C(sp)-heteroatom bond formation by iron-catalyzed soft couplings.

Carbon-heteroatom bonds are of great importance due to their prevalence in pharmaceuticals, agrochemicals, materials, and natural products. Despite the effective use of metal-catalyzed cross-coupling reactions between sp-hybridized organohalides and soft heteroatomic nucleophiles for carbon-heteroatom bond formation, the use of sp-hybridized organohalides remain limited and the coupling with thiols remains elusive. Here, we report the coupling of sp-hybridized benzyl or tertiary halides with soft thiol nucleophiles catalyzed by iron and extend the utility to alcohol and amine nucleophiles.

Reversible CO2 Hydrogenation, Neutron Crystallography, and Hydride Reactivity of a Triiridium Heptahydride Complex.

We report the structure, reactivity, and catalytic utility of a triiridium complex, [Ir3H6(µ3-H)(PN)3]2+ (2-H, PN = (2-pyridyl)CH2PBut2). Despite its unusual stability to unsaturated organics, electrophiles, and even CF3SO3D, we find that complex 2-H catalyzes hydrogenation of CO2 to formate (TONIr = 9,600) and reverse formic acid dehydrogenation (TONIr = 54,400). The hydrogenation operates via a reactive intermediate [Ir3H4(µ-H)4(PN)3]+ (5).

Click-chemistry-derived oxime library reveals efficient reactivators of nerve agent-inhibited butyrylcholinesterase suitable for pseudo-catalytic bioscavenging.

A library of 100 click-chemistry-derived oximes was evaluated as reactivators of butyrylcholinesterase (BChE) inhibited by the nerve agents (NAs) sarin, cyclosarin, VX, and tabun. While reactivation efficiency was highly dependent on the structure of both the NA and the oxime, for each NA-BChE conjugate, we identified reactivators more effective than currently approved oximes for NA poisoning. Detailed kinetic analysis indicated that this enhancement results from both improved molecular recognition-specifically, enhanced binding affinity of the phosphylated conjugates for the oximes-and increased maximal reactivation rates.

Compartmentalizing Donor-Acceptor Stenhouse Adducts for Structure-Property Relationship Analysis.

The development of photoswitches that absorb low energy light is of notable interest due to the growing demand for smart materials and therapeutics necessitating benign stimuli. Donor-acceptor Stenhouse adducts (DASAs) are molecular photoswitches that respond to light in the visible to near-infrared spectrum. As a result of their modular assembly, DASAs can be modified at the donor, acceptor, triene, and backbone heteroatom molecular compartments for the tuning of optical and photoswitching properties.

Recycling Organoiridium Waste to [(1,5-Cyclooctadiene)IrCl].

We report the first process for iridium element recovery from organoiridium waste that is quantitative, pyrolysis-free, and generates no iridium metal. The key step is oxidative degradation of the waste by bleach to crude iridium(IV) hydroxide. Its treatment with hydrazine and then hydrogen peroxide gives synthetically important hexachloroiridic acid, which is converted to [(1,5-cyclooctadiene)IrCl] in 87% yield.

Mono- and Difluoromethylation of 3(2)-Pyridazinones.

A method for direct -monofluoromethylation of pyridazinones with -monofluoromethyl--phenyl-2,3,4,5-tetramethylphenylsulfonium triflate is disclosed. A method for the - and -difluoromethylated pyridazinones with TMSCFBr as the only promising difluorocarbene precursor is also reported. Substrates with various relevant functional groups, including analogues of Lynparza, are tolerated under both methods.

Azidodifluoromethanide (NCF): In Situ Generation and Nucleophilic Addition to Aldehydes.

A facile one-pot approach for the azidodifluoromethylation of aldehydes via in situ-generated azidodifluoromethenide (NCF) utilizing commercially available TMSCFBr and NaN is disclosed. The formed -silyl ether products are obtained in yields of up to 91% in short reaction times at ambient temperature. Examples of both inter- and intramolecular [3 + 2] azide-alkyne cycloaddition reactions of the installed azidodifluoromethyl handles are also presented, demonstrating the prospective synthetic and biochemical functionality and utility.

Development and characterization of amino donor-acceptor Stenhouse adducts.

