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A series of anodically coloring electrochromic molecules comprised of thioalkyl‐substituted 3,4‐ethylenedioxythiophenes coupled to triphenylamine units that vary in position and degree of electron rich character of the substituents are reported, which influences the molecules geometric, electrochemical, optoelectronic, and excited‐state properties. Their redox properties are evaluated and it is discovered that modulation of both the first and second oxidation potential, formation of the cation radical, and dication respectively, can be varied from 0.03 to 0.18 V and 0.32 to 0.46 V versus Fc/Fc+ respectively. For the first time in ACE‐based molecular systems, the ability to vary the electrochemical potential separation between successive charge states is demonstrated, which directly influences the generation of color. The chemical oxidant, ferric triflate, is used to visualize the vibrantly colored cation radical solutions at 1 equivalent, followed by a second equivalent that opens a new and differing color palette for the dication state. Optical transitions are probed during electrochemical oxidation using an optically transparent thin layer electrode demonstrating selective control in generating successive charge states. Density functional theory simulations are used to analyze the excited state and elucidate how substituent identity affects the neutral, cation radical, and dication optical transitions, and thereby the resulting color. [ABSTRACT FROM AUTHOR]

The dehydrogenative coupling of alcohols and amines to form amide bonds is typically catalysed by homogeneous transition metal catalysts at high temperatures ranging from 130–140 °C. In our pursuit of an efficient and recyclable photocatalyst capable of conducting this transformation at room temperature, we report herein a COF‐mediated dehydrogenative synthesis. The TTT‐DHTD COF was strategically designed to incorporate a high density of functional units, specifically dithiophenedione, to trap photogenerated electrons and effectively facilitate hydrogen atom abstraction reactions. The photoactive TTT‐DHTD COF, synthesized using solvothermal methods showed high crystallinity and moderate surface area, providing an ideal platform for heterogeneous amide synthesis. Light absorption by the COF across the entire visible range, narrow band gap, and valence band position make it well‐suited for the efficient generation of excitons necessary for targeted dehydrogenation. Utilizing red light irradiation and employing extremely low loading of the COF, we have successfully prepared a wide range of amides, including challenging secondary amides, in good to excellent yields. The substrates' functional group tolerance, very mild reaction conditions, and the catalyst's significant recyclability represent substantial advancements over prior methodologies. [ABSTRACT FROM AUTHOR]

Herein, we report two distinct octaphyrins obtained by the condensation of new dithieno[3,2‐b:2',3'‐d]pyrrole based tetrapyrrane under two different acidic conditions. Fourfold meso‐substituted octaphyrin was the major product when the reaction was performed in the presence of an aryl aldehyde using trifluoroacetic acid. Whereas, the sixfold meso‐substituted octaphyrin was obtained when the precursor was condensed with pentafluorobenzaldehyde using para‐toluenesulfonic acid. Such a template effect of aryl aldehydes in oxidative coupling reactions is realized for the first time in literature. Experimental and theoretical studies suggested that the oxidized form of fourfold meso‐substituted octaphyrin is 32π antiaromatic and undergoes proton‐coupled electron transfer (PCET) to the protonated form of 34π aromatic congener upon treatment with protic acids. Furthermore, small organic molecules such as alcohols and amines were also found to promote chemical reduction. Single crystal X‐ray structure revealed that the aromatic counterpart is highly planar and stabilized by several intermolecular H‐bonding and F−F interactions, leading to a large 3D supramolecular arrangement and exhibited colorimetric sensing for fluoride and hydroxide anions. On the other hand, sixfold meso‐substituted octaphyrin did not show (anti)aromatic features, PCET or anion sensing, but its intriguing absorption features associated with protonation could make it an ideal candidate for pH‐dependent bioimaging. [ABSTRACT FROM AUTHOR]

