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Styrylchromones (SC) are a group of oxygen-containing heterocyclic compounds, which are characterized by the attachment of a styryl group to the chromone core. SC can be found in nature or can be chemically synthesized in the laboratory. As their presence in nature is scarce, the synthetic origin is the most common. Two types of SC are known: 2-styrylchromones and 3-styrylchromones. However, 2-styrylchromones are the most common, being more broadly found in nature and whose chemical synthesis is more commonly described. A wide variety of SC has been described in the literature, with different substituents in different positions, the majority of which are distributed on the A- and/or B-rings. Over the years, several biological activities have been attributed to SC. This work presents a comprehensive review of the biological activities attributed to SC and their structure-activity relationship, based on a published literature search, since 1989. The following biological activities are thoroughly reviewed and discussed in this review: antioxidant, antiallergic, antiviral, antibacterial, antifungal, anti-inflammatory and antitumoral, affinity and selectivity for A 3 adenosine receptors, neuroprotective, and α-glucosidase inhibition. In general, SC are composed by a promising scaffold with great potential for the development of new drugs., (© 2024 Wiley-VCH GmbH.)

Organic fluorescent materials with red/near-infrared (NIR) emission are highly promising for use in biotechnology due to their exceptional advantages. However, traditional red/NIR fluorophores often exhibit weak emission at high concentrations or in an aggregated state due to the aggregate-caused quenching effect, which severely limits their applicability in biological imaging. To address this challenge, we developed a series of cyanostyrene derivatives with aggregation-induced emission characteristics, including 2,3-Bis-(4-styryl-phenyl)-but-2-enedinitrile (DPB), 2,3-Bis-{4-[2-(4-methoxy- phenyl)-vinyl]-phenyl}-but-2-enedinitrile (DOB), 2,3-Bis-{4-[2-(4-diphenylamino- phenyl)-vinyl]-phenyl}-but-2-enedinitrile (DTB), and 2,3-Bis-[4-(2-{4-[phenyl- (4-triphenylvinyl-phenyl)-amino]-phenyl}-vinyl)- phenyl]-but-2-enedinitrile (DTTB). Notably, these compounds exhibited intense solid state fluorescence owing to AIE effect, especially DTTB shows NIR emission with high solid state quantum efficiency (712 nm, Φ F =14.2 %). Then we prepared DTTB@PS-PEG NPs nanoparticles by encapsulating DTTB with the amphiphilic polymer polystyrene-polyethylene glycol (PS-PEG). Importantly, DTTB@PS-PEG NPs exhibited highly efficient NIR luminescence (Φ F =28.7 %) and a large two-photon absorption cross-section (1900 GM) under 800 nm laser excitation. The bright two-photon fluorescence of DTTB@PS-PEG indicated that it can be a highly promising candidate for two-photon fluorescence probe. Therefore, this work provides valuable insights for the design of highly efficient and NIR-emitting two-photon fluorescent probes., (© 2024 Wiley-VCH GmbH.)

Sulfur-containing amino acids and peptides play critical roles in organisms. Thiol-ene reactions between the thiol residues of L-cysteine and the alkenyl fragments in the designed coupling partners serve as primary tools for constructing C─S bonds in the synthesis of unnatural sulfur-containing amino acid derivatives. These reactions are favored due to the preference for hydrogen transfer from thiol to β-sulfanyl carbon radical intermediates. In this paper, the study proposes utilizing carbon-centered radicals stabilized by the capto-dative effect, generated under photocatalytic conditions from N-aryl glycine derivatives. The aim is to compete with the thiol hydrogen, enabling radical C─C bond formation with β-sulfanyl carbon radicals. This protocol is robust in the presence of air and water, offers significant potential as a modular and efficient platform for synthesizing sulfur-containing amino acids and modifying peptides, particularly with abundant disulfides and styrenes., (© 2024 The Author(s). Advanced Science published by Wiley‐VCH GmbH.)

A novel method for synthesizing cationic styryl dyes through a nucleic acid-templated reaction has been developed. This approach overcomes issues associated with traditional synthesis methods, such as harsh conditions, low throughput, and wasteful chemicals. The presence of a nucleic acid template accelerated the styryl dye formation from quaternized heteroaromatic and cationic aldehyde substrates. These styryl dyes show remarkable optical properties change when bound to nucleic acids, hence the success of the synthesis could be readily monitored in situ by UV-Vis and fluorescence spectroscopy and the optical properties data were also observable at the same time. This method provides the desired products from a broad range of coupling partners. By employing different substrates and templates, it is possible to identify new dyes that can bind to a specific type of nucleic acid such as a G-quadruplex. The templated dye synthesis is also successfully demonstrated in live HeLa cells. This approach is a powerful tool for the rapid synthesis and screening of dyes specific for diverse types of nucleic acids or cellular organelles, facilitating new biological discoveries., (© 2024 Wiley-VCH GmbH.)