Donor-acceptor Stenhouse adducts (DASAs) are molecular photoswitches spurring wide interest because of their dynamic photophysical properties, complex photoswitching mechanism, and diverse applications. Despite breakthroughs in modularity for the donor, acceptor, and triene compartments, the backbone heteroatom remains static due to synthetic challenges. We provide a predictive tool and sought-after strategy to vary the heteroatom, introduce amino DASA photoswitches, and analyze backbone heteroatom effects on photophysical properties.

Measuring Heat Dissipation and Entropic Potential in Battery Cathodes Made with Conjugated and Conventional Polymer Binders Using Calorimetry.

This study explores the influence of electronic and ionic conductivities on the behavior of conjugated polymer binders through the measurement of entropic potential and heat generation in an operating lithium-ion battery. Specifically, the traditional poly(vinylidene fluoride) (PVDF) binder in LiNiCoAlO (NCA) cathode electrodes was replaced with semiconducting polymer binders based on poly(3,4-propylenedioxythiophene). Two conjugated polymers were explored: one is a homopolymer with all aliphatic side chains, and the other is a copolymer with both aliphatic and ethylene oxide side chains.

Virtual Screening of a Chemically Diverse "Superscaffold" Library Enables Ligand Discovery for a Key GPCR Target.

The advent of ultra-large libraries of drug-like compounds has significantly broadened the possibilities in structure-based virtual screening, accelerating the discovery and optimization of high-quality lead chemotypes for diverse clinical targets. Compared to traditional high-throughput screening, which is constrained to libraries of approximately one million compounds, the ultra-large virtual screening approach offers substantial advantages in both cost and time efficiency. By expanding the chemical space with compounds synthesized from easily accessible and reproducible reactions and utilizing a large, diverse set of building blocks, we can enhance both the diversity and quality of the discovered lead chemotypes.

Addition of Imidazolium-Based Ionic Liquid to Improve Methanol Production in Polyamine-Assisted CO Capture and Conversion Systems Using Pincer Catalysts.

Ionic liquids have been studied as CO capture agents. However, they are rarely used in combined CO capture and conversion processes. Utilizing imidazolium-based ionic liquids, the conversion of CO to methanol was greatly improved in polyamine assisted systems catalyzed by homogeneous pincer catalysts with Ru and Mn metal centers.

Integrated Carbon Dioxide Capture and Conversion to Methanol Utilizing Tertiary Amines over a Heterogenous Cu/ZnO/AlO Catalyst.

Increasing carbon dioxide emissions has sparked a growing interest in capturing these emissions at the source of their release. For such processes, amines can be used as carbon dioxide capture agents. Herein, CO was captured under ambient conditions using solutions of amines and polyamines in ethylene glycol.

Cross-Electrophile Coupling of Benzyl Halides and Disulfides Catalyzed by Iron.

Cross-electrophile couplings are influential reactions that typically require a terminal reductant or photoredox conditions. We discovered an iron-catalyzed reaction that couples benzyl halides with disulfides to yield thioether products in the absence of a terminal reductant and under photoredox conditions. The disclosed platform proceeds without sulfur-induced catalyst poisoning or the use of an exogenous base, supporting a broad scope and circumventing undesired elimination pathways.

A rapid electrochemical method to recycle carbon fiber composites using methyl radicals.

We introduce an electrochemical approach to recycle carbon fiber (CF) fabrics from amine-epoxy carbon fiber-reinforced polymers (CFRPs). Our novel method utilizes a Kolbe-like mechanism to generate methyl radicals from CHCOOH to cleave C-N bonds within epoxy matrices via hydrogen atom abstraction. Recovered CFs are then remanufactured into CFRPs without resizing.

Light-Driven Radiochemistry with Fluorine-18, Carbon-11 and Zirconium-89.

This review discusses recent advances in light-driven radiochemistry for three key isotopes: fluorine-18, carbon-11, and zirconium-89, and their applications in positron emission tomography (PET). In the case of fluorine-18, the predominant approach involves the use of cyclotron-produced [F]fluoride or reagents derived thereof. Light serves to activate either the substrate or the fluorine-18 labeled reagent.

Synthesis and characterization of trifluoromethylcarboxonium salts.