[Display omitted] • A mesoporous 3D- fjh covalent organic framework is prepared and characterized. • Molecular chromophore and redox active components are incorporated into 3D COF. • Visible-light responsive and redox activity metal-free 3D COF photocatalyst. • Generation of reactive radical species to induce visible-light photoredox catalysis. • Highly efficient photoredox catalysis is demonstrated using 3D COF photocatalyst. Visible-light photoredox catalysis has been emerged as prominent methodology for efficient chemical synthesis. However, the relying use of soluble noble-metal photoredox catalysts suffer from long-term supply, inefficient separation, and could pos serious threats to the environment. Development of recyclable metal-free photoredox catalyst is thus highly significance. Herein, suitable molecular chromophore and redox units are condensed into photo- and redox active mesoporous 3D COF (3D TAPPy-TFPA) that enable highly efficient photoredox catalysis. The 3D COF displayed high crystallinity, mesoporous channel, and excellent structural stability. Optical and electrochemical studies revealed the excellent light harvesting, redox activity and effective generation of reactive radical species to induce photoredox catalysis. As proof-of-concept, 3D TAPPy-TFPA efficiently catalyzed the visible-light induced photoredox thiol-ene cross coupling and thiol radical mediated acylation of amines with activities surpassing most of the reported soluble photoredox catalysts. Beside recoverable, 3D TAPPy-TFPA showcased the previously inaccessible diacylation of amine into di-amide with high selectivity. This report shows robust design of outstanding and low-cost photoredox catalyst and paves the development of functional 3D COFs. [ABSTRACT FROM AUTHOR]

Redox-active "structural pillar" molecular doping strategy boosts the electrode performances of 3D honeycomb-structured polyaniline hydrogel in flexible supercapacitors. [Display omitted] • A redox-active and large-sized molecular dopant is integrated to 3D honeycomb porous polyaniline (PANI) hydrogels. • It works as both the "structural pillar" and pseudocapacitive sites towards PANI-based flexible supercapacitors. • The energy storage mechanism is monitored by in-situ infrared and Raman spectroscopy in detail. To coordinate flexibility to electrodes without sacrificing their electrochemical properties is critical for the development of wearable supercapacitors (SCs). Polyaniline (PANI) is well-known pseudocapacitive electrode material due to its high conductivity and different oxidation states upon switchable structures. However, its rigid conjugated backbone and structural instability caused by repeated doping/de-doping during cycling severely impede its utilization in flexible SCs. Herein, we deploy a directional freezing and redox-active "structural pillar" molecular doping strategy to boost PANI-based flexible SCs with high performance. The directional freezing strategy constructs an interconnected 3D honeycomb hydrogel structure with PANI nanofibers, which guarantees fast ion diffusion and electron transport and meanwhile exposes abundant active sites. The large-sized dopant 2-amino-4-bromoanthraquinone-2-sulfonic acid sodium (AQNS) is used as the structural pillar to alleviate the structural instability of PANI during cycling and provides additional pseudocapacitance arising from its redox active quinone groups. Moreover, the negatively charged −SO 3 − on AQNS can further interact with H+ in the electrolyte to act as an internal proton reservoir, assisting the protonation of –NH- and −N = in PANI to facilitate its charge storage process. Consequently, the PANI-AQNS electrode achieves a high specific capacitance of 578 F g−1 at 1 A g−1 and its symmetric SCs exhibit a specific capacitance of 199 F g−1 at 0.5 A g−1 with an energy density of 13.61 W h kg−1 at a power density of 175 W kg−1. Upon 2000 cycles of dynamic deformations, the SCs can still maintain above 90 % of the initial capacitance, verifying their excellent flexibility-relevant property. [ABSTRACT FROM AUTHOR]

