Showing papers in "Collection of Czechoslovak Chemical Communications in 2023"

Chiral Carbon Dots: Synthesis and Applications in Circularly Polarized Luminescence, Biosensing and Biology.

Abstract: Chiral carbon dots (CDs) are a novel luminescent zero-dimensional carbon-based nanomaterial with chirality. They not only have the advantages of good biocompatibility, multi-color-emission, easy functionalization, but also exhibits highly symmetrical chiral optical characteristics, which broadens their applicability to enantioselectivity of some chiral amino acids like cysteine and lysine, asymmetric catalysis as well as biomedicine in gene expression and antibiosis. In addition, the exploration of the excited state chirality of CDs has developed its excellent circularly polarized luminescence (CPL) properties, opening up a new application scenario like recognition of chiral light sources and anti-counterfeit printing with information encryption. This review mainly focuses on the mature synthesis approaches of chiral CDs, including chiral ligand method and supramolecular self-assembly method, then we consider emerging applications of chiral CDs in CPL, biosensing and biological effect. Finally, we concluded with a perspective on the potential challenges and future opportunities of such fascinating chiral CDs.

MXenes Functionalized with Macrocyclic Hosts: From Molecular Design to Applications.

Abstract: Two-dimensional (2D) MXene has aroused wide attention for its excellent physical and chemical properties. The interlayer engineering formed by layer-by-layer stacking of MXene nanosheets can be employed for molecular sieving and water purification by incorporating specific groups onto the exterior surface of MXene. Macrocyclic hosts exhibiting unique structural features and recognition ability can construct smart devices for external stimuli with reversible features between macrocycles and guests. On that basis, macrocyclic hosts can be anchored to MXene to provide numerous insights into their compositions and intercalation states. In this review, the MXene prepared based on macrocyclic hosts from molecular design to applications is highlighted. Various MXenes functionalized with macrocyclic hosts are empowered in functional membrane (including water purification, organic solvent nanofiltration, and electromagnetic shielding), photocatalysis, sensing, and adsorption (interactions with specific guest). Hopefully, this review can bring new inspiration to the design of multifunctional MXene-based materials and improving its practical applications.

ZnO@C Microballs Wrapped with Ni(OH)2 Nanofilms for Electrochemical Sensing of Glucose and Hydrogen Peroxide.

Abstract: Tailor-made metal oxide/hydroxide core-shell structures are promising for the fabrication of an effective electrocatalyst. Here, we report the development of a core-shell structure based on carbon-doped and Ni(OH)2 nanofilms wrapped ZnO microballs (NFs-Ni(OH)2/ZnO@C MBs) for glucose and hydrogen peroxide (H2O2) monitoring. The unique ball-like morphology of the designed structure is achieved through a facile solvothermal strategy by the control of reaction conditions. Typically, ZnO@C MBs offer highly conductive core, and the shell of Ni(OH)2 nanofilms increases the density of catalytic active sites. The interesting morphology and the brilliant electrocatalytic efficacy of designed hybrid, encourage us to design a multi-mode sensor for glucose and H2O2 screening. The NFs-Ni(OH)2/ZnO@C MBs/GCE glucose sensor presented good sensitivities (647.899 & 161.550 μA (mmol L-1)-1 cm-2), a quick response (＜4 s), lower limit of detection (0.04 μmol L-1), and wide detection range (0.004-1.13 & 1.13-5.02 mmol L-1). Similarly, the same electrode revealed excellent H2O2 sensing features including good sensitivities, two linear parts of 3.5-452 and 452-1374 µmol L-1, and detection limit of 0.03 μmol L-1 as well as high selectivity. Thus, the development of novel hybrid core-shell structure is useful for potential applications in glucose and H2O2 screening from environmental and physiological samples.

Iron-Cobalt-Cerium Multimetallic Oxides Derived from Prussian Blue Precursors: Enhanced Oxygen Evolution Electrocatalysis.

