Ligand-Regulated Palladium-Catalyzed Regiodivergent Hydroarylation of the Distal Double Bond of Allenamides with Aryl Boronic Acid

The ligand-regulated regiodivergent hydroarylation of the distal double bond of allenamides with aryl boronic acid was achieved in the presence of palladium(II) catalysts, delivering a variety of functionalized enamide with excellent E selectivity and Markovnikov/anti-Markovnikov selectivity. Two possible coordination intermediates were proposed to be responsible for the regiodivergent hydroarylation: (1) The coordination Intermediate I, which was proposed to be formed through the coordination of MeCN, distal double bond, phenyl to palladium, led to the aryl group away from the Intermediate I, inducing excellent E selectivity and anti-Markovnikov selectivity. (2) A switch of regioselectivity to 1,2-Markovnikov hydroarylation was obtained using bidentate phosphine ligand (dppf or Xantphos). The formed coordination Intermediate II led to the N-tether away from the Intermediate II and at the trans position of aryl, resulting in excellent E selectivity and Markovnikov selectivity. Meanwhile, tentative investigation on the mechanism proved that the hydron source of this hydroarylation is more likely to be boronic acid. The transmetallation between aryl boronic acid and palladium catalyst was the initial step of this transformation.

Pentaphosphaferrocene-mediated synthesis of asymmetric organo-phosphines starting from white phosphorus

The synthesis of phosphines is based on white phosphorus, which is usually converted to PCl₃, to be afterwards substituted step by step in a non-atomic efficient manner. Herein, we describe an alternative efficient transition metal-mediated process to form asymmetrically substituted phosphines directly from white phosphorus (P₄). Thereby, P₄ is converted to [Cp*Fe(η⁵-P₅)] (1) (Cp* = η⁵-C₅(CH₃)₅) in which one of the phosphorus atoms is selectively functionalized to the 1,1-diorgano-substituted complex [Cp*Fe(η⁴-P₅R'R″)] (3). In a subsequent step, the phosphine PR'R″R‴ (R' ≠ R″ ≠ R‴ = alky, aryl) (4) is released by reacting it with a nucleophile R‴M (M = alkali metal) as racemates. The starting material 1 can be regenerated with P₄ and can be reused in multiple reaction cycles without isolation of the intermediates, and only the phosphine is distilled off.

Elastic gels based on flaxseed gum with konjac glucomannan and agar

In this study, we prepared hydrocolloid gels in which flaxseed gum (FSG), konjac glucomannan (KGM), and agar (AG) were blended in different ratios for use as a viscoelastic food. The prepared hydrogels' physicochemical properties were analyzed concerning their water solubility index (WSI), swelling power (SL), frequency sweep results, and microstructures. As the FSG ratio decreased, the WSI value of the compound gel tended to increase. However, it showed a tendency to have a relatively high SP value and a low tan δ value according to a specific KGM/FSG/AG mixing ratios (8:2:1.5 and 6:4:1.5). Through microstructure analysis, the FKA821.5 sample showed a relatively small, monodispersed gel building structure, correlated with the rheological results. In conclusion, the FKA821.5 gel was determined to have good water retention capacity and high structural strength. These results are expected to increase the applicability of FSG-based gelling agents in the food industry.

Comparison of photocatalytic activity of ZnO, Ag-ZnO, Cu-ZnO, Ag, Cu-ZnO and TPPS/ZnO for the degradation of methylene blue under UV and visible light irradiation

In this study, zinc oxide and silver and copper-doped zinc oxide nanorods were synthesized by a simple template-free precipitation technique. In addition, meso-tetrakis-(4-sulfonatophenyl) porphyrin (TPPS₄) was prepared and immobilized on ZnO nanorods (TPPS/ZnO). The synthesized photocatalysts were characterized by various techniques such as X-ray powder diffraction, scanning electron microscopy, UV-visible spectroscopy, diffuse reflectance spectroscopy, and Fourier transform Infrared spectroscopy. The potential of the obtained photocatalysts in the degradation of methylene blue was investigated under UV and visible light irradiation. The results revealed that the photocatalytic activity of TPPS/ZnO was higher than those of the pure ZnO and doped ZnO under visible light irradiation.