Metal-Organic Frameworks are a versatile class of hybrid materials that can offer tantalizing opportunities to tune its structure, chemical composition suitable for gas sensing application. CO2 - a major greenhouse gas emission is challenging due to its low reactivity. Hence, sensors with more adsorption/ reactive sites and CO2 activating sites are needed to develop effective CO2 sensors. Chemiresistive sensors that are based on change in electrical properties (resistance/ conductance) offer simpler instrumentation and are cost effective over other sensing technologies. The surge to develop effective CO2 sensors have allowed us to demonstrate a simple chemiresistor- UiO-66 (Ce). UiO-66 (Ce) was synthesized and characterized by powder X-ray diffraction, scanning electron microscopy and nitrogen sorption studies. The UiO-66 (Ce) showed a very high response of 88 % at 150 °C. By combining the well-known features of redox active Ce with UiO-66 based MOF, we have converted an innocent MOF into an effective chemiresistive CO2 sensor. The gas sensing characteristics can be attributed to a greater number of active sites for CO2 sensing on replacement of Zr with Ce in the nodes of UiO-66. [ABSTRACT FROM AUTHOR]

A series of new poly(amide-imide)s was prepared by polycondensation of our already reported diamine, N,N'-[((propane-2,2-diylbis(4,1-phenylene) bis(oxy))bis(4,1-phenylene)]bis(4-aminobenzamide) (BDM) containing flexible ether and amide linkages with different aromatic dianhydrides via simple two-step method. The synthesized poly(amide-imide)s were characterized by FTIR spectroscopy and elemental analysis. These poly(amide-imide)s demonstrated nice solubility in most of the organic solvents at ambient temperature and upon heating. They also revealed great thermal stability and showed glass transition temperatures (Tgs) exceeding 150 °C in addition to the temperature of 10% weight loss (T10) that fluctuated from 460 to 522 °C having more than 59% residual yield at 800 °C in nitrogen atmosphere indicating their flame retardant characteristics. Furthermore, they also showed interesting photoluminescent properties with blue green solution emission properties, redox activity, and lower onset oxidation potentials with appreciably shallow HOMO levels. [ABSTRACT FROM AUTHOR]

In this manuscript, we report the solvent‐dependent synthesis of 1D coordination polymers derived from two planar N2O2‐coordinate iron(II) complexes FeL1 and FeL2, which incorporate TTF(py)2 as a bridging bis‐monodentate ligand. The obtained 1D polymers were characterized through elemental analysis, Mössbauer spectroscopy, single crystal structure analysis for 2a·2 DMF, magnetic susceptibility measurements, X‐ray powder diffraction, cyclic voltammetry and diffuse reflectance spectroscopy, supplemented by DFT computation. The results revealed additive electronic properties of the sub‐units FeL and TTF(py)2 with only minor mutual influence. Intriguingly however, the solvent‐of‐synthesis is found to be a steering factor of the magnetic spin crossover properties of the resulting materials, yielding divergent behavior if obtained from DMF, MeCN or EtOH. This becomes strikingly evident for the magnetic properties of the DMF‐derived polymer which is found trapped in the low‐spin state in the single crystal 2a· 2 DMF, but shows a gradual spin crossover if all solvent is removed. [ABSTRACT FROM AUTHOR]

A metal-bound phosphorus atom can actively participate in various organometallic reactions as an electron reservoir and/or a group transfer site, because a phosphorus atom can adopt several distinct forms such as cationic phosphenium, anionic phosphide, neutral phosphine, or a phosphinyl radical, thus making it more versatile. Furthermore, the ability of the phosphorus atom to have various oxidation states promotes the phosphorus atom to be cooperatively engaged in the reaction occurring at a metal center. By using such properties of phosphorus, metal-ligand cooperative (MLC) reactions occurring at a P-M moiety embedded in several transition metal pincer systems are discussed in this chapter. [ABSTRACT FROM AUTHOR]