Abstract: Exploring non-precious metal-based electrocatalysts is still challenging in 21st century. In this work, a series of hexagonal bipyramidal Ce-based PBA materials as precursors with different Fe/Co metal ratios, namely as CeFex Co1-x -PBA, are successfully constructed via co-precipitation method and converted into corresponding metal oxides (denoted as Fex Co1-x CeOy ) via thermal treatment. Then, they as electrocatalysts realize highly efficient oxygen evolution reaction (OER). Especially, as-synthesized Fe0.7 Co0.3 CeOy electrocatalyst shows very low overpotentials of 320 mV at the current density of 10 mA cm-2 and the Tafel slop of 98.4 mV dec-1 in 1 M KOH with remarkable durability for 24 h, which was due to the synergistic effect of multi-metal FeCoCe centers. Furthermore, a two-electrode cell of Fe0.7 Co0.3 CeOy /NF||Pt/C/NF realizes outstanding overall water splitting with a voltage of only 1.71 V at 10 mA cm-2 and remarkable long-term durability, that is even superior to benchmark IrO2 /NF||Pt/C/NF counterpart.

A Further Study on Calcium Phosphate Gardens Grown from the Interface of κ-Carrageenan-based Hydrogels and Counterion Solutions.

Abstract: Originating from the concept of classical chemical gardens, a new field coined 'chemobrionics' has recently emerged. In the present work, two chemobrionic systems grown from a hydrogel/liquid interface at different time scales (for 1, 7, 14 or 28 days) were investigated, i.e., a calcium-based hydrogel with a phosphate counterion solution (Ca-gel) and a phosphate-based hydrogel with a calcium counterion solution (P-gel). The initial pH changes of the systems were investigated, and the obtained tubular structures were studied using optical microscopy, SEM, AFM, PXRD and TGA. One of the important findings is the tubes obtained in the Ca-gel system were straight and longer, which could be explained by the larger pH difference observed between the hydrogel and the counterion solution in this system (∆pH ~2.1) compared to the P-gel system (∆pH ~0). The Ca-gel structures remained overall more amorphous even though increased crystallinity was observed in both systems with increased time spent in counterion solution. Both systems contained hydroxyapatite phases, with additional calcite phases observed for the P-gel structures and traces of κ-carrageenan for the Ca-gel structures. Our study provides a promising method for making tubular macrostructures through controlling the reaction conditions such as maturation time and pH.

Development of Carbon Nanotube/Graphene- Based Alginate Interpenetrating Hydrogels for Removal of Antibiotic Pollutants.

Abstract: The extensive use of pharmaceutical antibiotics in treatment of human and animal infections has resulted in growing concerns about antibiotic pollution worldwide. In this work a novel interpenetrating polymer network (IPN) hydrogel has been developed to function as an effective and non-selective adsorbent for various antibiotic pollutants in aqueous solution. This IPN hydrogel is made of multiple active components, including carbon nanotube (CNTs), graphene oxide (GO), and urea-modified sodium alginate (SA). It can be readily prepared through efficient carbodiimide-mediated amide coupling reaction followed by calcium chloride-induced alginate cross-linking. The structural properties, swellability, and thermal stability of this hydrogel have been investigated, while its adsorption properties towards an important antibiotic pollutant, tetracycline, was thoroughly characterized based on adsorption kinetic and isotherm analyses. With a BET surface area of 38.7 m2/g, the IPN hydrogel shows an excellent adsorption capacity of 84.28 ± 4.2 mg/g towards tetracycline in water, while the adsorption capacity is decreased by only 18% after four cycles of use, demonstrating very good reusability. Adsorptive performance in removing two other antibiotics, neomycin and erythromycin, has also been examined and compared. Overall, our studies disclose that this newly designed hybrid hydrogel is an effective and reusable adsorbent material for treating antibiotic pollution in the environment.

Synthesis of Hydrogen-Bonded Open-[60]Fullerenol Dimers.

Abstract: Two open-[60]fullerenols were synthesized through a selective bond cleavage by reactions with N-oxide or singlet oxygen. Both open-[60]fullerenols having a bis(hemiketal) moiety were aggregated via intra- and intermolecular hydrogen-bondings to show a dimeric configuration in a face-to-face fashion where the hydroxy groups adopt a rhomboidal or chair-like arrangement as confirmed by X-ray diffraction analysis. The dimerization constant of one of the two open-[60]fullerenols was measured to be 22.2 ± 4.7 M-1 (300 K, CDCl3) which is twice as large as that of a previously-reported open-[60]fullerenol bearing three hydroxy groups. According to theoretical calculations, an averaged interaction energy was estimated to be ca. -1.95 kcal/mol per an H-bonding. By a loss of a water molecule from the bis(hemiketal) moiety, these open-[60]fullerenols are transformed into tetracarbonyl derivatives with a 16-membered-ring orifice. Despite being the same ring-atom count, a larger tilt angle of one of the carbonyl groups reduce the effective orifice size as suggested by theoretical calculations.