Determination of intracellular protein-ligand binding affinity by competition binding in-cell NMR

Structure-based drug development suffers from high attrition rates due to the poor activity of lead compounds in cellular and animal models caused by low cell penetrance, off-target binding or changes in the conformation of the target protein in the cellular environment. The latter two effects cause a change in the apparent binding affinity of the compound, which is indirectly assessed by cellular activity assays. To date, direct measurement of the intracellular binding affinity remains a challenging task. In this work, in-cell NMR spectroscopy was applied to measure intracellular dissociation constants in the nanomolar range by means of protein-observed competition binding experiments. Competition binding curves relative to a reference compound could be retrieved either from a series of independent cell samples or from a single real-time NMR bioreactor run. The method was validated using a set of sulfonamide-based inhibitors of human carbonic anhydrase II with known activity in the subnanomolar to submicromolar range. The intracellular affinities were similar to those obtained in vitro, indicating that these compounds selectively bind to the intracellular target. In principle, the approach can be applied to any soluble intracellular target that gives rise to measurable chemical shift changes upon ligand binding.

Effect of combined exposure to silica nanoparticles and cadmium chloride on female zebrafish ovaries

Silica nanoparticles (SiNPs) and cadmium chloride (CdCl2) are two important environmental pollutants. In previous research, found that SiNPs in zebrafish larvae can amplify the cardiovascular damage caused by cadmium. Whether SiNPs in the ovaries can amplify the adverse effects of cadmium on the zebrafish ovaries is worth studying problem. In this study, sexually mature female zebrafish were used as model organisms and exposed to 1 μmol/L CdCl2 and/or 25 μg/mL SiNPs for 30 days. The results showed that the structure and function of ovaries in the sole and combined exposure groups changed significantly, resulting in reduced ovarian quality, decreased number of mature oocytes, and the development of malformed offspring. A deep-sequencing analysis showed that organisms' lipid metabolism and transportation, estrogen metabolism, and response to the maturation, meiosis, and vitellogenin synthesis of oocytes were significantly affected by single exposure or combined exposure. These findings provide further insights into the harm of cooperation of CdCl2 and/or SiNPs to the aquatic ecosystems.

The Protein Folding Problem: The Role of Theory

The protein folding problem was first articulated as question of how order arose from disorder in proteins: How did the various native structures of proteins arise from interatomic driving forces encoded within their amino acid sequences, and how did they fold so fast? These matters have now been largely resolved by theory and statistical mechanics combined with experiments. There are general principles. Chain randomness is overcome by solvation-based codes. And in the needle-in-a-haystack metaphor, native states are found efficiently because protein haystacks (conformational ensembles) are funnel-shaped. Order-disorder theory has now grown to encompass a large swath of protein physical science across biology.

Using photocaging for fast time-resolved structural biology studies

Careful selection of photocaging approaches is critical to achieve fast and well synchronized reaction initiation and perform successful time-resolved structural biology experiments. This review summarizes the best characterized and most relevant photocaging groups previously described in the literature. It also provides a walkthrough of the essential factors to consider in designing a suitable photocaged molecule to address specific biological questions, focusing on photocaging groups with well characterized spectroscopic properties. The relationships between decay rates (k in s-1), quantum yields (ϕ) and molar extinction coefficients (ϵmax in M-1 cm-1) are highlighted for different groups. The effects of the nature of the photocaged group on these properties is also discussed. Four main photocaging scaffolds are presented in detail, o-nitrobenzyls, p-hydroxyphenyls, coumarinyls and nitrodibenzofuranyls, along with three examples of the use of this technology. Furthermore, a subset of specialty photocages are highlighted: photoacids, molecular photoswitches and metal-containing photocages. These extend the range of photocaging approaches by, for example, controlling pH or generating conformationally locked molecules.

