Lala)] (2) with a trans coordination of the tetradentate ligand. Trans-1 and 2 were studied as active catalysts for olefin epoxidation: i.e. styrene, cyclohexene, S(–)-limonene and (–)-α-pinene using H2O2 and tBuOOH as oxidants.

Highly Stable CsPbBr3 Nanocrystals for Photocatalytic Reduction of CO2: Ionic Liquid as a Surface Passivation Ligand and Reaction Precursor

All inorganic metal halide perovskites (MHPs) have been regarded as a new type of promising photocatalyst for the reduction of CO2. However, due to their strong ionicity and the labile surface ligands, there is still much room for improvement of the stability and efficiency of MHP photocatalysts. Here, we propose a new strategy simultaneously using ionic liquid (IL) as a surface passivation ligand and a precursor to mediate the growth and then stabilize CsPbBr3 MHPs for the photocatalytic reduction of CO2. First, the TEM and XRD results show that the prepared CsPbBr3 has a cubic morphology with the monoclinic phase when the IL of 1-octyl-3-methylimidazolium bromide ([Omim]Br) is used as the surface ligand. When the molar ratio of [Omim]Br to Pb(CH3COO)2 is optimized to 2, the photoluminescence quantum yield of the prepared CsPbBr3 can reach as high as 90.93%, suggesting the effective reduction of surface defects by the IL ligand. Importantly, the CsPbBr3 nanocrystals show high stability under the ambient stimuli of light, heat, and humidity. The subsequent FT-IR and XPS characterizations indicate that the presence of [Omim]Br on the surface of CsPbBr3 increases the Br-rich state, which accounts for the excellent optical property and stability of the CsPbBr3 nanocrystals. Finally, with the assistance of IL as the activator of CO2, the CsPbBr3 photocatalysts provide a high evolution rate of 24.56 and 6.66 μmol g–1 h–1 for CO and CH4, respectively. Multifunctional ILs as passivation ligands, reaction precursors, and CO2 activators provide an efficient pathway to fabricate stable metal halide perovskites for photocatalytic CO2 conversion.

One-Pot Rapid Synthesis of Cu2+-Doped GOD@MOF to Amplify the Antitumor Efficacy of Chemodynamic Therapy.

Chemodynamic therapy (CDT) relies on the transformation of intracellular hydrogen peroxide (H2O2) to hydroxyl radicals (·OH) with higher toxicity under the catalysis of Fenton/Fenton-like reagents, which amplifies the oxidative stress and induces significant cellular apoptosis. However, the CDT efficacy is generally limited by the overexpressed GSH and insufficient endogenous H2O2 in tumors. Co-delivery of Cu2+ and glucose oxidase (GOD) can lead to a Cu2+/Cu+ circulation to realize GSH depletion and amplify the Fenton-like reaction. pH-responsive metal-organic frameworks (MOFs) are the optical choice to deliver Fenton/Fenton-like ions to tumors. However, considering that the aqueous condition is requisite for GOD encapsulation, it is challenging to abundantly dope Cu2+ in ZIF-8 MOF nanoparticles in aqueous conditions due to the ease of precipitation and enlarged crystal size. In this work, a robust one-pot biomimetic mineralization method using excessive ligand precursors in aqueous conditions is developed to synthesize GOD@Cu-ZIF-8. Copper ions abundantly doped to the GOD@Cu-ZIF-8 can eliminate GSH to produce Cu+, which is further proceeded to the Fenton-like reaction in the presence of GOD-catalyzed H2O2. Through breaking the tumor microenvironment homeostasis and producing an enhanced CDT effect, the promising antitumor capability of GOD@Cu-ZIF-8 was evidenced by the experiments both in vitro and in vivo.

Triphenyltin(IV) Carboxylates with Exceptionally High Cytotoxicity against Different Breast Cancer Cell Lines.

Organotin(IV) carboxylates are a class of compounds explored as alternatives to platinum-containing chemotherapeutics due to propitious in vitro and in vivo results, and distinct mechanisms of action. In this study, triphenyltin(IV) derivatives of non-steroidal anti-inflammatory drugs (indomethacin (HIND) and flurbiprofen (HFBP)) are synthesized and characterized, namely [Ph3Sn(IND)] and [Ph3Sn(FBP)]. The crystal structure of [Ph3Sn(IND)] reveals penta-coordination of the central tin atom with almost perfect trigonal bipyramidal geometry with phenyl groups in the equatorial positions and two axially located oxygen atoms belonging to two distinct carboxylato (IND) ligands leading to formation of a coordination polymer with bridging carboxylato ligands. Employing MTT and CV probes, the antiproliferative effects of both organotin(IV) complexes, indomethacin, and flurbiprofen were evaluated on different breast carcinoma cells (BT-474, MDA-MB-468, MCF-7 and HCC1937). [Ph3Sn(IND)] and [Ph3Sn(FBP)], unlike the inactive ligand precursors, were found extremely active towards all examined cell lines, demonstrating IC50 concentrations in the range of 0.076-0.200 µM. Flow cytometry was employed to examine the mode of action showing that neither apoptotic nor autophagic mechanisms were triggered within the first 48 h of treatment. However, both tin(IV) complexes inhibited cell proliferation potentially related to the dramatic reduction in NO production, resulting from downregulation of nitric oxide synthase (iNOS) enzyme expression.