Unraveling the Nature and Strength of Non-covalent Interactions on the Surface of Fullerenes.

Abstract: The nature and strength of the noncovalent intermolecular interactions on the surface of fullerenes must be understood for the application of these molecules in pharmaceuticals and materials chemistry. Consequently, experimental and theoretical evaluations of such weak interactions have been conducted in parallel. Nevertheless, the nature of these interactions remains a topic of ongoing debate. In this context, this concept article summarizes recent advances in experimental and theoretical efforts aimed at characterizing the nature and strength of non-covalent interactions on fullerene surfaces. Specifically, this article summarizes recent studies conducted on host-guest chemistry based on various macrocycles and on catalyst chemistry based on conjugated molecular catalysts composed of fullerenes and amines. In addition, conformational isomerism analyses performed using fullerene-based molecular torsion balances and state-of-the-art computational chemistry are reviewed. These studies have enabled a comprehensive evaluation of the contributions of electrostatic, dispersive, and polar interactions on the surface of fullerenes.

Supported Palladium Phosphide Catalyst for the Wacker-Tsuji-Oxidation of Styrene.

Abstract: The substitution of pure metal particles by metal phosphides in catalysis represents a promising opportunity to lower the required metal quantity in the context of a sustainable use of metal resources. Herein we show the synthesis of palladium phosphide, Pd3P, supported on silica, which is tested as catalyst for the Wacker-Tsuji-oxidation of styrene to acetophenone. The synthesized catalyst is characterized by PXRD, SEM-EDX, FTIR, ICP-AES and XPS measurements. Four different reaction systems are investigated in this study including different co-catalysts and reaction media. Conversions of styrene up to 95% with a selectivity of 73% towards acetophenone are observed using Pd3P/SiO2 as catalyst, CuCl2 as co-catalyst and O2 as oxidant. An enhanced selectivity up to 100% towards acetophenone is obtained in other reaction systems. The use of Pd3P/SiO2 leads to an optimized selectivity and conversion in the oxidation reaction in comparison with the purely Pd-based system Pd/SiO2. These results give an insight on how the incorporation of phosphorus has a great effect on the performance of heterogeneous catalysts.

Fluorescence Sensing of Anions by Silanediols Bearing Substituted Naphthyl Groups.

Abstract: Silanediols bearing naphthyl moieties substituted at 5-position with an electron-withdrawing cyano group and an electron-donating N,N-dimethylamino group, respectively, have been prepared and characterized. The substituents on the naphthyl moieties strongly influence the reactivity, photophysical properties, and sensing abilities for anions. The silanediol bearing 1-(5-N,N-dimethylaminonaphthyl) groups exhibited large Stokes shifts based on intramolecular charge transfer and large quantum yields in organic solvents. The silanediol showed favorable ratiometric fluorescence responses of upon the addition of biologically important anions, AcO- and H2PO4- with the association constants of 4.08 × 104 and 8.76× 103mol-1dm3, respectively.

An Acrylonitrile-Based Copolymer Gel as an NMR Alignment Medium for Extraction of Residual Dipolar Couplings of Small Molecules in Aqueous Solution.

Abstract: An NMR weakly-aligning polymer gel has been prepared by copolymerization of acrylonitrile and 2-acrylamide-2-methyl-1-propanesulfonic acid in the presence of 1,4-butanediol diacrylate as a cross-linker. The polymer readily swells in water in a large range of temperatures, although the swelling ratio is decreased in saline solutions. The swollen gel can be mechanically compressed, in a reversible way, generating anisotropy, as easily shown in 2 H NMR experiments, and allowing measurement of 1 DCH residual dipolar couplings (RDCs) through F1-coupled HSQC experiments. The performance of this gel as a NMR alignment medium was evaluated in several water-soluble organic molecules and, while it provided RDCs of proper size for sucrose and even such as small molecule as 5-norbornen-2-ol, in the case of azidothymidine and cefuroxime sodium salt the strong interaction of these molecules with the gel prevented successful extraction of the RDCs.