Rigidity Bridging Flexibility to Harmonize Three Excited-State Deactivation Pathways for NIR-II-Fluorescent-Imaging-Guided Phototherapy

Small organic phototherapeutic molecules of the second near-infrared (NIR-II) window (1000-1700 nm) serve as promising candidates for theranostics. However, developing such versatile agents for fluorescence-guided photodynamic/photothermal therapy remains a demanding task stirred by competitive energy dissipation pathways, including radiative decay, internal conversion, and intersystem crossing. To the best of current knowledge, the current paradigm for addressing the issue has deliberately approached the optimum balance among three deactivation processes through offsetting from each other, possibly leading to a comprehensively compromised theranostic efficacy. Few reports aim to modulate the three deactivation pathways excluding sacrificing any one of them. Herein, a molecular design strategy to construct a phototherapeutic organic fluorophore CCNU-1060, armed with NIR-II luorescence-guided phototherapeutic properties, is rationally developed. With a flexible motor, tetraphenylethene, bridged to the rigidified coplanar core boron-azadipyrromethene, the desired CCNU-1060 is subsequently encapsulated into an amphiphilic matrix to form CCNU-1060 nanoparticles (NPs), which match or transcend its precursor NJ-1060 NPs in the three energy dissipation processes. CCNU-1060 NPs are utilized to realize high-spatial vessel imaging and effective NIR-II fluorescence-guided phototherapeutic tumor ablation. This study unlocks a viewpoint of molecular engineering that simultaneously regulates multiple energy dissipation pathways for the construction of versatile phototherapy agents.

Conjugated Polymers: Optical Toolbox for Bioimaging and Cancer Therapy

Conjugated polymers (CPs) are capable of coordinating the electron coupling phenomenon to bestow powerful optoelectronic features. The light-harvesting and light-amplifying properties of CPs are extensively used in figuring out the biomedical issues with special emphasis on accurate diagnosis, effective treatment, and precise theranostics. This review summarizes the recent progress of CP materials in bioimaging, cancer therapeutics, and introduces the design strategies by rationally tuning the optical properties. The recent advances of CPs in bioimaging applications are first summarized and the challenges to clear the future directions of CPs in the respective area are discussed. In the following sections, the focus is on the burgeoning applications of CPs in phototherapy of the tumor, and illustrates the underlying photo-transforming mechanism for further molecular designing. Besides, the recent progress in the CPs-assistant drug therapy, mainly including drug delivery, gene therapeutic, the optical-activated reversion of tumor resistance, and synergistic therapy has also been discussed elaborately. In the end, the potential challenges and future developments of CPs on cancer diagnosis and therapy are also illuminated for the improvement of optical functionalization and the promotion of clinical translation.

Multicomponent alkene azidoarylation by anion-mediated dual catalysis

Molecules that contain the β-arylethylamine motif have applications in the modulation of pain, treatment of neurological disorders and management of opioid addiction, among others, making it a privileged scaffold in drug discovery^1,2. De novo methods for their assembly are reliant on transformations that convert a small class of feedstocks into the target compounds via time-consuming multistep syntheses^3-5. Synthetic invention can drive the investigation of the chemical space around this scaffold to further expand its capabilities in biology^6-9. Here we report the development of a dual catalysis platform that enables a multicomponent coupling of alkenes, aryl electrophiles and a simple nitrogen nucleophile, providing single-step access to synthetically versatile and functionally diverse β-arylethylamines. Driven by visible light, two discrete copper catalysts orchestrate aryl-radical formation and azido-group transfer, which underpin an alkene azidoarylation process. The process shows broad scope in alkene and aryl components and an azide anion performs a multifaceted role both as a nitrogen source and in mediating the redox-neutral dual catalysis via inner-sphere electron transfer^10,11. The synthetic capabilities of this anion-mediated alkene functionalization process are likely to be of use in a variety of pharmaceutically relevant and wider synthetic applications.