Optical methods to modulate microtubule dynamics show promise for reaching the micron- and millisecond-scale resolution needed to decrypt the roles of the cytoskeleton in biology. However, optical microtubule stabilisers are under-developed. We introduce "STEpos" as GFP-orthogonal, light-responsive epothilone-based microtubule stabilisers. They use a novel styrylthiazole photoswitch in a design to modulate hydrogen-bonding and steric effects that control epothilone potency. STEpos photocontrol microtubule dynamics and cell division with micron- and second-scale spatiotemporal precision. They substantially improve potency, solubility, and ease-of-use compared to previous optical microtubule stabilisers, and the structure-photoswitching-activity relationship insights in this work will guide future optimisations. The STEpo reagents can contribute greatly to high-precision research in cytoskeleton biophysics, cargo transport, cell motility, cell division, development, and neuroscience., (© 2021 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.)

The dealkenylative alkenylation of alkene C(sp 3 )-C(sp 2 ) bonds has been an unexplored area for C-C bond formation. Herein 64 examples of β-alkylated styrene derivatives, synthesized through the reactions of readily accessible feedstock olefins with β-nitrostyrenes by ozone/Fe II -mediated radical substitutions, are reported. These reactions proceed with good efficiencies and high stereoselectivities under mild reaction conditions and tolerate an array of functional groups. Also demonstrated is the applicability of the strategy through several synthetic transformations of the products, as well as the syntheses of the natural product iso-moracin and the drug (E)-metanicotine., (© 2020 Wiley-VCH GmbH.)

Emulsion templated norbornadiene is cured via ring-opening metathesis polymerization yielding macroporous poly(norbornadiene) foams of 76% porosity exhibiting appealing stiffness combined with considerable ductility. The foams are readily oxidized in the presence of air at room temperature exhibiting an oxygen uptake capacity of more than 300 mg O 2 g -1 foam. In closed volumes of air, a final oxygen level of a maximum of 0.0005 vol%, that is, 5 ppm (v) can be achieved after several hours at room temperature. The synergism of the porous morphology and the chemical nature of the polymer allows for the first example of an organic oxygen scavenger material with properties distinctly surpassing the state-of-the art in the field., (© 2020 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Future wearable electronics requires safe and high-energy-density supercapacitors (SCs). Commercial SCs making use of organic electrolytes show high energy density, but the flammability of the electrolyte raises serious safety concerns. Aqueous SCs, on the other hand, are very safe, but the energy density is low due to the much narrower voltage window and the difficulty of fabricating thick electrodes. A new materials strategy named soft hybrid scaffold (SHS), which allows easy buildup of ultrathick electrodes made of 3D porous pseudo-material-modified carbon networks, is reported. The carbon network provides excellent mechanical stability and electric conductivity, the hierarchically porous structures ensure rapid ionic transport, and the pseudomaterials enlarge the electrochemical window. Asymmetric aqueous SCs using SHS electrodes show higher energy density than both commercial organic SCs and literature-reported aqueous SCs, with good cycle life and mechanical flexibility. The aqueous SC device is tailorable, waterproof, and fire-retardant, representing a high safety toward practical applications., (© 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The controlled syndiospecific polymerization of three Si-H-containing styrenes, that is, 4-(methylhydrosilyl)styrene (FSt-1), 4-(dimethylhydrosilyl)styrene (FSt-2) and 4-(diisopropylhydrosilyl)styrene (FSt-3), is realized in the presence of (C 5 Me 4 SiMe 3 )Sc (CH 2 C 6 H 5 ) 2 (THF)/[Ph 3 C][B(C 6 F 5 ) 4 ]. Then a series of FSt-b-styrene-b-FSt triblock copolymers (FSt-St-FSt) are synthesized facilely via a sequential monomer feeding process (FSt-2, styrene, and FSt-2, respectively) during the polymerization. The syndiotactic polystyrene (sPS) block in the middle endows the copolymer with high melting point above 250 °C, whereas the Si-H groups on monomer FSt-2 introduce functional pendants to the end-blocks (with Si-H content of 31-63 mol%). Finally by a mild and high-effective hydrosilylation reaction, novel polar-group functionalized sPS is obtained., (© 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Here we report fluorescence turn-on synthetic lipid rafts by self-assembly of a cationic distyrylanthracene derivative on a negatively-charged sheet in an aqueous solution. First, the negatively-charged 2D membrane structure is formed by lateral associations of aromatic rods with carboxylate groups. Then, the synthetic rafts are floated on the surface of the negatively-charged sheets through electrostatic interactions. The fluorescence of the synthetic rafts is turned on due to the aggregation of the positively-charged AIE dye on the sheets, facilitating monitoring of the formation of rafts. Concanavalin A (Con A) protein can load hierarchically onto the synthetic rafts at neutral pH to provide discrete Con A aggregates with a uniform size of ≈12 nm. The uniform aggregates of Con A on the synthetic rafts can stimulate Jurkat cells with enhanced efficiency, as compared with random-sized aggregates of Con A., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Chemiluminescent (CL) reactions are powerful analytical tools and are present in commercially available everyday objects such as glow sticks. Herein, the photons generated by chemiluminescence are exploited to induce covalent bond breakage and formation, using a chemically generated photonic field at ambient temperature through space as energy transducer. Remarkably, the generated photons enable both the cleavage of species generating radicals as well as the execution of [2 + 2] cycloadditions, demonstrating that disparate types of reactions can be triggered. The herein-presented photochemical concept establishes the field of CL-induced photochemistry, which is poised to enable photochemical transformations in situations where physical light sources, such as lamps, LEDs, and lasers cannot be employed, including in biological environments., (© 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The threat of chemical warfare agents (CWA) compels research into novel self-decontaminating materials (SDM) for the continued safety of first-responders, civilians, and active service personnel. The capacity to actively detoxify, as opposed to merely sequester, offending agents under typical environmental conditions defines the added value of SDMs in comparison to traditional adsorptive materials. Porous polymers, synthesized via the high internal phase emulsion (HIPE) templating, provide a facile fabrication method for materials with permeable open cellular structures that may serve in air filtration applications. PolyHIPEs comprising polydicyclopentadiene (polyDCPD) networks form stable hydroperoxide species following activation in air under ambient conditions. The hydroperoxide-containing polyDCPD materials react quickly with CWA simulants, Demeton-S and 2-chloroethyl ethyl sulfide, forming oxidation products as confirmed via gas chromatography mass spectrometry. The simplicity of the detoxification chemistry paired with the porous foam form factor presents an exciting opportunity for the development of self-decontaminating filter media., (© 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