Magnetic solid-phase extraction of fipronil from aqueous solution and eggshells using amine coated iron oxide nanoparticles.

Abstract: Fipronil, as a broad use insecticide, is regulated under directives and standards in many countries since it is classed as Class II moderately hazardous pesticide and Group C possible human carcinogen. In this study, amine coated iron oxide (NH2-Fe3O4) is used as a new adsorbent with high adsorption capacity in the removal of fipronil from aqueous solution and eggshells. The adsorption performance was studied through batch adsorption under different concentrations of fipronil (10-200 µg/mL), different nanoparticles amount (0.1-1 mg) at different pH (4.5-6.0) and temperature (25-75°C). Results showed that NH2-Fe3O4 nanoparticles (0.1 mg) have excellent adsorption efficiency (97.06%) at 25°C, and pH 5.5. It also showed higher adsorption capacity towards fipronil sulfide, fipronil sulfone and fipronil desulfinyl with removal efficiencies of 92.82%, 86.35% and 76.24% from aqueous solution and 97.62%, 76.97% and 62.65% from eggshells, respectively. Fipronil adsorption process on NH2-Fe3O4 nanoparticles showed best fitting to Langmuir adsorption isotherm indicating monolayer chemical adsorption by physicochemical interactions spontaneously on homogenous surfaces. Having higher adsorption capacity and reusability NH2-Fe3O4 nanoparticles were shown to be effective adsorbents for removal of fipronil from aqueous solution and eggshells.

3 a,6 a-Diaza-1,4-Diphosphapentalenes: Synthesis and Complexation with the Organic π-Acceptor 1,2,4,5-Tetracyanobenzene.

Abstract: The reaction of PCl3 with diethyl ketazine and 4-phenylcyclohexanone azine results in the formation of 1,4-dichloro-3a,6a-diaza-1,4-diphosphapentalenes which were reduced by magnesium in THF to give corresponding diazadiphosphapentalenes EtMeDDP and PhcHexDDP, containing two-coordinate phosphorus atoms. According to the CVA data, the new diazadiphosphapentalenes are strong electron donors showing oxidation peak potentials at 0.34 and 0.10 V, respectively, (vs. Ag/AgCl). Interaction of 1,2,4,5-tetracyanobenzene (TCNB) with the obtained diazadiphosphapentalenes in any stoichiometry produces sandwich complexes of the composition DDP-TCNB-DDP. Black-purple crystals of π-complexes contain infinite molecular chains with short P⋅⋅⋅P contacts between DDP molecules and short (Csp2 -H⋅⋅⋅N) contacts between TCNB molecules. Calculations showed that each TCNB molecule is an acceptor of ∼0.3e from two DDP molecules. Estimation of the HOMO-LUMO gap from the onset of optical absorption give values of 1.25 eV and 1.31 eV for [(EtMeDDP)2 (TCNB)] and [(PhcHexDDP)2 (TCNB)] respectively.

Conjugates of 1,3‐ and 1,2‐Acylglycerols with Stigmasterol ‐ Synthesis, NMR Characterization and Impact on Lipid Bilayers

Abstract: The main aim of research was synthesis and spectroscopic characterization of new conjugates in which stigmasterol was linked via carbonate or succinyl linker with 1,3- and 1,2-acylglycerols of palmitic and oleic acid. Acylglycerols containing stigmasterol residue at internal position have been synthesized from 2-benzyloxypropane-1,3-diol or dihydroxyacetone. Their asymmetric counterparts containing stigmasterol residue attached to sn-3 position have been obtained from (S)-solketal. Eight synthesized conjugates were used to create the liposomes as nanocarriers of phytosterols to increase their stability and protect them from degradation during thermal-oxidative treatments. Fluorimetric and ATR-FTIR methods were used to determine the impact of synthesized conjugates on the physicochemical properties of the lipid bilayer. The results indicate that conjugates with palmitic acid are better candidates for use as the potential stigmasterol nanocarriers compared to those with oleic acid because they increase the stiffness of the lipid bilayer and temperature of the main phase transition. The obtained results are the first step in designing of stigmasterol-enriched liposomal carriers with higher thermo-oxidative stability for their potential use in the food industry.