Intermolecular Charge-Transfer Luminescence by Self-Assembly of Pyridinium Luminophores in Solutions

Designing a luminophore for application both in solution and in the solid state is a highly challenging task given the distinct nature of intermolecular interactions in these phases. In this context, we demonstrate that self-assembly of non-emissive charged pyridinium luminophores enables luminescence in solutions through a mechanism that is characteristic for the crystal state. Specifically, protonation of pyridine luminophore subunits in a solution promotes oligomer formation through intermolecular π+ -π interactions, leading to an intermolecular charge-transfer type luminescence. The luminescence turn-on by protonation is utilized for a highly efficient solution-state luminescent sensing of hydrogen chloride and sulfonic acids (TfOH, TsOH and MsOH) with detection limits spanning the range from 0.06 to 0.33 ppm. The protonation followed by self-assembly results in a bathochromic shift of the emission from 420 nm to 550 nm.

One-Pot Construction of Indolo[2,3-b]quinoxalines through Ruthenium-Catalyzed Ortho C-H Bond Functionalization of 2-Arylquinoxalines with Sulfonyl Azides

The synthesis of N-substituted indolo[2,3-b]quinoxalines has been developed through a Ru(II)-catalyzed ortho C-H functionalization of 2-arylquinoxalines with sulfonyl azides and further oxidation with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone in one pot. This double C-N bond formation strategy provides a new efficient route for the preparation of a series of biologically relevant 6H-indolo[2,3-b]quinoxaline derivatives in up to 94% yield, suggesting a broad substrate scope applicability. The preliminary mechanistic studies reveal that the sequential C-N bond formations proceed through the formation of a five-membered ruthenacyclic intermediate in the first step and a radical mechanism in the second step.

Gastronomy unravelled by physics: Gastrophysics

Useful attempts to shed light on the nature of gastronomy from a scientific point of view and to unravel the crucial connection between food, eating and well-being are currently underrepresented in the scientific literature. However, several scientific disciplines ranging from the natural to the social sciences offer valuable new perspectives on gastronomy. As one of the key disciplines in natural science, physics offers original and rigorous perspectives on all processes and structures constrained by the laws of nature. The emerging discipline called gastrophysics employs the full range of concepts, techniques and methods from physics to generate useful scientific input to the complex and holistic reflections on gastronomy. Relying on a review of the existing literature, this article illustrates how a science-based gastrophysics emerges, to a large extent from the convoluted history of food science as well as from various recent ‐ and often overlapping ‐ attempts to combine modern scientific methodology to questions from gastronomy. However, the present review also insists on a physics-inspired methodology to handle scale and complexity in food preparation and consumption across length scales from sub-molecular to entire foods. We exemplify how gastrophysics directly helps to develop gastronomy and how it adds to current approaches in traditional food science. We also suggest that gastrophysics may prove relevant in the context of the ongoing food transformation, which focuses strongly on sustainability, but where the importance of gastronomic aspects in this transformation is greatly needed.

Identification of potential drug candidates to combat COVID-19: a structural study using the main protease (mpro) of SARS-CoV-2

The recent outbreak of the SARS-CoV-2 virus leading to the disease COVID 19 has become a global pandemic that is spreading rapidly and has caused a global health emergency. Hence, there is an urgent need of the hour to discover effective drugs to control the pandemic caused by this virus. Under such conditions, it would be imperative to repurpose already known drugs which could be a quick and effective alternative to discovering new drugs. The main protease (Mpro) of SARS-COV-2 is an attractive drug target because of its essential role in the processing of the majority of the non-structural proteins which are translated from viral RNA. Herein, we report the high-throughput virtual screening and molecular docking studies to search for the best potential inhibitors against Mpro from FDA approved drugs available in the ZINC database as well as the natural compounds from the Specs database. Our studies have identified six potential inhibitors of Mpro enzyme, out of which four are commercially available FDA approved drugs (Cobicistat, Iopromide, Cangrelor, and Fortovase) and two are from Specs database of natural compounds (Hopeaphenol and Cyclosieversiodide-A). While Cobicistat and Fortovase are known as HIV drugs, Iopromide is a contrast agent and Cangrelor is an anti-platelet drug. Furthermore, molecular dynamic (MD) simulations using GROMACS were performed to calculate the stability of the top-ranked compounds in the active site of Mpro. After extensive computational studies, we propose that Cobicistat and Hopeaphenol show potential to be excellent drugs that can form the basis of treating COVID-19 disease.Communicated by Ramaswamy H. Sarma.