Synthesis, characterization and antimicrobial properties of silver complexes derived from 5,6-Dimethylbenzimidazol-2-ylidene

Benzimidazoles are considered as a class of bioactive heterocyclic compounds that exhibit many biological activities such as antimicrobial. Benzimidazole-silver complexes also have strong antimicrobial activity, sometimes even higher than that of conventionally used silver antimicrobials. In this study, six new 5,6-dimethylbenzimidazolium ligand precursors which were functionalized by using 2-naphthylmethyl and their silver complexes were synthesized. All molecules were characterized by elemental analysis, 1H NMR, 13C NMR, and IR spectroscopy techniques. Additionally, µ-Dichloro-bis{[1-(2-naphthylmethyl)-3-(benzyl)-5,6-dimethylbenzimidazol-2-ylidene]silver(I)} was characterized structurally in the solid state by X-ray crystallography which was found to be dimeric with two bridging chlorides. In vitro antimicrobial activity of the synthesized compounds investigated in this work was tested against the reference strains: Escherichia coli (ATCC 25922), Staphylococcus aureus (ATCC 29213) and Pseudomonas aeruginosa (ATCC 27853), Candida albicans (ATCC MYA-2876) and Candida glabrata (ATCC 2001). Some of these new compounds have been found to display significant effectiveness. Also, the molecular docking analysis was performed for all optimized ligands and complexes against SarA

Organometallic Intermediates in the Synthesis of Photoluminescent Zirconium and Hafnium Complexes with Pyridine Dipyrrolide Ligands.

The two commercially available zirconium complexes tetrakis(dimethylamido)zirconium, Zr(NMe2)4, and tetrabenzylzirconium, ZrBn4, were investigated for their utility as starting materials in the synthesis of bis(pyridine dipyrrolide)zirconium photosensitizers, Zr(PDP)2. Reaction with one equivalent of the ligand precursor 2,6-bis(5-methyl-3-phenyl-1H-pyrrol-2-yl)pyridine, H2MePDPPh, resulted in the isolation and structural characterization of the complexes (MePDPPh)Zr(NMe2)2thf and (MePDPPh)ZrBn2, which could be converted to the desired photosensitizer Zr(MePDPPh)2 upon addition of a second equivalent of H2MePDPPh. Using the more sterically encumbered ligand precursor 2,6-bis(5-(2,4,6-trimethylphenyl)-3-phenyl-1H-pyrrol-2-yl)pyridine, H2MesPDPPh, only ZrBn4 yielded the desired bis-ligand complex Zr(MesPDPPh)2. Careful monitoring of the reaction at different temperatures revealed the importance of the organometallic intermediate (cyclo-MesPDPPh)ZrBn, which was characterized by X-ray diffraction analysis and 1H NMR spectroscopy and shown to contain a cyclometalated MesPDPPh unit. Taking inspiration from the results for zirconium, syntheses for two hafnium photosensitizers, Hf(MePDPPh)2 and Hf(MesPDPPh)2, were established and shown to proceed through similar intermediates starting from tetrabenzylhafnium, HfBn4. Initial studies of the photophysical properties of the photoluminescent hafnium complexes indicate similar optical properties compared to their zirconium analogues.

MOFs-derived hierarchical porous carbon supported Co@NC nanocapsules for pH universal oxygen reduction reaction and Zn-air batteries

The rational design and construction of the hierarchical porous structure of carbon framework to support transition metal-based catalysts is critical to increase their active sites density and facilitate mass/electron transport. Herein, we report a novel nanocapsules with cobalt core and nitrogen-doped carbon shells (Co@NC) supported on MOFs-derived hierarchical porous carbon framework. The rational hierarchical porous carbon framework with controllable size and micropore/mesoporous ratio was achieved by one-step pyrolysis of Zn(acac)2·phen ligand and ZIF-67 precursor, which is beneficial for the mass transport in the oxygen reduction reaction (ORR). The 0.4Co@NC-900 electrocatalyst display a distinguished ORR activity in the pH-universal range, with a half-wave potential of 0.91 V in alkaline and 0.76 V in acid electrolytes. The excellent ORR performance of our electrocatalyst can be attributed to its optimized micropore/mesoporous ratio of carbon framework with efficient mass transport, together with the graphitized carbon shell on Co nanoparticles which not only enhances the electron/proton transport, but also suppresses the chemical corrosion of the Co nanoparticles. Impressively, the Zinc-air battery as air electrode offers peak power density of 203 mW cm−2 and long-term stability of 130 h, showing an excellent battery performance. This study offers a fresh method of constructing ORR catalysts with increased activity and durability over a universal pH range.