Copper-Based Catalysts for Electrochemical Reduction of Carbon Dioxide to Ethylene.

Abstract: Electrochemical reduction of CO2 into high energy density multi-carbon chemicals or fuels (e. g., ethylene) via new renewable energy storage has extraordinary implications for carbon neutrality. Copper (Cu)-based catalysts have been recognized as the most promising catalysts for the electrochemical reduction of CO2 to ethylene (C2 H4 ) due to their moderate CO adsorption energy and moderate hydrogen precipitation potential. However, the poor selectivity, low current density and high overpotential of the CO2 RR into C2 H4 greatly limit its industrial applications. Meanwhile, the complex reaction mechanism is still unclear, which leads to blindness in the design of catalysts. Herein, we systematically summarized the latest research, proposed possible conversion mechanisms and categorized the general strategies to adjust of the structure and composition for CO2 RR, such as tip effect, defect engineering, crystal plane catalysis, synergistic effect, nanoconfinement effect and so on. Eventually, we provided a prospect of the future challenges for further development and progress in CO2 RR. Previous reviews have summarized catalyst designs for the reduction of CO2 to multi-carbon products, while lacking in targeting C2 H4 alone, an important industrial feedstock. This Review mainly aims to provide a comprehensive understanding for the design strategies and challenges of electrocatalytic CO2 reduction to C2 H4 through recent researches and further propose some guidelines for the future design of copper-based catalysts for electroreduction of CO2 to C2 H4 .

Synthesis of benzene derivatives with multiple PCl2 groups.

Abstract: The chlorination of 1,2-diphosphinobenzene with PCl5 to 1,2-bis(dichlorophosphino)benzene (2) was performed with high yields (93%) despite the high number of P-H functions. The method was further applied to other phosphanes, enabling the first synthesis and complete characterization of 1,2,4-tris(dichlorophosphino)benzene (6) and 1,2,4,5-tetrakis(dichlorophosphino)benzene (7), valuable precursor e.g. for binuclear complexes, coordination polymers, organic wires, or metal organic frameworks.

Technical Challenges and Prospects in Sustainable Plasma Catalytic Ammonia Production from Methane and Nitrogen.

Abstract: Ammonia is crucial for human life as an important ingredient for fertilizer, industrial and household chemicals, and is considered as a future fuel alternative and hydrogen storage molecule. There remain no viable alternatives to the energy-and capital-intensive Haber-Bosch (H-B) process. Efforts in the development of novel catalytic processes operated at milder conditions (low temperatures and ambient pressure), prominently electrochemistry and non-thermal plasma (NTP), and utilization of lower-cost H sources for ammonia formation than the ultrapure H2 have been witnessed in the last few years. Yet, limited progress from these routes has been made to date given unresolved low ammonia yield and technical challenges. Several rare works attempted to activate methane (CH4 ) and nitrogen (N2 ) by non-thermal plasma to produce ammonia and valued-added hydrocarbons have proven to be a promising research direction, rivalling the reaction between N2 and ultrapure H2 or water. The direct conversion of CH4 and N2 to ammonia is still at the beginning level, and it remains unclear that what extent these technologies must be improved to develop a commercial process. Toward this goal, this Perspective critiques current steps and miss-steps of sustainable plasma catalytic ammonia production from CH4 and N2 in terms of technology, plasma-catalyst synergy, mechanistic insights, and experimental protocols. We discuss mechanistic understandings of catalyst-promoted ammonia production and translate such discussions as well as key metrics achieved in the field into recommendations of feasible processes for ammonia and value-added hydrocarbons formation from CH4 and N2 .

Structural Analysis of Phase Change Materials (PCMs)/Expanded Graphite (EG) Composites and Their Thermal Behavior under Hot and Humid Conditions.