A novel hemostatic and absorbent wound dressing material compatible with 3D printing is developed to address deficiencies in current wound dressing protocol. The design involves an open celled, microporous hydrogel foam via a high internal phase emulsion (HIPE) template with biocompatible components and tunable hemostatic character by kaolin loading, the viscosity and cure kinetics of which are tailored for 3D printing applications. The use of nontoxic mineral oil organic phase results in cytocompatability with human dermal fibroblasts. Kaolin distribution is shown by X-ray diffraction and elemental dispersive spectroscopy to be exfoliated and dispersed in the hydrogel dressing. In addition to demonstrating high fluid absorption and noncytotoxicity of relevant cell lines, the high internal phase emulsion polymers (polyHIPEs) also match the hemostatic performance of commercial wound dressing materials. Furthermore, the polyHIPEs display the requisite rheological properties for 3D printing that result in the fabrication of a prototype dressing with hierarchical porosity and a large number of controllable form factors., (© 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

A randomized library is constructed based on pET30a-CYP119-T214V plasmid. This library of random mutants of CYP119-T214V was screened by means of the reduced CO difference spectra and epoxidation of styrene. By using directed evolution, a new CYP119 quadruple mutant S148P/I161T/K199E/T214V is constructed, expressed, and purified. This quadruple mutant significantly increases the turnover rate and conversion for the asymmetric epoxidation of styrene and its derivatives. The k cat. value of cis-β-methylstyrene epoxidation catalyzed by the quadruple mutant exhibits an approximately 10-fold increase, relative to the previously reported T213M mutant under the same conditions. This is the first engineered CYP119 peroxygenase for the epoxidation of cis-β-methylstyrene with a high turnover rate. The proposed mechanism, on the basis of a molecular docking study, for the asymmetric epoxidation suggests that the introduction of an acidic amino acid side chain into the active site and a hydrophobic amino acid into the substrate channels of CYP119 peroxygenase might result in high efficiency for the formation of compound I, and its subsequent peroxygenation by reconstructing the hydrogen-bonding interaction and increasing the substrate affinity and access., (© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