Stimuli responsive π-conjugated macrocyclic systems has shown significant attention in organic electronics, however, amongst them, porphyrins and phthalocyanines unveiled remarkable growth towards materials and biological applications. Herein, we report bulk electrolysis of Zn-phthalocyanine system (ZnPc-OMe) under potential difference of 1.5 V in chloroform results anion binding mechanism directs the formation of self-assembled nanospheres by diffusion controlled approach. Electrochemical and UV–Vis absorption studies of ZnPc-OMe suggest that anion (Cl−) binding ability towards 'Zn' whilst applied potential leads to the formation of H + [(Cl)ZnPc-OMe] - promote the enhanced current and charge generation. Microscopic analysis revealed that ZnPc-OMe and H + [(Cl)ZnPc-OMe] - exhibit the nanosheets and spheres with an average diameter of 0.5–1 μm and 300–500 nm, respectively. Powder X-ray diffraction analysis and raman spectra revealed the changes in crystalline phase transitions via ion-dipole and π-π stacking interactions. Thus, these unique features are atypical for phthalocyanine derivative hitherto unknown. Image 1 • Anion binding mechanism. • Improved charge and current production. • Hierarchical nanostructures. • Sensors and digital technological applications [ABSTRACT FROM AUTHOR]

Invasive mycoses remain underdiagnosed and difficult to treat. Hospitalized individuals with compromised immunity increase in number and constitute the main risk group for severe fungal infections. Current antifungal therapy is hampered by slow and insensitive diagnostics and frequent toxic side effects of standard antifungal drugs. Identification of new antifungal compounds with high efficacy and low toxicity is therefore urgently required. We investigated the antifungal activity of tempol, a cell-permeable nitroxide. To narrow down possible mode of action we used RNA-seq technology and metabolomics to probe for pathways specifically disrupted in the human fungal pathogen Candida albicans due to tempol administration. We found genes upregulated which are involved in iron homeostasis, mitochondrial stress, steroid synthesis, and amino acid metabolism. In an ex vivo whole blood infection, tempol treatment reduced C. albicans colony forming units and at the same time increased the release of pro-inflammatory cytokines, such as interleukin 8 (IL-8, monocyte chemoattractant protein-1, and macrophage migration inhibitory factor). In a systemic mouse model, tempol was partially protective with a significant reduction of fungal burden in the kidneys of infected animals during infection onset. The results obtained propose tempol as a promising new antifungal compound and open new opportunities for the future development of novel therapies.

2D transition metal dichalcogenides (TMDs) have garnered significant interest as cathode materials for aqueous zinc-ion batteries (AZIBs) due to their open transport channels and abundant Zn 2+ intercalation sites. However, unmodified TMDs exhibit low electrochemical activity and poor kinetics owing to the high binding energy and large hydration radius of divalent Zn 2+ . To overcome these limitations, an interlayer engineering strategy is proposed where K + is preintercalated into K-MoS 2 nanosheets, which then undergo in situ growth on carbon nanospheres (denoted as K-MoS 2 @C nanoflowers). This strategy stimulates in-plane redox-active sites, expands the interlayer spacing (from 6.16 to 9.42 Å), and induces the formation of abundant MoS 2 1T-phase. The K-MoS 2 @C cathode demonstrates excellent redox activity and fast kinetics, attributed to the potassium ions acting as a structural "stabilizer" and an electrostatic interaction "shield," accelerating charge transfer, promoting Zn 2+ diffusion, and ensuring structural stability. Meanwhile, the carbon nanospheres serve as a 3D conductive network for Zn 2+ and enhance the cathode's hydrophilicity. More significantly, the outstanding electrochemical performance of K-MoS 2 @C, along with its superior biocompatibility and degradability of its related components, can enable an implantable energy supply, providing novel opportunities for the application of transient electronics., (© 2023 Wiley‐VCH GmbH.)

A copper(II) benzene-1,3,5-tricarboxylate (BTC) metal-organic framework (MOF) was modified with poly(acrylic acid) (PAA) and then used in an electrochemical sensor for vancomycin. The MOF, synthesized via a single-pot method, has enhanced solubility and dispersibility in water as compared to HKUST-1 but without compromising its crystallinity and porosity. The MOF was placed on a glassy carbon electrode (GCE) where it shows enhanced electrocatalytic properties. This is assumed to be due to the presence of the poly(acrylic acid) that forms a network between various HKUST-1 crystals through dimer formation between the carboxy groups of BTC and PAA. This also led to better dispersion of the MOF and to improved interaction between MOF and vancomycin. The structural, spectral and electrochemical properties of the MOFs and their vancomycin complexes was characterized. The modified GCE is shown to be a viable tool for electrochemical determination (best at a working potential of 784 mV vs. Ag/AgCl) of the antibiotic vancomycin in spiked urine and serum samples. Response is linear in the 1–500 nM vancomycin concentration range, and the detection limit is 1 nM, with a relative standard deviation of ±4.3%. [ABSTRACT FROM AUTHOR]