Abstract: Expanded graphite (EG) has been used to store phase change materials (PCM) to enhance thermal conductivity and avoid leakage. However, systematic investigation on physical structure of various embedded PCMs in EG is not reported. Besides, effect of environment on thermal behavior of PCM/EG composites has not been investigated yet. In this work, three common PCMs were used to be embedded in EG and three PCM/EG composites were obtained, including myristic acid (MA), polyethylene glycol (PEG) and paraffin wax (PW). As a result, capillary force between EG and PCMs supported encapsulation of PCMs in EG. PCM/EG composites had narrower phase change range while supercooling degree values were different when various PCMs were used. Besides, the hot and humid environment had a side effect on thermal energy storage of PCMs and PCM/EG composites. The inherent hydrophilicity of PCMs was essential for resistance against side effect of moisture on thermal energy storage.

Antimicrobial Photodynamic Therapy for the Remote Eradication of Bacteria.

Abstract: The emergence of multi-drug resistant bacteria strains has been an uphill battle in modern healthcare worldwide, due to the increasing difficulty of killing them. The evolving pathogenicity of bacteria has led to researchers searching for more effective antimicrobial therapeutics to successfully eliminate them without undesirable consequences to the human body. In recent years, antimicrobial photodynamic therapy (APDT), an obsolete technique for cancer treatments, has been reported to eradicate bacteria and biofilm-related infections. The principle of antimicrobial photodynamic therapy solely relies on the photosensitizers (PSs) generating reactive oxygen species, in the presence of oxygen and light, to destroy pathogens. Thus, it can target a broad spectrum of microorganisms, owing to the indirect interaction between PSs and the bacteria, resulting in the less likelihood for the development of drug resistant bacteria strains. This review will focus on the recent progress of APDT in the last five years and some future perspectives of APDT. The mechanism of APDT against bacteria and biofilms, various PSs used for APDT, and some common multidrug-resistant bacteria strains will be briefly introduced. The reported in vivo applications of APDT in the several types of bacterial infections that includes periodontitis, wound infections, keratitis, endophthalmitis and tuberculosis in the last five years will be summarized in detail.

Antioxidant Activities of Hydroxylated Naphthalenes: The Role of Aryloxyl Radicals.

Abstract: Herein is delineated a first systematic framework for the definition of structure-antioxidant property relationships in the dihydroxynaphthalene (DHN) series. The results obtained by a combined experimental and theoretical approach revealed that 1,8-DHN is the best performing antioxidant platform, with its unique hydrogen-bonded peri-hydroxylation pattern contributing to a fast H atom transfer process. Moreover, the comparative analysis of the antioxidant properties of DHNs carried out by performing DPPH and FRAP assays and laser flash photolysis experiments, revealed the higher antioxidant power associated with an α-substitution pattern (i. e. in 1,8- and 1,6-DHN) with respect to DHNs exhibiting a β-substitution pattern (i. e. in 2,6- and 2,7-DHN). DFT calculations and isolation and characterization of the main oligomer intermediates formed during the oxidative polymerization of DHNs supported this evidence by providing unprecedented insight into the generation and fate of the intermediate naphthoxyl radicals, which emerged as the main factor governing the antioxidant activity of DHNs.

Microwave-Assisted Reductive Amination of Aldehydes and Ketones Over Rhodium-Based Heterogeneous Catalysts.

Abstract: Microwave (MW)-assisted reductive aminations of aldehydes and ketones were carried out in the presence of commercial and homemade heterogeneous Rh-based catalysts. Ultrasound (US) was used to improve dispersion and stability of metal nanoparticles, while commercial activated carbon and carbon nanofibers were used as supports. Moreover, various bio-derived molecules were selected as substrates, and aqueous ammonia was used as a cheap and non-toxic reagent. MW combined with heterogeneous Rh catalysts gave a 98.2 % yield in benzylamine at 80 °C with 10 bar H2 for 1 h; and a 43.3 % yield in phenylethylamine at 80 °C and 5 bar H2 for 2 h. Carbon nanofibers proved to be a better support for the metal active phase than simple activated carbon, since a limited yield in benzylamine (10.6 %) but a high selectivity for the reductive amination of ketones was obtained. Thus, raspberry ketone was converted to raspberry amine in a 63.0 % yield.

From a Fluorenyl Substituted Ylide-Functionalized Phosphine to a Neutral Phosphide via P-C Bond Cleavage.