Nickel/Photo-Cocatalyzed Regioselective Ring Opening of N-Tosyl Styrenyl Aziridines with Aldehydes

Aldehydes and aziridines are both intrinsic electrophilic reagents, and thus the coupling reaction between these two compounds is highly challenging. In this protocol, the merger of nickel and hydrogen-atom-transfer photocatalysis successfully enables the ring opening of N-tosyl styrenyl aziridines with aldehydes, providing a novel and atom-economical access to a variety of β-amino ketones with complete regiocontrol. The preliminary mechanistic studies reveal that the ring opening reaction proceeds with a cooperative catalytic mode: aldehydes are converted into acyl radicals by tetrabutylammonium decatungstate under irradiation, whereas the nickel catalyst is engaged in the ring opening of aziridines and the following carbon-carbon bond-forming step.

[Preparation of Fe3O4@BA-MOF magnetic solid-phase extraction material and its application to the detection of pesticide residues in tea]

Tea is one of the most popular beverages worldwide, and its quality is often affected by the excessive pesticide residues during production. During the detection of pesticide residues in tea by chromatography-mass spectrometry and other methods, a strong matrix effect attributed to tea polyphenols and pigments is observed, which seriously impacts the analysis results. In this study, Fe3O4 magnetic nanoparticles and boric acid-functionalized metal organic framework (BA-MOF) materials were combined to prepare a highly efficient adsorbent Fe3O4@BA-MOF for capturing tea polyphenols and pigments. An effective analysis method for pesticide residues in tea samples in combination with gas chromatography-mass spectrometry was established. The introduction of boronic acid ligands into the metal organic framework, as the recognition site of cis-diols, enhanced the polyphenol capture ability. Adsorption of the pigment in the matrix was achieved through π-π interactions between the MOF ligand and the pigment. This new material has significant advantages such as rapid magnetic separation, large surface area, and abundant functional sites. Fe3O4@BA-MOF was prepared by employing simple conditions and characterized by Fouriertransform infrared spectroscopy, scanning electron microscopy, and X-ray diffractometry to identify its functional groups and morphology. After investigating the adsorption effect of different doses of Fe3O4@BA-MOF adsorbents (5, 10, 30, 50, and 80 mg) on tea polyphenols, 50 mg of the adsorbent was added to the tea matrix and shaken thoroughly. The tea polyphenol content in the matrix solution was determined using an ultraviolet spectrophotometer. The polyphenols were reduced by 74.58% within 5 min. The effect of solution pH (2.0, 4.0, 6.0, and 7.0) on the adsorption efficiency was investigated, and pH 7.0 was chosen as the optimal condition. By adjusting the pH of the solution, Fe3O4@BA-MOF could be recycled, and it maintained the excellent adsorption performance after four cycles of use. The introduction of Fe3O4 magnetic nanoparticles led to rapid magnetic response characteristics during sample pretreatment and improved the pretreatment efficiency. In the actual application of tea pesticide detection, after Fe3O4@BA-MOF pretreatment, the average recovery rates of the ten pesticides were in the range of 75.8%-138.6%, and the RSD was in the range of 0.5%-18.7% (n=3). The Fe3O4@BA-MOF nanocomposite prepared by introducing the boric acid ligand into the MOF structure and incorporating Fe3O4 magnetic nanoparticles could specifically adsorb the tea polyphenol matrix. When applied to the detection of pesticide residues in tea, it purifies the matrix and improves the detection efficiency, thus being suitable for the detection and analysis of pesticides in tea.