A method for cobalt-catalyzed, carboxylate-directed functionalization of arene C-H bonds is reported. Alkynes, styrenes, and 1,3-dienes can be coupled with benzoic acids to provide cyclic products in good yields. The reactions proceed in the presence of a cobalt(II) hexafluoroacetylacetonate catalyst, (TMS) 2 NH base, Ce(SO 4 ) 2 cooxidant, and oxygen oxidant., (© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Precisely incorporating a wide range of structural and functional multiblocks along a polymer backbone is a significant challenge in polymer chemistry and offers promising opportunities to design highly ordered materials, including controlled polymer folding. Herein, a facile and versatile strategy for preparing functional multiblock copolymers composed of sequential peptides and well-defined vinyl polymers with a narrow polydispersity is reported. Cyclic oligopeptides have been developed that contain an alkoxyamine bond in the framework. By using this type of cyclic initiator, peptide-containing multiblock copolymers are successfully synthesized by nitroxide-mediated polymerization of styrene. To demonstrate the versatility of this method, radical (co)polymerizations were carried out for different monomers (p-chlorostyrene, 4-vinylpyridine, and styrene/acrylonitrile) and by three different cyclic peptide initiators with specific amino acid sequences. The resultant multiblock copolymer is foldable through intramolecular interactions between peptide blocks. It is believed that this approach will significantly advance the field of controlled polymer synthesis for complex structures and single-chain folding., (© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Dielectric elastomer (DE) actuators have been shown to have promising applications as soft electromechanical transducers in many emerging technologies. The DE actuators, which are capable of large actuation strain over a wide range of excitation frequencies, are highly desirable. Here, the first single-component DE of a triblock copolymer with attractive electromechanical performance is reported. Symmetric poly(styrene-b-butyl acrylate-b-styrene) (SBAS) is designed and synthesized. The SBAS actuator exhibits about 100% static actuation area strain and excellent dynamic performance, as evidenced by a wide half bandwidth of 300 Hz and a very high specific power of 1.2 W g -1 within the excitation frequency range of 300-800 Hz., (© 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The present communication reports a novel strategy to fabricate reversible shape-memory polymer that operates without the aid of external force on the basis of a two-phase structure design. The proof-of-concept material, crosslinked styrene-butadiene-styrene block copolymer (SBS, dispersed phase)/polycaprolactone-based polyurethane (PU, continuous phase) blend, possesses a closely connected microphase separation structure. That is, SBS phases are chemically bonded to crosslinked PU by means of a single crosslinking agent and two-step crosslinking process for increasing integrity of the system. Miscibility between components in the blend is no longer critical by taking advantage of the reactive blending technique. It is found that a suitable programming leads to compressed SBS, which serves as internal expansion stress provider as a result. The desired two-way shape-memory effect is realized by the joint action of the temperature-induced reversible opposite directional deformabilities of the crystalline phase of PU and compressed SBS, accompanying melting and orientated recrystallization of the former. Owing to the broadness of material selection and manufacturing convenience, the proposed approach opens an avenue toward mass production and application of the smart polymer., (© 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

An enantioselective redox-relay Heck alkynylation of di- and trisubstituted alkenols to construct propargylic stereocenters is disclosed using a new pyridine oxazoline ligand. This strategy allows direct access to chiral β-alkynyl carbonyl compounds employing allylic alcohol substrates in contrast to more traditional conjugate addition methods., (© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

It is a significant but challenging task to simultaneously reinforce and functionalize diene rubbers. Inspired by "sacrificial bonds", the authors engineer sacrificial hydrogen bonds formed by pendent urazole groups in crosslinked solution-polymerized styrene butadiene rubber (SSBR) via triazolinedione click chemistry. This post-crosslinking modification reveals the effects of the sacrificial bonds based on a consistent covalent network. The "cage effect" of the pre-crosslinked network facilitates the heterogeneous distribution of urazole groups, leading to the formation of hydrogen-bonded multiplets. These multiplets further aggregate into clusters with vicinal trapped polymer segments that form microphase separation from the SSBR matrix with a low content of urazole groups. The clusters based on hydrogen bonds, serving as sacrificial bonds, promote energy dissipation, significantly improving the mechanical properties of the modified SSBR, and enable an additional wide transition temperature region above room temperature, which endows the modified SSBR with promising triple-shape memory behavior., (© 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

A four-step catalytic process was developed to produce p-methylstyrene from methylfuran, a biomass-derived species. First, methylfuran was acylated over zeolite H-Beta with acetic anhydride. Second, the acetyl group was reduced to an ethyl group with hydrogen over copper chromite. Third, p-ethyltoluene was formed through Diels-Alder cycloaddition and dehydration of 2-ethyl-5-methyl-furan with ethylene over zeolite H-Beta. Dehydrogenation of p-ethyltoluene to yield p-methylstyrene completes the synthesis but was not investigated because it is a known process. The first two steps were accomplished in high yield (>88 %) and the Diels-Alder step resulted in a 67 % yield of p-ethyltoluene with a 99.5 % selectivity to the para isomer (final yield of 53.5 %). The methodology was also used for the preparation of p-divinylbenzene. It is shown that acylation of furans over H-Beta zeolites is a highly selective and high-yield reaction that could be used to produce other valuable molecules from biomass-derived furans., (© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Polymers bearing activated aziridine groups are attractive precursors to α-substituted-β-amino-functionalized materials due to the enhanced reactivity of the pendant aziridine functionalities toward ring-opening by nucleophiles. Two aziridine-containing styrenic monomers, 2-(4-vinylphenyl)aziridine (VPA) and N-mesyl-2-(4-vinylphenyl)aziridine (NMVPA), were polymerized under a variety of reversible deactivation radical polymerization conditions. Low-catalyst-concentration atom transfer radical polymerization (LCC-ATRP) and reversible addition-fragmentation chain-transfer (RAFT) polymerization were ineffective at producing well-defined polymers from VPA due to side reactions between the aziridine functionalities and the agents controlling the polymerizations (catalysts or chain transfer agents). PolyVPA produced under nitroxide-mediated polymerization (NMP) conditions had narrow molecular weight distribution at low to moderate conversions of monomer, but branched and eventually cross-linked polymers were formed at higher conversions due to ring-opening reactions of the aziridine groups. Most of these undesirable side reactions were eliminated by attaching a methanesulfonyl (mesyl) group to the aziridine nitrogen atom, and well-defined linear homopolymers with targeted molecular weights were realized from NMVPA under RAFT and NMP conditions; however, side reactions between the aziridine groups and the catalyst in LCC-ATRP still occured and the polymerization was uncontrolled using this technique., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Amino group-functionalized, ordered mesoporous polymers (OMP-NH2 ) were prepared using a solvent-free synthesis by grinding mixtures of solid raw precursors (aminophenol, terephthaldehyde), using block copolymer templates, and curing at 140-180 °C. OMP-NH2 was functionalized with acidic sites and incorporated with palladium, giving multifunctional solid catalysts with large Brunauer-Emmett-Teller (BET) surface areas, abundant and ordered mesopores, good thermal stabilities, controllable concentrations, and good dispersion of active centers. The resultant solid catalysts showed excellent catalytic activities and good reusability in biomass conversions and cross-coupling reactions-much superior to those of various reported solid catalysts such as Amberlyst 15, SBA-15-SO3 H, and Pd/C and comparable to those of homogeneous catalysts such as heteropoly acid, HCl, and palladium acetate. A facile green approach was developed for the synthesis of ordered mesoporous polymeric solid catalysts with excellent activities for conversion of low-cost feedstocks into useful chemicals and clean biofuels., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