Abstract: Bulky ylide-substituted phosphines have recently found application as potent ligands in homogeneous catalysis. The attempted synthesis of the ylide-substituted fluorenylphosphine YPhP(Cy)Flu [YPh = Cy3P(Ph)C; Flu = 9-methylfluorenyl] now resulted in the unexpected elimination of 9-methylenefluorene during the deprotonation step of the intermediary α-phosphino phosphonium salt to yield the secondary ylide-substituted phosphine YPhP(Cy)H. This phosphine underwent formal H2 elimination under basic conditions to form a cyclic phosphonium ylide with a P-C-P-C four-membered ring via deprotonation of one cyclohexyl group of the PCy3 moiety. Upon coordination to transition metals the secondary ylidylphosphine forms a neutral phosphide ligand by shift of the proton into the ylide-backbone and formation of zwitterionic metal complexes.

The Alchemist, Metal-Divider and Transmuter Carl F. Wenzel and his 1776 Award from the Royal Danish Academy of Sciences through Professor C. G. Kratzenstein.

Abstract: C. F. Wenzel was a chemist and an alchemist. He had deep knowledge of acids, bases and salts, and he was credited with the first formulation of the Law of Mass Action. Yet he was also an alchemist, who on the eve of the Chemical Revolution published his beliefs in transmutation and in the division of metals into their constituents, for which he was rewarded with the gold medal of the Royal Danish Academy of the Sciences. His promoter, Professor C. G. Kratzenstein, was himself a believer in transmutation, even if he voiced some reservations.

Polymeric Janus Fibers.

Abstract: Janus fibers are a class of composite materials comprising mechanical and chemical to biological functionality. Combining different materials and functionalities in one micro- or even nanoscale fiber enables otherwise unreachable synergistic physicochemical effects with unprecedented opportunities for technical or biomedical applications. Here, recent developments of processing technologies and applications of polymeric Janus fibers will be reviewed. Various examples in the fields of textiles, catalysis, sensors as well as medical applications, like drug delivery systems, tissue engineering and antimicrobial materials, are presented to illuminate the outstanding potential of such high-end functional materials for novel applications in the upcoming future.

3‐Pyrrolyl BODIPY Based Schiff Base Fluorophores: Selective Chemodosimetric and Optical Sensor for Diethyl Chlorophosphate

Abstract: .Diethyl chlorophosphate (DCP), an organophosphate, is utilized as a pesticide, herbicide, and for various other applications. Despite many uses of organophosphates, the organophosphates are noxious and harmful substances, and their selective detection is a critical concern in the context of the environment, physiology, and social security. In a methodological quest, here we have synthesized two Schiff base compounds 1 and 2 by introducing the hydroxyl group at the α-position of 3-pyrrolyl BODIPY either directly as hydroxylamine 1 or at the ortho position of aryl ring as 2-aminophenol 2. Both compounds 1, and 2 exhibited high selectivity and high sensitivity for DCP over other pesticides in the aqueous-alcoholic medium at physiological pH. This occurs via nucleophilic phosphorylation of the hydroxyl group, which resulted in both compounds exhibiting two different optical signals following the structure-function correlation of the pyrrolyl BODIPY systems. Upon binding DCP, compound 1 showed a quenching in the optical spectrum because of phosphorylation of hydroxyl group whereas compound 2 exhibited enhancements in both absorption and fluorescence spectra because of hydroxyl phosphorylation followed by intramolecular cyclization. Furthermore, the fluorescent microscopy experiments also indicated that the compound could be used as a fluorescent compound for sensing DCP in plant tissues.

Phosphinine Selenide: Noncovalent Interactions with Organoiodines and Elemental Iodine, and Reactivity towards Potassium Cyanide.

Abstract: Invited for this month's cover is the group of Prof. Dr. Christian Müller from Freie Universität Berlin, Germany. The cover picture shows a phosphinine selenide that interacts with organoiodines and halogens to form co-crystalline and charge-transfer adducts. More information can be found in the Research Article by Christian Müller and co-workers.

Unraveling the role of nickel functionalization in the electronic properties and structural features of 2D black phosphorene exposed to ambient conditions.