Synthesis, spectroscopic characterization, structural studies, thermal analysis and molecular docking of N-(2-methyl-5-nitrophenyl)-4-(pyridin-2-yl)pyrimidin-2-amine, a precursor for drug design against chronic myeloid leukemia

The synthesis, crystal structure and spectroscopic and electronic properties of N-(2-methyl-5-nitrophenyl)-4-(pyridin-2-yl)pyrimidin-2-amine (NPPA), C₁₆H₁₃N₅O₂, a potential template for drug design against chronic myelogenous leukemia (CML), is reported. The design and construction of the target molecule were carried out starting from the guanidinium nitrate salt (previously synthesized) and the corresponding enaminone. X-ray diffraction analysis and a study of the Hirshfeld surfaces revealed important interactions between the nitro-group O atoms and the H atoms of the pyridine and pyrimidine rings. A crystalline ordering in layers, by the stacking of rings through interactions of the π-π type, was observed and confirmed by a study of the shape-index surfaces and dispersion energy calculations. Quantitative electrostatic potential studies revealed the most positive value of the molecule on regions close to the N-H groups (34.8 kcal mol^-1); nevertheless, steric impediments and the planarity of the molecule do not allow the formation of hydrogen bonds from this group. This interaction is however activated when the molecule takes on a new extended conformation in the active pocket of the enzyme kinase (PDB ID 2hyy), interacting with protein residues that are fundamental in the inhibition process of CML. The most negative values of the molecule are seen in regions close to the nitro group (-35.4 and -34.0 kcal mol^-1). A molecular docking study revealed an energy affinity of ΔG = -10.3 kcal mol^-1 for NPPA which, despite not having a more negative value than the control molecule (Imatinib; ΔG = -12.8 kcal mol^-1), shows great potential to be used as a template for new drugs against CML.

Stimuli-Responsive Anion Transport through Acylhydrazone-Based Synthetic Anionophores

Photoswitchable acylhydrazone-based synthetic anionophores are reported. Single-crystal X-ray structure and ¹H NMR titration studies confirmed the chloride binding in solid and solution states. The ion transport activity of 1a was greatly attenuated through a phototriggered E to Z photoisomerization process, and the photoisomerized deactivated state showed high kinetic stability due to an intramolecular hydrogen bond. Switchable "OFF-ON" transport activity was achieved by the application of light and acid-catalyzed reactivation process.

Evolution of dynamical networks enhances catalysis in a designer enzyme

Activation heat capacity is emerging as a crucial factor in enzyme thermoadaptation, as shown by the non-Arrhenius behaviour of many natural enzymes. However, its physical origin and relationship to the evolution of catalytic activity remain uncertain. Here we show that directed evolution of a computationally designed Kemp eliminase reshapes protein dynamics, which gives rise to an activation heat capacity absent in the original design. These changes buttress transition-state stabilization. Extensive molecular dynamics simulations show that evolution results in the closure of solvent-exposed loops and a better packing of the active site. Remarkably, this gives rise to a correlated dynamical network that involves the transition state and large parts of the protein. This network tightens the transition-state ensemble, which induces a negative activation heat capacity and non-linearity in the activity-temperature dependence. Our results have implications for understanding enzyme evolution and suggest that selectively targeting the conformational dynamics of the transition-state ensemble by design and evolution will expedite the creation of novel enzymes.

Recent Advances in Metal-Nanoparticle-Catalyzed Coupling Reactions Assisted by Microwave Irradiation

Transition-metal-catalyzed coupling reactions are among some of the most important processes in synthetic chemistry as they are reliable tools for carbon–carbon and carbon–heteroatom bond formation. This short review focuses on recent advances in microwave-assisted­ coupling reactions using transition-metal-nanoparticle catalysts.