A red-green-blue (RGB) trichromophoric fluorescent organic nanoparticle exhibiting multi-colour emission was constructed; the blue-emitting cationic oligofluorene nanoparticle acted as an energy-donor scaffold to undergo fluorescence resonance energy transfer (FRET) to a red-emitting dye embedded in the nanoparticle (interior FRET) and to a green-emitting dye adsorbed on the surface through electrostatic interactions (exterior FRET). Each FRET event occurs independently and is free from sequential FRET, thus the resultant dual-FRET system exhibits multi-colour emission, including white, in aqueous solution and film state. A characteristic white-emissive nanoparticle showed visible responses upon perturbation of the exterior FRET efficiency by acceptor displacement, leading to highly sensitive responses toward polyanions in a ratiometric manner. Specifically, our system exhibits high sensitivity toward heparin with an extremely low detection limit., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Photocurable emulsion inks for use with solid freeform fabrication (SFF) to generate constructs with hierarchical porosity are presented. A high internal phase emulsion (HIPE) templating technique was utilized to prepare water-in-oil emulsions from a hydrophobic photopolymer, surfactant, and water. These HIPEs displayed strong shear thinning behavior that permitted layer-by-layer deposition into complex shapes and adequately high viscosity at low shear for shape retention after extrusion. Each layer was actively polymerized with an ultraviolet cure-on-dispense (CoD) technique and compositions with sufficient viscosity were able to produce tall, complex scaffolds with an internal lattice structure and microscale porosity. Evaluation of the rheological and cure properties indicated that the viscosity and cure rate both played an important role in print fidelity. These 3D printed polyHIPE constructs benefit from the tunable pore structure of emulsion templated material and the designed architecture of 3D printing. As such, these emulsion inks can be used to create ultra high porosity constructs with complex geometries and internal lattice structures not possible with traditional manufacturing techniques., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