Invasive mycoses remain underdiagnosed and difficult to treat. Hospitalized individuals with compromised immunity increase in number and constitute the main risk group for severe fungal infections. Current antifungal therapy is hampered by slow and insensitive diagnostics and frequent toxic side effects of standard antifungal drugs. Identification of new antifungal compounds with high efficacy and low toxicity is therefore urgently required. We investigated the antifungal activity of tempol, a cell-permeable nitroxide. To narrow down possible mode of action we used RNA-seq technology and metabolomics to probe for pathways specifically disrupted in the human fungal pathogen Candida albicans due to tempol administration. We found genes upregulated which are involved in iron homeostasis, mitochondrial stress, steroid synthesis, and amino acid metabolism. In an ex vivo whole blood infection, tempol treatment reduced C. albicans colony forming units and at the same time increased the release of pro-inflammatory cytokines, such as interleukin 8 (IL-8, monocyte chemoattractant protein-1, and macrophage migration inhibitory factor). In a systemic mouse model, tempol was partially protective with a significant reduction of fungal burden in the kidneys of infected animals during infection onset. The results obtained propose tempol as a promising new antifungal compound and open new opportunities for the future development of novel therapies. [ABSTRACT FROM AUTHOR]

Diffraction‐quality single crystals of two gold(I) complexes, namely bis(1,3‐dimesityl‐4,5‐naphthoquinoimidazol‐2‐ylidene)gold(I) chloride benzene monosolvate, [Au(C29H26N2O2)2]Cl·C6H6 or [(NQMes)2Au]Cl·C6H6, 2, and bis(1,3‐dimesityl‐4,5‐naphthoquinoimidazol‐2‐ylidene)gold(I) dichloridoaurate(I) dichloromethane disolvate, [Au(C29H26N2O2)2][AuCl2]·2CH2Cl2 or [(NQMes)2Au][AuCl2]·2CH2Cl2, 4, were isolated and studied with the aid of single‐crystal X‐ray diffraction analysis. Compound 2 crystallizes in a monoclinic space group C2/c with eight molecules in the unit cell, while compound 4 crystallizes in the triclinic space group P with two molecules in the unit cell. The crystal lattice of compound 2 reveals C—H...Cl− interactions that are present throughout the entire structure representing head‐to‐tail contacts between the aromatic (C—H) hydrogens of naphthoquinone and Cl− counter‐ions. Compound 4 stacks with the aid of short interactions between a naphthoquinone O atom of one molecule and the mesityl methyl group of another molecule along the a axis, leading to a one‐dimensional strand that is held together by strong π–η2 interactions between the imidazolium backbone and the [AuCl2]− counter‐ion. The bond angles defined by the AuI atom and two carbene C atoms [C(carbene)—Au—C(carbene)] in compounds 2 and 4 are nearly rectilinear, with an average value of ∼174.1 [2]°. Though 2 and 4 share the same cation, they differ in their counter‐anion, which alters the crystal lattice of the two compounds. The knowledge gleaned from these studies is expected to be useful in understanding the molecular interactions of 2 and 4 under physiological conditions. The crystal and molecular structures of two redox‐active bis(NHC)gold(I) (NHC is an N‐heterocyclic carbene) complexes have been probed in detail. The knowledge gleaned from these structural studies will be useful for simulating the interactions of these types of molecules under physiological conditions. [ABSTRACT FROM AUTHOR]