1 Introduction

2 Microwave-Assisted Coupling Reactions in Polar Solvents

3 Microwave-Assisted Coupling Reactions in Nonpolar Solvents

4 Conclusion

The reaction of thiourea and 1,3-dimethylthiourea towards organoiodines: oxidative bond formation and halogen bonding

By varying the halogen-bond-donor molecule, 11 new halogen-bonding cocrystals involving thiourea or 1,3-dimethylthiourea were obtained, namely, 1,3-dimethylthiourea-1,2-diiodo-3,4,5,6-tetrafluorobenzene (1/1), C₆F₄I₂·C₃H₈N₂S, 1, thiourea-1,3-diiodo-2,4,5,6-tetrafluorobenzene (1/1), C₆F₄I₂·CH₄N₂S, 2, 1,3-dimethylthiourea-1,3-diiodo-2,4,5,6-tetrafluorobenzene (1/1), C₆F₄I₂·C₃H₈N₂S, 3, 1,3-dimethylthiourea-1,3-diiodo-2,4,5,6-tetrafluorobenzene-methanol (1/1/1), C₆F₄I₂·C₃H₈N₂S·CH₄O, 4, 1,3-dimethylthiourea-1,3-diiodo-2,4,5,6-tetrafluorobenzene-ethanol (1/1/1), C₆F₄I₂·C₃H₈N₂S·C₂H₆O, 5, 1,3-dimethylthiourea-1,4-diiodo-2,3,5,6-tetrafluorobenzene (1/1), C₆F₄I₂·C₃H₈N₂S, 6, 1,3-dimethylthiourea-1,3,5-trifluoro-2,4,6-triiodobenzene (1/1), C₆F₃I₃·C₃H₈N₂S, 7, 1,3-dimethylthiourea-1,1,2,2-tetraiodoethene (1/1), C₆H₁₆N₄S₂·C₂I₄, 8, [(dimethylamino)methylidene](1,2,2-triiodoethenyl)sulfonium iodide-1,1,2,2-tetraiodoethene-acetone (1/1/1), C₅H₈I₃N₂S⁺·I^-·C₃H₆O·C₂I₄, 9, 2-amino-4-methyl-1,3-thiazol-3-ium iodide-1,1,2,2-tetraiodoethene (2/3), 2C₄H₇N₂S⁺·2I^-·3C₂I₄, 10, and 4,4-dimethyl-4H-1,3,5-thiadiazine-3,5-diium diiodide-1,1,2,2-tetraiodoethene (2/3), 2C₅H₁₂N₄S²⁺·4I^-·3C₂I₄, 11. When utilizing the common halogen-bond-donor molecules 1,2-, 1,3-, and 1,4-diiodotetrafluorobenzene, as well as 1,3,5-trifluoro-2,4,6-triiodobenzene, bifurcated I...S...I interactions were observed, resulting in the formation of isolated rings, chains, and sheets. Tetraiodoethylene (TIE) provided I...S...I cocrystals as well, but further yielded a sulfonium-containing product through the reaction of the S atom with TIE. This particular sulfonium motif is the first of its kind to be structurally characterized, and is stabilized in the solid state through a three-dimensional I...I halogen-bonding network. Thiourea reacted with acetone in the presence of TIE to provide two novel heterocyclic products, again stabilized in the solid state through I...I halogen bonding.

Total Synthesis of Lamellarins G, J, L, and Z Using One-Pot Halogen Dance/Negishi Coupling

A bottom-up synthesis of lamellarins G, J, L, and Z was achieved via one-pot halogen dance/Negishi coupling of a lithiated dibromopyrrole derivative. The easily accessible dibromopyrrole bearing an ester moiety underwent halogen dance smoothly at -78 °C within 10 min. The resultant α-pyrrolyllithium was transmetalated to the corresponding organozinc species, which was then coupled with an aryl iodide in the presence of catalytic palladium to provide the fully substituted pyrrole. Subsequent halogen-lithium exchange was performed to incorporate a boronate group exclusively at the β position proximal to the ester moiety. This synthetic intermediate allowed stepwise diarylation for the total synthesis of lamellarins G, J, L, and Z.