The low-temperature protonation of trifluoroacetic acid with the superacids HF/SbF and HF/AsF resulted in the syntheses of the first examples of trifluoromethylcarboxonium salts. The less acidic trifluoromethylacetamide was also protonated in the same fashion, resulting in exclusive protonation of the carbonyl function. Their [SbF] and [AsF] salts were characterized by crystal structures, vibrational and multinuclear NMR spectra, and by electronic structure calculations.

Control of Properties through Hydrogen Bonding Interactions in Conjugated Polymers.

Molecular design is crucial for endowing conjugated polymers (CPs) with unique properties and enhanced electronic performance. Introducing Hydrogen-bonding (H-bonding) into CPs has been a broadly exploited, yet still emerging strategy capable of tuning a range of properties encompassing solubility, crystallinity, electronic properties, solid-state morphology, and stability, as well as mechanical properties and self-healing properties. Different H-bonding groups can be utilized to tailor CPs properties based on the applications of interest.

Generation and Aerobic Oxidation of Azavinyl Captodative Radicals.

We describe a cascade reaction that selectively incorporates oxygen into the carbon-carbon backbone of alkynes using air as the source. The process starts by lithiating readily available, electron-deficient 1,2,3-triazoles, resulting in an amphoteric lithium ketenimine intermediate. This intermediate can react with both electrophiles and nucleophiles.

Room Temperature Synthesis of a Well-Defined Conjugated Polymer Using Direct Arylation Polymerization (DArP).

While a major improvement to the sustainability of conjugated polymer synthesis, traditional direct arylation polymerization (DArP) still requires high temperatures (typically >100 °C), necessitating a significant energy input requirement. Performing DArP at reduced or ambient temperatures would represent an improvement to the sustainability of the reaction. Here we describe the first report of a well-defined conjugated polymer synthesized by DArP at room temperature.

Electrochemical Cycling of Redox-Active Boron Cluster-Based Materials in the Solid State.

This work demonstrates the first successful electrochemical cycling of a redox-active boron cluster-based material in the solid state. Specifically, we designed and synthesized an ether-functionalized dodecaborate cluster, B(OCH), which is the smallest redox-active building block in the B(OR) family. This species can reversibly access four oxidation states in solution, ranging from a dianion to a radical cation.

Relating Structure to Properties in Non-Conjugated Pendant Electroactive Polymers.

Non-conjugated pendant electroactive polymers (NCPEPs) are an emerging class of polymers that offer the potential of combining the desirable optoelectronic properties of conjugated polymers with the superior synthetic methodologies and stability of traditional non-conjugated polymers. Despite an increasing number of studies focused on NCPEPs, particularly on understanding fundamental structure-property relationships, no attempts have been made to provide an overview on established relationships to date. This review showcases selected reports on NCPEP homopolymers and copolymers that demonstrate how optical, electronic, and physical properties of the polymers are affected by tuning of key structural variables such as the chemical structure of the polymer backbone, molecular weight, tacticity, spacer length, the nature of the pendant group, and in the case of copolymers the ratios between different comonomers and between individual polymer blocks.

Photoredox Catalysis for the Synthesis of N-CF H Compounds Using 1-((N-(difluoromethyl)-4-methylphenyl)-sulfonamido)pyridin-1-ium Trifluoromethanesulfonate.

N-(difluoromethyl)amino (-NCF H) compounds are of great interest given their unique and underexplored physiochemical properties. The lack of structural diversity in NCF H compounds is likely due in part to the shortage of protocols for efficient installation. Presented herein is a new shelf-stable pyridinium reagent that enables the direct installation of the N-(difluoromethyl)sulfonamide moiety [N(Ts)CF H)] onto (hetero)arenes and alkenes for the diversification of aryl and alkyl NCF H compounds.

High-Performance Intrinsically Stretchable Polymer Solar Cell with Record Efficiency and Stretchability Enabled by Thymine-Functionalized Terpolymer.

Designing new polymer semiconductors for intrinsically stretchable polymer solar cells (IS-PSCs) with high power conversion efficiency (PCE) and durability is critical for wearable electronics applications. Nearly all high-performance PSCs are constructed using fully conjugated polymer donors () and small-molecule acceptors (SMA). However, a successful molecular design of s for high-performance and mechanically durable IS-PSCs without sacrificing conjugation has not been realized.