2,3-Butanediol (2,3-BD) is a renewable alcohol that can be prepared in high yield from biomass sugars. 2,3-BD was selectively dehydrated in a solvent-free process to a complex mixture of 2-ethyl-2,4,5-trimethyl-1,3-dioxolanes and 4,5-dimethyl-2isopropyl dioxolanes with the heterogeneous acid catalyst Amberlyst-15. The purified dioxolane mixture exhibited an anti-knock index of 90.5, comparable to high octane gasoline, and a volumetric net heat of combustion 34 % higher than ethanol. The solubility of the dioxolane mixture in water was only 0.8 g per 100 mL, nearly an order of magnitude lower than the common gasoline oxygenate methyl tert-butyl ether. The dioxolane mixture has potential applications as a sustainable gasoline blending component, diesel oxygenate, and industrial solvent., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Reversible photo-cross-linking of a DNA duplex through the [2+2] photocycloaddition of styrylpyrene is reported. Styrylpyrene moieties on d-threoninol linkers were introduced into complementary positions on DNA strands. Irradiation of the styrylpyrene pair in the duplex with visible light at λ=455 nm induced a [2+2] photocycloaddition between styrylpyrenes that cross-linked the two strands of the duplex. Two diastereomers were formed after [2+2] photocycloaddition as a result of rotation of the styrylpyrene residues. Also, the cycloreversion reaction was induced by UV light at λ=340 nm, which reversibly yielded the uncross-linked strands., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Conventional free radical polymerization and post-alkylation of 4-diphenylphosphino styrene (DPPS) generate a new class of high-molecular-weight phosphonium-containing homopolymers with tunable thermal, viscoelastic, and wetting properties. Post-alkylation and subsequent anion exchange provide an effective method for tuning Tg values and thermal stability as a function of alkyl chain length and counteranion selection (X(-) , BF4 (-) , TfO(-) , and Tf2 N(-) ). Rheological characterization facilitates the generation of time-temperature-superposition (TTS) pseudomaster curves and subsequent analysis of frequency sweeps at various temperatures reveals two relaxation modes corresponding to long-range segmental motion and the onset of viscous flow. Contact angle measurements reveal the influence of counteranion selection on wetting properties, revealing increased contact angles for homopolymers containing nucleophilic counteranions. These investigations provide fundamental insight into phosphonium-containing polymers, aiming to guide future research and applications involving electro-active polymeric devices., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Revealing chemokine receptor CXCR4 expression, distribution, and internalization levels in different cancers helps to evaluate cancer progression or prognosis and to set personalized treatment strategy. We here describe a sensitive and high-throughput immunoassay for determining CXCR4 expression and distribution in cancer cells. The assay is accessible to a wide range of users in an ordinary lab only by dip-coating poly(styrene-co-N-isopropylacrylamide) spheres on the glass substrate. The self- assembled spheres form three-dimensional photonic colloidal crystals which enhance the fluorescence of CF647 and Alexa Fluor 647 by a factor of up to 1000. CXCR4 in cells is detected by using the sandwich immunoassay, where the primary antibody recognizes CXCR4 and the secondary antibody is labeled with CF647. With the newly established assay, we quantified the total expression of CXCR4, its distribution on the cell membrane and cytoplasm, and revealed their internalization level upon SDF-1α activation in various cancer cells, even for those with extremely low expression level., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Herein, we report a new visible-light-promoted strategy to access radical trifluoromethylthiolation reactions by combining halide and photoredox catalysis. This approach allows for the synthesis of vinyl-SCF3 compounds of relevance in pharmaceutical chemistry directly from alkenes under mild conditions with irradiation from household light sources. Furthermore, alkyl-SCF3-containing cyclic ketone and oxindole derivatives can be accessed by radical-polar crossover semi-pinacol and cyclization processes. Inexpensive halide salts play a crucial role in activating the trifluoromethylthiolating reagent towards photoredox catalysis and aid the formation of the SCF3 radical., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The oxidative nitration of styrenes in ethyl acetate represents a metal-free, environmentally friendly, and sustainable technique to recover even low concentrations of NO2 in air. Favorable features are that the product mixture comprising nitroalcohols, nitroketones, and nitro nitrates simplifies at lower concentrations of NO2 . Experiments in a miniplant-type 10 L wet scrubber demonstrated that the recycling technique is well applicable on larger scales at which initial NO2 concentrations of >10 000 ppm were reliably reduced to less than 40 ppm., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Emulsion-templated highly porous polymers (polyHIPEs), containing distinct regions differing in composition, morphology, and/or properties, are prepared by the simultaneous polymerization of two high internal phase emulsions (HIPEs) contained within the same mould. The HIPEs are placed together in the mould and subjected to thiol-acrylate photopolymerization. The resulting polyHIPE material is found to contain two distinct semicircular regions, reflecting the composition of each HIPE. The original interface between the two emulsions becomes a copolymerized band between 100 and 300 μm wide, which is found to be mechanically robust. The separate polyHIPE layers are distinguished from one another by their differing average void diameter, chemical composition, and extent of contraction upon drying., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Highly enantioselective epoxidation of α-substituted styrenes with aqueous H2 O2 is described by using a chiral iron complex as the catalyst and N-protected amino acids (AAs) as coligands. The amino acids synergistically cooperate with the iron center in promoting an efficient activation of H2 O2 to catalyze epoxidation of this challenging class of substrates with good yields and stereoselectivities (up to 97%ee) in short reaction times., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

A new regioselective alkylation of pyridines at their 4-position was achieved with styrenes in the presence of yttrium trichloride, BuLi, and diisobutylaluminium hydride (DIBAL-H) in THF. Alternatively, similar products were more simply prepared from pyridines and benzyl Grignard reagents. These reactions are not only a useful preparation of 4-substituted pyridines but are also complementary to other relevant reactions usually giving 2-substituted pyridines., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

A simple copper-catalyzed direct radical carbooxygenation of styrenes is developed utilizing alkyl bromides as radical resources. This catalytic radical difunctionalization accomplishes both alkylation and alkoxylation of styrenes in one pot. A broad range of styrenes and alcohols are well tolerated in this transformation. The EPR experiment shows that alkyl halides could oxidize Cu(I) to Cu(II) in this transformation., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The combined use of Pd(OAc)2 , Cu(OAc)2 , and dioxygen in molten tetrabutylammonium acetate (TBAA) promotes an unusual cyclopropanation reaction between aryl methyl ketones and styrenes. The process is a dehydrogenative cyclizing coupling that involves a twofold CH activation at the α-position of the ketone. The substrate scope highlights the flexibility of the catalyst; a reaction mechanism is also proposed., (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