Localized Chemotherapy Based on Injectable Hydrogel Boosts the Antitumor Activity of Adoptively Transferred T Lymphocytes In Vivo

The adoptive transfer of antigen-specific T cells has been successfully applied in the treatment of hematological malignancies. However, its application in the treatment of solid tumors has been overshadowed by the immunosuppressive tumor microenvironment. In this context, a preprocessing strategy is developed to reprogram the immunosuppressive tumor microenvironment using a thermoresponsive hydrogel loaded with doxorubicin (DOX@Gel). Compared with hydrogel-based chemotherapy alone or adoptive T cell therapy alone, this combination exhibits enhanced anti-tumor efficacy. In addition to the direct killing of tumor cells, the local chemotherapy releases tumor-associated antigens which enhance the proliferation and effector function of endogenous and adoptively transferred T cells. Moreover, DOX@Gel significantly reduces the numbers of both myeloid derived suppressor cells and Tregs in tumor microenvironment. It is suggested that DOX@Gel promotes the efficacy of adoptively transferred T cells against solid tumors, overcoming the key limitations of adoptive T cell therapy.

Electrochemistry of Thin Films with In Situ/Operando Grazing Incidence X-Ray Scattering: Bypassing Electrolyte Scattering for High Fidelity Time Resolved Studies

Electroactive polymer thin films undergo repeated reversible structural change during operation in electrochemical applications. While synchrotron X-ray scattering is powerful for the characterization of stand-alone and ex situ organic thin films, in situ/operando structural characterization has been underutilized-in large part due to complications arising from supporting electrolyte scattering. This has greatly hampered the development of application relevant structure property relationships. Therefore, a new methodology for in situ/operando X-ray characterization that separates the incident and scattered X-ray beam path from the electrolyte is developed. As a proof of concept, the operando structural characterization of weakly-scattering, organic mixed conducting thin films in an aqueous electrolyte environment is demonstrated, accessing previously unexplored changes in the π-π peak and diffuse scatter, while capturing the solvent swollen thin film structure which is inaccessible in previous ex situ studies. These in situ/operando measurements improve the sensitivity to structural changes, capturing minute changes not possible ex situ, and have multimodal potential such as combined Raman measurements that also serve to validate the true in situ/operando conditions of the cell. Finally, new directions enabled by this in situ/operando cell design are examined and state of the art measurements are compared.

Near-Field Energy Transfer into Silicon Inversely Proportional to Distance Using Quasi-2D Colloidal Quantum Well Donors

Silicon is the most prevalent material system for light-harvesting applications; however, its inherent indirect bandgap and consequent weak absorption limits its potential in optoelectronics. This paper proposes to address this limitation by combining the sensitization of silicon with extraordinarily large absorption cross sections of quasi-2D colloidal quantum well nanoplatelets (NPLs) and to demonstrate excitation transfer from these NPLs to bulk silicon. Here, the distance dependency, d, of the resulting Förster resonant energy transfer from the NPL monolayer into a silicon substrate is systematically studied by tuning the thickness of a spacer layer (of Al₂ O₃ ) in between them (varied from 1 to 50 nm in thickness). A slowly varying distance dependence of d^-1 with 25% efficiency at a donor-acceptor distance of 20 nm is observed. These results are corroborated with full electromagnetic solutions, which show that the inverse distance relationship emanates from the delocalized electric field intensity across both the NPL layer and the silicon because of the excitation of strong in-plane dipoles in the NPL monolayer. These findings pave the way for using colloidal NPLs as strong light-harvesting donors in combination with crystalline silicon as an acceptor medium for application in photovoltaic devices and other optoelectronic platforms.

Photoredox-Catalyzed Dehydrogenative Csp3-Csp2 Cross-Coupling of Alkylarenes to Aldehydes in Flow

Executing photoredox reactions in flow offers solutions to frequently encountered issues regarding reproducibility, reaction time, and scale-up. Here, we report the transfer of a photoredox-catalyzed benzylic coupling of alkylarenes to aldehydes to a flow chemistry setting leading to improvements in terms of higher concentration, shorter residence times, better yields, ease of catalyst preparation, and enhanced substrate scope. Its applicability has been demonstrated by a multi-gram-scale reaction using high-power light-emitting diodes (LEDs), late-stage functionalization of selected active pharmaceutical ingredients (APIs), and also a photocatalyst recycling method.