Graphical abstract The TOC graphic, and accompanying article, detail the solid, solution, and electronic structure of a 6-coordinate ferracyclopentane. The article also explores conditions that selectively lead to C-C bond formation, where one of these conditions is pictured in the graphical abstract. While addition of 5 equivalents of CO to the ferracyclopentane leads to exclusive C(sp 3)-C(sp 3) reductive elimination of cyclobutane, addition of only 2 equivalents exclusively forms cyclopentanone. The latter product is formed from initial insertion of the metallacyclopentane into a coordinated CO ligand, followed by C(sp 3)-C(sp 2) reductive elimination. Abstract A six-coordinate iron metallacyclopentane, (phen) 2 Fe(CH 2) 4 , supported by two 1,10-phenanthroline (phen) ligands, has been synthesized and structurally and spectroscopically characterized. The complex is diamagnetic and an idealized octahedral geometry was observed in the solid state. The electronic structure of (phen) 2 Fe(CH 2) 4 was determined by a combination of X-ray diffraction, Mössbauer spectroscopy, and DFT analyses and is best described as a low-spin Fe(III) center antiferromagnetically coupled to a radical anion delocalized equally over both phen ligands. The reactivity of (phen) 2 Fe(CH 2) 4 under different conditions was explored. Thermolysis or photolysis promoted elimination reactions and mixtures of isomeric butenes and butane were observed. Reactions of (phen) 2 Fe(CH 2) 4 with ethylene and isoprene yielded 3% and 11% of reductive elimination product cyclobutane, respectively, along with butane and butene isomers. Addition of π-accepting ligands such as carbon monoxide, maleic anhydride, or 1,4-benzoquinone to (phen) 2 Fe(CH 2) 4 promoted C(sp 3)-C(sp 3) reductive elimination as judged by high selectivity for cyclobutane formation. Two electron oxidation of (phen) 2 Fe(CH 2) 4 with two equivalents of ferrocenium tetraphenylborate also exclusively yielded cyclobutane in 95% yield. The electronic structure and reactivity of related bis(bipyridine) iron dialkyl compounds previously isolated by Kochi and co-workers were also revisited and their electronic structures revised based on structural, spectroscopic and computational data. [ABSTRACT FROM AUTHOR]

Abstract: In this focus review we aim to highlight an exciting class of materials, electroactive amphiphiles (EAAs). This class of functional amphiphilic molecules has been the subject of sporadic investigations over the last few decades, but little attempt has been made to date to gather or organise these investigations into a logical fashion. Here we attempted to gather the most important contributions, provide a framework in which to discuss them, and, more importantly, point towards the areas where we believe these EAAs will contribute to solving wider scientific problems and open new opportunities. Our discussions cover materials based on low molecular weight ferrocenes, viologens and anilines, as well as examples of polymeric and supramolecular EAAs. With the advances of modern analytical techniques and new tools for modelling and understanding optoelectronic properties, we believe that this area of research is ready for further exploration and exploitation. [ABSTRACT FROM AUTHOR]

Present work demonstrates enhanced supercapacitive performance of CoO-rGO electrode using redox electrolyte. The long range electrostatic force developed during deposition of CoO-rGO composite thin film orient the molecules into the hexagonal crystal structure. The incorporated CoO particles into rGO nano-sheets make the structure more porous for the intercalation of the electrolyte ions through the electrode material. Additionally, 0.025 M K 3 [Fe(CN) 6 ] + 0.025 M K 4 [Fe(CN) 6 ] redox couple into KOH electrolyte enhances the supercapacitive performance than bare KOH electrolyte. The maximum specific capacitance of 1005 F g −1 is observed due to the combined effect of K 3 [Fe(CN) 6 ] and K 4 [Fe(CN) 6 ] redox couple into KOH electrolyte. Also, energy density of 86.74 Wh kg −1 at power density of 3.54  kW   kg −1 suggest potential application of CoO-rGO composite thin film in the development of high energy density supercapacitor based on redox active electrolyte. [ABSTRACT FROM AUTHOR]