An air- and moisture-stable fluoroiodane in the presence of AgBF4 is suitable for selective geminal difluorination of styrenes under mild reaction conditions. One of the CF bonds is formed by transfer of electrophilic fluorine from the hypervalent iodine reagent, while the other one arises from the tetrafluoroborate counterion of silver. Deuterium-isotope-labelling experiments and rearrangement of methyl styrene substrates suggest that the reaction proceeds through a phenonium ion intermediate., (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The copper-catalyzed radical aminofluorination of styrenes with N-fluorobenzenesulfonimide (NFSI) is realized with high regioselectivity, thus affording aminofluorination products with regioselectivities opposite that of the palladium-catalyzed and noncatalyzed processes. Preliminary mechanistic studies suggested the reaction went through a radical pathway and was supported by DFT calculations. In these reactions, NFSI is utilized as both a radical nitrogen source and radical fluorine source, thus rendering it an attractive reagent., (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

A palladium-catalyzed selective C-H bond trifluoroethylation of aryl iodides has been explored. The reaction allows for the efficient synthesis of a variety of ortho-trifluoroethyl-substituted styrenes. Preliminary mechanistic studies indicate that the reaction might involve a key Pd(IV) intermediate, which is generated through the rate-determining oxidative addition of CF3CH2I to a palladacycle; the bulky nature of CF3CH2I influences the reactivity. Reductive elimination from the Pd(IV) complex then leads to the formation of the aryl-CH2CF3 bond., (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The direct dehydrative activation of allylic alcohols and subsequent cross-coupling with alkenes by using palladium catalyst containing a phosphoramidite ligand is described. The activation of the allyl alcohol does not require stoichiometric additives, thus allowing clean, waste-free reactions. The scope is demonstrated by application of the protocol to a series allylic alcohols and vinyl arenes, leading to variety of 1,4-diene products. Based on kinetic studies, a mechanism is proposed that involves a palladium hydride species that activates the allyl alcohol to form the allyl intermediate., (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The C-C bond forming catalytic hydroaminoalkylation of terminal alkenes, 1,3-dienes, or styrenes allows a direct and highly atom efficient (100 %) synthesis of amines which can result in the formation of two regioisomers, the linear and the branched product. We present a new titanium catalyst with 2,6-bis(phenylamino)pyridinato ligands for intermolecular hydroaminoalkylation reactions of styrenes and 1-phenyl-1,3-butadienes that delivers the corresponding linear hydroaminoalkylation products with excellent regioselectivities., (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The growth factor bone morphogenetic protein 2 (BMP-2) is utilized in surgical procedures to improve bone regeneration; however, current treatments deliver BMP-2 at amounts greater than 100,000 fold of physiological levels, which increases treatment costs and risk of side effects. Drug-eluting microcarriers developed to improve these therapies have faced significant commercialization challenges including particle size distributions, solvent removal, low encapsulation efficiency, and bioactivity loss. In this study, a solvent-free method is presented for fabrication of uniform polyHIPE microspheres for controlled growth factor release. Emulsion templating principles and fluid dynamics were used to fabricate uniform particles with tunable particle size (200-800 μm) and pore size (10-30 μm). The ability to independently tune particle and pore size is expected to provide excellent control of release kinetics. Overall, this solvent-free method for making porous microspheres displays strong promise for the controlled release of BMP-2 and other growth factors., (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The synthesis of enantiomerically pure aluminium, gallium and indium complexes supported by chiral (R,R)-((HH)ONNO(HH)) (1), (R,R)-((MeH)ONNO(HMe)) (2), (R,R)-((tButBu)ONNO(tButBu)) (3), (R,R)-((MeNO2)ONNO(MeNO2)) (4), (R,R)-((HOMe)ONNO(HOMe)) (5) and (R,R)-((ClCl)ONNO(ClCl)) (6) (1,2)-diphenylethylene-salen ligands is described. Several of these complexes have been crystallographically authenticated, which highlights a diversity of coordination patterns. Whereas all Ga complexes form [Ga2(CH2SiMe3)4(ONNO)] bimetallic species (ONNO = 1-3), aluminium [AlR(ONNO)] (R = Me, CH2SiMe3) and indium [In(CH2SiMe3)(ONNO)] derivatives are monometallic for ONNO = 1, 2 and 4-6, and only form the bimetallic complexes [Al2R4(ONNO)] and [In2(CH2SiMe3)4(ONNO)] for the most sterically crowded ligand 3. The [AlMe(ONNO)] complexes react with iPrOH to give [AlOiPr(ONNO)] complexes that are robust towards further iPrOH. The [In(CH2SiMe3)(ONNO)] congeners are inert towards excess alcohol, whereas the Ga compounds decompose easily. All these alkyl complexes, as well as the [AlOiPr(ONNO)] derivatives, catalyse the ring-opening polymerisation (ROP) of racemic lactide (rac-LA). The [AlMe(ONNO)] complexes require additional alcohol to afford controlled reactions, but [AlOiPr(ONNO)] complexes are single-component catalysts for the isoselective ROP of rac-LA, with values of Pm in the range 0.80-0.90. Experimental evidence unexpectedly shows that chain-end control leads to the isoselectivity of these aluminium catalysts; also, the more crowded the coordination sphere, the higher the isoselectivity. The bimetallic Ga complexes do not afford controlled reactions, but the binary [In(ONNO)(CH2SiMe3)/(PhCH2OH)] systems competently mediate non-stereoselective ROP; evidence is given that an activated monomer mechanism is at work. Kinetic studies show that catalytic activity decreases when electronic density and steric congestion at the metal atom increase., (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Inedible and/or waste biomass reserves are being strongly focused upon as a suitable new energy and chemical source. Raffinose, which is an indigestible trisaccharide composed of glucose, galactose, and fructose, is found abundantly in beet molasses, sugar cane, and seeds of many leguminous plants. Herein, we demonstrate the one-pot synthesis of furan derivatives and sugar alcohols from raffinose by using heterogeneous acid, base, and/or metal-supported catalysts. The combination of Amberlyst-15 and hydrotalcite (HT) showed a high activity (37% yield) for 5-hydroxymethyl-2-furaldehyde (HMF) through continuous hydrolysis, isomerization, and dehydration reactions. In addition, the use of a hydrotalcite-supported ruthenium catalyst (Ru/HT) successfully afforded 2,5-diformylfuran (DFF, 27% yield) from HMF produced by raffinose, directly. Moreover, the hydrogenation of hexoses obtained by raffinose hydrolysis into sugar alcohols (galactitol, mannitol, sorbitol) was also achieved in a high yield (91%) with Amberlyst-15 and Ru/HT catalysts. Thus, we suggest that raffinose has great potential for the synthesis of important industrial intermediates under mild reaction conditions., (Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