Abstract: Layered black phosphorus (BP) is endowed with peculiar chemico-physical properties that make it a highly promising candidate in the field of electronics. Nevertheless, as other 2D materials with atomic scale thickness, it suffers from easy degradation under ambient conditions. Herein, it is shown that the functionalization of BP with preformed and in situ grown Ni NPs, affects the electronic properties of the material. In particular, Ni functionalization performed in situ leads to a narrowing of the average BP band gap from 1.15 to 0.95 eV and to a marked shift in the conduction band maximum from -0.33 V to -0.07 V, which, in turn, improve the ambient stability. Structural studies carried out by XAS can well distinguish the two nanohybrids and reveal that once Ni NPs are grown on BP nanosheets, a Ni-P coordinative bond is formed, featuring a short Ni-P distance of 2.27 Å, which is not observed when preformed Ni NPs are immobilized on BP. Comparing the XANES and EXAFS spectra of fresh and aged samples of both nanohybrids, suggests that the interaction between Ni and P atoms results in a stabilization effect exerted via a dual electronic and redox mechanism, that infers a much superior ambient stability to BP, even if the surface functionalization is far to achieve a full coverage.

Bis(acyl)phosphide - Ambidentate Ligands for the Synthesis of Group 14 and 15 Main Group Element Compounds.

Abstract: The reactivity of the bis(acyl)phosphide ion [P(COR)2]- (BAP-, R = Ph, Mes) with silicon halides SiX4 (X = Cl, Br) and pnictogen chlorides ECl3 (E = As, Sb and Bi) was investigated. The reaction with SiX4 leads to the hexacoordinate silanes SiX2(BAP)2 in which BAP- is coordinated in the chelating k2-O,O' mode, analogously to acac-. Unexpectedly, the coordination behaviour of BAP- differs from the one of acac- in the interpnictogen compounds E(BAP)3 (E = As, Sb) in which the formation of a E-P bonds is favoured over k2-O,O' chelation via the oxygen centres. Finally, the reaction of BiCl3 with three equivalents of Na(BAP) leads to the formation of red, crystalline Bi2(BAP)4, an air stable dibismuthine, as product of a redox reaction.

Phase-Selective Synthesis of Cobalt Sulfide Heterostructure Catalysts as Efficient Counter electrodes in Dye-Sensitized Solar Cells.

Abstract: Developing a cost-saving, high-efficiency, and simple synthesis of counter electrode (CE) material to replace pricy Pt for dye-sensitized solar cells (DSSCs) has become a research hotspot. Owing to the electronic coupling effects between various components, semiconductor heterostructures can significantly enhance the catalytic performance and endurance of counter electrodes. However, the strategy to controllably synthesize the same element in several phase heterostructures used as the CE in DSSCs is still absent. Here, we fabricate well-defined CoS2/CoS heterostructures and use them as CE catalysts in DSSCs. The as-designed CoS2/CoS heterostructures display high catalytic performance and endurance for the triiodide reduction in DSSCs thanks to the combined and synergistic effects. As a result, a DSSC with CoS2/CoS achieves a high power conversion efficiency of 9.47% under illumination, surpassing that of pristine Pt-based CE (9.20%). Besides, the CoS2/CoS heterostructures possess a quick activity initiation process and extended stability, broadening their potential applications in various areas. Therefore, our proposed synthetic approach could offer new insights for synthesizing functional heterostructure materials with improved catalytic activities in DSSCs.

Dynamic Covalent Reactions and Chirality Sensing with Diphenylethene Derived Hemiaminals.

Abstract: The differentiation of enantiomers is of significance in synthetic chemistry and pharmaceutical chemistry. Herein, we report a facile method for chirality sensing of monoalcohols, a challenging target due to the poor reactivity, by combining dynamic covalent chemistry with helical chirality. Four diphenylethene (DPE) derived cyclic hemiaminals were constructed, and the incorporation of a broad range of alcohols and thiols with high efficiency was achieved. The reversibility was further verified by dynamic component exchange. The helical chirality of the DPE motif was induced through chirality transfer by the central chirality of the analytes, resulting in circular dichroism responses. The chirality differentiation of seven chiral secondary alcohols including both alkyl and aryl alcohols was realized, further allowing the quantification of enantiomeric excess with high accuracy. The results described should lay a foundation for future endeavors in chemical sensing, asymmetric synthesis, and chiroptical materials.