This study describes the development of a functional porous polymer for use as a scaffold to support 3D hepatocyte culture. A high internal phase emulsion (HIPE) is prepared containing the monomers styrene (STY), divinylbenzene (DVB), and 2-ethylhexyl acrylate (EHA) in the external oil phase and the monomer acrylic acid (Aa) in the internal aqueous phase. Upon thermal polymerization with azobisisobutyronitrile (AIBN), the resulting porous polymer (polyHIPE) is found to have an open-cell morphology and a porosity of 89%, both suitable characteristics for 3D cell scaffold applications. X-ray photo-electron spectroscopy reveals that the polyHIPE surface contained 7.5% carboxylic acid functionality, providing a useful substrate for subsequent surface modifications and bio-conjugations. Initial bio-compatibility assessments with human hepatocytes show that the acid functionality does not have any detrimental effect on cell adhesion. It is therefore believed that this material can be a useful precursor scaffold towards 3D substrates that offer tailored surface functionality for enhanced cell adhesion., (© 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

A small series of donor-acceptor molecular dyads has been synthesized and fully characterized. In each case, the acceptor is a dicyanovinyl unit and the donor is a boron dipyrromethene (BODIPY) dye equipped with a single styryl arm bearing a terminal amino group. In the absence of the acceptor, the BODIPY-based dyes are strongly fluorescent in the far-red region and the relaxed excited-singlet states possess significant charge-transfer character. As such, the emission maxima depend on both the solvent polarity and temperature. With the corresponding push-pull molecules, there is a low-energy charge-transfer state that can be observed by both absorption and emission spectroscopy. Here, charge-recombination fluorescence is weak and decays over a few hundred picoseconds or so to recover the ground state. Overall, these results permit evaluation of the factors affecting the probability of charge-recombination fluorescence in push-pull dyes. The photophysical studies are supported by cyclic voltammetry and DFT calculations., (Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Carbon nanofibers (CNFs) were functionalized with aryl sulfonic acid groups using in situ diazonium coupling. The use of diazonium coupling yielded an acidic carbon material, in which the introduced acidic groups are readily accessible to the triglyceride substrate. The material is an efficient catalyst for the transesterification of triolein and methanol, outperforming conventional sulfonated carbons in both stability and activity per acid site. Upon comparing CNFs with varying degrees of functionalization, a linear correlation between sulfonic acid sites and catalytic performance was found., (Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Polymeric micelles consisting of asymmetric triblock copolymers were successfully used for fabrication of robust hybrid nanoparticles with highly biocompatible calcium phosphate shells. The hydrophobic polystyrene core encapsulates hydrophobic fluorescent dyes such as Nile red. The anionic polyacrylic acid provides the site for the mineralization reaction of calcium phosphate. The polyethylene glycol corona stabilizes the hybrid nanoparticles. Fluorescent dyes can be used as imaging agents for determining the location of the nanoparticles and to give an observable indication of drug delivery, while the calcium phosphate shell can enhance the fluorescence of the encapsulated dye., (Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

An eight-orders of magnitude enhancement in current across Hg/X-styrene-Si junctions is caused by merely altering a substituent, X. Interface states are passivated and, depending on X, the Si Schottky junction encompasses the full range from Ohmic to strongly rectifying. This powerful electrostatic molecular effect has immediate implications for interface band alignment and sensing., (Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)